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* [PATCH v4 00/17] Introduce partial kernel_read_file() support
@ 2020-07-29 17:58 Kees Cook
  2020-07-29 17:58 ` [PATCH v4 01/17] test_firmware: Test platform fw loading on non-EFI systems Kees Cook
                   ` (16 more replies)
  0 siblings, 17 replies; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

v4:
- add more reviews (mimi, luis)
- adjusted comment (mimi)
- fixed build error when not building firmware tests (0day, sfr)
- fixed needless .xz read (tiwai)
- rebased to driver-core-next
v3: https://lore.kernel.org/lkml/20200724213640.389191-1-keescook@chromium.org/
v2: lost to the ether
v1: https://lore.kernel.org/lkml/20200717174309.1164575-1-keescook@chromium.org/

Hi,

Here's my tree for adding partial read support in kernel_read_file(),
which fixes a number of issues along the way. It's got Scott's firmware
and IMA patches ported and everything tests cleanly for me (even with
CONFIG_IMA_APPRAISE=y), and now appears to pass 0day. :)

The intention is for this to go via Greg's tree since Scott's driver
code will depend on it.

Thanks,

-Kees

Kees Cook (13):
  test_firmware: Test platform fw loading on non-EFI systems
  fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum
  fs/kernel_read_file: Remove FIRMWARE_EFI_EMBEDDED enum
  fs/kernel_read_file: Split into separate source file
  fs/kernel_read_file: Remove redundant size argument
  fs/kernel_read_file: Switch buffer size arg to size_t
  fs/kernel_read_file: Add file_size output argument
  LSM: Introduce kernel_post_load_data() hook
  firmware_loader: Use security_post_load_data()
  module: Call security_kernel_post_load_data()
  LSM: Add "contents" flag to kernel_read_file hook
  fs/kernel_file_read: Add "offset" arg for partial reads
  firmware: Store opt_flags in fw_priv

Scott Branden (4):
  fs/kernel_read_file: Split into separate include file
  IMA: Add support for file reads without contents
  firmware: Add request_partial_firmware_into_buf()
  test_firmware: Test partial read support

 drivers/base/firmware_loader/fallback.c       |  19 +-
 drivers/base/firmware_loader/fallback.h       |   5 +-
 .../base/firmware_loader/fallback_platform.c  |  11 +-
 drivers/base/firmware_loader/firmware.h       |   7 +-
 drivers/base/firmware_loader/main.c           | 135 ++++++++++---
 drivers/firmware/efi/embedded-firmware.c      |  21 +-
 drivers/firmware/efi/embedded-firmware.h      |  21 ++
 fs/Makefile                                   |   3 +-
 fs/exec.c                                     | 132 +-----------
 fs/kernel_read_file.c                         | 189 ++++++++++++++++++
 include/linux/efi_embedded_fw.h               |  13 --
 include/linux/firmware.h                      |  12 ++
 include/linux/fs.h                            |  39 ----
 include/linux/ima.h                           |  19 +-
 include/linux/kernel_read_file.h              |  55 +++++
 include/linux/lsm_hook_defs.h                 |   6 +-
 include/linux/lsm_hooks.h                     |  12 ++
 include/linux/security.h                      |  19 +-
 kernel/kexec.c                                |   2 +-
 kernel/kexec_file.c                           |  19 +-
 kernel/module.c                               |  24 ++-
 lib/test_firmware.c                           | 159 +++++++++++++--
 security/integrity/digsig.c                   |   8 +-
 security/integrity/ima/ima_fs.c               |  10 +-
 security/integrity/ima/ima_main.c             |  70 +++++--
 security/integrity/ima/ima_policy.c           |   1 +
 security/loadpin/loadpin.c                    |  17 +-
 security/security.c                           |  26 ++-
 security/selinux/hooks.c                      |   8 +-
 .../selftests/firmware/fw_filesystem.sh       |  91 +++++++++
 30 files changed, 839 insertions(+), 314 deletions(-)
 create mode 100644 drivers/firmware/efi/embedded-firmware.h
 create mode 100644 fs/kernel_read_file.c
 create mode 100644 include/linux/kernel_read_file.h

-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 01/17] test_firmware: Test platform fw loading on non-EFI systems
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-07-29 17:58 ` [PATCH v4 02/17] fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum Kees Cook
                   ` (15 subsequent siblings)
  16 siblings, 0 replies; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, stable, Scott Branden, Luis Chamberlain, Mimi Zohar,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

On non-EFI systems, it wasn't possible to test the platform firmware
loader because it will have never set "checked_fw" during __init.
Instead, allow the test code to override this check. Additionally split
the declarations into a private header file so it there is greater
enforcement of the symbol visibility.

Fixes: 548193cba2a7 ("test_firmware: add support for firmware_request_platform")
Cc: stable@vger.kernel.org
Acked-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/firmware/efi/embedded-firmware.c | 21 ++++++++++++++++-----
 drivers/firmware/efi/embedded-firmware.h | 21 +++++++++++++++++++++
 include/linux/efi_embedded_fw.h          | 13 -------------
 lib/test_firmware.c                      |  5 +++++
 4 files changed, 42 insertions(+), 18 deletions(-)
 create mode 100644 drivers/firmware/efi/embedded-firmware.h

diff --git a/drivers/firmware/efi/embedded-firmware.c b/drivers/firmware/efi/embedded-firmware.c
index a1b199de9006..0fb03cd0a5a2 100644
--- a/drivers/firmware/efi/embedded-firmware.c
+++ b/drivers/firmware/efi/embedded-firmware.c
@@ -14,11 +14,22 @@
 #include <linux/vmalloc.h>
 #include <crypto/sha.h>
 
+#include "embedded-firmware.h"
+
+#ifdef CONFIG_TEST_FIRMWARE
+# define EFI_EMBEDDED_FW_VISIBILITY
+#else
+# define EFI_EMBEDDED_FW_VISIBILITY static
+#endif
+
+EFI_EMBEDDED_FW_VISIBILITY LIST_HEAD(efi_embedded_fw_list);
+EFI_EMBEDDED_FW_VISIBILITY bool efi_embedded_fw_checked;
+
 /* Exported for use by lib/test_firmware.c only */
-LIST_HEAD(efi_embedded_fw_list);
+#ifdef CONFIG_TEST_FIRMWARE
 EXPORT_SYMBOL_GPL(efi_embedded_fw_list);
-
-static bool checked_for_fw;
+EXPORT_SYMBOL_GPL(efi_embedded_fw_checked);
+#endif
 
 static const struct dmi_system_id * const embedded_fw_table[] = {
 #ifdef CONFIG_TOUCHSCREEN_DMI
@@ -119,14 +130,14 @@ void __init efi_check_for_embedded_firmwares(void)
 		}
 	}
 
-	checked_for_fw = true;
+	efi_embedded_fw_checked = true;
 }
 
 int efi_get_embedded_fw(const char *name, const u8 **data, size_t *size)
 {
 	struct efi_embedded_fw *iter, *fw = NULL;
 
-	if (!checked_for_fw) {
+	if (!efi_embedded_fw_checked) {
 		pr_warn("Warning %s called while we did not check for embedded fw\n",
 			__func__);
 		return -ENOENT;
diff --git a/drivers/firmware/efi/embedded-firmware.h b/drivers/firmware/efi/embedded-firmware.h
new file mode 100644
index 000000000000..bb894eae0906
--- /dev/null
+++ b/drivers/firmware/efi/embedded-firmware.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _EFI_EMBEDDED_FW_INTERNAL_H_
+#define _EFI_EMBEDDED_FW_INTERNAL_H_
+
+/*
+ * This struct and efi_embedded_fw_list are private to the efi-embedded fw
+ * implementation they only in separate header for use by lib/test_firmware.c.
+ */
+struct efi_embedded_fw {
+	struct list_head list;
+	const char *name;
+	const u8 *data;
+	size_t length;
+};
+
+#ifdef CONFIG_TEST_FIRMWARE
+extern struct list_head efi_embedded_fw_list;
+extern bool efi_embedded_fw_checked;
+#endif
+
+#endif /* _EFI_EMBEDDED_FW_INTERNAL_H_ */
diff --git a/include/linux/efi_embedded_fw.h b/include/linux/efi_embedded_fw.h
index 57eac5241303..4ad5db9f5312 100644
--- a/include/linux/efi_embedded_fw.h
+++ b/include/linux/efi_embedded_fw.h
@@ -7,19 +7,6 @@
 
 #define EFI_EMBEDDED_FW_PREFIX_LEN		8
 
-/*
- * This struct and efi_embedded_fw_list are private to the efi-embedded fw
- * implementation they are in this header for use by lib/test_firmware.c only!
- */
-struct efi_embedded_fw {
-	struct list_head list;
-	const char *name;
-	const u8 *data;
-	size_t length;
-};
-
-extern struct list_head efi_embedded_fw_list;
-
 /**
  * struct efi_embedded_fw_desc - This struct is used by the EFI embedded-fw
  *                               code to search for embedded firmwares.
diff --git a/lib/test_firmware.c b/lib/test_firmware.c
index 9fee2b93a8d1..62af792e151c 100644
--- a/lib/test_firmware.c
+++ b/lib/test_firmware.c
@@ -489,6 +489,7 @@ static ssize_t trigger_request_store(struct device *dev,
 static DEVICE_ATTR_WO(trigger_request);
 
 #ifdef CONFIG_EFI_EMBEDDED_FIRMWARE
+#include "../drivers/firmware/efi/embedded-firmware.h"
 static ssize_t trigger_request_platform_store(struct device *dev,
 					      struct device_attribute *attr,
 					      const char *buf, size_t count)
@@ -501,6 +502,7 @@ static ssize_t trigger_request_platform_store(struct device *dev,
 	};
 	struct efi_embedded_fw efi_embedded_fw;
 	const struct firmware *firmware = NULL;
+	bool saved_efi_embedded_fw_checked;
 	char *name;
 	int rc;
 
@@ -513,6 +515,8 @@ static ssize_t trigger_request_platform_store(struct device *dev,
 	efi_embedded_fw.data = (void *)test_data;
 	efi_embedded_fw.length = sizeof(test_data);
 	list_add(&efi_embedded_fw.list, &efi_embedded_fw_list);
+	saved_efi_embedded_fw_checked = efi_embedded_fw_checked;
+	efi_embedded_fw_checked = true;
 
 	pr_info("loading '%s'\n", name);
 	rc = firmware_request_platform(&firmware, name, dev);
@@ -530,6 +534,7 @@ static ssize_t trigger_request_platform_store(struct device *dev,
 	rc = count;
 
 out:
+	efi_embedded_fw_checked = saved_efi_embedded_fw_checked;
 	release_firmware(firmware);
 	list_del(&efi_embedded_fw.list);
 	kfree(name);
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 02/17] fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
  2020-07-29 17:58 ` [PATCH v4 01/17] test_firmware: Test platform fw loading on non-EFI systems Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-07-29 17:58 ` [PATCH v4 03/17] fs/kernel_read_file: Remove FIRMWARE_EFI_EMBEDDED enum Kees Cook
                   ` (14 subsequent siblings)
  16 siblings, 0 replies; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, stable, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

FIRMWARE_PREALLOC_BUFFER is a "how", not a "what", and confuses the LSMs
that are interested in filtering between types of things. The "how"
should be an internal detail made uninteresting to the LSMs.

Fixes: a098ecd2fa7d ("firmware: support loading into a pre-allocated buffer")
Fixes: fd90bc559bfb ("ima: based on policy verify firmware signatures (pre-allocated buffer)")
Fixes: 4f0496d8ffa3 ("ima: based on policy warn about loading firmware (pre-allocated buffer)")
Cc: stable@vger.kernel.org
Acked-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
To aid in backporting, this change is made before moving
kernel_read_file() to separate header/source files.
---
 drivers/base/firmware_loader/main.c | 5 ++---
 fs/exec.c                           | 7 ++++---
 include/linux/fs.h                  | 2 +-
 kernel/module.c                     | 2 +-
 security/integrity/digsig.c         | 2 +-
 security/integrity/ima/ima_fs.c     | 2 +-
 security/integrity/ima/ima_main.c   | 6 ++----
 7 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 9da0c9d5f538..fe68ae278201 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -465,14 +465,12 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
 	int i, len;
 	int rc = -ENOENT;
 	char *path;
-	enum kernel_read_file_id id = READING_FIRMWARE;
 	size_t msize = INT_MAX;
 	void *buffer = NULL;
 
 	/* Already populated data member means we're loading into a buffer */
 	if (!decompress && fw_priv->data) {
 		buffer = fw_priv->data;
-		id = READING_FIRMWARE_PREALLOC_BUFFER;
 		msize = fw_priv->allocated_size;
 	}
 
@@ -496,7 +494,8 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
 
 		/* load firmware files from the mount namespace of init */
 		rc = kernel_read_file_from_path_initns(path, &buffer,
-						       &size, msize, id);
+						       &size, msize,
+						       READING_FIRMWARE);
 		if (rc) {
 			if (rc != -ENOENT)
 				dev_warn(device, "loading %s failed with error %d\n",
diff --git a/fs/exec.c b/fs/exec.c
index e6e8a9a70327..2bf549757ce7 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -927,6 +927,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 {
 	loff_t i_size, pos;
 	ssize_t bytes = 0;
+	void *allocated = NULL;
 	int ret;
 
 	if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0)
@@ -950,8 +951,8 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 		goto out;
 	}
 
-	if (id != READING_FIRMWARE_PREALLOC_BUFFER)
-		*buf = vmalloc(i_size);
+	if (!*buf)
+		*buf = allocated = vmalloc(i_size);
 	if (!*buf) {
 		ret = -ENOMEM;
 		goto out;
@@ -980,7 +981,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 
 out_free:
 	if (ret < 0) {
-		if (id != READING_FIRMWARE_PREALLOC_BUFFER) {
+		if (allocated) {
 			vfree(*buf);
 			*buf = NULL;
 		}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index f5abba86107d..f34d47ba49de 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2993,10 +2993,10 @@ static inline void i_readcount_inc(struct inode *inode)
 #endif
 extern int do_pipe_flags(int *, int);
 
+/* This is a list of *what* is being read, not *how*. */
 #define __kernel_read_file_id(id) \
 	id(UNKNOWN, unknown)		\
 	id(FIRMWARE, firmware)		\
-	id(FIRMWARE_PREALLOC_BUFFER, firmware)	\
 	id(FIRMWARE_EFI_EMBEDDED, firmware)	\
 	id(MODULE, kernel-module)		\
 	id(KEXEC_IMAGE, kexec-image)		\
diff --git a/kernel/module.c b/kernel/module.c
index aa183c9ac0a2..d2d12c299dd8 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3991,7 +3991,7 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
 {
 	struct load_info info = { };
 	loff_t size;
-	void *hdr;
+	void *hdr = NULL;
 	int err;
 
 	err = may_init_module();
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index e9cbadade74b..ac02b7632353 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -169,7 +169,7 @@ int __init integrity_add_key(const unsigned int id, const void *data,
 
 int __init integrity_load_x509(const unsigned int id, const char *path)
 {
-	void *data;
+	void *data = NULL;
 	loff_t size;
 	int rc;
 	key_perm_t perm;
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index e3fcad871861..15a44c5022f7 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -272,7 +272,7 @@ static const struct file_operations ima_ascii_measurements_ops = {
 
 static ssize_t ima_read_policy(char *path)
 {
-	void *data;
+	void *data = NULL;
 	char *datap;
 	loff_t size;
 	int rc, pathlen = strlen(path);
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index c1583d98c5e5..f80ee4ce4669 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -611,19 +611,17 @@ void ima_post_path_mknod(struct dentry *dentry)
 int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
 {
 	/*
-	 * READING_FIRMWARE_PREALLOC_BUFFER
-	 *
 	 * Do devices using pre-allocated memory run the risk of the
 	 * firmware being accessible to the device prior to the completion
 	 * of IMA's signature verification any more than when using two
-	 * buffers?
+	 * buffers? It may be desirable to include the buffer address
+	 * in this API and walk all the dma_map_single() mappings to check.
 	 */
 	return 0;
 }
 
 const int read_idmap[READING_MAX_ID] = {
 	[READING_FIRMWARE] = FIRMWARE_CHECK,
-	[READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK,
 	[READING_MODULE] = MODULE_CHECK,
 	[READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK,
 	[READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 03/17] fs/kernel_read_file: Remove FIRMWARE_EFI_EMBEDDED enum
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
  2020-07-29 17:58 ` [PATCH v4 01/17] test_firmware: Test platform fw loading on non-EFI systems Kees Cook
  2020-07-29 17:58 ` [PATCH v4 02/17] fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-07-29 17:58 ` [PATCH v4 04/17] fs/kernel_read_file: Split into separate include file Kees Cook
                   ` (13 subsequent siblings)
  16 siblings, 0 replies; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, stable, Scott Branden, Luis Chamberlain, Mimi Zohar,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

The "FIRMWARE_EFI_EMBEDDED" enum is a "where", not a "what". It
should not be distinguished separately from just "FIRMWARE", as this
confuses the LSMs about what is being loaded. Additionally, there was
no actual validation of the firmware contents happening.

Fixes: e4c2c0ff00ec ("firmware: Add new platform fallback mechanism and firmware_request_platform()")
Cc: stable@vger.kernel.org
Acked-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
To aid in backporting, this change is made before moving
kernel_read_file() to separate header/source files.
---
 drivers/base/firmware_loader/fallback_platform.c | 2 +-
 include/linux/fs.h                               | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/base/firmware_loader/fallback_platform.c b/drivers/base/firmware_loader/fallback_platform.c
index 685edb7dd05a..6958ab1a8059 100644
--- a/drivers/base/firmware_loader/fallback_platform.c
+++ b/drivers/base/firmware_loader/fallback_platform.c
@@ -17,7 +17,7 @@ int firmware_fallback_platform(struct fw_priv *fw_priv, u32 opt_flags)
 	if (!(opt_flags & FW_OPT_FALLBACK_PLATFORM))
 		return -ENOENT;
 
-	rc = security_kernel_load_data(LOADING_FIRMWARE_EFI_EMBEDDED);
+	rc = security_kernel_load_data(LOADING_FIRMWARE);
 	if (rc)
 		return rc;
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index f34d47ba49de..0d4f7aacf286 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2993,11 +2993,10 @@ static inline void i_readcount_inc(struct inode *inode)
 #endif
 extern int do_pipe_flags(int *, int);
 
-/* This is a list of *what* is being read, not *how*. */
+/* This is a list of *what* is being read, not *how* nor *where*. */
 #define __kernel_read_file_id(id) \
 	id(UNKNOWN, unknown)		\
 	id(FIRMWARE, firmware)		\
-	id(FIRMWARE_EFI_EMBEDDED, firmware)	\
 	id(MODULE, kernel-module)		\
 	id(KEXEC_IMAGE, kexec-image)		\
 	id(KEXEC_INITRAMFS, kexec-initramfs)	\
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 04/17] fs/kernel_read_file: Split into separate include file
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (2 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 03/17] fs/kernel_read_file: Remove FIRMWARE_EFI_EMBEDDED enum Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-07-30  2:22   ` James Morris
  2020-07-29 17:58 ` [PATCH v4 05/17] fs/kernel_read_file: Split into separate source file Kees Cook
                   ` (12 subsequent siblings)
  16 siblings, 1 reply; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Christoph Hellwig, Mimi Zohar,
	Luis Chamberlain, Takashi Iwai, Jessica Yu, SeongJae Park,
	KP Singh, linux-efi, linux-security-module, linux-integrity,
	selinux, linux-kselftest, linux-kernel

From: Scott Branden <scott.branden@broadcom.com>

Move kernel_read_file* out of linux/fs.h to its own linux/kernel_read_file.h
include file. That header gets pulled in just about everywhere
and doesn't really need functions not related to the general fs interface.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20200706232309.12010-2-scott.branden@broadcom.com
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/base/firmware_loader/main.c |  1 +
 fs/exec.c                           |  1 +
 include/linux/fs.h                  | 38 ---------------------
 include/linux/ima.h                 |  1 +
 include/linux/kernel_read_file.h    | 51 +++++++++++++++++++++++++++++
 include/linux/security.h            |  1 +
 kernel/kexec_file.c                 |  1 +
 kernel/module.c                     |  1 +
 security/integrity/digsig.c         |  1 +
 security/integrity/ima/ima_fs.c     |  1 +
 security/integrity/ima/ima_main.c   |  1 +
 security/integrity/ima/ima_policy.c |  1 +
 security/loadpin/loadpin.c          |  1 +
 security/security.c                 |  1 +
 security/selinux/hooks.c            |  1 +
 15 files changed, 64 insertions(+), 38 deletions(-)
 create mode 100644 include/linux/kernel_read_file.h

diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index fe68ae278201..7fd677281806 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -12,6 +12,7 @@
 
 #include <linux/capability.h>
 #include <linux/device.h>
+#include <linux/kernel_read_file.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/timer.h>
diff --git a/fs/exec.c b/fs/exec.c
index 2bf549757ce7..07a7fe9ac5be 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -23,6 +23,7 @@
  * formats.
  */
 
+#include <linux/kernel_read_file.h>
 #include <linux/slab.h>
 #include <linux/file.h>
 #include <linux/fdtable.h>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0d4f7aacf286..76283ff04d37 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2993,44 +2993,6 @@ static inline void i_readcount_inc(struct inode *inode)
 #endif
 extern int do_pipe_flags(int *, int);
 
-/* This is a list of *what* is being read, not *how* nor *where*. */
-#define __kernel_read_file_id(id) \
-	id(UNKNOWN, unknown)		\
-	id(FIRMWARE, firmware)		\
-	id(MODULE, kernel-module)		\
-	id(KEXEC_IMAGE, kexec-image)		\
-	id(KEXEC_INITRAMFS, kexec-initramfs)	\
-	id(POLICY, security-policy)		\
-	id(X509_CERTIFICATE, x509-certificate)	\
-	id(MAX_ID, )
-
-#define __fid_enumify(ENUM, dummy) READING_ ## ENUM,
-#define __fid_stringify(dummy, str) #str,
-
-enum kernel_read_file_id {
-	__kernel_read_file_id(__fid_enumify)
-};
-
-static const char * const kernel_read_file_str[] = {
-	__kernel_read_file_id(__fid_stringify)
-};
-
-static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
-{
-	if ((unsigned)id >= READING_MAX_ID)
-		return kernel_read_file_str[READING_UNKNOWN];
-
-	return kernel_read_file_str[id];
-}
-
-extern int kernel_read_file(struct file *, void **, loff_t *, loff_t,
-			    enum kernel_read_file_id);
-extern int kernel_read_file_from_path(const char *, void **, loff_t *, loff_t,
-				      enum kernel_read_file_id);
-extern int kernel_read_file_from_path_initns(const char *, void **, loff_t *, loff_t,
-					     enum kernel_read_file_id);
-extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t,
-				    enum kernel_read_file_id);
 extern ssize_t kernel_read(struct file *, void *, size_t, loff_t *);
 ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos);
 extern ssize_t kernel_write(struct file *, const void *, size_t, loff_t *);
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 9164e1534ec9..148636bfcc8f 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -7,6 +7,7 @@
 #ifndef _LINUX_IMA_H
 #define _LINUX_IMA_H
 
+#include <linux/kernel_read_file.h>
 #include <linux/fs.h>
 #include <linux/security.h>
 #include <linux/kexec.h>
diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h
new file mode 100644
index 000000000000..78cf3d7dc835
--- /dev/null
+++ b/include/linux/kernel_read_file.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_KERNEL_READ_FILE_H
+#define _LINUX_KERNEL_READ_FILE_H
+
+#include <linux/file.h>
+#include <linux/types.h>
+
+/* This is a list of *what* is being read, not *how* nor *where*. */
+#define __kernel_read_file_id(id) \
+	id(UNKNOWN, unknown)		\
+	id(FIRMWARE, firmware)		\
+	id(MODULE, kernel-module)		\
+	id(KEXEC_IMAGE, kexec-image)		\
+	id(KEXEC_INITRAMFS, kexec-initramfs)	\
+	id(POLICY, security-policy)		\
+	id(X509_CERTIFICATE, x509-certificate)	\
+	id(MAX_ID, )
+
+#define __fid_enumify(ENUM, dummy) READING_ ## ENUM,
+#define __fid_stringify(dummy, str) #str,
+
+enum kernel_read_file_id {
+	__kernel_read_file_id(__fid_enumify)
+};
+
+static const char * const kernel_read_file_str[] = {
+	__kernel_read_file_id(__fid_stringify)
+};
+
+static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
+{
+	if ((unsigned int)id >= READING_MAX_ID)
+		return kernel_read_file_str[READING_UNKNOWN];
+
+	return kernel_read_file_str[id];
+}
+
+int kernel_read_file(struct file *file,
+		     void **buf, loff_t *size, loff_t max_size,
+		     enum kernel_read_file_id id);
+int kernel_read_file_from_path(const char *path,
+			       void **buf, loff_t *size, loff_t max_size,
+			       enum kernel_read_file_id id);
+int kernel_read_file_from_path_initns(const char *path,
+				      void **buf, loff_t *size, loff_t max_size,
+				      enum kernel_read_file_id id);
+int kernel_read_file_from_fd(int fd,
+			     void **buf, loff_t *size, loff_t max_size,
+			     enum kernel_read_file_id id);
+
+#endif /* _LINUX_KERNEL_READ_FILE_H */
diff --git a/include/linux/security.h b/include/linux/security.h
index 0a0a03b36a3b..42df0d9b4c37 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -23,6 +23,7 @@
 #ifndef __LINUX_SECURITY_H
 #define __LINUX_SECURITY_H
 
+#include <linux/kernel_read_file.h>
 #include <linux/key.h>
 #include <linux/capability.h>
 #include <linux/fs.h>
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 09cc78df53c6..1358069ce9e9 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -24,6 +24,7 @@
 #include <linux/elf.h>
 #include <linux/elfcore.h>
 #include <linux/kernel.h>
+#include <linux/kernel_read_file.h>
 #include <linux/syscalls.h>
 #include <linux/vmalloc.h>
 #include "kexec_internal.h"
diff --git a/kernel/module.c b/kernel/module.c
index d2d12c299dd8..cc8d83841568 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -18,6 +18,7 @@
 #include <linux/fs.h>
 #include <linux/sysfs.h>
 #include <linux/kernel.h>
+#include <linux/kernel_read_file.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/elf.h>
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index ac02b7632353..f8869be45d8f 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -10,6 +10,7 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/cred.h>
+#include <linux/kernel_read_file.h>
 #include <linux/key-type.h>
 #include <linux/digsig.h>
 #include <linux/vmalloc.h>
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 15a44c5022f7..e13ffece3726 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -13,6 +13,7 @@
  */
 
 #include <linux/fcntl.h>
+#include <linux/kernel_read_file.h>
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/seq_file.h>
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index f80ee4ce4669..dab4a13221cf 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -18,6 +18,7 @@
 #include <linux/module.h>
 #include <linux/file.h>
 #include <linux/binfmts.h>
+#include <linux/kernel_read_file.h>
 #include <linux/mount.h>
 #include <linux/mman.h>
 #include <linux/slab.h>
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index e493063a3c34..f8390f6081f0 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -9,6 +9,7 @@
 
 #include <linux/init.h>
 #include <linux/list.h>
+#include <linux/kernel_read_file.h>
 #include <linux/fs.h>
 #include <linux/security.h>
 #include <linux/magic.h>
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index ee5cb944f4ad..81bc95127f92 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -11,6 +11,7 @@
 
 #include <linux/module.h>
 #include <linux/fs.h>
+#include <linux/kernel_read_file.h>
 #include <linux/lsm_hooks.h>
 #include <linux/mount.h>
 #include <linux/path.h>
diff --git a/security/security.c b/security/security.c
index 70a7ad357bc6..19d3150f68f4 100644
--- a/security/security.c
+++ b/security/security.c
@@ -16,6 +16,7 @@
 #include <linux/export.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/kernel_read_file.h>
 #include <linux/lsm_hooks.h>
 #include <linux/integrity.h>
 #include <linux/ima.h>
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index efa6108b1ce9..5de45010fb1a 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -24,6 +24,7 @@
 #include <linux/init.h>
 #include <linux/kd.h>
 #include <linux/kernel.h>
+#include <linux/kernel_read_file.h>
 #include <linux/tracehook.h>
 #include <linux/errno.h>
 #include <linux/sched/signal.h>
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 05/17] fs/kernel_read_file: Split into separate source file
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (3 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 04/17] fs/kernel_read_file: Split into separate include file Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-07-29 17:58 ` [PATCH v4 06/17] fs/kernel_read_file: Remove redundant size argument Kees Cook
                   ` (11 subsequent siblings)
  16 siblings, 0 replies; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

These routines are used in places outside of exec(2), so in preparation
for refactoring them, move them into a separate source file,
fs/kernel_read_file.c.

Acked-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 fs/Makefile           |   3 +-
 fs/exec.c             | 132 ----------------------------------------
 fs/kernel_read_file.c | 138 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 140 insertions(+), 133 deletions(-)
 create mode 100644 fs/kernel_read_file.c

diff --git a/fs/Makefile b/fs/Makefile
index 2ce5112b02c8..a05fc247b2a7 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -13,7 +13,8 @@ obj-y :=	open.o read_write.o file_table.o super.o \
 		seq_file.o xattr.o libfs.o fs-writeback.o \
 		pnode.o splice.o sync.o utimes.o d_path.o \
 		stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \
-		fs_types.o fs_context.o fs_parser.o fsopen.o
+		fs_types.o fs_context.o fs_parser.o fsopen.o \
+		kernel_read_file.o
 
 ifeq ($(CONFIG_BLOCK),y)
 obj-y +=	buffer.o block_dev.o direct-io.o mpage.o
diff --git a/fs/exec.c b/fs/exec.c
index 07a7fe9ac5be..d619b79aab30 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -923,138 +923,6 @@ struct file *open_exec(const char *name)
 }
 EXPORT_SYMBOL(open_exec);
 
-int kernel_read_file(struct file *file, void **buf, loff_t *size,
-		     loff_t max_size, enum kernel_read_file_id id)
-{
-	loff_t i_size, pos;
-	ssize_t bytes = 0;
-	void *allocated = NULL;
-	int ret;
-
-	if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0)
-		return -EINVAL;
-
-	ret = deny_write_access(file);
-	if (ret)
-		return ret;
-
-	ret = security_kernel_read_file(file, id);
-	if (ret)
-		goto out;
-
-	i_size = i_size_read(file_inode(file));
-	if (i_size <= 0) {
-		ret = -EINVAL;
-		goto out;
-	}
-	if (i_size > SIZE_MAX || (max_size > 0 && i_size > max_size)) {
-		ret = -EFBIG;
-		goto out;
-	}
-
-	if (!*buf)
-		*buf = allocated = vmalloc(i_size);
-	if (!*buf) {
-		ret = -ENOMEM;
-		goto out;
-	}
-
-	pos = 0;
-	while (pos < i_size) {
-		bytes = kernel_read(file, *buf + pos, i_size - pos, &pos);
-		if (bytes < 0) {
-			ret = bytes;
-			goto out_free;
-		}
-
-		if (bytes == 0)
-			break;
-	}
-
-	if (pos != i_size) {
-		ret = -EIO;
-		goto out_free;
-	}
-
-	ret = security_kernel_post_read_file(file, *buf, i_size, id);
-	if (!ret)
-		*size = pos;
-
-out_free:
-	if (ret < 0) {
-		if (allocated) {
-			vfree(*buf);
-			*buf = NULL;
-		}
-	}
-
-out:
-	allow_write_access(file);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(kernel_read_file);
-
-int kernel_read_file_from_path(const char *path, void **buf, loff_t *size,
-			       loff_t max_size, enum kernel_read_file_id id)
-{
-	struct file *file;
-	int ret;
-
-	if (!path || !*path)
-		return -EINVAL;
-
-	file = filp_open(path, O_RDONLY, 0);
-	if (IS_ERR(file))
-		return PTR_ERR(file);
-
-	ret = kernel_read_file(file, buf, size, max_size, id);
-	fput(file);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
-
-int kernel_read_file_from_path_initns(const char *path, void **buf,
-				      loff_t *size, loff_t max_size,
-				      enum kernel_read_file_id id)
-{
-	struct file *file;
-	struct path root;
-	int ret;
-
-	if (!path || !*path)
-		return -EINVAL;
-
-	task_lock(&init_task);
-	get_fs_root(init_task.fs, &root);
-	task_unlock(&init_task);
-
-	file = file_open_root(root.dentry, root.mnt, path, O_RDONLY, 0);
-	path_put(&root);
-	if (IS_ERR(file))
-		return PTR_ERR(file);
-
-	ret = kernel_read_file(file, buf, size, max_size, id);
-	fput(file);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns);
-
-int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size,
-			     enum kernel_read_file_id id)
-{
-	struct fd f = fdget(fd);
-	int ret = -EBADF;
-
-	if (!f.file)
-		goto out;
-
-	ret = kernel_read_file(f.file, buf, size, max_size, id);
-out:
-	fdput(f);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(kernel_read_file_from_fd);
-
 #if defined(CONFIG_HAVE_AOUT) || defined(CONFIG_BINFMT_FLAT) || \
     defined(CONFIG_BINFMT_ELF_FDPIC)
 ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len)
diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c
new file mode 100644
index 000000000000..54d972d4befc
--- /dev/null
+++ b/fs/kernel_read_file.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/fs.h>
+#include <linux/fs_struct.h>
+#include <linux/kernel_read_file.h>
+#include <linux/security.h>
+#include <linux/vmalloc.h>
+
+int kernel_read_file(struct file *file, void **buf, loff_t *size,
+		     loff_t max_size, enum kernel_read_file_id id)
+{
+	loff_t i_size, pos;
+	ssize_t bytes = 0;
+	void *allocated = NULL;
+	int ret;
+
+	if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0)
+		return -EINVAL;
+
+	ret = deny_write_access(file);
+	if (ret)
+		return ret;
+
+	ret = security_kernel_read_file(file, id);
+	if (ret)
+		goto out;
+
+	i_size = i_size_read(file_inode(file));
+	if (i_size <= 0) {
+		ret = -EINVAL;
+		goto out;
+	}
+	if (i_size > SIZE_MAX || (max_size > 0 && i_size > max_size)) {
+		ret = -EFBIG;
+		goto out;
+	}
+
+	if (!*buf)
+		*buf = allocated = vmalloc(i_size);
+	if (!*buf) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	pos = 0;
+	while (pos < i_size) {
+		bytes = kernel_read(file, *buf + pos, i_size - pos, &pos);
+		if (bytes < 0) {
+			ret = bytes;
+			goto out_free;
+		}
+
+		if (bytes == 0)
+			break;
+	}
+
+	if (pos != i_size) {
+		ret = -EIO;
+		goto out_free;
+	}
+
+	ret = security_kernel_post_read_file(file, *buf, i_size, id);
+	if (!ret)
+		*size = pos;
+
+out_free:
+	if (ret < 0) {
+		if (allocated) {
+			vfree(*buf);
+			*buf = NULL;
+		}
+	}
+
+out:
+	allow_write_access(file);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kernel_read_file);
+
+int kernel_read_file_from_path(const char *path, void **buf, loff_t *size,
+			       loff_t max_size, enum kernel_read_file_id id)
+{
+	struct file *file;
+	int ret;
+
+	if (!path || !*path)
+		return -EINVAL;
+
+	file = filp_open(path, O_RDONLY, 0);
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+
+	ret = kernel_read_file(file, buf, size, max_size, id);
+	fput(file);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
+
+int kernel_read_file_from_path_initns(const char *path, void **buf,
+				      loff_t *size, loff_t max_size,
+				      enum kernel_read_file_id id)
+{
+	struct file *file;
+	struct path root;
+	int ret;
+
+	if (!path || !*path)
+		return -EINVAL;
+
+	task_lock(&init_task);
+	get_fs_root(init_task.fs, &root);
+	task_unlock(&init_task);
+
+	file = file_open_root(root.dentry, root.mnt, path, O_RDONLY, 0);
+	path_put(&root);
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+
+	ret = kernel_read_file(file, buf, size, max_size, id);
+	fput(file);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns);
+
+int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size,
+			     enum kernel_read_file_id id)
+{
+	struct fd f = fdget(fd);
+	int ret = -EBADF;
+
+	if (!f.file)
+		goto out;
+
+	ret = kernel_read_file(f.file, buf, size, max_size, id);
+out:
+	fdput(f);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kernel_read_file_from_fd);
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 06/17] fs/kernel_read_file: Remove redundant size argument
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (4 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 05/17] fs/kernel_read_file: Split into separate source file Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-07-30  2:25   ` James Morris
  2020-07-29 17:58 ` [PATCH v4 07/17] fs/kernel_read_file: Switch buffer size arg to size_t Kees Cook
                   ` (10 subsequent siblings)
  16 siblings, 1 reply; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

In preparation for refactoring kernel_read_file*(), remove the redundant
"size" argument which is not needed: it can be included in the return
code, with callers adjusted. (VFS reads already cannot be larger than
INT_MAX.)

Acked-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/base/firmware_loader/main.c | 10 ++++++----
 fs/kernel_read_file.c               | 20 +++++++++-----------
 include/linux/kernel_read_file.h    |  8 ++++----
 kernel/kexec_file.c                 | 14 +++++++-------
 kernel/module.c                     |  7 +++----
 security/integrity/digsig.c         |  5 +++--
 security/integrity/ima/ima_fs.c     |  6 ++++--
 7 files changed, 36 insertions(+), 34 deletions(-)

diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 7fd677281806..9b425437afe6 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -462,7 +462,7 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
 					     size_t in_size,
 					     const void *in_buffer))
 {
-	loff_t size;
+	size_t size;
 	int i, len;
 	int rc = -ENOENT;
 	char *path;
@@ -494,10 +494,9 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
 		fw_priv->size = 0;
 
 		/* load firmware files from the mount namespace of init */
-		rc = kernel_read_file_from_path_initns(path, &buffer,
-						       &size, msize,
+		rc = kernel_read_file_from_path_initns(path, &buffer, msize,
 						       READING_FIRMWARE);
-		if (rc) {
+		if (rc < 0) {
 			if (rc != -ENOENT)
 				dev_warn(device, "loading %s failed with error %d\n",
 					 path, rc);
@@ -506,6 +505,9 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
 					 path);
 			continue;
 		}
+		size = rc;
+		rc = 0;
+
 		dev_dbg(device, "Loading firmware from %s\n", path);
 		if (decompress) {
 			dev_dbg(device, "f/w decompressing %s\n",
diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c
index 54d972d4befc..dc28a8def597 100644
--- a/fs/kernel_read_file.c
+++ b/fs/kernel_read_file.c
@@ -5,7 +5,7 @@
 #include <linux/security.h>
 #include <linux/vmalloc.h>
 
-int kernel_read_file(struct file *file, void **buf, loff_t *size,
+int kernel_read_file(struct file *file, void **buf,
 		     loff_t max_size, enum kernel_read_file_id id)
 {
 	loff_t i_size, pos;
@@ -29,7 +29,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 		ret = -EINVAL;
 		goto out;
 	}
-	if (i_size > SIZE_MAX || (max_size > 0 && i_size > max_size)) {
+	if (i_size > INT_MAX || (max_size > 0 && i_size > max_size)) {
 		ret = -EFBIG;
 		goto out;
 	}
@@ -59,8 +59,6 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 	}
 
 	ret = security_kernel_post_read_file(file, *buf, i_size, id);
-	if (!ret)
-		*size = pos;
 
 out_free:
 	if (ret < 0) {
@@ -72,11 +70,11 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
 
 out:
 	allow_write_access(file);
-	return ret;
+	return ret == 0 ? pos : ret;
 }
 EXPORT_SYMBOL_GPL(kernel_read_file);
 
-int kernel_read_file_from_path(const char *path, void **buf, loff_t *size,
+int kernel_read_file_from_path(const char *path, void **buf,
 			       loff_t max_size, enum kernel_read_file_id id)
 {
 	struct file *file;
@@ -89,14 +87,14 @@ int kernel_read_file_from_path(const char *path, void **buf, loff_t *size,
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	ret = kernel_read_file(file, buf, size, max_size, id);
+	ret = kernel_read_file(file, buf, max_size, id);
 	fput(file);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
 
 int kernel_read_file_from_path_initns(const char *path, void **buf,
-				      loff_t *size, loff_t max_size,
+				      loff_t max_size,
 				      enum kernel_read_file_id id)
 {
 	struct file *file;
@@ -115,13 +113,13 @@ int kernel_read_file_from_path_initns(const char *path, void **buf,
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	ret = kernel_read_file(file, buf, size, max_size, id);
+	ret = kernel_read_file(file, buf, max_size, id);
 	fput(file);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns);
 
-int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size,
+int kernel_read_file_from_fd(int fd, void **buf, loff_t max_size,
 			     enum kernel_read_file_id id)
 {
 	struct fd f = fdget(fd);
@@ -130,7 +128,7 @@ int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size,
 	if (!f.file)
 		goto out;
 
-	ret = kernel_read_file(f.file, buf, size, max_size, id);
+	ret = kernel_read_file(f.file, buf, max_size, id);
 out:
 	fdput(f);
 	return ret;
diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h
index 78cf3d7dc835..0ca0bdbed1bd 100644
--- a/include/linux/kernel_read_file.h
+++ b/include/linux/kernel_read_file.h
@@ -36,16 +36,16 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
 }
 
 int kernel_read_file(struct file *file,
-		     void **buf, loff_t *size, loff_t max_size,
+		     void **buf, loff_t max_size,
 		     enum kernel_read_file_id id);
 int kernel_read_file_from_path(const char *path,
-			       void **buf, loff_t *size, loff_t max_size,
+			       void **buf, loff_t max_size,
 			       enum kernel_read_file_id id);
 int kernel_read_file_from_path_initns(const char *path,
-				      void **buf, loff_t *size, loff_t max_size,
+				      void **buf, loff_t max_size,
 				      enum kernel_read_file_id id);
 int kernel_read_file_from_fd(int fd,
-			     void **buf, loff_t *size, loff_t max_size,
+			     void **buf, loff_t max_size,
 			     enum kernel_read_file_id id);
 
 #endif /* _LINUX_KERNEL_READ_FILE_H */
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 1358069ce9e9..eda19ca256a3 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -220,13 +220,12 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 {
 	int ret;
 	void *ldata;
-	loff_t size;
 
 	ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,
-				       &size, INT_MAX, READING_KEXEC_IMAGE);
-	if (ret)
+				       INT_MAX, READING_KEXEC_IMAGE);
+	if (ret < 0)
 		return ret;
-	image->kernel_buf_len = size;
+	image->kernel_buf_len = ret;
 
 	/* Call arch image probe handlers */
 	ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
@@ -243,11 +242,12 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 	/* It is possible that there no initramfs is being loaded */
 	if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
 		ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf,
-					       &size, INT_MAX,
+					       INT_MAX,
 					       READING_KEXEC_INITRAMFS);
-		if (ret)
+		if (ret < 0)
 			goto out;
-		image->initrd_buf_len = size;
+		image->initrd_buf_len = ret;
+		ret = 0;
 	}
 
 	if (cmdline_len) {
diff --git a/kernel/module.c b/kernel/module.c
index cc8d83841568..0792ce3bf643 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3991,7 +3991,6 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
 SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
 {
 	struct load_info info = { };
-	loff_t size;
 	void *hdr = NULL;
 	int err;
 
@@ -4005,12 +4004,12 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
 		      |MODULE_INIT_IGNORE_VERMAGIC))
 		return -EINVAL;
 
-	err = kernel_read_file_from_fd(fd, &hdr, &size, INT_MAX,
+	err = kernel_read_file_from_fd(fd, &hdr, INT_MAX,
 				       READING_MODULE);
-	if (err)
+	if (err < 0)
 		return err;
 	info.hdr = hdr;
-	info.len = size;
+	info.len = err;
 
 	return load_module(&info, uargs, flags);
 }
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index f8869be45d8f..97661ffabc4e 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -171,16 +171,17 @@ int __init integrity_add_key(const unsigned int id, const void *data,
 int __init integrity_load_x509(const unsigned int id, const char *path)
 {
 	void *data = NULL;
-	loff_t size;
+	size_t size;
 	int rc;
 	key_perm_t perm;
 
-	rc = kernel_read_file_from_path(path, &data, &size, 0,
+	rc = kernel_read_file_from_path(path, &data, 0,
 					READING_X509_CERTIFICATE);
 	if (rc < 0) {
 		pr_err("Unable to open file: %s (%d)", path, rc);
 		return rc;
 	}
+	size = rc;
 
 	perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ;
 
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index e13ffece3726..602f52717757 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -275,7 +275,7 @@ static ssize_t ima_read_policy(char *path)
 {
 	void *data = NULL;
 	char *datap;
-	loff_t size;
+	size_t size;
 	int rc, pathlen = strlen(path);
 
 	char *p;
@@ -284,11 +284,13 @@ static ssize_t ima_read_policy(char *path)
 	datap = path;
 	strsep(&datap, "\n");
 
-	rc = kernel_read_file_from_path(path, &data, &size, 0, READING_POLICY);
+	rc = kernel_read_file_from_path(path, &data, 0, READING_POLICY);
 	if (rc < 0) {
 		pr_err("Unable to open file: %s (%d)", path, rc);
 		return rc;
 	}
+	size = rc;
+	rc = 0;
 
 	datap = data;
 	while (size > 0 && (p = strsep(&datap, "\n"))) {
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 07/17] fs/kernel_read_file: Switch buffer size arg to size_t
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (5 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 06/17] fs/kernel_read_file: Remove redundant size argument Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-07-30  2:25   ` James Morris
  2020-07-29 17:58 ` [PATCH v4 08/17] fs/kernel_read_file: Add file_size output argument Kees Cook
                   ` (9 subsequent siblings)
  16 siblings, 1 reply; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

In preparation for further refactoring of kernel_read_file*(), rename
the "max_size" argument to the more accurate "buf_size", and correct
its type to size_t. Add kerndoc to explain the specifics of how the
arguments will be used. Note that with buf_size now size_t, it can no
longer be negative (and was never called with a negative value). Adjust
callers to use it as a "maximum size" when *buf is NULL.

Acked-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 fs/kernel_read_file.c            | 34 +++++++++++++++++++++++---------
 include/linux/kernel_read_file.h |  8 ++++----
 security/integrity/digsig.c      |  2 +-
 security/integrity/ima/ima_fs.c  |  2 +-
 4 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c
index dc28a8def597..e21a76001fff 100644
--- a/fs/kernel_read_file.c
+++ b/fs/kernel_read_file.c
@@ -5,15 +5,31 @@
 #include <linux/security.h>
 #include <linux/vmalloc.h>
 
+/**
+ * kernel_read_file() - read file contents into a kernel buffer
+ *
+ * @file	file to read from
+ * @buf		pointer to a "void *" buffer for reading into (if
+ *		*@buf is NULL, a buffer will be allocated, and
+ *		@buf_size will be ignored)
+ * @buf_size	size of buf, if already allocated. If @buf not
+ *		allocated, this is the largest size to allocate.
+ * @id		the kernel_read_file_id identifying the type of
+ *		file contents being read (for LSMs to examine)
+ *
+ * Returns number of bytes read (no single read will be bigger
+ * than INT_MAX), or negative on error.
+ *
+ */
 int kernel_read_file(struct file *file, void **buf,
-		     loff_t max_size, enum kernel_read_file_id id)
+		     size_t buf_size, enum kernel_read_file_id id)
 {
 	loff_t i_size, pos;
 	ssize_t bytes = 0;
 	void *allocated = NULL;
 	int ret;
 
-	if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0)
+	if (!S_ISREG(file_inode(file)->i_mode))
 		return -EINVAL;
 
 	ret = deny_write_access(file);
@@ -29,7 +45,7 @@ int kernel_read_file(struct file *file, void **buf,
 		ret = -EINVAL;
 		goto out;
 	}
-	if (i_size > INT_MAX || (max_size > 0 && i_size > max_size)) {
+	if (i_size > INT_MAX || i_size > buf_size) {
 		ret = -EFBIG;
 		goto out;
 	}
@@ -75,7 +91,7 @@ int kernel_read_file(struct file *file, void **buf,
 EXPORT_SYMBOL_GPL(kernel_read_file);
 
 int kernel_read_file_from_path(const char *path, void **buf,
-			       loff_t max_size, enum kernel_read_file_id id)
+			       size_t buf_size, enum kernel_read_file_id id)
 {
 	struct file *file;
 	int ret;
@@ -87,14 +103,14 @@ int kernel_read_file_from_path(const char *path, void **buf,
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	ret = kernel_read_file(file, buf, max_size, id);
+	ret = kernel_read_file(file, buf, buf_size, id);
 	fput(file);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
 
 int kernel_read_file_from_path_initns(const char *path, void **buf,
-				      loff_t max_size,
+				      size_t buf_size,
 				      enum kernel_read_file_id id)
 {
 	struct file *file;
@@ -113,13 +129,13 @@ int kernel_read_file_from_path_initns(const char *path, void **buf,
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	ret = kernel_read_file(file, buf, max_size, id);
+	ret = kernel_read_file(file, buf, buf_size, id);
 	fput(file);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns);
 
-int kernel_read_file_from_fd(int fd, void **buf, loff_t max_size,
+int kernel_read_file_from_fd(int fd, void **buf, size_t buf_size,
 			     enum kernel_read_file_id id)
 {
 	struct fd f = fdget(fd);
@@ -128,7 +144,7 @@ int kernel_read_file_from_fd(int fd, void **buf, loff_t max_size,
 	if (!f.file)
 		goto out;
 
-	ret = kernel_read_file(f.file, buf, max_size, id);
+	ret = kernel_read_file(f.file, buf, buf_size, id);
 out:
 	fdput(f);
 	return ret;
diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h
index 0ca0bdbed1bd..910039e7593e 100644
--- a/include/linux/kernel_read_file.h
+++ b/include/linux/kernel_read_file.h
@@ -36,16 +36,16 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
 }
 
 int kernel_read_file(struct file *file,
-		     void **buf, loff_t max_size,
+		     void **buf, size_t buf_size,
 		     enum kernel_read_file_id id);
 int kernel_read_file_from_path(const char *path,
-			       void **buf, loff_t max_size,
+			       void **buf, size_t buf_size,
 			       enum kernel_read_file_id id);
 int kernel_read_file_from_path_initns(const char *path,
-				      void **buf, loff_t max_size,
+				      void **buf, size_t buf_size,
 				      enum kernel_read_file_id id);
 int kernel_read_file_from_fd(int fd,
-			     void **buf, loff_t max_size,
+			     void **buf, size_t buf_size,
 			     enum kernel_read_file_id id);
 
 #endif /* _LINUX_KERNEL_READ_FILE_H */
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 97661ffabc4e..04f779c4f5ed 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -175,7 +175,7 @@ int __init integrity_load_x509(const unsigned int id, const char *path)
 	int rc;
 	key_perm_t perm;
 
-	rc = kernel_read_file_from_path(path, &data, 0,
+	rc = kernel_read_file_from_path(path, &data, INT_MAX,
 					READING_X509_CERTIFICATE);
 	if (rc < 0) {
 		pr_err("Unable to open file: %s (%d)", path, rc);
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 602f52717757..692b83e82edf 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -284,7 +284,7 @@ static ssize_t ima_read_policy(char *path)
 	datap = path;
 	strsep(&datap, "\n");
 
-	rc = kernel_read_file_from_path(path, &data, 0, READING_POLICY);
+	rc = kernel_read_file_from_path(path, &data, INT_MAX, READING_POLICY);
 	if (rc < 0) {
 		pr_err("Unable to open file: %s (%d)", path, rc);
 		return rc;
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 08/17] fs/kernel_read_file: Add file_size output argument
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (6 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 07/17] fs/kernel_read_file: Switch buffer size arg to size_t Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-07-30  2:26   ` James Morris
  2020-07-29 17:58 ` [PATCH v4 09/17] LSM: Introduce kernel_post_load_data() hook Kees Cook
                   ` (8 subsequent siblings)
  16 siblings, 1 reply; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

In preparation for adding partial read support, add an optional output
argument to kernel_read_file*() that reports the file size so callers
can reason more easily about their reading progress.

Acked-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/base/firmware_loader/main.c |  1 +
 fs/kernel_read_file.c               | 19 +++++++++++++------
 include/linux/kernel_read_file.h    |  4 ++++
 kernel/kexec_file.c                 |  4 ++--
 kernel/module.c                     |  2 +-
 security/integrity/digsig.c         |  2 +-
 security/integrity/ima/ima_fs.c     |  2 +-
 7 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 9b425437afe6..6a5d407279e3 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -495,6 +495,7 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
 
 		/* load firmware files from the mount namespace of init */
 		rc = kernel_read_file_from_path_initns(path, &buffer, msize,
+						       NULL,
 						       READING_FIRMWARE);
 		if (rc < 0) {
 			if (rc != -ENOENT)
diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c
index e21a76001fff..2e29c38eb4df 100644
--- a/fs/kernel_read_file.c
+++ b/fs/kernel_read_file.c
@@ -14,6 +14,8 @@
  *		@buf_size will be ignored)
  * @buf_size	size of buf, if already allocated. If @buf not
  *		allocated, this is the largest size to allocate.
+ * @file_size	if non-NULL, the full size of @file will be
+ *		written here.
  * @id		the kernel_read_file_id identifying the type of
  *		file contents being read (for LSMs to examine)
  *
@@ -22,7 +24,8 @@
  *
  */
 int kernel_read_file(struct file *file, void **buf,
-		     size_t buf_size, enum kernel_read_file_id id)
+		     size_t buf_size, size_t *file_size,
+		     enum kernel_read_file_id id)
 {
 	loff_t i_size, pos;
 	ssize_t bytes = 0;
@@ -49,6 +52,8 @@ int kernel_read_file(struct file *file, void **buf,
 		ret = -EFBIG;
 		goto out;
 	}
+	if (file_size)
+		*file_size = i_size;
 
 	if (!*buf)
 		*buf = allocated = vmalloc(i_size);
@@ -91,7 +96,8 @@ int kernel_read_file(struct file *file, void **buf,
 EXPORT_SYMBOL_GPL(kernel_read_file);
 
 int kernel_read_file_from_path(const char *path, void **buf,
-			       size_t buf_size, enum kernel_read_file_id id)
+			       size_t buf_size, size_t *file_size,
+			       enum kernel_read_file_id id)
 {
 	struct file *file;
 	int ret;
@@ -103,14 +109,14 @@ int kernel_read_file_from_path(const char *path, void **buf,
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	ret = kernel_read_file(file, buf, buf_size, id);
+	ret = kernel_read_file(file, buf, buf_size, file_size, id);
 	fput(file);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
 
 int kernel_read_file_from_path_initns(const char *path, void **buf,
-				      size_t buf_size,
+				      size_t buf_size, size_t *file_size,
 				      enum kernel_read_file_id id)
 {
 	struct file *file;
@@ -129,13 +135,14 @@ int kernel_read_file_from_path_initns(const char *path, void **buf,
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	ret = kernel_read_file(file, buf, buf_size, id);
+	ret = kernel_read_file(file, buf, buf_size, file_size, id);
 	fput(file);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns);
 
 int kernel_read_file_from_fd(int fd, void **buf, size_t buf_size,
+			     size_t *file_size,
 			     enum kernel_read_file_id id)
 {
 	struct fd f = fdget(fd);
@@ -144,7 +151,7 @@ int kernel_read_file_from_fd(int fd, void **buf, size_t buf_size,
 	if (!f.file)
 		goto out;
 
-	ret = kernel_read_file(f.file, buf, buf_size, id);
+	ret = kernel_read_file(f.file, buf, buf_size, file_size, id);
 out:
 	fdput(f);
 	return ret;
diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h
index 910039e7593e..023293eaf948 100644
--- a/include/linux/kernel_read_file.h
+++ b/include/linux/kernel_read_file.h
@@ -37,15 +37,19 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
 
 int kernel_read_file(struct file *file,
 		     void **buf, size_t buf_size,
+		     size_t *file_size,
 		     enum kernel_read_file_id id);
 int kernel_read_file_from_path(const char *path,
 			       void **buf, size_t buf_size,
+			       size_t *file_size,
 			       enum kernel_read_file_id id);
 int kernel_read_file_from_path_initns(const char *path,
 				      void **buf, size_t buf_size,
+				      size_t *file_size,
 				      enum kernel_read_file_id id);
 int kernel_read_file_from_fd(int fd,
 			     void **buf, size_t buf_size,
+			     size_t *file_size,
 			     enum kernel_read_file_id id);
 
 #endif /* _LINUX_KERNEL_READ_FILE_H */
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index eda19ca256a3..878ca684a3a1 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -222,7 +222,7 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 	void *ldata;
 
 	ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,
-				       INT_MAX, READING_KEXEC_IMAGE);
+				       INT_MAX, NULL, READING_KEXEC_IMAGE);
 	if (ret < 0)
 		return ret;
 	image->kernel_buf_len = ret;
@@ -242,7 +242,7 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 	/* It is possible that there no initramfs is being loaded */
 	if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
 		ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf,
-					       INT_MAX,
+					       INT_MAX, NULL,
 					       READING_KEXEC_INITRAMFS);
 		if (ret < 0)
 			goto out;
diff --git a/kernel/module.c b/kernel/module.c
index 0792ce3bf643..16558bc842de 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4004,7 +4004,7 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
 		      |MODULE_INIT_IGNORE_VERMAGIC))
 		return -EINVAL;
 
-	err = kernel_read_file_from_fd(fd, &hdr, INT_MAX,
+	err = kernel_read_file_from_fd(fd, &hdr, INT_MAX, NULL,
 				       READING_MODULE);
 	if (err < 0)
 		return err;
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 04f779c4f5ed..8a523dfd7fd7 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -175,7 +175,7 @@ int __init integrity_load_x509(const unsigned int id, const char *path)
 	int rc;
 	key_perm_t perm;
 
-	rc = kernel_read_file_from_path(path, &data, INT_MAX,
+	rc = kernel_read_file_from_path(path, &data, INT_MAX, NULL,
 					READING_X509_CERTIFICATE);
 	if (rc < 0) {
 		pr_err("Unable to open file: %s (%d)", path, rc);
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 692b83e82edf..5fc56ccb6678 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -284,7 +284,7 @@ static ssize_t ima_read_policy(char *path)
 	datap = path;
 	strsep(&datap, "\n");
 
-	rc = kernel_read_file_from_path(path, &data, INT_MAX, READING_POLICY);
+	rc = kernel_read_file_from_path(path, &data, INT_MAX, NULL, READING_POLICY);
 	if (rc < 0) {
 		pr_err("Unable to open file: %s (%d)", path, rc);
 		return rc;
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 09/17] LSM: Introduce kernel_post_load_data() hook
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (7 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 08/17] fs/kernel_read_file: Add file_size output argument Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-08-06 21:59   ` Mimi Zohar
  2020-08-07  0:21   ` KP Singh
  2020-07-29 17:58 ` [PATCH v4 10/17] firmware_loader: Use security_post_load_data() Kees Cook
                   ` (7 subsequent siblings)
  16 siblings, 2 replies; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

There are a few places in the kernel where LSMs would like to have
visibility into the contents of a kernel buffer that has been loaded or
read. While security_kernel_post_read_file() (which includes the
buffer) exists as a pairing for security_kernel_read_file(), no such
hook exists to pair with security_kernel_load_data().

Earlier proposals for just using security_kernel_post_read_file() with a
NULL file argument were rejected (i.e. "file" should always be valid for
the security_..._file hooks, but it appears at least one case was
left in the kernel during earlier refactoring. (This will be fixed in
a subsequent patch.)

Since not all cases of security_kernel_load_data() can have a single
contiguous buffer made available to the LSM hook (e.g. kexec image
segments are separately loaded), there needs to be a way for the LSM to
reason about its expectations of the hook coverage. In order to handle
this, add a "contents" argument to the "kernel_load_data" hook that
indicates if the newly added "kernel_post_load_data" hook will be called
with the full contents once loaded. That way, LSMs requiring full contents
can choose to unilaterally reject "kernel_load_data" with contents=false
(which is effectively the existing hook coverage), but when contents=true
they can allow it and later evaluate the "kernel_post_load_data" hook
once the buffer is loaded.

With this change, LSMs can gain coverage over non-file-backed data loads
(e.g. init_module(2) and firmware userspace helper), which will happen
in subsequent patches.

Additionally prepare IMA to start processing these cases.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/base/firmware_loader/fallback.c       |  2 +-
 .../base/firmware_loader/fallback_platform.c  |  2 +-
 include/linux/ima.h                           | 12 +++++++++--
 include/linux/lsm_hook_defs.h                 |  4 +++-
 include/linux/lsm_hooks.h                     |  9 ++++++++
 include/linux/security.h                      | 12 +++++++++--
 kernel/kexec.c                                |  2 +-
 kernel/module.c                               |  2 +-
 security/integrity/ima/ima_main.c             | 21 ++++++++++++++++++-
 security/loadpin/loadpin.c                    |  2 +-
 security/security.c                           | 18 +++++++++++++---
 security/selinux/hooks.c                      |  2 +-
 12 files changed, 73 insertions(+), 15 deletions(-)

diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
index 5327bfc6ba71..a196aacce22c 100644
--- a/drivers/base/firmware_loader/fallback.c
+++ b/drivers/base/firmware_loader/fallback.c
@@ -613,7 +613,7 @@ static bool fw_run_sysfs_fallback(u32 opt_flags)
 		return false;
 
 	/* Also permit LSMs and IMA to fail firmware sysfs fallback */
-	ret = security_kernel_load_data(LOADING_FIRMWARE);
+	ret = security_kernel_load_data(LOADING_FIRMWARE, false);
 	if (ret < 0)
 		return false;
 
diff --git a/drivers/base/firmware_loader/fallback_platform.c b/drivers/base/firmware_loader/fallback_platform.c
index 6958ab1a8059..a12c79d47efc 100644
--- a/drivers/base/firmware_loader/fallback_platform.c
+++ b/drivers/base/firmware_loader/fallback_platform.c
@@ -17,7 +17,7 @@ int firmware_fallback_platform(struct fw_priv *fw_priv, u32 opt_flags)
 	if (!(opt_flags & FW_OPT_FALLBACK_PLATFORM))
 		return -ENOENT;
 
-	rc = security_kernel_load_data(LOADING_FIRMWARE);
+	rc = security_kernel_load_data(LOADING_FIRMWARE, false);
 	if (rc)
 		return rc;
 
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 148636bfcc8f..502e36ad7804 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -20,7 +20,9 @@ extern void ima_post_create_tmpfile(struct inode *inode);
 extern void ima_file_free(struct file *file);
 extern int ima_file_mmap(struct file *file, unsigned long prot);
 extern int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot);
-extern int ima_load_data(enum kernel_load_data_id id);
+extern int ima_load_data(enum kernel_load_data_id id, bool contents);
+extern int ima_post_load_data(char *buf, loff_t size,
+			      enum kernel_load_data_id id);
 extern int ima_read_file(struct file *file, enum kernel_read_file_id id);
 extern int ima_post_read_file(struct file *file, void *buf, loff_t size,
 			      enum kernel_read_file_id id);
@@ -78,7 +80,13 @@ static inline int ima_file_mprotect(struct vm_area_struct *vma,
 	return 0;
 }
 
-static inline int ima_load_data(enum kernel_load_data_id id)
+static inline int ima_load_data(enum kernel_load_data_id id, bool contents)
+{
+	return 0;
+}
+
+static inline int ima_post_load_data(char *buf, loff_t size,
+				     enum kernel_load_data_id id)
 {
 	return 0;
 }
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index af998f93d256..7ed5d31ac9cc 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -184,7 +184,9 @@ LSM_HOOK(void, LSM_RET_VOID, cred_getsecid, const struct cred *c, u32 *secid)
 LSM_HOOK(int, 0, kernel_act_as, struct cred *new, u32 secid)
 LSM_HOOK(int, 0, kernel_create_files_as, struct cred *new, struct inode *inode)
 LSM_HOOK(int, 0, kernel_module_request, char *kmod_name)
-LSM_HOOK(int, 0, kernel_load_data, enum kernel_load_data_id id)
+LSM_HOOK(int, 0, kernel_load_data, enum kernel_load_data_id id, bool contents)
+LSM_HOOK(int, 0, kernel_post_load_data, char *buf, loff_t size,
+	 enum kernel_read_file_id id)
 LSM_HOOK(int, 0, kernel_read_file, struct file *file,
 	 enum kernel_read_file_id id)
 LSM_HOOK(int, 0, kernel_post_read_file, struct file *file, char *buf,
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 95b7c1d32062..812d626195fc 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -635,7 +635,16 @@
  * @kernel_load_data:
  *	Load data provided by userspace.
  *	@id kernel load data identifier
+ *	@contents if a subsequent @kernel_post_load_data will be called.
  *	Return 0 if permission is granted.
+ * @kernel_post_load_data:
+ *	Load data provided by a non-file source (usually userspace buffer).
+ *	@buf pointer to buffer containing the data contents.
+ *	@size length of the data contents.
+ *	@id kernel load data identifier
+ *	Return 0 if permission is granted.
+ *	This must be paired with a prior @kernel_load_data call that had
+ *	@contents set to true.
  * @kernel_read_file:
  *	Read a file specified by userspace.
  *	@file contains the file structure pointing to the file being read
diff --git a/include/linux/security.h b/include/linux/security.h
index 42df0d9b4c37..e748974c707b 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -387,7 +387,9 @@ void security_cred_getsecid(const struct cred *c, u32 *secid);
 int security_kernel_act_as(struct cred *new, u32 secid);
 int security_kernel_create_files_as(struct cred *new, struct inode *inode);
 int security_kernel_module_request(char *kmod_name);
-int security_kernel_load_data(enum kernel_load_data_id id);
+int security_kernel_load_data(enum kernel_load_data_id id, bool contents);
+int security_kernel_post_load_data(char *buf, loff_t size,
+				   enum kernel_load_data_id id);
 int security_kernel_read_file(struct file *file, enum kernel_read_file_id id);
 int security_kernel_post_read_file(struct file *file, char *buf, loff_t size,
 				   enum kernel_read_file_id id);
@@ -1014,7 +1016,13 @@ static inline int security_kernel_module_request(char *kmod_name)
 	return 0;
 }
 
-static inline int security_kernel_load_data(enum kernel_load_data_id id)
+static inline int security_kernel_load_data(enum kernel_load_data_id id, bool contents)
+{
+	return 0;
+}
+
+static inline int security_kernel_post_load_data(char *buf, loff_t size,
+						 enum kernel_load_data_id id)
 {
 	return 0;
 }
diff --git a/kernel/kexec.c b/kernel/kexec.c
index f977786fe498..c82c6c06f051 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -205,7 +205,7 @@ static inline int kexec_load_check(unsigned long nr_segments,
 		return -EPERM;
 
 	/* Permit LSMs and IMA to fail the kexec */
-	result = security_kernel_load_data(LOADING_KEXEC_IMAGE);
+	result = security_kernel_load_data(LOADING_KEXEC_IMAGE, false);
 	if (result < 0)
 		return result;
 
diff --git a/kernel/module.c b/kernel/module.c
index 16558bc842de..d773f32f8dfd 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2970,7 +2970,7 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
 	if (info->len < sizeof(*(info->hdr)))
 		return -ENOEXEC;
 
-	err = security_kernel_load_data(LOADING_MODULE);
+	err = security_kernel_load_data(LOADING_MODULE, false);
 	if (err)
 		return err;
 
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index dab4a13221cf..85000dc8595c 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -676,6 +676,8 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
 /**
  * ima_load_data - appraise decision based on policy
  * @id: kernel load data caller identifier
+ * @contents: whether the full contents will be available in a later
+ *	      call to ima_post_load_data().
  *
  * Callers of this LSM hook can not measure, appraise, or audit the
  * data provided by userspace.  Enforce policy rules requring a file
@@ -683,7 +685,7 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
  *
  * For permission return 0, otherwise return -EACCES.
  */
-int ima_load_data(enum kernel_load_data_id id)
+int ima_load_data(enum kernel_load_data_id id, bool contents)
 {
 	bool ima_enforce, sig_enforce;
 
@@ -723,6 +725,23 @@ int ima_load_data(enum kernel_load_data_id id)
 	return 0;
 }
 
+/**
+ * ima_post_load_data - appraise decision based on policy
+ * @buf: pointer to in memory file contents
+ * @size: size of in memory file contents
+ * @id: kernel load data caller identifier
+ *
+ * Measure/appraise/audit in memory buffer based on policy.  Policy rules
+ * are written in terms of a policy identifier.
+ *
+ * On success return 0.  On integrity appraisal error, assuming the file
+ * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
+ */
+int ima_post_load_data(char *buf, loff_t size, enum kernel_load_data_id load_id)
+{
+	return 0;
+}
+
 /*
  * process_buffer_measurement - Measure the buffer to ima log.
  * @buf: pointer to the buffer that needs to be added to the log.
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index 81bc95127f92..db320a43f42e 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -176,7 +176,7 @@ static int loadpin_read_file(struct file *file, enum kernel_read_file_id id)
 	return 0;
 }
 
-static int loadpin_load_data(enum kernel_load_data_id id)
+static int loadpin_load_data(enum kernel_load_data_id id, bool contents)
 {
 	return loadpin_read_file(NULL, (enum kernel_read_file_id) id);
 }
diff --git a/security/security.c b/security/security.c
index 19d3150f68f4..568bb77e84f4 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1695,17 +1695,29 @@ int security_kernel_post_read_file(struct file *file, char *buf, loff_t size,
 }
 EXPORT_SYMBOL_GPL(security_kernel_post_read_file);
 
-int security_kernel_load_data(enum kernel_load_data_id id)
+int security_kernel_load_data(enum kernel_load_data_id id, bool contents)
 {
 	int ret;
 
-	ret = call_int_hook(kernel_load_data, 0, id);
+	ret = call_int_hook(kernel_load_data, 0, id, contents);
 	if (ret)
 		return ret;
-	return ima_load_data(id);
+	return ima_load_data(id, contents);
 }
 EXPORT_SYMBOL_GPL(security_kernel_load_data);
 
+int security_kernel_post_load_data(char *buf, loff_t size,
+				   enum kernel_load_data_id id)
+{
+	int ret;
+
+	ret = call_int_hook(kernel_post_load_data, 0, buf, size, id);
+	if (ret)
+		return ret;
+	return ima_post_load_data(buf, size, id);
+}
+EXPORT_SYMBOL_GPL(security_kernel_post_load_data);
+
 int security_task_fix_setuid(struct cred *new, const struct cred *old,
 			     int flags)
 {
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 5de45010fb1a..1a5c68196faf 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4019,7 +4019,7 @@ static int selinux_kernel_read_file(struct file *file,
 	return rc;
 }
 
-static int selinux_kernel_load_data(enum kernel_load_data_id id)
+static int selinux_kernel_load_data(enum kernel_load_data_id id, bool contents)
 {
 	int rc = 0;
 
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 10/17] firmware_loader: Use security_post_load_data()
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (8 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 09/17] LSM: Introduce kernel_post_load_data() hook Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-08-06 22:07   ` Mimi Zohar
  2020-07-29 17:58 ` [PATCH v4 11/17] module: Call security_kernel_post_load_data() Kees Cook
                   ` (6 subsequent siblings)
  16 siblings, 1 reply; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

Now that security_post_load_data() is wired up, use it instead
of the NULL file argument style of security_post_read_file(),
and update the security_kernel_load_data() call to indicate that a
security_kernel_post_load_data() call is expected.

Wire up the IMA check to match earlier logic. Perhaps a generalized
change to ima_post_load_data() might look something like this:

    return process_buffer_measurement(buf, size,
                                      kernel_load_data_id_str(load_id),
                                      read_idmap[load_id] ?: FILE_CHECK,
                                      0, NULL);

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/base/firmware_loader/fallback.c       |  8 ++++----
 .../base/firmware_loader/fallback_platform.c  |  7 ++++++-
 security/integrity/ima/ima_main.c             | 20 +++++++++----------
 3 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
index a196aacce22c..7cfdfdcb819c 100644
--- a/drivers/base/firmware_loader/fallback.c
+++ b/drivers/base/firmware_loader/fallback.c
@@ -272,9 +272,9 @@ static ssize_t firmware_loading_store(struct device *dev,
 				dev_err(dev, "%s: map pages failed\n",
 					__func__);
 			else
-				rc = security_kernel_post_read_file(NULL,
-						fw_priv->data, fw_priv->size,
-						READING_FIRMWARE);
+				rc = security_kernel_post_load_data(fw_priv->data,
+						fw_priv->size,
+						LOADING_FIRMWARE);
 
 			/*
 			 * Same logic as fw_load_abort, only the DONE bit
@@ -613,7 +613,7 @@ static bool fw_run_sysfs_fallback(u32 opt_flags)
 		return false;
 
 	/* Also permit LSMs and IMA to fail firmware sysfs fallback */
-	ret = security_kernel_load_data(LOADING_FIRMWARE, false);
+	ret = security_kernel_load_data(LOADING_FIRMWARE, true);
 	if (ret < 0)
 		return false;
 
diff --git a/drivers/base/firmware_loader/fallback_platform.c b/drivers/base/firmware_loader/fallback_platform.c
index a12c79d47efc..4d1157af0e86 100644
--- a/drivers/base/firmware_loader/fallback_platform.c
+++ b/drivers/base/firmware_loader/fallback_platform.c
@@ -17,7 +17,7 @@ int firmware_fallback_platform(struct fw_priv *fw_priv, u32 opt_flags)
 	if (!(opt_flags & FW_OPT_FALLBACK_PLATFORM))
 		return -ENOENT;
 
-	rc = security_kernel_load_data(LOADING_FIRMWARE, false);
+	rc = security_kernel_load_data(LOADING_FIRMWARE, true);
 	if (rc)
 		return rc;
 
@@ -27,6 +27,11 @@ int firmware_fallback_platform(struct fw_priv *fw_priv, u32 opt_flags)
 
 	if (fw_priv->data && size > fw_priv->allocated_size)
 		return -ENOMEM;
+
+	rc = security_kernel_post_load_data((u8 *)data, size, LOADING_FIRMWARE);
+	if (rc)
+		return rc;
+
 	if (!fw_priv->data)
 		fw_priv->data = vmalloc(size);
 	if (!fw_priv->data)
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 85000dc8595c..1a7bc4c7437d 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -648,15 +648,6 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
 	enum ima_hooks func;
 	u32 secid;
 
-	if (!file && read_id == READING_FIRMWARE) {
-		if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
-		    (ima_appraise & IMA_APPRAISE_ENFORCE)) {
-			pr_err("Prevent firmware loading_store.\n");
-			return -EACCES;	/* INTEGRITY_UNKNOWN */
-		}
-		return 0;
-	}
-
 	/* permit signed certs */
 	if (!file && read_id == READING_X509_CERTIFICATE)
 		return 0;
@@ -706,7 +697,7 @@ int ima_load_data(enum kernel_load_data_id id, bool contents)
 		}
 		break;
 	case LOADING_FIRMWARE:
-		if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE)) {
+		if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE) && !contents) {
 			pr_err("Prevent firmware sysfs fallback loading.\n");
 			return -EACCES;	/* INTEGRITY_UNKNOWN */
 		}
@@ -739,6 +730,15 @@ int ima_load_data(enum kernel_load_data_id id, bool contents)
  */
 int ima_post_load_data(char *buf, loff_t size, enum kernel_load_data_id load_id)
 {
+	if (load_id == LOADING_FIRMWARE) {
+		if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
+		    (ima_appraise & IMA_APPRAISE_ENFORCE)) {
+			pr_err("Prevent firmware loading_store.\n");
+			return -EACCES; /* INTEGRITY_UNKNOWN */
+		}
+		return 0;
+	}
+
 	return 0;
 }
 
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 11/17] module: Call security_kernel_post_load_data()
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (9 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 10/17] firmware_loader: Use security_post_load_data() Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-08-05 14:53   ` Jessica Yu
  2020-07-29 17:58 ` [PATCH v4 12/17] LSM: Add "contents" flag to kernel_read_file hook Kees Cook
                   ` (5 subsequent siblings)
  16 siblings, 1 reply; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Jessica Yu, Scott Branden, Mimi Zohar,
	Luis Chamberlain, Takashi Iwai, SeongJae Park, KP Singh,
	linux-efi, linux-security-module, linux-integrity, selinux,
	linux-kselftest, linux-kernel

Now that there is an API for checking loaded contents for modules
loaded without a file, call into the LSM hooks.

Cc: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 kernel/module.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index d773f32f8dfd..72e33e25d7b9 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2970,7 +2970,7 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
 	if (info->len < sizeof(*(info->hdr)))
 		return -ENOEXEC;
 
-	err = security_kernel_load_data(LOADING_MODULE, false);
+	err = security_kernel_load_data(LOADING_MODULE, true);
 	if (err)
 		return err;
 
@@ -2980,11 +2980,17 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
 		return -ENOMEM;
 
 	if (copy_chunked_from_user(info->hdr, umod, info->len) != 0) {
-		vfree(info->hdr);
-		return -EFAULT;
+		err = -EFAULT;
+		goto out;
 	}
 
-	return 0;
+	err = security_kernel_post_load_data((char *)info->hdr, info->len,
+					     LOADING_MODULE);
+out:
+	if (err)
+		vfree(info->hdr);
+
+	return err;
 }
 
 static void free_copy(struct load_info *info)
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 12/17] LSM: Add "contents" flag to kernel_read_file hook
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (10 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 11/17] module: Call security_kernel_post_load_data() Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-08-07  0:23   ` Mimi Zohar
  2020-07-29 17:58 ` [PATCH v4 13/17] IMA: Add support for file reads without contents Kees Cook
                   ` (4 subsequent siblings)
  16 siblings, 1 reply; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

As with the kernel_load_data LSM hook, add a "contents" flag to the
kernel_read_file LSM hook that indicates whether the LSM can expect
a matching call to the kernel_post_read_file LSM hook with the full
contents of the file. With the coming addition of partial file read
support for kernel_read_file*() API, the LSM will no longer be able
to always see the entire contents of a file during the read calls.

For cases where the LSM must read examine the complete file contents,
it will need to do so on its own every time the kernel_read_file
hook is called with contents=false (or reject such cases). Adjust all
existing LSMs to retain existing behavior.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 fs/kernel_read_file.c             |  2 +-
 include/linux/ima.h               |  6 ++++--
 include/linux/lsm_hook_defs.h     |  2 +-
 include/linux/lsm_hooks.h         |  3 +++
 include/linux/security.h          |  6 ++++--
 security/integrity/ima/ima_main.c | 10 +++++++++-
 security/loadpin/loadpin.c        | 14 ++++++++++++--
 security/security.c               |  7 ++++---
 security/selinux/hooks.c          |  5 +++--
 9 files changed, 41 insertions(+), 14 deletions(-)

diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c
index 2e29c38eb4df..d73bc3fa710a 100644
--- a/fs/kernel_read_file.c
+++ b/fs/kernel_read_file.c
@@ -39,7 +39,7 @@ int kernel_read_file(struct file *file, void **buf,
 	if (ret)
 		return ret;
 
-	ret = security_kernel_read_file(file, id);
+	ret = security_kernel_read_file(file, id, true);
 	if (ret)
 		goto out;
 
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 502e36ad7804..259023039dc9 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -23,7 +23,8 @@ extern int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot);
 extern int ima_load_data(enum kernel_load_data_id id, bool contents);
 extern int ima_post_load_data(char *buf, loff_t size,
 			      enum kernel_load_data_id id);
-extern int ima_read_file(struct file *file, enum kernel_read_file_id id);
+extern int ima_read_file(struct file *file, enum kernel_read_file_id id,
+			 bool contents);
 extern int ima_post_read_file(struct file *file, void *buf, loff_t size,
 			      enum kernel_read_file_id id);
 extern void ima_post_path_mknod(struct dentry *dentry);
@@ -91,7 +92,8 @@ static inline int ima_post_load_data(char *buf, loff_t size,
 	return 0;
 }
 
-static inline int ima_read_file(struct file *file, enum kernel_read_file_id id)
+static inline int ima_read_file(struct file *file, enum kernel_read_file_id id,
+				bool contents)
 {
 	return 0;
 }
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 7ed5d31ac9cc..f953aa938eaf 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -188,7 +188,7 @@ LSM_HOOK(int, 0, kernel_load_data, enum kernel_load_data_id id, bool contents)
 LSM_HOOK(int, 0, kernel_post_load_data, char *buf, loff_t size,
 	 enum kernel_read_file_id id)
 LSM_HOOK(int, 0, kernel_read_file, struct file *file,
-	 enum kernel_read_file_id id)
+	 enum kernel_read_file_id id, bool contents)
 LSM_HOOK(int, 0, kernel_post_read_file, struct file *file, char *buf,
 	 loff_t size, enum kernel_read_file_id id)
 LSM_HOOK(int, 0, task_fix_setuid, struct cred *new, const struct cred *old,
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 812d626195fc..b66433b5aa15 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -650,6 +650,7 @@
  *	@file contains the file structure pointing to the file being read
  *	by the kernel.
  *	@id kernel read file identifier
+ *	@contents if a subsequent @kernel_post_read_file will be called.
  *	Return 0 if permission is granted.
  * @kernel_post_read_file:
  *	Read a file specified by userspace.
@@ -658,6 +659,8 @@
  *	@buf pointer to buffer containing the file contents.
  *	@size length of the file contents.
  *	@id kernel read file identifier
+ *	This must be paired with a prior @kernel_read_file call that had
+ *	@contents set to true.
  *	Return 0 if permission is granted.
  * @task_fix_setuid:
  *	Update the module's state after setting one or more of the user
diff --git a/include/linux/security.h b/include/linux/security.h
index e748974c707b..a5d66b89cd6c 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -390,7 +390,8 @@ int security_kernel_module_request(char *kmod_name);
 int security_kernel_load_data(enum kernel_load_data_id id, bool contents);
 int security_kernel_post_load_data(char *buf, loff_t size,
 				   enum kernel_load_data_id id);
-int security_kernel_read_file(struct file *file, enum kernel_read_file_id id);
+int security_kernel_read_file(struct file *file, enum kernel_read_file_id id,
+			      bool contents);
 int security_kernel_post_read_file(struct file *file, char *buf, loff_t size,
 				   enum kernel_read_file_id id);
 int security_task_fix_setuid(struct cred *new, const struct cred *old,
@@ -1028,7 +1029,8 @@ static inline int security_kernel_post_load_data(char *buf, loff_t size,
 }
 
 static inline int security_kernel_read_file(struct file *file,
-					    enum kernel_read_file_id id)
+					    enum kernel_read_file_id id,
+					    bool contents)
 {
 	return 0;
 }
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 1a7bc4c7437d..dc4f90660aa6 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -602,6 +602,7 @@ void ima_post_path_mknod(struct dentry *dentry)
  * ima_read_file - pre-measure/appraise hook decision based on policy
  * @file: pointer to the file to be measured/appraised/audit
  * @read_id: caller identifier
+ * @contents: whether a subsequent call will be made to ima_post_read_file()
  *
  * Permit reading a file based on policy. The policy rules are written
  * in terms of the policy identifier.  Appraising the integrity of
@@ -609,8 +610,15 @@ void ima_post_path_mknod(struct dentry *dentry)
  *
  * For permission return 0, otherwise return -EACCES.
  */
-int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
+int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
+		  bool contents)
 {
+	/* Reject all partial reads during appraisal. */
+	if (!contents) {
+		if (ima_appraise & IMA_APPRAISE_ENFORCE)
+			return -EACCES;
+	}
+
 	/*
 	 * Do devices using pre-allocated memory run the risk of the
 	 * firmware being accessible to the device prior to the completion
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index db320a43f42e..a1778ebef137 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -117,11 +117,21 @@ static void loadpin_sb_free_security(struct super_block *mnt_sb)
 	}
 }
 
-static int loadpin_read_file(struct file *file, enum kernel_read_file_id id)
+static int loadpin_read_file(struct file *file, enum kernel_read_file_id id,
+			     bool contents)
 {
 	struct super_block *load_root;
 	const char *origin = kernel_read_file_id_str(id);
 
+	/*
+	 * If we will not know that we'll be seeing the full contents
+	 * then we cannot trust a load will be complete and unchanged
+	 * off disk. Treat all contents=false hooks as if there were
+	 * no associated file struct.
+	 */
+	if (!contents)
+		file = NULL;
+
 	/* If the file id is excluded, ignore the pinning. */
 	if ((unsigned int)id < ARRAY_SIZE(ignore_read_file_id) &&
 	    ignore_read_file_id[id]) {
@@ -178,7 +188,7 @@ static int loadpin_read_file(struct file *file, enum kernel_read_file_id id)
 
 static int loadpin_load_data(enum kernel_load_data_id id, bool contents)
 {
-	return loadpin_read_file(NULL, (enum kernel_read_file_id) id);
+	return loadpin_read_file(NULL, (enum kernel_read_file_id) id, contents);
 }
 
 static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = {
diff --git a/security/security.c b/security/security.c
index 568bb77e84f4..6a38fc533a5a 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1672,14 +1672,15 @@ int security_kernel_module_request(char *kmod_name)
 	return integrity_kernel_module_request(kmod_name);
 }
 
-int security_kernel_read_file(struct file *file, enum kernel_read_file_id id)
+int security_kernel_read_file(struct file *file, enum kernel_read_file_id id,
+			      bool contents)
 {
 	int ret;
 
-	ret = call_int_hook(kernel_read_file, 0, file, id);
+	ret = call_int_hook(kernel_read_file, 0, file, id, contents);
 	if (ret)
 		return ret;
-	return ima_read_file(file, id);
+	return ima_read_file(file, id, contents);
 }
 EXPORT_SYMBOL_GPL(security_kernel_read_file);
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 1a5c68196faf..6d183bbc12a6 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4004,13 +4004,14 @@ static int selinux_kernel_module_from_file(struct file *file)
 }
 
 static int selinux_kernel_read_file(struct file *file,
-				    enum kernel_read_file_id id)
+				    enum kernel_read_file_id id,
+				    bool contents)
 {
 	int rc = 0;
 
 	switch (id) {
 	case READING_MODULE:
-		rc = selinux_kernel_module_from_file(file);
+		rc = selinux_kernel_module_from_file(contents ? file : NULL);
 		break;
 	default:
 		break;
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 13/17] IMA: Add support for file reads without contents
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (11 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 12/17] LSM: Add "contents" flag to kernel_read_file hook Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-07-29 17:58 ` [PATCH v4 14/17] fs/kernel_file_read: Add "offset" arg for partial reads Kees Cook
                   ` (3 subsequent siblings)
  16 siblings, 0 replies; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

From: Scott Branden <scott.branden@broadcom.com>

When the kernel_read_file LSM hook is called with contents=false, IMA
can appraise the file directly, without requiring a filled buffer. When
such a buffer is available, though, IMA can continue to use it instead
of forcing a double read here.

Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Link: https://lore.kernel.org/lkml/20200706232309.12010-10-scott.branden@broadcom.com/
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 security/integrity/ima/ima_main.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index dc4f90660aa6..de57fce5bced 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -613,11 +613,8 @@ void ima_post_path_mknod(struct dentry *dentry)
 int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
 		  bool contents)
 {
-	/* Reject all partial reads during appraisal. */
-	if (!contents) {
-		if (ima_appraise & IMA_APPRAISE_ENFORCE)
-			return -EACCES;
-	}
+	enum ima_hooks func;
+	u32 secid;
 
 	/*
 	 * Do devices using pre-allocated memory run the risk of the
@@ -626,7 +623,20 @@ int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
 	 * buffers? It may be desirable to include the buffer address
 	 * in this API and walk all the dma_map_single() mappings to check.
 	 */
-	return 0;
+
+	/*
+	 * There will be a call made to ima_post_read_file() with
+	 * a filled buffer, so we don't need to perform an extra
+	 * read early here.
+	 */
+	if (contents)
+		return 0;
+
+	/* Read entire file for all partial reads. */
+	func = read_idmap[read_id] ?: FILE_CHECK;
+	security_task_getsecid(current, &secid);
+	return process_measurement(file, current_cred(), secid, NULL,
+				   0, MAY_READ, func);
 }
 
 const int read_idmap[READING_MAX_ID] = {
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 14/17] fs/kernel_file_read: Add "offset" arg for partial reads
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (12 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 13/17] IMA: Add support for file reads without contents Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-07-29 17:58 ` [PATCH v4 15/17] firmware: Store opt_flags in fw_priv Kees Cook
                   ` (2 subsequent siblings)
  16 siblings, 0 replies; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

To perform partial reads, callers of kernel_read_file*() must have a
non-NULL file_size argument and a preallocated buffer. The new "offset"
argument can then be used to seek to specific locations in the file to
fill the buffer to, at most, "buf_size" per call.

Where possible, the LSM hooks can report whether a full file has been
read or not so that the contents can be reasoned about.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/base/firmware_loader/main.c |  2 +-
 fs/kernel_read_file.c               | 78 ++++++++++++++++++++---------
 include/linux/kernel_read_file.h    |  8 +--
 kernel/kexec_file.c                 |  4 +-
 kernel/module.c                     |  2 +-
 security/integrity/digsig.c         |  2 +-
 security/integrity/ima/ima_fs.c     |  3 +-
 7 files changed, 65 insertions(+), 34 deletions(-)

diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 6a5d407279e3..ff1808ed7547 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -494,7 +494,7 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
 		fw_priv->size = 0;
 
 		/* load firmware files from the mount namespace of init */
-		rc = kernel_read_file_from_path_initns(path, &buffer, msize,
+		rc = kernel_read_file_from_path_initns(path, 0, &buffer, msize,
 						       NULL,
 						       READING_FIRMWARE);
 		if (rc < 0) {
diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c
index d73bc3fa710a..90d255fbdd9b 100644
--- a/fs/kernel_read_file.c
+++ b/fs/kernel_read_file.c
@@ -9,6 +9,7 @@
  * kernel_read_file() - read file contents into a kernel buffer
  *
  * @file	file to read from
+ * @offset	where to start reading from (see below).
  * @buf		pointer to a "void *" buffer for reading into (if
  *		*@buf is NULL, a buffer will be allocated, and
  *		@buf_size will be ignored)
@@ -19,19 +20,31 @@
  * @id		the kernel_read_file_id identifying the type of
  *		file contents being read (for LSMs to examine)
  *
+ * @offset must be 0 unless both @buf and @file_size are non-NULL
+ * (i.e. the caller must be expecting to read partial file contents
+ * via an already-allocated @buf, in at most @buf_size chunks, and
+ * will be able to determine when the entire file was read by
+ * checking @file_size). This isn't a recommended way to read a
+ * file, though, since it is possible that the contents might
+ * change between calls to kernel_read_file().
+ *
  * Returns number of bytes read (no single read will be bigger
  * than INT_MAX), or negative on error.
  *
  */
-int kernel_read_file(struct file *file, void **buf,
+int kernel_read_file(struct file *file, loff_t offset, void **buf,
 		     size_t buf_size, size_t *file_size,
 		     enum kernel_read_file_id id)
 {
 	loff_t i_size, pos;
-	ssize_t bytes = 0;
+	size_t copied;
 	void *allocated = NULL;
+	bool whole_file;
 	int ret;
 
+	if (offset != 0 && (!*buf || !file_size))
+		return -EINVAL;
+
 	if (!S_ISREG(file_inode(file)->i_mode))
 		return -EINVAL;
 
@@ -39,19 +52,27 @@ int kernel_read_file(struct file *file, void **buf,
 	if (ret)
 		return ret;
 
-	ret = security_kernel_read_file(file, id, true);
-	if (ret)
-		goto out;
-
 	i_size = i_size_read(file_inode(file));
 	if (i_size <= 0) {
 		ret = -EINVAL;
 		goto out;
 	}
-	if (i_size > INT_MAX || i_size > buf_size) {
+	/* The file is too big for sane activities. */
+	if (i_size > INT_MAX) {
+		ret = -EFBIG;
+		goto out;
+	}
+	/* The entire file cannot be read in one buffer. */
+	if (!file_size && offset == 0 && i_size > buf_size) {
 		ret = -EFBIG;
 		goto out;
 	}
+
+	whole_file = (offset == 0 && i_size <= buf_size);
+	ret = security_kernel_read_file(file, id, whole_file);
+	if (ret)
+		goto out;
+
 	if (file_size)
 		*file_size = i_size;
 
@@ -62,9 +83,14 @@ int kernel_read_file(struct file *file, void **buf,
 		goto out;
 	}
 
-	pos = 0;
-	while (pos < i_size) {
-		bytes = kernel_read(file, *buf + pos, i_size - pos, &pos);
+	pos = offset;
+	copied = 0;
+	while (copied < buf_size) {
+		ssize_t bytes;
+		size_t wanted = min_t(size_t, buf_size - copied,
+					      i_size - pos);
+
+		bytes = kernel_read(file, *buf + copied, wanted, &pos);
 		if (bytes < 0) {
 			ret = bytes;
 			goto out_free;
@@ -72,14 +98,17 @@ int kernel_read_file(struct file *file, void **buf,
 
 		if (bytes == 0)
 			break;
+		copied += bytes;
 	}
 
-	if (pos != i_size) {
-		ret = -EIO;
-		goto out_free;
-	}
+	if (whole_file) {
+		if (pos != i_size) {
+			ret = -EIO;
+			goto out_free;
+		}
 
-	ret = security_kernel_post_read_file(file, *buf, i_size, id);
+		ret = security_kernel_post_read_file(file, *buf, i_size, id);
+	}
 
 out_free:
 	if (ret < 0) {
@@ -91,11 +120,11 @@ int kernel_read_file(struct file *file, void **buf,
 
 out:
 	allow_write_access(file);
-	return ret == 0 ? pos : ret;
+	return ret == 0 ? copied : ret;
 }
 EXPORT_SYMBOL_GPL(kernel_read_file);
 
-int kernel_read_file_from_path(const char *path, void **buf,
+int kernel_read_file_from_path(const char *path, loff_t offset, void **buf,
 			       size_t buf_size, size_t *file_size,
 			       enum kernel_read_file_id id)
 {
@@ -109,14 +138,15 @@ int kernel_read_file_from_path(const char *path, void **buf,
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	ret = kernel_read_file(file, buf, buf_size, file_size, id);
+	ret = kernel_read_file(file, offset, buf, buf_size, file_size, id);
 	fput(file);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
 
-int kernel_read_file_from_path_initns(const char *path, void **buf,
-				      size_t buf_size, size_t *file_size,
+int kernel_read_file_from_path_initns(const char *path, loff_t offset,
+				      void **buf, size_t buf_size,
+				      size_t *file_size,
 				      enum kernel_read_file_id id)
 {
 	struct file *file;
@@ -135,14 +165,14 @@ int kernel_read_file_from_path_initns(const char *path, void **buf,
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	ret = kernel_read_file(file, buf, buf_size, file_size, id);
+	ret = kernel_read_file(file, offset, buf, buf_size, file_size, id);
 	fput(file);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns);
 
-int kernel_read_file_from_fd(int fd, void **buf, size_t buf_size,
-			     size_t *file_size,
+int kernel_read_file_from_fd(int fd, loff_t offset, void **buf,
+			     size_t buf_size, size_t *file_size,
 			     enum kernel_read_file_id id)
 {
 	struct fd f = fdget(fd);
@@ -151,7 +181,7 @@ int kernel_read_file_from_fd(int fd, void **buf, size_t buf_size,
 	if (!f.file)
 		goto out;
 
-	ret = kernel_read_file(f.file, buf, buf_size, file_size, id);
+	ret = kernel_read_file(f.file, offset, buf, buf_size, file_size, id);
 out:
 	fdput(f);
 	return ret;
diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h
index 023293eaf948..575ffa1031d3 100644
--- a/include/linux/kernel_read_file.h
+++ b/include/linux/kernel_read_file.h
@@ -35,19 +35,19 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
 	return kernel_read_file_str[id];
 }
 
-int kernel_read_file(struct file *file,
+int kernel_read_file(struct file *file, loff_t offset,
 		     void **buf, size_t buf_size,
 		     size_t *file_size,
 		     enum kernel_read_file_id id);
-int kernel_read_file_from_path(const char *path,
+int kernel_read_file_from_path(const char *path, loff_t offset,
 			       void **buf, size_t buf_size,
 			       size_t *file_size,
 			       enum kernel_read_file_id id);
-int kernel_read_file_from_path_initns(const char *path,
+int kernel_read_file_from_path_initns(const char *path, loff_t offset,
 				      void **buf, size_t buf_size,
 				      size_t *file_size,
 				      enum kernel_read_file_id id);
-int kernel_read_file_from_fd(int fd,
+int kernel_read_file_from_fd(int fd, loff_t offset,
 			     void **buf, size_t buf_size,
 			     size_t *file_size,
 			     enum kernel_read_file_id id);
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 878ca684a3a1..45726bc8f6ce 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -221,7 +221,7 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 	int ret;
 	void *ldata;
 
-	ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,
+	ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf,
 				       INT_MAX, NULL, READING_KEXEC_IMAGE);
 	if (ret < 0)
 		return ret;
@@ -241,7 +241,7 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 #endif
 	/* It is possible that there no initramfs is being loaded */
 	if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
-		ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf,
+		ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf,
 					       INT_MAX, NULL,
 					       READING_KEXEC_INITRAMFS);
 		if (ret < 0)
diff --git a/kernel/module.c b/kernel/module.c
index 72e33e25d7b9..a89900adeb6c 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4010,7 +4010,7 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
 		      |MODULE_INIT_IGNORE_VERMAGIC))
 		return -EINVAL;
 
-	err = kernel_read_file_from_fd(fd, &hdr, INT_MAX, NULL,
+	err = kernel_read_file_from_fd(fd, 0, &hdr, INT_MAX, NULL,
 				       READING_MODULE);
 	if (err < 0)
 		return err;
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 8a523dfd7fd7..0f518dcfde05 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -175,7 +175,7 @@ int __init integrity_load_x509(const unsigned int id, const char *path)
 	int rc;
 	key_perm_t perm;
 
-	rc = kernel_read_file_from_path(path, &data, INT_MAX, NULL,
+	rc = kernel_read_file_from_path(path, 0, &data, INT_MAX, NULL,
 					READING_X509_CERTIFICATE);
 	if (rc < 0) {
 		pr_err("Unable to open file: %s (%d)", path, rc);
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 5fc56ccb6678..ea8ff8a07b36 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -284,7 +284,8 @@ static ssize_t ima_read_policy(char *path)
 	datap = path;
 	strsep(&datap, "\n");
 
-	rc = kernel_read_file_from_path(path, &data, INT_MAX, NULL, READING_POLICY);
+	rc = kernel_read_file_from_path(path, 0, &data, INT_MAX, NULL,
+					READING_POLICY);
 	if (rc < 0) {
 		pr_err("Unable to open file: %s (%d)", path, rc);
 		return rc;
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 15/17] firmware: Store opt_flags in fw_priv
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (13 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 14/17] fs/kernel_file_read: Add "offset" arg for partial reads Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-07-29 17:58 ` [PATCH v4 16/17] firmware: Add request_partial_firmware_into_buf() Kees Cook
  2020-07-29 17:58 ` [PATCH v4 17/17] test_firmware: Test partial read support Kees Cook
  16 siblings, 0 replies; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

Instead of passing opt_flags around so much, store it in the private
structure so it can be examined by internals without needing to add more
arguments to functions.

Co-developed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/base/firmware_loader/fallback.c       | 11 +++-----
 drivers/base/firmware_loader/fallback.h       |  5 ++--
 .../base/firmware_loader/fallback_platform.c  |  4 +--
 drivers/base/firmware_loader/firmware.h       |  3 ++-
 drivers/base/firmware_loader/main.c           | 25 +++++++++++--------
 5 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
index 7cfdfdcb819c..0a94c8739959 100644
--- a/drivers/base/firmware_loader/fallback.c
+++ b/drivers/base/firmware_loader/fallback.c
@@ -490,13 +490,11 @@ fw_create_instance(struct firmware *firmware, const char *fw_name,
 /**
  * fw_load_sysfs_fallback() - load a firmware via the sysfs fallback mechanism
  * @fw_sysfs: firmware sysfs information for the firmware to load
- * @opt_flags: flags of options, FW_OPT_*
  * @timeout: timeout to wait for the load
  *
  * In charge of constructing a sysfs fallback interface for firmware loading.
  **/
-static int fw_load_sysfs_fallback(struct fw_sysfs *fw_sysfs,
-				  u32 opt_flags, long timeout)
+static int fw_load_sysfs_fallback(struct fw_sysfs *fw_sysfs, long timeout)
 {
 	int retval = 0;
 	struct device *f_dev = &fw_sysfs->dev;
@@ -518,7 +516,7 @@ static int fw_load_sysfs_fallback(struct fw_sysfs *fw_sysfs,
 	list_add(&fw_priv->pending_list, &pending_fw_head);
 	mutex_unlock(&fw_lock);
 
-	if (opt_flags & FW_OPT_UEVENT) {
+	if (fw_priv->opt_flags & FW_OPT_UEVENT) {
 		fw_priv->need_uevent = true;
 		dev_set_uevent_suppress(f_dev, false);
 		dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_name);
@@ -580,10 +578,10 @@ static int fw_load_from_user_helper(struct firmware *firmware,
 	}
 
 	fw_sysfs->fw_priv = firmware->priv;
-	ret = fw_load_sysfs_fallback(fw_sysfs, opt_flags, timeout);
+	ret = fw_load_sysfs_fallback(fw_sysfs, timeout);
 
 	if (!ret)
-		ret = assign_fw(firmware, device, opt_flags);
+		ret = assign_fw(firmware, device);
 
 out_unlock:
 	usermodehelper_read_unlock();
@@ -625,7 +623,6 @@ static bool fw_run_sysfs_fallback(u32 opt_flags)
  * @fw: pointer to firmware image
  * @name: name of firmware file to look for
  * @device: device for which firmware is being loaded
- * @opt_flags: options to control firmware loading behaviour
  * @ret: return value from direct lookup which triggered the fallback mechanism
  *
  * This function is called if direct lookup for the firmware failed, it enables
diff --git a/drivers/base/firmware_loader/fallback.h b/drivers/base/firmware_loader/fallback.h
index 2afdb6adb23f..3af7205b302f 100644
--- a/drivers/base/firmware_loader/fallback.h
+++ b/drivers/base/firmware_loader/fallback.h
@@ -67,10 +67,9 @@ static inline void unregister_sysfs_loader(void)
 #endif /* CONFIG_FW_LOADER_USER_HELPER */
 
 #ifdef CONFIG_EFI_EMBEDDED_FIRMWARE
-int firmware_fallback_platform(struct fw_priv *fw_priv, u32 opt_flags);
+int firmware_fallback_platform(struct fw_priv *fw_priv);
 #else
-static inline int firmware_fallback_platform(struct fw_priv *fw_priv,
-					     u32 opt_flags)
+static inline int firmware_fallback_platform(struct fw_priv *fw_priv)
 {
 	return -ENOENT;
 }
diff --git a/drivers/base/firmware_loader/fallback_platform.c b/drivers/base/firmware_loader/fallback_platform.c
index 4d1157af0e86..38de68d7e973 100644
--- a/drivers/base/firmware_loader/fallback_platform.c
+++ b/drivers/base/firmware_loader/fallback_platform.c
@@ -8,13 +8,13 @@
 #include "fallback.h"
 #include "firmware.h"
 
-int firmware_fallback_platform(struct fw_priv *fw_priv, u32 opt_flags)
+int firmware_fallback_platform(struct fw_priv *fw_priv)
 {
 	const u8 *data;
 	size_t size;
 	int rc;
 
-	if (!(opt_flags & FW_OPT_FALLBACK_PLATFORM))
+	if (!(fw_priv->opt_flags & FW_OPT_FALLBACK_PLATFORM))
 		return -ENOENT;
 
 	rc = security_kernel_load_data(LOADING_FIRMWARE, true);
diff --git a/drivers/base/firmware_loader/firmware.h b/drivers/base/firmware_loader/firmware.h
index 933e2192fbe8..7ad5fe52bc72 100644
--- a/drivers/base/firmware_loader/firmware.h
+++ b/drivers/base/firmware_loader/firmware.h
@@ -68,6 +68,7 @@ struct fw_priv {
 	void *data;
 	size_t size;
 	size_t allocated_size;
+	u32 opt_flags;
 #ifdef CONFIG_FW_LOADER_PAGED_BUF
 	bool is_paged_buf;
 	struct page **pages;
@@ -136,7 +137,7 @@ static inline void fw_state_done(struct fw_priv *fw_priv)
 	__fw_state_set(fw_priv, FW_STATUS_DONE);
 }
 
-int assign_fw(struct firmware *fw, struct device *device, u32 opt_flags);
+int assign_fw(struct firmware *fw, struct device *device);
 
 #ifdef CONFIG_FW_LOADER_PAGED_BUF
 void fw_free_paged_buf(struct fw_priv *fw_priv);
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index ff1808ed7547..67d8afa91ae0 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -168,7 +168,9 @@ static int fw_cache_piggyback_on_request(const char *name);
 
 static struct fw_priv *__allocate_fw_priv(const char *fw_name,
 					  struct firmware_cache *fwc,
-					  void *dbuf, size_t size)
+					  void *dbuf,
+					  size_t size,
+					  u32 opt_flags)
 {
 	struct fw_priv *fw_priv;
 
@@ -186,6 +188,7 @@ static struct fw_priv *__allocate_fw_priv(const char *fw_name,
 	fw_priv->fwc = fwc;
 	fw_priv->data = dbuf;
 	fw_priv->allocated_size = size;
+	fw_priv->opt_flags = opt_flags;
 	fw_state_init(fw_priv);
 #ifdef CONFIG_FW_LOADER_USER_HELPER
 	INIT_LIST_HEAD(&fw_priv->pending_list);
@@ -210,8 +213,10 @@ static struct fw_priv *__lookup_fw_priv(const char *fw_name)
 /* Returns 1 for batching firmware requests with the same name */
 static int alloc_lookup_fw_priv(const char *fw_name,
 				struct firmware_cache *fwc,
-				struct fw_priv **fw_priv, void *dbuf,
-				size_t size, u32 opt_flags)
+				struct fw_priv **fw_priv,
+				void *dbuf,
+				size_t size,
+				u32 opt_flags)
 {
 	struct fw_priv *tmp;
 
@@ -227,7 +232,7 @@ static int alloc_lookup_fw_priv(const char *fw_name,
 		}
 	}
 
-	tmp = __allocate_fw_priv(fw_name, fwc, dbuf, size);
+	tmp = __allocate_fw_priv(fw_name, fwc, dbuf, size, opt_flags);
 	if (tmp) {
 		INIT_LIST_HEAD(&tmp->list);
 		if (!(opt_flags & FW_OPT_NOCACHE))
@@ -635,7 +640,7 @@ static int fw_add_devm_name(struct device *dev, const char *name)
 }
 #endif
 
-int assign_fw(struct firmware *fw, struct device *device, u32 opt_flags)
+int assign_fw(struct firmware *fw, struct device *device)
 {
 	struct fw_priv *fw_priv = fw->priv;
 	int ret;
@@ -654,8 +659,8 @@ int assign_fw(struct firmware *fw, struct device *device, u32 opt_flags)
 	 * should be fixed in devres or driver core.
 	 */
 	/* don't cache firmware handled without uevent */
-	if (device && (opt_flags & FW_OPT_UEVENT) &&
-	    !(opt_flags & FW_OPT_NOCACHE)) {
+	if (device && (fw_priv->opt_flags & FW_OPT_UEVENT) &&
+	    !(fw_priv->opt_flags & FW_OPT_NOCACHE)) {
 		ret = fw_add_devm_name(device, fw_priv->fw_name);
 		if (ret) {
 			mutex_unlock(&fw_lock);
@@ -667,7 +672,7 @@ int assign_fw(struct firmware *fw, struct device *device, u32 opt_flags)
 	 * After caching firmware image is started, let it piggyback
 	 * on request firmware.
 	 */
-	if (!(opt_flags & FW_OPT_NOCACHE) &&
+	if (!(fw_priv->opt_flags & FW_OPT_NOCACHE) &&
 	    fw_priv->fwc->state == FW_LOADER_START_CACHE) {
 		if (fw_cache_piggyback_on_request(fw_priv->fw_name))
 			kref_get(&fw_priv->ref);
@@ -778,7 +783,7 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
 #endif
 
 	if (ret == -ENOENT)
-		ret = firmware_fallback_platform(fw->priv, opt_flags);
+		ret = firmware_fallback_platform(fw->priv);
 
 	if (ret) {
 		if (!(opt_flags & FW_OPT_NO_WARN))
@@ -787,7 +792,7 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
 				 name, ret);
 		ret = firmware_fallback_sysfs(fw, name, device, opt_flags, ret);
 	} else
-		ret = assign_fw(fw, device, opt_flags);
+		ret = assign_fw(fw, device);
 
  out:
 	if (ret < 0) {
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 16/17] firmware: Add request_partial_firmware_into_buf()
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (14 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 15/17] firmware: Store opt_flags in fw_priv Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  2020-07-29 17:58 ` [PATCH v4 17/17] test_firmware: Test partial read support Kees Cook
  16 siblings, 0 replies; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

From: Scott Branden <scott.branden@broadcom.com>

Add request_partial_firmware_into_buf() to allow for portions of a
firmware file to be read into a buffer. This is needed when large firmware
must be loaded in portions from a file on memory constrained systems.

Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/base/firmware_loader/firmware.h |   4 +
 drivers/base/firmware_loader/main.c     | 101 +++++++++++++++++++-----
 include/linux/firmware.h                |  12 +++
 3 files changed, 99 insertions(+), 18 deletions(-)

diff --git a/drivers/base/firmware_loader/firmware.h b/drivers/base/firmware_loader/firmware.h
index 7ad5fe52bc72..3f6eda46b3a2 100644
--- a/drivers/base/firmware_loader/firmware.h
+++ b/drivers/base/firmware_loader/firmware.h
@@ -32,6 +32,8 @@
  * @FW_OPT_FALLBACK_PLATFORM: Enable fallback to device fw copy embedded in
  *	the platform's main firmware. If both this fallback and the sysfs
  *      fallback are enabled, then this fallback will be tried first.
+ * @FW_OPT_PARTIAL: Allow partial read of firmware instead of needing to read
+ *	entire file.
  */
 enum fw_opt {
 	FW_OPT_UEVENT			= BIT(0),
@@ -41,6 +43,7 @@ enum fw_opt {
 	FW_OPT_NOCACHE			= BIT(4),
 	FW_OPT_NOFALLBACK_SYSFS		= BIT(5),
 	FW_OPT_FALLBACK_PLATFORM	= BIT(6),
+	FW_OPT_PARTIAL			= BIT(7),
 };
 
 enum fw_status {
@@ -68,6 +71,7 @@ struct fw_priv {
 	void *data;
 	size_t size;
 	size_t allocated_size;
+	size_t offset;
 	u32 opt_flags;
 #ifdef CONFIG_FW_LOADER_PAGED_BUF
 	bool is_paged_buf;
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 67d8afa91ae0..54c5d57b6327 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -170,10 +170,19 @@ static struct fw_priv *__allocate_fw_priv(const char *fw_name,
 					  struct firmware_cache *fwc,
 					  void *dbuf,
 					  size_t size,
+					  size_t offset,
 					  u32 opt_flags)
 {
 	struct fw_priv *fw_priv;
 
+	/* For a partial read, the buffer must be preallocated. */
+	if ((opt_flags & FW_OPT_PARTIAL) && !dbuf)
+		return NULL;
+
+	/* Only partial reads are allowed to use an offset. */
+	if (offset != 0 && !(opt_flags & FW_OPT_PARTIAL))
+		return NULL;
+
 	fw_priv = kzalloc(sizeof(*fw_priv), GFP_ATOMIC);
 	if (!fw_priv)
 		return NULL;
@@ -188,6 +197,7 @@ static struct fw_priv *__allocate_fw_priv(const char *fw_name,
 	fw_priv->fwc = fwc;
 	fw_priv->data = dbuf;
 	fw_priv->allocated_size = size;
+	fw_priv->offset = offset;
 	fw_priv->opt_flags = opt_flags;
 	fw_state_init(fw_priv);
 #ifdef CONFIG_FW_LOADER_USER_HELPER
@@ -216,12 +226,17 @@ static int alloc_lookup_fw_priv(const char *fw_name,
 				struct fw_priv **fw_priv,
 				void *dbuf,
 				size_t size,
+				size_t offset,
 				u32 opt_flags)
 {
 	struct fw_priv *tmp;
 
 	spin_lock(&fwc->lock);
-	if (!(opt_flags & FW_OPT_NOCACHE)) {
+	/*
+	 * Do not merge requests that are marked to be non-cached or
+	 * are performing partial reads.
+	 */
+	if (!(opt_flags & (FW_OPT_NOCACHE | FW_OPT_PARTIAL))) {
 		tmp = __lookup_fw_priv(fw_name);
 		if (tmp) {
 			kref_get(&tmp->ref);
@@ -232,7 +247,7 @@ static int alloc_lookup_fw_priv(const char *fw_name,
 		}
 	}
 
-	tmp = __allocate_fw_priv(fw_name, fwc, dbuf, size, opt_flags);
+	tmp = __allocate_fw_priv(fw_name, fwc, dbuf, size, offset, opt_flags);
 	if (tmp) {
 		INIT_LIST_HEAD(&tmp->list);
 		if (!(opt_flags & FW_OPT_NOCACHE))
@@ -485,6 +500,9 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
 		return -ENOMEM;
 
 	for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
+		size_t file_size = 0;
+		size_t *file_size_ptr = NULL;
+
 		/* skip the unset customized path */
 		if (!fw_path[i][0])
 			continue;
@@ -498,9 +516,18 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
 
 		fw_priv->size = 0;
 
+		/*
+		 * The total file size is only examined when doing a partial
+		 * read; the "full read" case needs to fail if the whole
+		 * firmware was not completely loaded.
+		 */
+		if ((fw_priv->opt_flags & FW_OPT_PARTIAL) && buffer)
+			file_size_ptr = &file_size;
+
 		/* load firmware files from the mount namespace of init */
-		rc = kernel_read_file_from_path_initns(path, 0, &buffer, msize,
-						       NULL,
+		rc = kernel_read_file_from_path_initns(path, fw_priv->offset,
+						       &buffer, msize,
+						       file_size_ptr,
 						       READING_FIRMWARE);
 		if (rc < 0) {
 			if (rc != -ENOENT)
@@ -691,7 +718,7 @@ int assign_fw(struct firmware *fw, struct device *device)
 static int
 _request_firmware_prepare(struct firmware **firmware_p, const char *name,
 			  struct device *device, void *dbuf, size_t size,
-			  u32 opt_flags)
+			  size_t offset, u32 opt_flags)
 {
 	struct firmware *firmware;
 	struct fw_priv *fw_priv;
@@ -710,7 +737,7 @@ _request_firmware_prepare(struct firmware **firmware_p, const char *name,
 	}
 
 	ret = alloc_lookup_fw_priv(name, &fw_cache, &fw_priv, dbuf, size,
-				  opt_flags);
+				   offset, opt_flags);
 
 	/*
 	 * bind with 'priv' now to avoid warning in failure path
@@ -757,9 +784,10 @@ static void fw_abort_batch_reqs(struct firmware *fw)
 static int
 _request_firmware(const struct firmware **firmware_p, const char *name,
 		  struct device *device, void *buf, size_t size,
-		  u32 opt_flags)
+		  size_t offset, u32 opt_flags)
 {
 	struct firmware *fw = NULL;
+	bool nondirect = false;
 	int ret;
 
 	if (!firmware_p)
@@ -771,18 +799,22 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
 	}
 
 	ret = _request_firmware_prepare(&fw, name, device, buf, size,
-					opt_flags);
+					offset, opt_flags);
 	if (ret <= 0) /* error or already assigned */
 		goto out;
 
 	ret = fw_get_filesystem_firmware(device, fw->priv, "", NULL);
+
+	/* Only full reads can support decompression, platform, and sysfs. */
+	if (!(opt_flags & FW_OPT_PARTIAL))
+		nondirect = true;
+
 #ifdef CONFIG_FW_LOADER_COMPRESS
-	if (ret == -ENOENT)
+	if (ret == -ENOENT && nondirect)
 		ret = fw_get_filesystem_firmware(device, fw->priv, ".xz",
 						 fw_decompress_xz);
 #endif
-
-	if (ret == -ENOENT)
+	if (ret == -ENOENT && nondirect)
 		ret = firmware_fallback_platform(fw->priv);
 
 	if (ret) {
@@ -790,7 +822,9 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
 			dev_warn(device,
 				 "Direct firmware load for %s failed with error %d\n",
 				 name, ret);
-		ret = firmware_fallback_sysfs(fw, name, device, opt_flags, ret);
+		if (nondirect)
+			ret = firmware_fallback_sysfs(fw, name, device,
+						      opt_flags, ret);
 	} else
 		ret = assign_fw(fw, device);
 
@@ -833,7 +867,7 @@ request_firmware(const struct firmware **firmware_p, const char *name,
 
 	/* Need to pin this module until return */
 	__module_get(THIS_MODULE);
-	ret = _request_firmware(firmware_p, name, device, NULL, 0,
+	ret = _request_firmware(firmware_p, name, device, NULL, 0, 0,
 				FW_OPT_UEVENT);
 	module_put(THIS_MODULE);
 	return ret;
@@ -860,7 +894,7 @@ int firmware_request_nowarn(const struct firmware **firmware, const char *name,
 
 	/* Need to pin this module until return */
 	__module_get(THIS_MODULE);
-	ret = _request_firmware(firmware, name, device, NULL, 0,
+	ret = _request_firmware(firmware, name, device, NULL, 0, 0,
 				FW_OPT_UEVENT | FW_OPT_NO_WARN);
 	module_put(THIS_MODULE);
 	return ret;
@@ -884,7 +918,7 @@ int request_firmware_direct(const struct firmware **firmware_p,
 	int ret;
 
 	__module_get(THIS_MODULE);
-	ret = _request_firmware(firmware_p, name, device, NULL, 0,
+	ret = _request_firmware(firmware_p, name, device, NULL, 0, 0,
 				FW_OPT_UEVENT | FW_OPT_NO_WARN |
 				FW_OPT_NOFALLBACK_SYSFS);
 	module_put(THIS_MODULE);
@@ -909,7 +943,7 @@ int firmware_request_platform(const struct firmware **firmware,
 
 	/* Need to pin this module until return */
 	__module_get(THIS_MODULE);
-	ret = _request_firmware(firmware, name, device, NULL, 0,
+	ret = _request_firmware(firmware, name, device, NULL, 0, 0,
 				FW_OPT_UEVENT | FW_OPT_FALLBACK_PLATFORM);
 	module_put(THIS_MODULE);
 	return ret;
@@ -965,13 +999,44 @@ request_firmware_into_buf(const struct firmware **firmware_p, const char *name,
 		return -EOPNOTSUPP;
 
 	__module_get(THIS_MODULE);
-	ret = _request_firmware(firmware_p, name, device, buf, size,
+	ret = _request_firmware(firmware_p, name, device, buf, size, 0,
 				FW_OPT_UEVENT | FW_OPT_NOCACHE);
 	module_put(THIS_MODULE);
 	return ret;
 }
 EXPORT_SYMBOL(request_firmware_into_buf);
 
+/**
+ * request_partial_firmware_into_buf() - load partial firmware into a previously allocated buffer
+ * @firmware_p: pointer to firmware image
+ * @name: name of firmware file
+ * @device: device for which firmware is being loaded and DMA region allocated
+ * @buf: address of buffer to load firmware into
+ * @size: size of buffer
+ * @offset: offset into file to read
+ *
+ * This function works pretty much like request_firmware_into_buf except
+ * it allows a partial read of the file.
+ */
+int
+request_partial_firmware_into_buf(const struct firmware **firmware_p,
+				  const char *name, struct device *device,
+				  void *buf, size_t size, size_t offset)
+{
+	int ret;
+
+	if (fw_cache_is_setup(device, name))
+		return -EOPNOTSUPP;
+
+	__module_get(THIS_MODULE);
+	ret = _request_firmware(firmware_p, name, device, buf, size, offset,
+				FW_OPT_UEVENT | FW_OPT_NOCACHE |
+				FW_OPT_PARTIAL);
+	module_put(THIS_MODULE);
+	return ret;
+}
+EXPORT_SYMBOL(request_partial_firmware_into_buf);
+
 /**
  * release_firmware() - release the resource associated with a firmware image
  * @fw: firmware resource to release
@@ -1004,7 +1069,7 @@ static void request_firmware_work_func(struct work_struct *work)
 
 	fw_work = container_of(work, struct firmware_work, work);
 
-	_request_firmware(&fw, fw_work->name, fw_work->device, NULL, 0,
+	_request_firmware(&fw, fw_work->name, fw_work->device, NULL, 0, 0,
 			  fw_work->opt_flags);
 	fw_work->cont(fw, fw_work->context);
 	put_device(fw_work->device); /* taken in request_firmware_nowait() */
diff --git a/include/linux/firmware.h b/include/linux/firmware.h
index cb3e2c06ed8a..c15acadc6cf4 100644
--- a/include/linux/firmware.h
+++ b/include/linux/firmware.h
@@ -53,6 +53,9 @@ int request_firmware_direct(const struct firmware **fw, const char *name,
 			    struct device *device);
 int request_firmware_into_buf(const struct firmware **firmware_p,
 	const char *name, struct device *device, void *buf, size_t size);
+int request_partial_firmware_into_buf(const struct firmware **firmware_p,
+				      const char *name, struct device *device,
+				      void *buf, size_t size, size_t offset);
 
 void release_firmware(const struct firmware *fw);
 #else
@@ -102,6 +105,15 @@ static inline int request_firmware_into_buf(const struct firmware **firmware_p,
 	return -EINVAL;
 }
 
+static inline int request_partial_firmware_into_buf
+					(const struct firmware **firmware_p,
+					 const char *name,
+					 struct device *device,
+					 void *buf, size_t size, size_t offset)
+{
+	return -EINVAL;
+}
+
 #endif
 
 int firmware_request_cache(struct device *device, const char *name);
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* [PATCH v4 17/17] test_firmware: Test partial read support
  2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
                   ` (15 preceding siblings ...)
  2020-07-29 17:58 ` [PATCH v4 16/17] firmware: Add request_partial_firmware_into_buf() Kees Cook
@ 2020-07-29 17:58 ` Kees Cook
  16 siblings, 0 replies; 28+ messages in thread
From: Kees Cook @ 2020-07-29 17:58 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

From: Scott Branden <scott.branden@broadcom.com>

Add additional hooks to test_firmware to pass in support
for partial file read using request_firmware_into_buf():

	buf_size: size of buffer to request firmware into
	partial: indicates that a partial file request is being made
	file_offset: to indicate offset into file to request

Also update firmware selftests to use the new partial read test API.

Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 lib/test_firmware.c                           | 154 ++++++++++++++++--
 .../selftests/firmware/fw_filesystem.sh       |  91 +++++++++++
 2 files changed, 233 insertions(+), 12 deletions(-)

diff --git a/lib/test_firmware.c b/lib/test_firmware.c
index 62af792e151c..387acb94eeea 100644
--- a/lib/test_firmware.c
+++ b/lib/test_firmware.c
@@ -50,6 +50,9 @@ struct test_batched_req {
  * @name: the name of the firmware file to look for
  * @into_buf: when the into_buf is used if this is true
  *	request_firmware_into_buf() will be used instead.
+ * @buf_size: size of buf to allocate when into_buf is true
+ * @file_offset: file offset to request when calling request_firmware_into_buf
+ * @partial: partial read opt when calling request_firmware_into_buf
  * @sync_direct: when the sync trigger is used if this is true
  *	request_firmware_direct() will be used instead.
  * @send_uevent: whether or not to send a uevent for async requests
@@ -89,6 +92,9 @@ struct test_batched_req {
 struct test_config {
 	char *name;
 	bool into_buf;
+	size_t buf_size;
+	size_t file_offset;
+	bool partial;
 	bool sync_direct;
 	bool send_uevent;
 	u8 num_requests;
@@ -183,6 +189,9 @@ static int __test_firmware_config_init(void)
 	test_fw_config->num_requests = TEST_FIRMWARE_NUM_REQS;
 	test_fw_config->send_uevent = true;
 	test_fw_config->into_buf = false;
+	test_fw_config->buf_size = TEST_FIRMWARE_BUF_SIZE;
+	test_fw_config->file_offset = 0;
+	test_fw_config->partial = false;
 	test_fw_config->sync_direct = false;
 	test_fw_config->req_firmware = request_firmware;
 	test_fw_config->test_result = 0;
@@ -236,28 +245,35 @@ static ssize_t config_show(struct device *dev,
 			dev_name(dev));
 
 	if (test_fw_config->name)
-		len += scnprintf(buf+len, PAGE_SIZE - len,
+		len += scnprintf(buf + len, PAGE_SIZE - len,
 				"name:\t%s\n",
 				test_fw_config->name);
 	else
-		len += scnprintf(buf+len, PAGE_SIZE - len,
+		len += scnprintf(buf + len, PAGE_SIZE - len,
 				"name:\tEMTPY\n");
 
-	len += scnprintf(buf+len, PAGE_SIZE - len,
+	len += scnprintf(buf + len, PAGE_SIZE - len,
 			"num_requests:\t%u\n", test_fw_config->num_requests);
 
-	len += scnprintf(buf+len, PAGE_SIZE - len,
+	len += scnprintf(buf + len, PAGE_SIZE - len,
 			"send_uevent:\t\t%s\n",
 			test_fw_config->send_uevent ?
 			"FW_ACTION_HOTPLUG" :
 			"FW_ACTION_NOHOTPLUG");
-	len += scnprintf(buf+len, PAGE_SIZE - len,
+	len += scnprintf(buf + len, PAGE_SIZE - len,
 			"into_buf:\t\t%s\n",
 			test_fw_config->into_buf ? "true" : "false");
-	len += scnprintf(buf+len, PAGE_SIZE - len,
+	len += scnprintf(buf + len, PAGE_SIZE - len,
+			"buf_size:\t%zu\n", test_fw_config->buf_size);
+	len += scnprintf(buf + len, PAGE_SIZE - len,
+			"file_offset:\t%zu\n", test_fw_config->file_offset);
+	len += scnprintf(buf + len, PAGE_SIZE - len,
+			"partial:\t\t%s\n",
+			test_fw_config->partial ? "true" : "false");
+	len += scnprintf(buf + len, PAGE_SIZE - len,
 			"sync_direct:\t\t%s\n",
 			test_fw_config->sync_direct ? "true" : "false");
-	len += scnprintf(buf+len, PAGE_SIZE - len,
+	len += scnprintf(buf + len, PAGE_SIZE - len,
 			"read_fw_idx:\t%u\n", test_fw_config->read_fw_idx);
 
 	mutex_unlock(&test_fw_mutex);
@@ -315,6 +331,30 @@ static ssize_t test_dev_config_show_bool(char *buf, bool val)
 	return snprintf(buf, PAGE_SIZE, "%d\n", val);
 }
 
+static int test_dev_config_update_size_t(const char *buf,
+					 size_t size,
+					 size_t *cfg)
+{
+	int ret;
+	long new;
+
+	ret = kstrtol(buf, 10, &new);
+	if (ret)
+		return ret;
+
+	mutex_lock(&test_fw_mutex);
+	*(size_t *)cfg = new;
+	mutex_unlock(&test_fw_mutex);
+
+	/* Always return full write size even if we didn't consume all */
+	return size;
+}
+
+static ssize_t test_dev_config_show_size_t(char *buf, size_t val)
+{
+	return snprintf(buf, PAGE_SIZE, "%zu\n", val);
+}
+
 static ssize_t test_dev_config_show_int(char *buf, int val)
 {
 	return snprintf(buf, PAGE_SIZE, "%d\n", val);
@@ -400,6 +440,83 @@ static ssize_t config_into_buf_show(struct device *dev,
 }
 static DEVICE_ATTR_RW(config_into_buf);
 
+static ssize_t config_buf_size_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	int rc;
+
+	mutex_lock(&test_fw_mutex);
+	if (test_fw_config->reqs) {
+		pr_err("Must call release_all_firmware prior to changing config\n");
+		rc = -EINVAL;
+		mutex_unlock(&test_fw_mutex);
+		goto out;
+	}
+	mutex_unlock(&test_fw_mutex);
+
+	rc = test_dev_config_update_size_t(buf, count,
+					   &test_fw_config->buf_size);
+
+out:
+	return rc;
+}
+
+static ssize_t config_buf_size_show(struct device *dev,
+				    struct device_attribute *attr,
+				    char *buf)
+{
+	return test_dev_config_show_size_t(buf, test_fw_config->buf_size);
+}
+static DEVICE_ATTR_RW(config_buf_size);
+
+static ssize_t config_file_offset_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t count)
+{
+	int rc;
+
+	mutex_lock(&test_fw_mutex);
+	if (test_fw_config->reqs) {
+		pr_err("Must call release_all_firmware prior to changing config\n");
+		rc = -EINVAL;
+		mutex_unlock(&test_fw_mutex);
+		goto out;
+	}
+	mutex_unlock(&test_fw_mutex);
+
+	rc = test_dev_config_update_size_t(buf, count,
+					   &test_fw_config->file_offset);
+
+out:
+	return rc;
+}
+
+static ssize_t config_file_offset_show(struct device *dev,
+				       struct device_attribute *attr,
+				       char *buf)
+{
+	return test_dev_config_show_size_t(buf, test_fw_config->file_offset);
+}
+static DEVICE_ATTR_RW(config_file_offset);
+
+static ssize_t config_partial_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t count)
+{
+	return test_dev_config_update_bool(buf,
+					   count,
+					   &test_fw_config->partial);
+}
+
+static ssize_t config_partial_show(struct device *dev,
+				   struct device_attribute *attr,
+				   char *buf)
+{
+	return test_dev_config_show_bool(buf, test_fw_config->partial);
+}
+static DEVICE_ATTR_RW(config_partial);
+
 static ssize_t config_sync_direct_store(struct device *dev,
 					struct device_attribute *attr,
 					const char *buf, size_t count)
@@ -655,11 +772,21 @@ static int test_fw_run_batch_request(void *data)
 		if (!test_buf)
 			return -ENOSPC;
 
-		req->rc = request_firmware_into_buf(&req->fw,
-						    req->name,
-						    req->dev,
-						    test_buf,
-						    TEST_FIRMWARE_BUF_SIZE);
+		if (test_fw_config->partial)
+			req->rc = request_partial_firmware_into_buf
+						(&req->fw,
+						 req->name,
+						 req->dev,
+						 test_buf,
+						 test_fw_config->buf_size,
+						 test_fw_config->file_offset);
+		else
+			req->rc = request_firmware_into_buf
+						(&req->fw,
+						 req->name,
+						 req->dev,
+						 test_buf,
+						 test_fw_config->buf_size);
 		if (!req->fw)
 			kfree(test_buf);
 	} else {
@@ -932,6 +1059,9 @@ static struct attribute *test_dev_attrs[] = {
 	TEST_FW_DEV_ATTR(config_name),
 	TEST_FW_DEV_ATTR(config_num_requests),
 	TEST_FW_DEV_ATTR(config_into_buf),
+	TEST_FW_DEV_ATTR(config_buf_size),
+	TEST_FW_DEV_ATTR(config_file_offset),
+	TEST_FW_DEV_ATTR(config_partial),
 	TEST_FW_DEV_ATTR(config_sync_direct),
 	TEST_FW_DEV_ATTR(config_send_uevent),
 	TEST_FW_DEV_ATTR(config_read_fw_idx),
diff --git a/tools/testing/selftests/firmware/fw_filesystem.sh b/tools/testing/selftests/firmware/fw_filesystem.sh
index fcc281373b4d..c2a2a100114b 100755
--- a/tools/testing/selftests/firmware/fw_filesystem.sh
+++ b/tools/testing/selftests/firmware/fw_filesystem.sh
@@ -149,6 +149,26 @@ config_unset_into_buf()
 	echo 0 >  $DIR/config_into_buf
 }
 
+config_set_buf_size()
+{
+	echo $1 >  $DIR/config_buf_size
+}
+
+config_set_file_offset()
+{
+	echo $1 >  $DIR/config_file_offset
+}
+
+config_set_partial()
+{
+	echo 1 >  $DIR/config_partial
+}
+
+config_unset_partial()
+{
+	echo 0 >  $DIR/config_partial
+}
+
 config_set_sync_direct()
 {
 	echo 1 >  $DIR/config_sync_direct
@@ -207,6 +227,35 @@ read_firmwares()
 	done
 }
 
+read_partial_firmwares()
+{
+	if [ "$(cat $DIR/config_into_buf)" == "1" ]; then
+		fwfile="${FW_INTO_BUF}"
+	else
+		fwfile="${FW}"
+	fi
+
+	if [ "$1" = "xzonly" ]; then
+		fwfile="${fwfile}-orig"
+	fi
+
+	# Strip fwfile down to match partial offset and length
+	partial_data="$(cat $fwfile)"
+	partial_data="${partial_data:$2:$3}"
+
+	for i in $(seq 0 3); do
+		config_set_read_fw_idx $i
+
+		read_firmware="$(cat $DIR/read_firmware)"
+
+		# Verify the contents are what we expect.
+		if [ $read_firmware != $partial_data ]; then
+			echo "request #$i: partial firmware was not loaded" >&2
+			exit 1
+		fi
+	done
+}
+
 read_firmwares_expect_nofile()
 {
 	for i in $(seq 0 3); do
@@ -242,6 +291,21 @@ test_batched_request_firmware_into_buf_nofile()
 	echo "OK"
 }
 
+test_request_partial_firmware_into_buf_nofile()
+{
+	echo -n "Test request_partial_firmware_into_buf() off=$1 size=$2 nofile: "
+	config_reset
+	config_set_name nope-test-firmware.bin
+	config_set_into_buf
+	config_set_partial
+	config_set_buf_size $2
+	config_set_file_offset $1
+	config_trigger_sync
+	read_firmwares_expect_nofile
+	release_all_firmware
+	echo "OK"
+}
+
 test_batched_request_firmware_direct_nofile()
 {
 	echo -n "Batched request_firmware_direct() nofile try #$1: "
@@ -356,6 +420,21 @@ test_request_firmware_nowait_custom()
 	echo "OK"
 }
 
+test_request_partial_firmware_into_buf()
+{
+	echo -n "Test request_partial_firmware_into_buf() off=$1 size=$2: "
+	config_reset
+	config_set_name $TEST_FIRMWARE_INTO_BUF_FILENAME
+	config_set_into_buf
+	config_set_partial
+	config_set_buf_size $2
+	config_set_file_offset $1
+	config_trigger_sync
+	read_partial_firmwares normal $1 $2
+	release_all_firmware
+	echo "OK"
+}
+
 # Only continue if batched request triggers are present on the
 # test-firmware driver
 test_config_present
@@ -383,6 +462,12 @@ for i in $(seq 1 5); do
 	test_request_firmware_nowait_custom $i normal
 done
 
+# Partial loads cannot use fallback, so do not repeat tests.
+test_request_partial_firmware_into_buf 0 10
+test_request_partial_firmware_into_buf 0 5
+test_request_partial_firmware_into_buf 1 6
+test_request_partial_firmware_into_buf 2 10
+
 # Test for file not found, errors are expected, the failure would be
 # a hung task, which would require a hard reset.
 echo
@@ -407,6 +492,12 @@ for i in $(seq 1 5); do
 	test_request_firmware_nowait_custom_nofile $i
 done
 
+# Partial loads cannot use fallback, so do not repeat tests.
+test_request_partial_firmware_into_buf_nofile 0 10
+test_request_partial_firmware_into_buf_nofile 0 5
+test_request_partial_firmware_into_buf_nofile 1 6
+test_request_partial_firmware_into_buf_nofile 2 10
+
 test "$HAS_FW_LOADER_COMPRESS" != "yes" && exit 0
 
 # test with both files present
-- 
2.25.1


^ permalink raw reply	[flat|nested] 28+ messages in thread

* Re: [PATCH v4 04/17] fs/kernel_read_file: Split into separate include file
  2020-07-29 17:58 ` [PATCH v4 04/17] fs/kernel_read_file: Split into separate include file Kees Cook
@ 2020-07-30  2:22   ` James Morris
  0 siblings, 0 replies; 28+ messages in thread
From: James Morris @ 2020-07-30  2:22 UTC (permalink / raw)
  To: Kees Cook
  Cc: Greg Kroah-Hartman, Scott Branden, Christoph Hellwig, Mimi Zohar,
	Luis Chamberlain, Takashi Iwai, Jessica Yu, SeongJae Park,
	KP Singh, linux-efi, linux-security-module, linux-integrity,
	selinux, linux-kselftest, linux-kernel

On Wed, 29 Jul 2020, Kees Cook wrote:

> From: Scott Branden <scott.branden@broadcom.com>
> 
> Move kernel_read_file* out of linux/fs.h to its own linux/kernel_read_file.h
> include file. That header gets pulled in just about everywhere
> and doesn't really need functions not related to the general fs interface.
> 
> Suggested-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Scott Branden <scott.branden@broadcom.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Link: https://lore.kernel.org/r/20200706232309.12010-2-scott.branden@broadcom.com
> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
> Signed-off-by: Kees Cook <keescook@chromium.org>


Acked-by: James Morris <jamorris@linux.microsoft.com>


-- 
James Morris
<jmorris@namei.org>


^ permalink raw reply	[flat|nested] 28+ messages in thread

* Re: [PATCH v4 06/17] fs/kernel_read_file: Remove redundant size argument
  2020-07-29 17:58 ` [PATCH v4 06/17] fs/kernel_read_file: Remove redundant size argument Kees Cook
@ 2020-07-30  2:25   ` James Morris
  0 siblings, 0 replies; 28+ messages in thread
From: James Morris @ 2020-07-30  2:25 UTC (permalink / raw)
  To: Kees Cook
  Cc: Greg Kroah-Hartman, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

On Wed, 29 Jul 2020, Kees Cook wrote:

> In preparation for refactoring kernel_read_file*(), remove the redundant
> "size" argument which is not needed: it can be included in the return
> code, with callers adjusted. (VFS reads already cannot be larger than
> INT_MAX.)
> 
> Acked-by: Scott Branden <scott.branden@broadcom.com>
> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: James Morris <jamorris@linux.microsoft.com>

-- 
James Morris
<jmorris@namei.org>


^ permalink raw reply	[flat|nested] 28+ messages in thread

* Re: [PATCH v4 07/17] fs/kernel_read_file: Switch buffer size arg to size_t
  2020-07-29 17:58 ` [PATCH v4 07/17] fs/kernel_read_file: Switch buffer size arg to size_t Kees Cook
@ 2020-07-30  2:25   ` James Morris
  0 siblings, 0 replies; 28+ messages in thread
From: James Morris @ 2020-07-30  2:25 UTC (permalink / raw)
  To: Kees Cook
  Cc: Greg Kroah-Hartman, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

On Wed, 29 Jul 2020, Kees Cook wrote:

> In preparation for further refactoring of kernel_read_file*(), rename
> the "max_size" argument to the more accurate "buf_size", and correct
> its type to size_t. Add kerndoc to explain the specifics of how the
> arguments will be used. Note that with buf_size now size_t, it can no
> longer be negative (and was never called with a negative value). Adjust
> callers to use it as a "maximum size" when *buf is NULL.
> 
> Acked-by: Scott Branden <scott.branden@broadcom.com>
> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
> Signed-off-by: Kees Cook <keescook@chromium.org>


Reviewed-by: James Morris <jamorris@linux.microsoft.com>


-- 
James Morris
<jmorris@namei.org>


^ permalink raw reply	[flat|nested] 28+ messages in thread

* Re: [PATCH v4 08/17] fs/kernel_read_file: Add file_size output argument
  2020-07-29 17:58 ` [PATCH v4 08/17] fs/kernel_read_file: Add file_size output argument Kees Cook
@ 2020-07-30  2:26   ` James Morris
  0 siblings, 0 replies; 28+ messages in thread
From: James Morris @ 2020-07-30  2:26 UTC (permalink / raw)
  To: Kees Cook
  Cc: Greg Kroah-Hartman, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

On Wed, 29 Jul 2020, Kees Cook wrote:

> In preparation for adding partial read support, add an optional output
> argument to kernel_read_file*() that reports the file size so callers
> can reason more easily about their reading progress.
> 
> Acked-by: Scott Branden <scott.branden@broadcom.com>
> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
> Signed-off-by: Kees Cook <keescook@chromium.org>


Reviewed-by: James Morris <jamorris@linux.microsoft.com>


-- 
James Morris
<jmorris@namei.org>


^ permalink raw reply	[flat|nested] 28+ messages in thread

* Re: [PATCH v4 11/17] module: Call security_kernel_post_load_data()
  2020-07-29 17:58 ` [PATCH v4 11/17] module: Call security_kernel_post_load_data() Kees Cook
@ 2020-08-05 14:53   ` Jessica Yu
  2020-08-07  0:22     ` KP Singh
  0 siblings, 1 reply; 28+ messages in thread
From: Jessica Yu @ 2020-08-05 14:53 UTC (permalink / raw)
  To: Kees Cook
  Cc: Greg Kroah-Hartman, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, SeongJae Park, KP Singh, linux-efi,
	linux-security-module, linux-integrity, selinux, linux-kselftest,
	linux-kernel

+++ Kees Cook [29/07/20 10:58 -0700]:
>Now that there is an API for checking loaded contents for modules
>loaded without a file, call into the LSM hooks.
>
>Cc: Jessica Yu <jeyu@kernel.org>
>Signed-off-by: Kees Cook <keescook@chromium.org>

Acked-by: Jessica Yu <jeyu@kernel.org>

^ permalink raw reply	[flat|nested] 28+ messages in thread

* Re: [PATCH v4 09/17] LSM: Introduce kernel_post_load_data() hook
  2020-07-29 17:58 ` [PATCH v4 09/17] LSM: Introduce kernel_post_load_data() hook Kees Cook
@ 2020-08-06 21:59   ` Mimi Zohar
  2020-08-07  0:21   ` KP Singh
  1 sibling, 0 replies; 28+ messages in thread
From: Mimi Zohar @ 2020-08-06 21:59 UTC (permalink / raw)
  To: Kees Cook, Greg Kroah-Hartman
  Cc: Scott Branden, Luis Chamberlain, Takashi Iwai, Jessica Yu,
	SeongJae Park, KP Singh, linux-efi, linux-security-module,
	linux-integrity, selinux, linux-kselftest, linux-kernel

On Wed, 2020-07-29 at 10:58 -0700, Kees Cook wrote:
> There are a few places in the kernel where LSMs would like to have
> visibility into the contents of a kernel buffer that has been loaded or
> read. While security_kernel_post_read_file() (which includes the
> buffer) exists as a pairing for security_kernel_read_file(), no such
> hook exists to pair with security_kernel_load_data().
> 
> Earlier proposals for just using security_kernel_post_read_file() with a
> NULL file argument were rejected (i.e. "file" should always be valid for
> the security_..._file hooks, but it appears at least one case was
> left in the kernel during earlier refactoring. (This will be fixed in
> a subsequent patch.)
> 
> Since not all cases of security_kernel_load_data() can have a single
> contiguous buffer made available to the LSM hook (e.g. kexec image
> segments are separately loaded), there needs to be a way for the LSM to
> reason about its expectations of the hook coverage. In order to handle
> this, add a "contents" argument to the "kernel_load_data" hook that
> indicates if the newly added "kernel_post_load_data" hook will be called
> with the full contents once loaded. That way, LSMs requiring full contents
> can choose to unilaterally reject "kernel_load_data" with contents=false
> (which is effectively the existing hook coverage), but when contents=true
> they can allow it and later evaluate the "kernel_post_load_data" hook
> once the buffer is loaded.
> 
> With this change, LSMs can gain coverage over non-file-backed data loads
> (e.g. init_module(2) and firmware userspace helper), which will happen
> in subsequent patches.
> 
> Additionally prepare IMA to start processing these cases.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>

Thanks, Kees.   Other than a missing "name" field, it looks good.

The security_kernel_post_load_data hook may be used to verify appended
signatures and to measure the buffer data.  Passing the kernel module
(load_info.name) and firmware (fw_name) names is critical at least for
IMA-measurement.

thanks,

Mimi


^ permalink raw reply	[flat|nested] 28+ messages in thread

* Re: [PATCH v4 10/17] firmware_loader: Use security_post_load_data()
  2020-07-29 17:58 ` [PATCH v4 10/17] firmware_loader: Use security_post_load_data() Kees Cook
@ 2020-08-06 22:07   ` Mimi Zohar
  0 siblings, 0 replies; 28+ messages in thread
From: Mimi Zohar @ 2020-08-06 22:07 UTC (permalink / raw)
  To: Kees Cook, Greg Kroah-Hartman
  Cc: Scott Branden, Luis Chamberlain, Takashi Iwai, Jessica Yu,
	SeongJae Park, KP Singh, linux-efi, linux-security-module,
	linux-integrity, selinux, linux-kselftest, linux-kernel

On Wed, 2020-07-29 at 10:58 -0700, Kees Cook wrote:
> Now that security_post_load_data() is wired up, use it instead
> of the NULL file argument style of security_post_read_file(),
> and update the security_kernel_load_data() call to indicate that a
> security_kernel_post_load_data() call is expected.
> 
> Wire up the IMA check to match earlier logic. Perhaps a generalized
> change to ima_post_load_data() might look something like this:
> 
>     return process_buffer_measurement(buf, size,
>                                       kernel_load_data_id_str(load_id),
>                                       read_idmap[load_id] ?: FILE_CHECK,
>                                       0, NULL);
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>

Other than one change and one question below, it looks good.

Reviewed-by:  Mimi Zohar <zohar@linux.ibm.com>

<snip>

> diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> index 85000dc8595c..1a7bc4c7437d 100644
> --- a/security/integrity/ima/ima_main.c
> +++ b/security/integrity/ima/ima_main.c

> @@ -706,7 +697,7 @@ int ima_load_data(enum kernel_load_data_id id, bool contents)
>  		}
>  		break;
>  	case LOADING_FIRMWARE:
> -		if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE)) {
> +		if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE) && !contents) {
>  			pr_err("Prevent firmware sysfs fallback loading.\n");

Appended signatures are limited to kernel modules and, more recently,
to the kexec kernel image, not firmware.  Without a file descriptor,
file signatures stored as an xattrs are not applicable either.  We
might as well fail earlier, rather than later.  Adding "!contents" is
unnecessary.

>  			return -EACCES;	/* INTEGRITY_UNKNOWN */
>  		}
> @@ -739,6 +730,15 @@ int ima_load_data(enum kernel_load_data_id id, bool contents)
>   */
>  int ima_post_load_data(char *buf, loff_t size, enum kernel_load_data_id load_id)
>  {
> +	if (load_id == LOADING_FIRMWARE) {
> +		if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
> +		    (ima_appraise & IMA_APPRAISE_ENFORCE)) {
> +			pr_err("Prevent firmware loading_store.\n");
> +			return -EACCES; /* INTEGRITY_UNKNOWN */
> +		}
> +		return 0;
> +	}

Even with failing LOADING_FIRMWARE early in ima_load_data(), is this
still needed for fw_sysfs_loading()?

thanks,

Mimi

> +
>  	return 0;
>  }
>  


^ permalink raw reply	[flat|nested] 28+ messages in thread

* Re: [PATCH v4 09/17] LSM: Introduce kernel_post_load_data() hook
  2020-07-29 17:58 ` [PATCH v4 09/17] LSM: Introduce kernel_post_load_data() hook Kees Cook
  2020-08-06 21:59   ` Mimi Zohar
@ 2020-08-07  0:21   ` KP Singh
  1 sibling, 0 replies; 28+ messages in thread
From: KP Singh @ 2020-08-07  0:21 UTC (permalink / raw)
  To: Kees Cook
  Cc: Greg Kroah-Hartman, Scott Branden, Mimi Zohar, Luis Chamberlain,
	Takashi Iwai, Jessica Yu, SeongJae Park, linux-efi,
	Linux Security Module list, linux-integrity, selinux,
	linux-kselftest, open list

On Wed, Jul 29, 2020 at 7:59 PM Kees Cook <keescook@chromium.org> wrote:
>
> There are a few places in the kernel where LSMs would like to have
> visibility into the contents of a kernel buffer that has been loaded or
> read. While security_kernel_post_read_file() (which includes the
> buffer) exists as a pairing for security_kernel_read_file(), no such
> hook exists to pair with security_kernel_load_data().
>
> Earlier proposals for just using security_kernel_post_read_file() with a
> NULL file argument were rejected (i.e. "file" should always be valid for
> the security_..._file hooks, but it appears at least one case was
> left in the kernel during earlier refactoring. (This will be fixed in
> a subsequent patch.)
>
> Since not all cases of security_kernel_load_data() can have a single
> contiguous buffer made available to the LSM hook (e.g. kexec image
> segments are separately loaded), there needs to be a way for the LSM to
> reason about its expectations of the hook coverage. In order to handle
> this, add a "contents" argument to the "kernel_load_data" hook that
> indicates if the newly added "kernel_post_load_data" hook will be called
> with the full contents once loaded. That way, LSMs requiring full contents
> can choose to unilaterally reject "kernel_load_data" with contents=false
> (which is effectively the existing hook coverage), but when contents=true
> they can allow it and later evaluate the "kernel_post_load_data" hook
> once the buffer is loaded.
>
> With this change, LSMs can gain coverage over non-file-backed data loads
> (e.g. init_module(2) and firmware userspace helper), which will happen
> in subsequent patches.
>
> Additionally prepare IMA to start processing these cases.
>
> Signed-off-by: Kees Cook <keescook@chromium.org>

Thanks for adding this! Would be really useful for us.

Reviewed-by: KP Singh <kpsingh@google.com>

> ---
>  drivers/base/firmware_loader/fallback.c       |  2 +-

[...]

> index 5de45010fb1a..1a5c68196faf 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -4019,7 +4019,7 @@ static int selinux_kernel_read_file(struct file *file,
>         return rc;
>  }
>
> -static int selinux_kernel_load_data(enum kernel_load_data_id id)
> +static int selinux_kernel_load_data(enum kernel_load_data_id id, bool contents)
>  {
>         int rc = 0;
>
> --
> 2.25.1
>

^ permalink raw reply	[flat|nested] 28+ messages in thread

* Re: [PATCH v4 11/17] module: Call security_kernel_post_load_data()
  2020-08-05 14:53   ` Jessica Yu
@ 2020-08-07  0:22     ` KP Singh
  0 siblings, 0 replies; 28+ messages in thread
From: KP Singh @ 2020-08-07  0:22 UTC (permalink / raw)
  To: Jessica Yu
  Cc: Kees Cook, Greg Kroah-Hartman, Scott Branden, Mimi Zohar,
	Luis Chamberlain, Takashi Iwai, SeongJae Park, linux-efi,
	Linux Security Module list, linux-integrity, selinux,
	linux-kselftest, open list

On Wed, Aug 5, 2020 at 4:53 PM Jessica Yu <jeyu@kernel.org> wrote:
>
> +++ Kees Cook [29/07/20 10:58 -0700]:
> >Now that there is an API for checking loaded contents for modules
> >loaded without a file, call into the LSM hooks.
> >
> >Cc: Jessica Yu <jeyu@kernel.org>
> >Signed-off-by: Kees Cook <keescook@chromium.org>
>
> Acked-by: Jessica Yu <jeyu@kernel.org>

Thanks!

Reviewed-by: KP Singh <kpsingh@google.com>

^ permalink raw reply	[flat|nested] 28+ messages in thread

* Re: [PATCH v4 12/17] LSM: Add "contents" flag to kernel_read_file hook
  2020-07-29 17:58 ` [PATCH v4 12/17] LSM: Add "contents" flag to kernel_read_file hook Kees Cook
@ 2020-08-07  0:23   ` Mimi Zohar
  0 siblings, 0 replies; 28+ messages in thread
From: Mimi Zohar @ 2020-08-07  0:23 UTC (permalink / raw)
  To: Kees Cook, Greg Kroah-Hartman
  Cc: Scott Branden, Luis Chamberlain, Takashi Iwai, Jessica Yu,
	SeongJae Park, KP Singh, linux-efi, linux-security-module,
	linux-integrity, selinux, linux-kselftest, linux-kernel

On Wed, 2020-07-29 at 10:58 -0700, Kees Cook wrote:
> As with the kernel_load_data LSM hook, add a "contents" flag to the
> kernel_read_file LSM hook that indicates whether the LSM can expect
> a matching call to the kernel_post_read_file LSM hook with the full
> contents of the file. With the coming addition of partial file read
> support for kernel_read_file*() API, the LSM will no longer be able
> to always see the entire contents of a file during the read calls.
> 
> For cases where the LSM must read examine the complete file contents,
> it will need to do so on its own every time the kernel_read_file
> hook is called with contents=false (or reject such cases). Adjust all
> existing LSMs to retain existing behavior.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>


^ permalink raw reply	[flat|nested] 28+ messages in thread

end of thread, back to index

Thread overview: 28+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-29 17:58 [PATCH v4 00/17] Introduce partial kernel_read_file() support Kees Cook
2020-07-29 17:58 ` [PATCH v4 01/17] test_firmware: Test platform fw loading on non-EFI systems Kees Cook
2020-07-29 17:58 ` [PATCH v4 02/17] fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum Kees Cook
2020-07-29 17:58 ` [PATCH v4 03/17] fs/kernel_read_file: Remove FIRMWARE_EFI_EMBEDDED enum Kees Cook
2020-07-29 17:58 ` [PATCH v4 04/17] fs/kernel_read_file: Split into separate include file Kees Cook
2020-07-30  2:22   ` James Morris
2020-07-29 17:58 ` [PATCH v4 05/17] fs/kernel_read_file: Split into separate source file Kees Cook
2020-07-29 17:58 ` [PATCH v4 06/17] fs/kernel_read_file: Remove redundant size argument Kees Cook
2020-07-30  2:25   ` James Morris
2020-07-29 17:58 ` [PATCH v4 07/17] fs/kernel_read_file: Switch buffer size arg to size_t Kees Cook
2020-07-30  2:25   ` James Morris
2020-07-29 17:58 ` [PATCH v4 08/17] fs/kernel_read_file: Add file_size output argument Kees Cook
2020-07-30  2:26   ` James Morris
2020-07-29 17:58 ` [PATCH v4 09/17] LSM: Introduce kernel_post_load_data() hook Kees Cook
2020-08-06 21:59   ` Mimi Zohar
2020-08-07  0:21   ` KP Singh
2020-07-29 17:58 ` [PATCH v4 10/17] firmware_loader: Use security_post_load_data() Kees Cook
2020-08-06 22:07   ` Mimi Zohar
2020-07-29 17:58 ` [PATCH v4 11/17] module: Call security_kernel_post_load_data() Kees Cook
2020-08-05 14:53   ` Jessica Yu
2020-08-07  0:22     ` KP Singh
2020-07-29 17:58 ` [PATCH v4 12/17] LSM: Add "contents" flag to kernel_read_file hook Kees Cook
2020-08-07  0:23   ` Mimi Zohar
2020-07-29 17:58 ` [PATCH v4 13/17] IMA: Add support for file reads without contents Kees Cook
2020-07-29 17:58 ` [PATCH v4 14/17] fs/kernel_file_read: Add "offset" arg for partial reads Kees Cook
2020-07-29 17:58 ` [PATCH v4 15/17] firmware: Store opt_flags in fw_priv Kees Cook
2020-07-29 17:58 ` [PATCH v4 16/17] firmware: Add request_partial_firmware_into_buf() Kees Cook
2020-07-29 17:58 ` [PATCH v4 17/17] test_firmware: Test partial read support Kees Cook

SELinux Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/selinux/0 selinux/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 selinux selinux/ https://lore.kernel.org/selinux \
		selinux@vger.kernel.org
	public-inbox-index selinux

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.selinux


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git