From: Kees Cook <keescook@chromium.org>
To: Scott Branden <scott.branden@broadcom.com>
Cc: Kees Cook <keescook@chromium.org>,
stable@vger.kernel.org, Mimi Zohar <zohar@linux.ibm.com>,
Matthew Wilcox <willy@infradead.org>,
James Morris <jmorris@namei.org>,
Luis Chamberlain <mcgrof@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Jessica Yu <jeyu@kernel.org>,
Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
"Serge E. Hallyn" <serge@hallyn.com>,
Casey Schaufler <casey@schaufler-ca.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Peter Zijlstra <peterz@infradead.org>,
Matthew Garrett <matthewgarrett@google.com>,
David Howells <dhowells@redhat.com>,
Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
Randy Dunlap <rdunlap@infradead.org>,
"Joel Fernandes (Google)" <joel@joelfernandes.org>,
KP Singh <kpsingh@google.com>, Dave Olsthoorn <dave@bewaar.me>,
Hans de Goede <hdegoede@redhat.com>,
Peter Jones <pjones@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Stephen Boyd <stephen.boyd@linaro.org>,
Paul Moore <paul@paul-moore.com>,
Stephen Smalley <stephen.smalley.work@gmail.com>,
linux-security-module@vger.kernel.org,
linux-integrity@vger.kernel.org, selinux@vger.kernel.org,
linux-fsdevel@vger.kernel.org, kexec@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 02/13] fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum
Date: Fri, 17 Jul 2020 10:42:57 -0700 [thread overview]
Message-ID: <20200717174309.1164575-3-keescook@chromium.org> (raw)
In-Reply-To: <20200717174309.1164575-1-keescook@chromium.org>
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
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 ca871b13524e..c2f57cedcd6f 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 3f881a892ea7..95fc775ed937 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 0c6573b98c36..26105148f4d2 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3988,7 +3988,7 @@ 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
next prev parent reply other threads:[~2020-07-17 17:44 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-17 17:42 [PATCH 00/13] Introduce partial kernel_read_file() support Kees Cook
2020-07-17 17:42 ` [PATCH 01/13] firmware_loader: EFI firmware loader must handle pre-allocated buffer Kees Cook
2020-07-17 19:08 ` Scott Branden
2020-07-17 17:42 ` Kees Cook [this message]
2020-07-17 19:09 ` [PATCH 02/13] fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum Scott Branden
2020-07-17 17:42 ` [PATCH 03/13] fs/kernel_read_file: Remove FIRMWARE_EFI_EMBEDDED enum Kees Cook
2020-07-17 19:10 ` Scott Branden
2020-07-17 17:42 ` [PATCH 04/13] fs/kernel_read_file: Split into separate include file Kees Cook
2020-07-17 17:43 ` [PATCH 05/13] fs/kernel_read_file: Split into separate source file Kees Cook
2020-07-17 19:11 ` Scott Branden
2020-07-17 17:43 ` [PATCH 06/13] fs/kernel_read_file: Remove redundant size argument Kees Cook
2020-07-17 19:04 ` Scott Branden
2020-07-17 19:55 ` Scott Branden
2020-07-17 22:06 ` Kees Cook
2020-07-18 5:44 ` Scott Branden
2020-07-21 21:43 ` Scott Branden
2020-07-21 21:50 ` Kees Cook
2020-07-17 17:43 ` [PATCH 07/13] fs/kernel_read_file: Switch buffer size arg to size_t Kees Cook
2020-07-20 8:34 ` David Laight
2020-07-17 17:43 ` [PATCH 08/13] fs/kernel_read_file: Add file_size output argument Kees Cook
2020-07-17 17:43 ` [PATCH 09/13] LSM: Introduce kernel_post_load_data() hook Kees Cook
2020-07-17 17:43 ` [PATCH 10/13] firmware_loader: Use security_post_load_data() Kees Cook
2020-07-17 17:43 ` [PATCH 11/13] module: Call security_kernel_post_load_data() Kees Cook
2020-07-17 17:43 ` [PATCH 12/13] LSM: Add "contents" flag to kernel_read_file hook Kees Cook
2020-07-17 17:43 ` [PATCH 13/13] fs/kernel_file_read: Add "offset" arg for partial reads Kees Cook
2020-07-17 19:17 ` [PATCH 00/13] Introduce partial kernel_read_file() support Scott Branden
2020-07-17 22:10 ` Kees Cook
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