From: Kees Cook <keescook@chromium.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kees Cook <keescook@chromium.org>,
Scott Branden <scott.branden@broadcom.com>,
Mimi Zohar <zohar@linux.ibm.com>,
Luis Chamberlain <mcgrof@kernel.org>,
Takashi Iwai <tiwai@suse.de>, Jessica Yu <jeyu@kernel.org>,
SeongJae Park <sjpark@amazon.de>, KP Singh <kpsingh@chromium.org>,
linux-efi@vger.kernel.org, linux-security-module@vger.kernel.org,
linux-integrity@vger.kernel.org, selinux@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v4 07/17] fs/kernel_read_file: Switch buffer size arg to size_t
Date: Wed, 29 Jul 2020 10:58:35 -0700 [thread overview]
Message-ID: <20200729175845.1745471-8-keescook@chromium.org> (raw)
In-Reply-To: <20200729175845.1745471-1-keescook@chromium.org>
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
next prev parent reply other threads:[~2020-07-29 17:59 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
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 ` Kees Cook [this message]
2020-07-30 2:25 ` [PATCH v4 07/17] fs/kernel_read_file: Switch buffer size arg to size_t 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
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