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
Reviewed-by: Mimi Zohar
Reviewed-by: Luis Chamberlain
Signed-off-by: Kees Cook
---
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
#include
+/**
+ * kernel_read_file() - read file contents into a kernel buffer
+ *
+ * @file file to read from
+ * @bufpointer 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
