From: Eric Biggers <ebiggers@xxxxxxxxxx>
On 32-bit systems, the buffer allocated by kernel_read_file() is too
small if the file size is > SIZE_MAX, due to truncation to size_t.
Fortunately, since the 'count' argument to kernel_read() is also
truncated to size_t, only the allocated space is filled; then, -EIO is
returned since 'pos != i_size' after the read loop.
But this is not obvious and seems incidental. We should be more
explicit about this case. So, fail early if i_size > SIZE_MAX.
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
fs/exec.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index 1ebf6e5a521d..fc281b738a98 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -908,14 +908,14 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
goto out;
i_size = i_size_read(file_inode(file));
- if (max_size > 0 && i_size > max_size) {
- ret = -EFBIG;
- goto out;
- }
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 (id != READING_FIRMWARE_PREALLOC_BUFFER)
*buf = vmalloc(i_size);
--
2.19.0.rc2.392.g5ba43deb5a-goog
