This is a note to let you know that I've just added the patch titled
jfs: validate max amount of blocks before allocation.
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
jfs-validate-max-amount-of-blocks-before-allocation.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit cb53beca5fda07d34bb5e49784a3f28461e08eb6
Author: Alexei Filippov <halip0503@xxxxxxxxx>
Date: Sat Aug 19 20:32:16 2023 +0300
jfs: validate max amount of blocks before allocation.
[ Upstream commit 0225e10972fa809728b8d4c1bd2772b3ec3fdb57 ]
The lack of checking bmp->db_max_freebud in extBalloc() can lead to
shift out of bounds, so this patch prevents undefined behavior, because
bmp->db_max_freebud == -1 only if there is no free space.
Signed-off-by: Aleksei Filippov <halip0503@xxxxxxxxx>
Signed-off-by: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-and-tested-by: syzbot+5f088f29593e6b4c8db8@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?id=01abadbd6ae6a08b1f1987aa61554c6b3ac19ff2
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/jfs/jfs_extent.c b/fs/jfs/jfs_extent.c
index f65bd6b35412b..d4e063dbb9a0b 100644
--- a/fs/jfs/jfs_extent.c
+++ b/fs/jfs/jfs_extent.c
@@ -508,6 +508,11 @@ extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
* blocks in the map. in that case, we'll start off with the
* maximum free.
*/
+
+ /* give up if no space left */
+ if (bmp->db_maxfreebud == -1)
+ return -ENOSPC;
+
max = (s64) 1 << bmp->db_maxfreebud;
if (*nblocks >= max && *nblocks > nbperpage)
nb = nblks = (max > nbperpage) ? max : nbperpage;
