This is a note to let you know that I've just added the patch titled
jfs: fix null ptr deref in dtInsertEntry
to the 6.10-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-fix-null-ptr-deref-in-dtinsertentry.patch
and it can be found in the queue-6.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 15cc64095bcbdf6a8e92248a8b6a679495b295ba
Author: Edward Adam Davis <eadavis@xxxxxx>
Date: Thu Apr 11 20:05:28 2024 +0800
jfs: fix null ptr deref in dtInsertEntry
[ Upstream commit ce6dede912f064a855acf6f04a04cbb2c25b8c8c ]
[syzbot reported]
general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 PID: 5061 Comm: syz-executor404 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:dtInsertEntry+0xd0c/0x1780 fs/jfs/jfs_dtree.c:3713
...
[Analyze]
In dtInsertEntry(), when the pointer h has the same value as p, after writing
name in UniStrncpy_to_le(), p->header.flag will be cleared. This will cause the
previously true judgment "p->header.flag & BT-LEAF" to change to no after writing
the name operation, this leads to entering an incorrect branch and accessing the
uninitialized object ih when judging this condition for the second time.
[Fix]
After got the page, check freelist first, if freelist == 0 then exit dtInsert()
and return -EINVAL.
Reported-by: syzbot+bba84aef3a26fb93deb9@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
Signed-off-by: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c
index 031d8f570f581..5d3127ca68a42 100644
--- a/fs/jfs/jfs_dtree.c
+++ b/fs/jfs/jfs_dtree.c
@@ -834,6 +834,8 @@ int dtInsert(tid_t tid, struct inode *ip,
* the full page.
*/
DT_GETSEARCH(ip, btstack->top, bn, mp, p, index);
+ if (p->header.freelist == 0)
+ return -EINVAL;
/*
* insert entry for new key
