From: Edward Adam Davis eadavis@qq.com

stable inclusion from stable-v6.6.47 commit 6ea10dbb1e6c58384136e9adfd75f81951e423f6 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAMMM9 CVE: CVE-2024-44939

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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[ 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@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis eadavis@qq.com Signed-off-by: Dave Kleikamp dave.kleikamp@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Wenyu Huang huangwenyu5@huawei.com --- fs/jfs/jfs_dtree.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c index ea2c8f0fe832c..0c16f7f8eaa2b 100644 --- a/fs/jfs/jfs_dtree.c +++ b/fs/jfs/jfs_dtree.c @@ -847,6 +847,8 @@ 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