CVE-2024-44939 Information

Description

In the Linux kernel the following vulnerability has been resolved:

jfs: fix null ptr deref in dtInsertEntry

[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.

Reference

https://git.kernel.org/stable/c/6ea10dbb1e6c58384136e9adfd75f81951e423f6 https://git.kernel.org/stable/c/9c2ac38530d1a3ee558834dfa16c85a40fd0e702 https://git.kernel.org/stable/c/ce6dede912f064a855acf6f04a04cbb2c25b8c8c