CVE-2024-44939: jfs: fix null ptr deref in dtInsertEntry
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/jfsdtree.c:3713 ... [Analyze] In dtInsertEntry(), when the pointer h has the same value as p, after writing name in UniStrncpytole(), 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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.129-1Fixed in 6.1.135-1Fixed in 6.12.25-1Fixed in 6.12.27-1 - Upgrade
Upgrade
debian/linux-6.1to a version that resolves this vulnerability.Fixed in 6.1.129-1~deb11u1
Event History
Frequently Asked Questions
What is the severity of CVE-2024-44939?
CVE-2024-44939 is classified as a high-severity vulnerability due to its potential to cause system crashes through null pointer dereferences.
How do I fix CVE-2024-44939?
To fix CVE-2024-44939, update to the latest patched version of the Linux kernel, specifically versions 6.1.123-1, 6.1.128-1, 6.12.12-1, or 6.12.16-1.
What systems are affected by CVE-2024-44939?
CVE-2024-44939 affects certain versions of the Linux kernel, particularly versions up to 6.10.6 and 6.6.47.
What components of the Linux kernel does CVE-2024-44939 impact?
CVE-2024-44939 specifically impacts the JFS file system within the Linux kernel, leading to potential security issues.
Is there a risk of data loss with CVE-2024-44939?
Yes, CVE-2024-44939 can lead to system crashes, which may increase the risk of data loss if not addressed promptly.