Use After Free Affecting kernel-syms-azure package, versions <6.4.0-150600.8.20.1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-SLES156-KERNELSYMSAZURE-8504368
- published14 Dec 2024
- disclosed13 Dec 2024
Introduced: 13 Dec 2024
NewCVE-2024-50121 (opens in a new tab)How to fix?
Upgrade SLES:15.6 kernel-syms-azure to version 6.4.0-150600.8.20.1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-syms-azure package and not the kernel-syms-azure package as distributed by SLES.
See How to fix? for SLES:15.6 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
nfsd: cancel nfsd_shrinker_work using sync mode in nfs4_state_shutdown_net
In the normal case, when we excute echo 0 > /proc/fs/nfsd/threads, the
function nfs4_state_destroy_net in nfs4_state_shutdown_net will
release all resources related to the hashed nfs4_client. If the
nfsd_client_shrinker is running concurrently, the expire_client
function will first unhash this client and then destroy it. This can
lead to the following warning. Additionally, numerous use-after-free
errors may occur as well.
nfsd_client_shrinker echo 0 > /proc/fs/nfsd/threads
expire_client nfsd_shutdown_net unhash_client ... nfs4_state_shutdown_net /* won't wait shrinker exit / / cancel_work(&nn->nfsd_shrinker_work)
nfsd_file for this /* won't destroy unhashed client1 */
client1 still alive nfs4_state_destroy_net */
nfsd_file_cache_shutdown /* trigger warning */ kmem_cache_destroy(nfsd_file_slab) kmem_cache_destroy(nfsd_file_mark_slab)
/* release nfsd_file and mark */ __destroy_client
==================================================================== BUG nfsd_file (Not tainted): Objects remaining in nfsd_file on __kmem_cache_shutdown()
CPU: 4 UID: 0 PID: 764 Comm: sh Not tainted 6.12.0-rc3+ #1
dump_stack_lvl+0x53/0x70 slab_err+0xb0/0xf0 __kmem_cache_shutdown+0x15c/0x310 kmem_cache_destroy+0x66/0x160 nfsd_file_cache_shutdown+0xac/0x210 [nfsd] nfsd_destroy_serv+0x251/0x2a0 [nfsd] nfsd_svc+0x125/0x1e0 [nfsd] write_threads+0x16a/0x2a0 [nfsd] nfsctl_transaction_write+0x74/0xa0 [nfsd] vfs_write+0x1a5/0x6d0 ksys_write+0xc1/0x160 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e
==================================================================== BUG nfsd_file_mark (Tainted: G B W ): Objects remaining nfsd_file_mark on __kmem_cache_shutdown()
dump_stack_lvl+0x53/0x70 slab_err+0xb0/0xf0 __kmem_cache_shutdown+0x15c/0x310 kmem_cache_destroy+0x66/0x160 nfsd_file_cache_shutdown+0xc8/0x210 [nfsd] nfsd_destroy_serv+0x251/0x2a0 [nfsd] nfsd_svc+0x125/0x1e0 [nfsd] write_threads+0x16a/0x2a0 [nfsd] nfsctl_transaction_write+0x74/0xa0 [nfsd] vfs_write+0x1a5/0x6d0 ksys_write+0xc1/0x160 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e
To resolve this issue, cancel nfsd_shrinker_work using synchronous
mode in nfs4_state_shutdown_net.
References
- https://www.suse.com/security/cve/CVE-2024-50121.html
- https://bugzilla.suse.com/1232925
- https://git.kernel.org/stable/c/add1df5eba163a3a6ece11cb85890e2e410baaea
- https://git.kernel.org/stable/c/d5ff2fb2e7167e9483846e34148e60c0c016a1f6
- https://git.kernel.org/stable/c/f965dc0f099a54fca100acf6909abe52d0c85328