GHSA-V6JM-7R7P-9979
Vulnerability from github – Published: 2025-01-08 18:30 – Updated: 2025-11-03 21:32In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix nfs4_openowner leak when concurrent nfsd4_open occur
The action force umount(umount -f) will attempt to kill all rpc_task even umount operation may ultimately fail if some files remain open. Consequently, if an action attempts to open a file, it can potentially send two rpc_task to nfs server.
NFS CLIENT
thread1 thread2 open("file") ... nfs4_do_open _nfs4_do_open _nfs4_open_and_get_state _nfs4_proc_open nfs4_run_open_task / rpc_task1 / rpc_run_task rpc_wait_for_completion_task
umount -f
nfs_umount_begin
rpc_killall_tasks
rpc_signal_task
rpc_task1 been wakeup
and return -512
_nfs4_do_open // while loop ... nfs4_run_open_task / rpc_task2 / rpc_run_task rpc_wait_for_completion_task
While processing an open request, nfsd will first attempt to find or allocate an nfs4_openowner. If it finds an nfs4_openowner that is not marked as NFS4_OO_CONFIRMED, this nfs4_openowner will released. Since two rpc_task can attempt to open the same file simultaneously from the client to server, and because two instances of nfsd can run concurrently, this situation can lead to lots of memory leak. Additionally, when we echo 0 to /proc/fs/nfsd/threads, warning will be triggered.
NFS SERVER
nfsd1 nfsd2 echo 0 > /proc/fs/nfsd/threads
nfsd4_open nfsd4_process_open1 find_or_alloc_open_stateowner // alloc oo1, stateid1 nfsd4_open nfsd4_process_open1 find_or_alloc_open_stateowner // find oo1, without NFS4_OO_CONFIRMED release_openowner unhash_openowner_locked list_del_init(&oo->oo_perclient) // cannot find this oo // from client, LEAK!!! alloc_stateowner // alloc oo2
nfsd4_process_open2 init_open_stateid // associate oo1 // with stateid1, stateid1 LEAK!!! nfs4_get_vfs_file // alloc nfsd_file1 and nfsd_file_mark1 // all LEAK!!!
nfsd4_process_open2
...
write_threads
...
nfsd_destroy_serv
nfsd_shutdown_net
nfs4_state_shutdown_net
nfs4_state_destroy_net
destroy_client
__destroy_client
// won't find oo1!!!
nfsd_shutdown_generic
nfsd_file_cache_shutdown
kmem_cache_destroy
for nfsd_file_slab
and nfsd_file_mark_slab
// bark since nfsd_file1
// and nfsd_file_mark1
// still alive
======================================================================= BUG nfsd_file (Not tainted): Objects remaining in nfsd_file on __kmem_cache_shutdown()
Slab 0xffd4000004438a80 objects=34 used=1 fp=0xff11000110e2ad28 flags=0x17ffffc0000240(workingset|head|node=0|zone=2|lastcpupid=0x1fffff) CPU: 4 UID: 0 PID: 757 Comm: sh Not tainted 6.12.0-rc6+ #19 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 Call Trace: dum ---truncated---
{
"affected": [],
"aliases": [
"CVE-2024-56779"
],
"database_specific": {
"cwe_ids": [
"CWE-401"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-01-08T18:15:18Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: fix nfs4_openowner leak when concurrent nfsd4_open occur\n\nThe action force umount(umount -f) will attempt to kill all rpc_task even\numount operation may ultimately fail if some files remain open.\nConsequently, if an action attempts to open a file, it can potentially\nsend two rpc_task to nfs server.\n\n NFS CLIENT\nthread1 thread2\nopen(\"file\")\n...\nnfs4_do_open\n _nfs4_do_open\n _nfs4_open_and_get_state\n _nfs4_proc_open\n nfs4_run_open_task\n /* rpc_task1 */\n rpc_run_task\n rpc_wait_for_completion_task\n\n umount -f\n nfs_umount_begin\n rpc_killall_tasks\n rpc_signal_task\n rpc_task1 been wakeup\n and return -512\n _nfs4_do_open // while loop\n ...\n nfs4_run_open_task\n /* rpc_task2 */\n rpc_run_task\n rpc_wait_for_completion_task\n\nWhile processing an open request, nfsd will first attempt to find or\nallocate an nfs4_openowner. If it finds an nfs4_openowner that is not\nmarked as NFS4_OO_CONFIRMED, this nfs4_openowner will released. Since\ntwo rpc_task can attempt to open the same file simultaneously from the\nclient to server, and because two instances of nfsd can run\nconcurrently, this situation can lead to lots of memory leak.\nAdditionally, when we echo 0 to /proc/fs/nfsd/threads, warning will be\ntriggered.\n\n NFS SERVER\nnfsd1 nfsd2 echo 0 \u003e /proc/fs/nfsd/threads\n\nnfsd4_open\n nfsd4_process_open1\n find_or_alloc_open_stateowner\n // alloc oo1, stateid1\n nfsd4_open\n nfsd4_process_open1\n find_or_alloc_open_stateowner\n // find oo1, without NFS4_OO_CONFIRMED\n release_openowner\n unhash_openowner_locked\n list_del_init(\u0026oo-\u003eoo_perclient)\n // cannot find this oo\n // from client, LEAK!!!\n alloc_stateowner // alloc oo2\n\n nfsd4_process_open2\n init_open_stateid\n // associate oo1\n // with stateid1, stateid1 LEAK!!!\n nfs4_get_vfs_file\n // alloc nfsd_file1 and nfsd_file_mark1\n // all LEAK!!!\n\n nfsd4_process_open2\n ...\n\n write_threads\n ...\n nfsd_destroy_serv\n nfsd_shutdown_net\n nfs4_state_shutdown_net\n nfs4_state_destroy_net\n destroy_client\n __destroy_client\n // won\u0027t find oo1!!!\n nfsd_shutdown_generic\n nfsd_file_cache_shutdown\n kmem_cache_destroy\n for nfsd_file_slab\n and nfsd_file_mark_slab\n // bark since nfsd_file1\n // and nfsd_file_mark1\n // still alive\n\n=======================================================================\nBUG nfsd_file (Not tainted): Objects remaining in nfsd_file on\n__kmem_cache_shutdown()\n-----------------------------------------------------------------------\n\nSlab 0xffd4000004438a80 objects=34 used=1 fp=0xff11000110e2ad28\nflags=0x17ffffc0000240(workingset|head|node=0|zone=2|lastcpupid=0x1fffff)\nCPU: 4 UID: 0 PID: 757 Comm: sh Not tainted 6.12.0-rc6+ #19\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS\n1.16.1-2.fc37 04/01/2014\nCall Trace:\n \u003cTASK\u003e\n dum\n---truncated---",
"id": "GHSA-v6jm-7r7p-9979",
"modified": "2025-11-03T21:32:05Z",
"published": "2025-01-08T18:30:49Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-56779"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0ab0a3ad24e970e894abcac58f85c332d1726749"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2d505a801e57428057563762f67a5a62009b2600"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/37dfc81266d3a32294524bfadd3396614f8633ee"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/45abb68c941ebc9a35c6d3a7b08196712093c636"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6f73f920b7ad0084373e46121d7ac34117aed652"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/98100e88dd8865999dc6379a3356cd799795fe7b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a85364f0d30dee01c5d5b4afa55a9629a8f36d8e"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.