ghsa-vvj3-j4jg-68hm
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
bpf, sockmap: Avoid using sk_socket after free when sending
The sk->sk_socket is not locked or referenced in backlog thread, and during the call to skb_send_sock(), there is a race condition with the release of sk_socket. All types of sockets(tcp/udp/unix/vsock) will be affected.
Race conditions: ''' CPU0 CPU1
backlog::skb_send_sock sendmsg_unlocked sock_sendmsg sock_sendmsg_nosec close(fd): ... ops->release() -> sock_map_close() sk_socket->ops = NULL free(socket) sock->ops->sendmsg ^ panic here '''
The ref of psock become 0 after sock_map_close() executed. ''' void sock_map_close() { ... if (likely(psock)) { ... // !! here we remove psock and the ref of psock become 0 sock_map_remove_links(sk, psock) psock = sk_psock_get(sk); if (unlikely(!psock)) goto no_psock; <=== Control jumps here via goto ... cancel_delayed_work_sync(&psock->work); <=== not executed sk_psock_put(sk, psock); ... } '''
Based on the fact that we already wait for the workqueue to finish in sock_map_close() if psock is held, we simply increase the psock reference count to avoid race conditions.
With this patch, if the backlog thread is running, sock_map_close() will wait for the backlog thread to complete and cancel all pending work.
If no backlog running, any pending work that hasn't started by then will fail when invoked by sk_psock_get(), as the psock reference count have been zeroed, and sk_psock_drop() will cancel all jobs via cancel_delayed_work_sync().
In summary, we require synchronization to coordinate the backlog thread and close() thread.
The panic I catched: ''' Workqueue: events sk_psock_backlog RIP: 0010:sock_sendmsg+0x21d/0x440 RAX: 0000000000000000 RBX: ffffc9000521fad8 RCX: 0000000000000001 ... Call Trace: ? die_addr+0x40/0xa0 ? exc_general_protection+0x14c/0x230 ? asm_exc_general_protection+0x26/0x30 ? sock_sendmsg+0x21d/0x440 ? sock_sendmsg+0x3e0/0x440 ? __pfx_sock_sendmsg+0x10/0x10 __skb_send_sock+0x543/0xb70 sk_psock_backlog+0x247/0xb80 ... '''
{
"affected": [],
"aliases": [
"CVE-2025-38154"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-07-03T09:15:30Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: Avoid using sk_socket after free when sending\n\nThe sk-\u003esk_socket is not locked or referenced in backlog thread, and\nduring the call to skb_send_sock(), there is a race condition with\nthe release of sk_socket. All types of sockets(tcp/udp/unix/vsock)\nwill be affected.\n\nRace conditions:\n\u0027\u0027\u0027\nCPU0 CPU1\n\nbacklog::skb_send_sock\n sendmsg_unlocked\n sock_sendmsg\n sock_sendmsg_nosec\n close(fd):\n ...\n ops-\u003erelease() -\u003e sock_map_close()\n sk_socket-\u003eops = NULL\n free(socket)\n sock-\u003eops-\u003esendmsg\n ^\n panic here\n\u0027\u0027\u0027\n\nThe ref of psock become 0 after sock_map_close() executed.\n\u0027\u0027\u0027\nvoid sock_map_close()\n{\n ...\n if (likely(psock)) {\n ...\n // !! here we remove psock and the ref of psock become 0\n sock_map_remove_links(sk, psock)\n psock = sk_psock_get(sk);\n if (unlikely(!psock))\n goto no_psock; \u003c=== Control jumps here via goto\n ...\n cancel_delayed_work_sync(\u0026psock-\u003ework); \u003c=== not executed\n sk_psock_put(sk, psock);\n ...\n}\n\u0027\u0027\u0027\n\nBased on the fact that we already wait for the workqueue to finish in\nsock_map_close() if psock is held, we simply increase the psock\nreference count to avoid race conditions.\n\nWith this patch, if the backlog thread is running, sock_map_close() will\nwait for the backlog thread to complete and cancel all pending work.\n\nIf no backlog running, any pending work that hasn\u0027t started by then will\nfail when invoked by sk_psock_get(), as the psock reference count have\nbeen zeroed, and sk_psock_drop() will cancel all jobs via\ncancel_delayed_work_sync().\n\nIn summary, we require synchronization to coordinate the backlog thread\nand close() thread.\n\nThe panic I catched:\n\u0027\u0027\u0027\nWorkqueue: events sk_psock_backlog\nRIP: 0010:sock_sendmsg+0x21d/0x440\nRAX: 0000000000000000 RBX: ffffc9000521fad8 RCX: 0000000000000001\n...\nCall Trace:\n \u003cTASK\u003e\n ? die_addr+0x40/0xa0\n ? exc_general_protection+0x14c/0x230\n ? asm_exc_general_protection+0x26/0x30\n ? sock_sendmsg+0x21d/0x440\n ? sock_sendmsg+0x3e0/0x440\n ? __pfx_sock_sendmsg+0x10/0x10\n __skb_send_sock+0x543/0xb70\n sk_psock_backlog+0x247/0xb80\n...\n\u0027\u0027\u0027",
"id": "GHSA-vvj3-j4jg-68hm",
"modified": "2025-07-03T09:30:34Z",
"published": "2025-07-03T09:30:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38154"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/15c0250dae3b48a398447d2b364603821ed4ed90"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4c6fa65ab2aec7df94809478c8d28ef38676a1b7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4edb40b05cb6a261775abfd8046804ca139a5546"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7c0a16f6ea2b1c82a03bccd5d1bdb4a7bbd4d987"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8259eb0e06d8f64c700f5fbdb28a5c18e10de291"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b19cbf0b9a91f5a0d93fbcd761ff71c48ab40ed9"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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