ghsa-22x4-j6vj-fmm5
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
bpf, sockmap: Fix race between element replace and close()
Element replace (with a socket different from the one stored) may race with socket's close() link popping & unlinking. __sock_map_delete() unconditionally unrefs the (wrong) element:
// set map[0] = s0 map_update_elem(map, 0, s0)
// drop fd of s0 close(s0) sock_map_close() lock_sock(sk) (s0!) sock_map_remove_links(sk) link = sk_psock_link_pop() sock_map_unlink(sk, link) sock_map_delete_from_link // replace map[0] with s1 map_update_elem(map, 0, s1) sock_map_update_elem (s1!) lock_sock(sk) sock_map_update_common psock = sk_psock(sk) spin_lock(&stab->lock) osk = stab->sks[idx] sock_map_add_link(..., &stab->sks[idx]) sock_map_unref(osk, &stab->sks[idx]) psock = sk_psock(osk) sk_psock_put(sk, psock) if (refcount_dec_and_test(&psock)) sk_psock_drop(sk, psock) spin_unlock(&stab->lock) unlock_sock(sk) __sock_map_delete spin_lock(&stab->lock) sk = *psk // s1 replaced s0; sk == s1 if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch sk = xchg(psk, NULL) if (sk) sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle psock = sk_psock(sk) sk_psock_put(sk, psock) if (refcount_dec_and_test()) sk_psock_drop(sk, psock) spin_unlock(&stab->lock) release_sock(sk)
Then close(map) enqueues bpf_map_free_deferred, which finally calls sock_map_free(). This results in some refcount_t warnings along with a KASAN splat [1].
Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may have been replaced.
[1]: BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330 Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063
CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 Workqueue: events_unbound bpf_map_free_deferred Call Trace: dump_stack_lvl+0x68/0x90 print_report+0x174/0x4f6 kasan_report+0xb9/0x190 kasan_check_range+0x10f/0x1e0 sock_map_free+0x10e/0x330 bpf_map_free_deferred+0x173/0x320 process_one_work+0x846/0x1420 worker_thread+0x5b3/0xf80 kthread+0x29e/0x360 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x1a/0x30
Allocated by task 1202: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 __kasan_slab_alloc+0x85/0x90 kmem_cache_alloc_noprof+0x131/0x450 sk_prot_alloc+0x5b/0x220 sk_alloc+0x2c/0x870 unix_create1+0x88/0x8a0 unix_create+0xc5/0x180 __sock_create+0x241/0x650 __sys_socketpair+0x1ce/0x420 __x64_sys_socketpair+0x92/0x100 do_syscall_64+0x93/0x180 entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 46: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 kasan_save_free_info+0x37/0x60 __kasan_slab_free+0x4b/0x70 kmem_cache_free+0x1a1/0x590 __sk_destruct+0x388/0x5a0 sk_psock_destroy+0x73e/0xa50 process_one_work+0x846/0x1420 worker_thread+0x5b3/0xf80 kthread+0x29e/0x360 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x1a/0x30
The bu ---truncated---
{
"affected": [],
"aliases": [
"CVE-2024-56664"
],
"database_specific": {
"cwe_ids": [
"CWE-362"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-12-27T15:15:26Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: Fix race between element replace and close()\n\nElement replace (with a socket different from the one stored) may race\nwith socket\u0027s close() link popping \u0026 unlinking. __sock_map_delete()\nunconditionally unrefs the (wrong) element:\n\n// set map[0] = s0\nmap_update_elem(map, 0, s0)\n\n// drop fd of s0\nclose(s0)\n sock_map_close()\n lock_sock(sk) (s0!)\n sock_map_remove_links(sk)\n link = sk_psock_link_pop()\n sock_map_unlink(sk, link)\n sock_map_delete_from_link\n // replace map[0] with s1\n map_update_elem(map, 0, s1)\n sock_map_update_elem\n (s1!) lock_sock(sk)\n sock_map_update_common\n psock = sk_psock(sk)\n spin_lock(\u0026stab-\u003elock)\n osk = stab-\u003esks[idx]\n sock_map_add_link(..., \u0026stab-\u003esks[idx])\n sock_map_unref(osk, \u0026stab-\u003esks[idx])\n psock = sk_psock(osk)\n sk_psock_put(sk, psock)\n if (refcount_dec_and_test(\u0026psock))\n sk_psock_drop(sk, psock)\n spin_unlock(\u0026stab-\u003elock)\n unlock_sock(sk)\n __sock_map_delete\n spin_lock(\u0026stab-\u003elock)\n sk = *psk // s1 replaced s0; sk == s1\n if (!sk_test || sk_test == sk) // sk_test (s0) != sk (s1); no branch\n sk = xchg(psk, NULL)\n if (sk)\n sock_map_unref(sk, psk) // unref s1; sks[idx] will dangle\n psock = sk_psock(sk)\n sk_psock_put(sk, psock)\n if (refcount_dec_and_test())\n sk_psock_drop(sk, psock)\n spin_unlock(\u0026stab-\u003elock)\n release_sock(sk)\n\nThen close(map) enqueues bpf_map_free_deferred, which finally calls\nsock_map_free(). This results in some refcount_t warnings along with\na KASAN splat [1].\n\nFix __sock_map_delete(), do not allow sock_map_unref() on elements that\nmay have been replaced.\n\n[1]:\nBUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330\nWrite of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063\n\nCPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014\nWorkqueue: events_unbound bpf_map_free_deferred\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0x68/0x90\n print_report+0x174/0x4f6\n kasan_report+0xb9/0x190\n kasan_check_range+0x10f/0x1e0\n sock_map_free+0x10e/0x330\n bpf_map_free_deferred+0x173/0x320\n process_one_work+0x846/0x1420\n worker_thread+0x5b3/0xf80\n kthread+0x29e/0x360\n ret_from_fork+0x2d/0x70\n ret_from_fork_asm+0x1a/0x30\n \u003c/TASK\u003e\n\nAllocated by task 1202:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n __kasan_slab_alloc+0x85/0x90\n kmem_cache_alloc_noprof+0x131/0x450\n sk_prot_alloc+0x5b/0x220\n sk_alloc+0x2c/0x870\n unix_create1+0x88/0x8a0\n unix_create+0xc5/0x180\n __sock_create+0x241/0x650\n __sys_socketpair+0x1ce/0x420\n __x64_sys_socketpair+0x92/0x100\n do_syscall_64+0x93/0x180\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nFreed by task 46:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n kasan_save_free_info+0x37/0x60\n __kasan_slab_free+0x4b/0x70\n kmem_cache_free+0x1a1/0x590\n __sk_destruct+0x388/0x5a0\n sk_psock_destroy+0x73e/0xa50\n process_one_work+0x846/0x1420\n worker_thread+0x5b3/0xf80\n kthread+0x29e/0x360\n ret_from_fork+0x2d/0x70\n ret_from_fork_asm+0x1a/0x30\n\nThe bu\n---truncated---",
"id": "GHSA-22x4-j6vj-fmm5",
"modified": "2025-01-17T15:32:32Z",
"published": "2024-12-27T15:31:56Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-56664"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b015f19fedd2e12283a8450dd0aefce49ec57015"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b79a0d1e9a374d1b376933a354c4fcd01fce0365"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/bf2318e288f636a882eea39f7e1015623629f168"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ed1fc5d76b81a4d681211333c026202cad4d5649"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
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