ghsa-48pg-x75p-m28c
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
tcp: tcp_rtx_synack() can be called from process context
Laurent reported the enclosed report [1]
This bug triggers with following coditions:
0) Kernel built with CONFIG_DEBUG_PREEMPT=y
1) A new passive FastOpen TCP socket is created. This FO socket waits for an ACK coming from client to be a complete ESTABLISHED one. 2) A socket operation on this socket goes through lock_sock() release_sock() dance. 3) While the socket is owned by the user in step 2), a retransmit of the SYN is received and stored in socket backlog. 4) At release_sock() time, the socket backlog is processed while in process context. 5) A SYNACK packet is cooked in response of the SYN retransmit. 6) -> tcp_rtx_synack() is called in process context.
Before blamed commit, tcp_rtx_synack() was always called from BH handler, from a timer handler.
Fix this by using TCP_INC_STATS() & NET_INC_STATS() which do not assume caller is in non preemptible context.
[1] BUG: using __this_cpu_add() in preemptible [00000000] code: epollpep/2180 caller is tcp_rtx_synack.part.0+0x36/0xc0 CPU: 10 PID: 2180 Comm: epollpep Tainted: G OE 5.16.0-0.bpo.4-amd64 #1 Debian 5.16.12-1~bpo11+1 Hardware name: Supermicro SYS-5039MC-H8TRF/X11SCD-F, BIOS 1.7 11/23/2021 Call Trace: dump_stack_lvl+0x48/0x5e check_preemption_disabled+0xde/0xe0 tcp_rtx_synack.part.0+0x36/0xc0 tcp_rtx_synack+0x8d/0xa0 ? kmem_cache_alloc+0x2e0/0x3e0 ? apparmor_file_alloc_security+0x3b/0x1f0 inet_rtx_syn_ack+0x16/0x30 tcp_check_req+0x367/0x610 tcp_rcv_state_process+0x91/0xf60 ? get_nohz_timer_target+0x18/0x1a0 ? lock_timer_base+0x61/0x80 ? preempt_count_add+0x68/0xa0 tcp_v4_do_rcv+0xbd/0x270 __release_sock+0x6d/0xb0 release_sock+0x2b/0x90 sock_setsockopt+0x138/0x1140 ? __sys_getsockname+0x7e/0xc0 ? aa_sk_perm+0x3e/0x1a0 __sys_setsockopt+0x198/0x1e0 __x64_sys_setsockopt+0x21/0x30 do_syscall_64+0x38/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae
{
"affected": [],
"aliases": [
"CVE-2022-49372"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-02-26T07:01:13Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: tcp_rtx_synack() can be called from process context\n\nLaurent reported the enclosed report [1]\n\nThis bug triggers with following coditions:\n\n0) Kernel built with CONFIG_DEBUG_PREEMPT=y\n\n1) A new passive FastOpen TCP socket is created.\n This FO socket waits for an ACK coming from client to be a complete\n ESTABLISHED one.\n2) A socket operation on this socket goes through lock_sock()\n release_sock() dance.\n3) While the socket is owned by the user in step 2),\n a retransmit of the SYN is received and stored in socket backlog.\n4) At release_sock() time, the socket backlog is processed while\n in process context.\n5) A SYNACK packet is cooked in response of the SYN retransmit.\n6) -\u003e tcp_rtx_synack() is called in process context.\n\nBefore blamed commit, tcp_rtx_synack() was always called from BH handler,\nfrom a timer handler.\n\nFix this by using TCP_INC_STATS() \u0026 NET_INC_STATS()\nwhich do not assume caller is in non preemptible context.\n\n[1]\nBUG: using __this_cpu_add() in preemptible [00000000] code: epollpep/2180\ncaller is tcp_rtx_synack.part.0+0x36/0xc0\nCPU: 10 PID: 2180 Comm: epollpep Tainted: G OE 5.16.0-0.bpo.4-amd64 #1 Debian 5.16.12-1~bpo11+1\nHardware name: Supermicro SYS-5039MC-H8TRF/X11SCD-F, BIOS 1.7 11/23/2021\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0x48/0x5e\n check_preemption_disabled+0xde/0xe0\n tcp_rtx_synack.part.0+0x36/0xc0\n tcp_rtx_synack+0x8d/0xa0\n ? kmem_cache_alloc+0x2e0/0x3e0\n ? apparmor_file_alloc_security+0x3b/0x1f0\n inet_rtx_syn_ack+0x16/0x30\n tcp_check_req+0x367/0x610\n tcp_rcv_state_process+0x91/0xf60\n ? get_nohz_timer_target+0x18/0x1a0\n ? lock_timer_base+0x61/0x80\n ? preempt_count_add+0x68/0xa0\n tcp_v4_do_rcv+0xbd/0x270\n __release_sock+0x6d/0xb0\n release_sock+0x2b/0x90\n sock_setsockopt+0x138/0x1140\n ? __sys_getsockname+0x7e/0xc0\n ? aa_sk_perm+0x3e/0x1a0\n __sys_setsockopt+0x198/0x1e0\n __x64_sys_setsockopt+0x21/0x30\n do_syscall_64+0x38/0xc0\n entry_SYSCALL_64_after_hwframe+0x44/0xae",
"id": "GHSA-48pg-x75p-m28c",
"modified": "2025-10-21T12:31:25Z",
"published": "2025-10-21T12:31:25Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49372"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0a0f7f84148445c9f02f226928803a870139d820"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0a375c822497ed6ad6b5da0792a12a6f1af10c0b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3db889f883e65bbd3b1401279bfc1e9ed255c481"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/58bd38cbc961fd799842b7be8c5222310f04b908"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/88cd232146207ff1d41dededed5e77c0d4438113"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/bdc28a8fb43cc476e33b11519235adb816ce00e8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c348b0f8d035fc4bdc040796889beec7218bd1b8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d05c2fdf8e10528bb6751bd95243e862d5402a9b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d8e1bc6029acac796293310aacef7b7336f35b6a"
}
],
"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
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