ghsa-36qj-697h-rh8p
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
tcp_bpf: Call sk_msg_free() when tcp_bpf_send_verdict() fails to allocate psock->cork.
syzbot reported the splat below. [0]
The repro does the following:
- Load a sk_msg prog that calls bpf_msg_cork_bytes(msg, cork_bytes)
- Attach the prog to a SOCKMAP
- Add a socket to the SOCKMAP
- Activate fault injection
- Send data less than cork_bytes
At 5., the data is carried over to the next sendmsg() as it is smaller than the cork_bytes specified by bpf_msg_cork_bytes().
Then, tcp_bpf_send_verdict() tries to allocate psock->cork to hold the data, but this fails silently due to fault injection + __GFP_NOWARN.
If the allocation fails, we need to revert the sk->sk_forward_alloc change done by sk_msg_alloc().
Let's call sk_msg_free() when tcp_bpf_send_verdict fails to allocate psock->cork.
The "copied" also needs to be updated such that a proper error can be returned to the caller, sendmsg. It fails to allocate psock->cork. Nothing has been corked so far, so this patch simply sets "copied" to 0.
[0]: WARNING: net/ipv4/af_inet.c:156 at inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156, CPU#1: syz-executor/5983 Modules linked in: CPU: 1 UID: 0 PID: 5983 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156 Code: 0f 0b 90 e9 62 fe ff ff e8 7a db b5 f7 90 0f 0b 90 e9 95 fe ff ff e8 6c db b5 f7 90 0f 0b 90 e9 bb fe ff ff e8 5e db b5 f7 90 <0f> 0b 90 e9 e1 fe ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 9f fc RSP: 0018:ffffc90000a08b48 EFLAGS: 00010246 RAX: ffffffff8a09d0b2 RBX: dffffc0000000000 RCX: ffff888024a23c80 RDX: 0000000000000100 RSI: 0000000000000fff RDI: 0000000000000000 RBP: 0000000000000fff R08: ffff88807e07c627 R09: 1ffff1100fc0f8c4 R10: dffffc0000000000 R11: ffffed100fc0f8c5 R12: ffff88807e07c380 R13: dffffc0000000000 R14: ffff88807e07c60c R15: 1ffff1100fc0f872 FS: 00005555604c4500(0000) GS:ffff888125af1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555604df5c8 CR3: 0000000032b06000 CR4: 00000000003526f0 Call Trace: __sk_destruct+0x86/0x660 net/core/sock.c:2339 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0xca8/0x1770 kernel/rcu/tree.c:2861 handle_softirqs+0x286/0x870 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
{
"affected": [],
"aliases": [
"CVE-2025-39913"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-10-01T08:15:34Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp_bpf: Call sk_msg_free() when tcp_bpf_send_verdict() fails to allocate psock-\u003ecork.\n\nsyzbot reported the splat below. [0]\n\nThe repro does the following:\n\n 1. Load a sk_msg prog that calls bpf_msg_cork_bytes(msg, cork_bytes)\n 2. Attach the prog to a SOCKMAP\n 3. Add a socket to the SOCKMAP\n 4. Activate fault injection\n 5. Send data less than cork_bytes\n\nAt 5., the data is carried over to the next sendmsg() as it is\nsmaller than the cork_bytes specified by bpf_msg_cork_bytes().\n\nThen, tcp_bpf_send_verdict() tries to allocate psock-\u003ecork to hold\nthe data, but this fails silently due to fault injection + __GFP_NOWARN.\n\nIf the allocation fails, we need to revert the sk-\u003esk_forward_alloc\nchange done by sk_msg_alloc().\n\nLet\u0027s call sk_msg_free() when tcp_bpf_send_verdict fails to allocate\npsock-\u003ecork.\n\nThe \"*copied\" also needs to be updated such that a proper error can\nbe returned to the caller, sendmsg. It fails to allocate psock-\u003ecork.\nNothing has been corked so far, so this patch simply sets \"*copied\"\nto 0.\n\n[0]:\nWARNING: net/ipv4/af_inet.c:156 at inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156, CPU#1: syz-executor/5983\nModules linked in:\nCPU: 1 UID: 0 PID: 5983 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025\nRIP: 0010:inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156\nCode: 0f 0b 90 e9 62 fe ff ff e8 7a db b5 f7 90 0f 0b 90 e9 95 fe ff ff e8 6c db b5 f7 90 0f 0b 90 e9 bb fe ff ff e8 5e db b5 f7 90 \u003c0f\u003e 0b 90 e9 e1 fe ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 9f fc\nRSP: 0018:ffffc90000a08b48 EFLAGS: 00010246\nRAX: ffffffff8a09d0b2 RBX: dffffc0000000000 RCX: ffff888024a23c80\nRDX: 0000000000000100 RSI: 0000000000000fff RDI: 0000000000000000\nRBP: 0000000000000fff R08: ffff88807e07c627 R09: 1ffff1100fc0f8c4\nR10: dffffc0000000000 R11: ffffed100fc0f8c5 R12: ffff88807e07c380\nR13: dffffc0000000000 R14: ffff88807e07c60c R15: 1ffff1100fc0f872\nFS: 00005555604c4500(0000) GS:ffff888125af1000(0000) knlGS:0000000000000000\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00005555604df5c8 CR3: 0000000032b06000 CR4: 00000000003526f0\nCall Trace:\n \u003cIRQ\u003e\n __sk_destruct+0x86/0x660 net/core/sock.c:2339\n rcu_do_batch kernel/rcu/tree.c:2605 [inline]\n rcu_core+0xca8/0x1770 kernel/rcu/tree.c:2861\n handle_softirqs+0x286/0x870 kernel/softirq.c:579\n __do_softirq kernel/softirq.c:613 [inline]\n invoke_softirq kernel/softirq.c:453 [inline]\n __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680\n irq_exit_rcu+0x9/0x30 kernel/softirq.c:696\n instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]\n sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052\n \u003c/IRQ\u003e",
"id": "GHSA-36qj-697h-rh8p",
"modified": "2025-10-02T15:31:15Z",
"published": "2025-10-01T09:30:25Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39913"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/05366527f44cf4b884f3d9462ae8009be9665856"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/08f58d10f5abf11d297cc910754922498c921f91"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/539920180c55f5e13a2488a2339f94e6b8cb69e0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/66bcb04a441fbf15d66834b7e3eefb313dd750c8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7429b8b9bfbc276fd304fbaebc405f46b421fedf"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9c2a6456bdf9794474460d885c359b6c4522d6e3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a3967baad4d533dc254c31e0d221e51c8d223d58"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/de89e58368f8f07df005ecc1c86ad94898a999f2"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
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