From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3CF95381E98 for ; Sat, 15 Aug 2026 06:33:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786775616; cv=none; b=gBKbsCiWXGvdrW+eNCKMtEBbvs1GHHK/KBLlVQFkN4fCs/zkmPAgJDu4Uj+8wGMpnC8EKwW2+BAv0CmJDHsebJZfAEKeFWUJ73Hw2MJfVMRVfduysVWtvVdPofJczLryFpFst9jaXc1tljuBZoa9ZKm3Z7qawlFYdgHOY/VMRDw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786775616; c=relaxed/simple; bh=ZocQYVta15N5e5zpUTEEhuhIXictLmGxGw6DXyoKsw4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=M5f+YwrR2ni0QTnRBRikACJQC8claWcoWqk9hJXKXb0yd4W4EpSfFlobH2wgA1MbDmmG6u4XGQBq9UVFoWNQ71gnsC/CviVkzh2t7mC4kXfE3h8Az51IJ/daFmS7RdcaU2q3go3XEyKs2tNp5uFmlAPAdNnm4EHjB+QOLBH+bcE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=e0g80F9R; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="e0g80F9R" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4ACE01F000E9; Sat, 15 Aug 2026 06:33:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786775614; bh=iWVTjAWewcgxaoMb8LfdhV+l5P3J3KvRsdQvY238Fi4=; h=From:To:Cc:Subject:Date:Reply-To; b=e0g80F9RA1QO3oSKSL03PbplG0rpk6cEvtfXNO0C2iuNDqdOfrW3wtSdeM/WCAbp1 fQABExT0fZu1802DVXEP8rt0PY/97XmJ8ZnilZ/mP2EasUMCEcKmKwPnQLVNMBo0uB 6eJCVi4Zita1F9lpnygC9s0XOLjqysGsEycK7Vjs= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-74257: sockmap: Fix use-after-free in udp_bpf_recvmsg() Date: Sat, 15 Aug 2026 15:09:44 +0900 Message-ID: <2026081541-CVE-2026-74257-09ff@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=8219; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=IhExc9gBdWn3BUllhKBv1vJtR77kzLskkyxjtw0GCLc=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkNjIwyts+2V5dt+Xf5YN6NyKU8tky/D2/cXnQo03OG+ Jk3Hb61HbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjARnR0M8yvO9n2wz5xjXPjY qjzwy/8Obr1fCxkWLEzUEV1/f3foxqjpQRlK575OWnPNGgA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: sockmap: Fix use-after-free in udp_bpf_recvmsg() syzbot reported use-after-free of struct sk_msg in sk_msg_recvmsg(). [0] sk_msg_recvmsg() peeks sk_msg from psock->ingress_msg under a lock, but its processing is lockless. Thus, sk_msg_recvmsg() must be serialised by callers, otherwise multiple threads could touch the same sk_msg. For example, TCP uses lock_sock(), and AF_UNIX uses unix_sk(sk)->iolock. Initially, udp_bpf_recvmsg() had used lock_sock(), but the cited commit removed it. Let's serialise sk_msg_recvmsg() with lock_sock() in udp_bpf_recvmsg(). Note that holding spin_lock_bh(&sk->sk_receive_queue.lock) is not an option due to copy_page_to_iter() in sk_msg_recvmsg(). [0]: BUG: KASAN: slab-use-after-free in sk_msg_recvmsg+0xb54/0xc30 net/core/skmsg.c:428 Read of size 4 at addr ffff88814cdcf000 by task syz.0.24/6020 CPU: 1 UID: 0 PID: 6020 Comm: syz.0.24 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 sk_msg_recvmsg+0xb54/0xc30 net/core/skmsg.c:428 udp_bpf_recvmsg+0x4bd/0xe00 net/ipv4/udp_bpf.c:84 inet_recvmsg+0x260/0x270 net/ipv4/af_inet.c:891 sock_recvmsg_nosec net/socket.c:1078 [inline] sock_recvmsg+0x1a8/0x270 net/socket.c:1100 ____sys_recvmsg+0x1e6/0x4a0 net/socket.c:2812 ___sys_recvmsg+0x215/0x590 net/socket.c:2854 do_recvmmsg+0x334/0x800 net/socket.c:2949 __sys_recvmmsg net/socket.c:3023 [inline] __do_sys_recvmmsg net/socket.c:3046 [inline] __se_sys_recvmmsg net/socket.c:3039 [inline] __x64_sys_recvmmsg+0x198/0x250 net/socket.c:3039 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb319f9aeb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb31ad97028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007fb31a216090 RCX: 00007fb319f9aeb9 RDX: 0000000000000001 RSI: 0000200000000400 RDI: 0000000000000004 RBP: 00007fb31a008c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000040000021 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb31a216128 R14: 00007fb31a216090 R15: 00007ffe21dd0a98 Allocated by task 6019: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x3d1/0x6e0 mm/slub.c:5780 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] alloc_sk_msg net/core/skmsg.c:510 [inline] sk_psock_skb_ingress_self+0x60/0x350 net/core/skmsg.c:612 sk_psock_verdict_apply net/core/skmsg.c:1038 [inline] sk_psock_verdict_recv+0x7d9/0x8d0 net/core/skmsg.c:1236 udp_read_skb+0x73e/0x7e0 net/ipv4/udp.c:2045 sk_psock_verdict_data_ready+0x12d/0x550 net/core/skmsg.c:1257 __udp_enqueue_schedule_skb+0xc54/0x10b0 net/ipv4/udp.c:1789 __udp_queue_rcv_skb net/ipv4/udp.c:2346 [inline] udp_queue_rcv_one_skb+0xac5/0x19c0 net/ipv4/udp.c:2475 __udp4_lib_mcast_deliver+0xc06/0xcf0 net/ipv4/udp.c:2585 __udp4_lib_rcv+0x10f6/0x2620 net/ipv4/udp.c:2724 ip_protocol_deliver_rcu+0x282/0x440 net/ipv4/ip_input.c:207 ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:241 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 dst_input include/net/dst.h:474 [inline] ip_sublist_rcv_finish+0x221/0x2a0 net/ipv4/ip_input.c:584 ip_list_rcv_finish net/ipv4/ip_input.c:628 [inline] ip_sublist_rcv+0x5c6/0xa70 net/ipv4/ip_input.c:644 ip_list_rcv+0x3f1/0x450 net/ipv4/ip_input.c:678 __netif_receive_skb_list_ptype net/core/dev.c:6195 [inline] __netif_receive_skb_list_core+0x7e5/0x810 net/core/dev.c:6242 __netif_receive_skb_list net/core/dev.c:6294 [inline] netif_receive_skb_list_internal+0x995/0xcf0 net/core/dev.c:6385 netif_receive_skb_list+0x54/0x410 net/core/dev.c:6437 xdp_recv_frames net/bpf/test_run.c:269 [inline] xdp_test_run_batch net/bpf/test_run.c:350 [inline] bpf_test_run_xdp_live+0x1946/0x1cf0 net/bpf/test_run.c:379 bpf_prog_test_run_xdp+0x81c/0x1160 net/bpf/test_run.c:1396 bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4703 __sys_bpf+0x5cb/0x920 kernel/bpf/syscall.c:6182 __do_sys_bpf kernel/bpf/syscall.c:6274 [inline] __se_sys_bpf kernel/bpf/syscall.c:6272 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6272 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6021: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6674 [inline] kfree+0x1be/0x650 mm/slub.c:6882 kfree_sk_msg include/linux/skmsg.h:385 [inline] sk_msg_recvmsg+0xaa8/0xc30 net/core/skmsg.c:483 udp_bpf_recvmsg+0x4bd/0xe00 net/ipv4/udp_bpf.c:84 inet_recvmsg+0x260/0x270 net/ipv4/af_inet.c:891 sock_recvmsg_nosec net/socket.c:1078 [inline] sock_recvmsg+0x1a8/0x270 net/socket.c:1100 ____sys_recvmsg+0x1e6/0x4a0 net/socket.c:2812 ___sys_recvmsg+0x215/0x590 net/socket.c:2854 do_recvmmsg+0x334/0x800 net/socket.c:2949 __sys_recvmmsg net/socket.c:3023 [inline] __do_sys_recvmmsg net/socket.c:3046 [inline] __se_sys_recvmmsg net/socket.c:3039 [inline] __x64_sys_recvmmsg+0x198/0x250 net/socket.c:3039 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The Linux kernel CVE team has assigned CVE-2026-74257 to this issue. Affected and fixed versions =========================== Issue introduced in 5.14 with commit 9f2470fbc4cb4583c080bb729a998933ba61aca4 and fixed in 6.18.40 with commit 81567d2b3f4dc4fc32f8b61433738bce2cafd4a1 Issue introduced in 5.14 with commit 9f2470fbc4cb4583c080bb729a998933ba61aca4 and fixed in 7.1.5 with commit 39d44ed6904bfa9a1c6d0538672dd50c7b85520e Issue introduced in 5.14 with commit 9f2470fbc4cb4583c080bb729a998933ba61aca4 and fixed in 7.2-rc1 with commit c010995b29c8939c6aa69e3cb26f8dbee163d156 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-74257 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: net/ipv4/udp_bpf.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/81567d2b3f4dc4fc32f8b61433738bce2cafd4a1 https://git.kernel.org/stable/c/39d44ed6904bfa9a1c6d0538672dd50c7b85520e https://git.kernel.org/stable/c/c010995b29c8939c6aa69e3cb26f8dbee163d156