{"id":"CVE-2024-47711","summary":"af_unix: Don't return OOB skb in manage_oob().","details":"In the Linux kernel, the following vulnerability has been resolved:\n\naf_unix: Don't return OOB skb in manage_oob().\n\nsyzbot reported use-after-free in unix_stream_recv_urg(). [0]\n\nThe scenario is\n\n  1. send(MSG_OOB)\n  2. recv(MSG_OOB)\n     -\u003e The consumed OOB remains in recv queue\n  3. send(MSG_OOB)\n  4. recv()\n     -\u003e manage_oob() returns the next skb of the consumed OOB\n     -\u003e This is also OOB, but unix_sk(sk)-\u003eoob_skb is not cleared\n  5. recv(MSG_OOB)\n     -\u003e unix_sk(sk)-\u003eoob_skb is used but already freed\n\nThe recent commit 8594d9b85c07 (\"af_unix: Don't call skb_get() for OOB\nskb.\") uncovered the issue.\n\nIf the OOB skb is consumed and the next skb is peeked in manage_oob(),\nwe still need to check if the skb is OOB.\n\nLet's do so by falling back to the following checks in manage_oob()\nand add the test case in selftest.\n\nNote that we need to add a similar check for SIOCATMARK.\n\n[0]:\nBUG: KASAN: slab-use-after-free in unix_stream_read_actor+0xa6/0xb0 net/unix/af_unix.c:2959\nRead of size 4 at addr ffff8880326abcc4 by task syz-executor178/5235\n\nCPU: 0 UID: 0 PID: 5235 Comm: syz-executor178 Not tainted 6.11.0-rc5-syzkaller-00742-gfbdaffe41adc #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024\nCall Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:93 [inline]\n dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119\n print_address_description mm/kasan/report.c:377 [inline]\n print_report+0x169/0x550 mm/kasan/report.c:488\n kasan_report+0x143/0x180 mm/kasan/report.c:601\n unix_stream_read_actor+0xa6/0xb0 net/unix/af_unix.c:2959\n unix_stream_recv_urg+0x1df/0x320 net/unix/af_unix.c:2640\n unix_stream_read_generic+0x2456/0x2520 net/unix/af_unix.c:2778\n unix_stream_recvmsg+0x22b/0x2c0 net/unix/af_unix.c:2996\n sock_recvmsg_nosec net/socket.c:1046 [inline]\n sock_recvmsg+0x22f/0x280 net/socket.c:1068\n ____sys_recvmsg+0x1db/0x470 net/socket.c:2816\n ___sys_recvmsg net/socket.c:2858 [inline]\n __sys_recvmsg+0x2f0/0x3e0 net/socket.c:2888\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7f5360d6b4e9\nCode: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 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 \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48\nRSP: 002b:00007fff29b3a458 EFLAGS: 00000246 ORIG_RAX: 000000000000002f\nRAX: ffffffffffffffda RBX: 00007fff29b3a638 RCX: 00007f5360d6b4e9\nRDX: 0000000000002001 RSI: 0000000020000640 RDI: 0000000000000003\nRBP: 00007f5360dde610 R08: 0000000000000000 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001\nR13: 00007fff29b3a628 R14: 0000000000000001 R15: 0000000000000001\n \u003c/TASK\u003e\n\nAllocated by task 5235:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x3f/0x80 mm/kasan/common.c:68\n unpoison_slab_object mm/kasan/common.c:312 [inline]\n __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338\n kasan_slab_alloc include/linux/kasan.h:201 [inline]\n slab_post_alloc_hook mm/slub.c:3988 [inline]\n slab_alloc_node mm/slub.c:4037 [inline]\n kmem_cache_alloc_node_noprof+0x16b/0x320 mm/slub.c:4080\n __alloc_skb+0x1c3/0x440 net/core/skbuff.c:667\n alloc_skb include/linux/skbuff.h:1320 [inline]\n alloc_skb_with_frags+0xc3/0x770 net/core/skbuff.c:6528\n sock_alloc_send_pskb+0x91a/0xa60 net/core/sock.c:2815\n sock_alloc_send_skb include/net/sock.h:1778 [inline]\n queue_oob+0x108/0x680 net/unix/af_unix.c:2198\n unix_stream_sendmsg+0xd24/0xf80 net/unix/af_unix.c:2351\n sock_sendmsg_nosec net/socket.c:730 [inline]\n __sock_sendmsg+0x221/0x270 net/socket.c:745\n ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597\n ___sys_sendmsg net/socket.c:2651 [inline]\n __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2680\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nFreed by task 5235:\n kasan_save_stack mm/kasan/common.c:47\n---truncated---","modified":"2026-03-20T12:39:11.139190Z","published":"2024-10-21T11:53:44.102Z","related":["USN-7276-1","USN-7277-1","openSUSE-SU-2024:14500-1","openSUSE-SU-2025:14705-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/47xxx/CVE-2024-47711.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/4a7f9a2591a923bdde4bd7eac33490b6ae3b257c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5aa57d9f2d5311f19434d95b2a81610aa263e23b"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/47xxx/CVE-2024-47711.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-47711"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"93c99f21db360957d49853e5666b5c147f593bda"},{"fixed":"4a7f9a2591a923bdde4bd7eac33490b6ae3b257c"},{"fixed":"5aa57d9f2d5311f19434d95b2a81610aa263e23b"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0"},{"last_affected":"71f8d9a4f6e094bae951765d1d18b44827013001"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-47711.json"}}],"schema_version":"1.7.5"}