In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
sockmap: Fix use-after-free in udp_bpf_recvmsg()<\/p>\n
syzbot reported use-after-free of struct sk_msg in sk_msg_recvmsg(). [0]<\/p>\n
sk_msg_recvmsg() peeks sk_msg from psock->ingress_msg under a lock,
\nbut its processing is lockless.<\/p>\n
Thus, sk_msg_recvmsg() must be serialised by callers, otherwise
\nmultiple threads could touch the same sk_msg.<\/p>\n
For example, TCP uses lock_sock(), and AF_UNIX uses unix_sk(sk)->iolock.<\/p>\n
Initially, udp_bpf_recvmsg() had used lock_sock(), but the cited
\ncommit removed it.<\/p>\n
Let’s serialise sk_msg_recvmsg() with lock_sock() in udp_bpf_recvmsg().<\/p>\n
Note that holding spin_lock_bh(&sk->sk_receive_queue.lock) is not
\nan option due to copy_page_to_iter() in sk_msg_recvmsg().<\/p>\n
[0]:
\nBUG: KASAN: slab-use-after-free in sk_msg_recvmsg+0xb54\/0xc30 net\/core\/skmsg.c:428
\nRead of size 4 at addr ffff88814cdcf000 by task syz.0.24\/6020<\/p>\n
CPU: 1 UID: 0 PID: 6020 Comm: syz.0.24 Not tainted syzkaller #0 PREEMPT(full)
\nHardware name: Google Compute Engine\/Google Compute Engine, BIOS Google 01\/13\/2026
\nCall Trace:<\/p>\n
dump_stack_lvl+0xe8\/0x150 lib\/dump_stack.c:120
\n print_address_description mm\/kasan\/report.c:378 [inline]
\n print_report+0xba\/0x230 mm\/kasan\/report.c:482
\n kasan_report+0x117\/0x150 mm\/kasan\/report.c:595
\n sk_msg_recvmsg+0xb54\/0xc30 net\/core\/skmsg.c:428
\n udp_bpf_recvmsg+0x4bd\/0xe00 net\/ipv4\/udp_bpf.c:84
\n inet_recvmsg+0x260\/0x270 net\/ipv4\/af_inet.c:891
\n sock_recvmsg_nosec net\/socket.c:1078 [inline]
\n sock_recvmsg+0x1a8\/0x270 net\/socket.c:1100
\n ____sys_recvmsg+0x1e6\/0x4a0 net\/socket.c:2812
\n ___sys_recvmsg+0x215\/0x590 net\/socket.c:2854
\n do_recvmmsg+0x334\/0x800 net\/socket.c:2949
\n __sys_recvmmsg net\/socket.c:3023 [inline]
\n __do_sys_recvmmsg net\/socket.c:3046 [inline]
\n __se_sys_recvmmsg net\/socket.c:3039 [inline]
\n __x64_sys_recvmmsg+0x198\/0x250 net\/socket.c:3039
\n do_syscall_x64 arch\/x86\/entry\/syscall_64.c:63 [inline]
\n do_syscall_64+0xe2\/0xf80 arch\/x86\/entry\/syscall_64.c:94
\n entry_SYSCALL_64_after_hwframe+0x77\/0x7f
\nRIP: 0033:0x7fb319f9aeb9
\nCode: 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 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
\nRSP: 002b:00007fb31ad97028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
\nRAX: ffffffffffffffda RBX: 00007fb31a216090 RCX: 00007fb319f9aeb9
\nRDX: 0000000000000001 RSI: 0000200000000400 RDI: 0000000000000004
\nRBP: 00007fb31a008c1f R08: 0000000000000000 R09: 0000000000000000
\nR10: 0000000040000021 R11: 0000000000000246 R12: 0000000000000000
\nR13: 00007fb31a216128 R14: 00007fb31a216090 R15: 00007ffe21dd0a98<\/p>\n
Allocated by task 6019:
\n kasan_save_stack mm\/kasan\/common.c:57 [inline]
\n kasan_save_track+0x3e\/0x80 mm\/kasan\/common.c:78
\n poison_kmalloc_redzone mm\/kasan\/common.c:398 [inline]
\n __kasan_kmalloc+0x93\/0xb0 mm\/kasan\/common.c:415
\n kasan_kmalloc include\/linux\/kasan.h:263 [inline]
\n __kmalloc_cache_noprof+0x3d1\/0x6e0 mm\/slub.c:5780
\n kmalloc_noprof include\/linux\/slab.h:957 [inline]
\n kzalloc_noprof include\/linux\/slab.h:1094 [inline]
\n alloc_sk_msg net\/core\/skmsg.c:510 [inline]
\n sk_psock_skb_ingress_self+0x60\/0x350 net\/core\/skmsg.c:612
\n sk_psock_verdict_apply net\/core\/skmsg.c:1038 [inline]
\n sk_psock_verdict_recv+0x7d9\/0x8d0 net\/core\/skmsg.c:1236
\n udp_read_skb+0x73e\/0x7e0 net\/ipv4\/udp.c:2045
\n sk_psock_verdict_data_ready+0x12d\/0x550 net\/core\/skmsg.c:1257
\n __udp_enqueue_schedule_skb+0xc54\/0x10b0 net\/ipv4\/udp.c:1789
\n __udp_queue_rcv_skb net\/ipv4\/udp.c:2346 [inline]
\n udp_queue_rcv_one_skb+0xac5\/0x19c0 net\/ipv4\/udp.c:2475
\n __udp4_lib_mcast_deliver+0xc06\/0xcf0 net\/ipv4\/udp.c:2585
\n __udp4_lib_rcv+0x10f6\/0x2620 net\/ipv4\/udp.c:2724
\n ip_protocol_deliver_rcu+0x282\/0x440 net\/ipv4\/ip_input.c:207
\n ip_local_deliver_finish+0x3bb\/0x6f0 net\/ipv4\/ip_input.c:241
\n NF_HOOK+0x336\/0x3c0 include\/linux\/netfilter.h:318
\n dst_input include\/net\/dst.h:474 [inline]
\n ip_sublist_rcv_finish+0x221\/0x2a0 net\/ipv4\/ip_input.c:584
\n ip_list_rcv_finish net\/ipv4\/ip_inp
\n—truncated—<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
sockmap: Fix use-after-free in udp_bpf_recvmsg()<\/p>\n
syzbot reported use-after-free of struct sk_msg in sk_msg_recvmsg(). [0]<\/p>\n
sk_msg_<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-7188","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/7188","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7188"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7188"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7188"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}