CVE-2022-50291

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> kcm: annotate data-races around kcm-&gt;rx_psock<br /> <br /> kcm-&gt;rx_psock can be read locklessly in kcm_rfree().<br /> Annotate the read and writes accordingly.<br /> <br /> We do the same for kcm-&gt;rx_wait in the following patch.<br /> <br /> syzbot reported:<br /> BUG: KCSAN: data-race in kcm_rfree / unreserve_rx_kcm<br /> <br /> write to 0xffff888123d827b8 of 8 bytes by task 2758 on cpu 1:<br /> unreserve_rx_kcm+0x72/0x1f0 net/kcm/kcmsock.c:313<br /> kcm_rcv_strparser+0x2b5/0x3a0 net/kcm/kcmsock.c:373<br /> __strp_recv+0x64c/0xd20 net/strparser/strparser.c:301<br /> strp_recv+0x6d/0x80 net/strparser/strparser.c:335<br /> tcp_read_sock+0x13e/0x5a0 net/ipv4/tcp.c:1703<br /> strp_read_sock net/strparser/strparser.c:358 [inline]<br /> do_strp_work net/strparser/strparser.c:406 [inline]<br /> strp_work+0xe8/0x180 net/strparser/strparser.c:415<br /> process_one_work+0x3d3/0x720 kernel/workqueue.c:2289<br /> worker_thread+0x618/0xa70 kernel/workqueue.c:2436<br /> kthread+0x1a9/0x1e0 kernel/kthread.c:376<br /> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306<br /> <br /> read to 0xffff888123d827b8 of 8 bytes by task 5859 on cpu 0:<br /> kcm_rfree+0x14c/0x220 net/kcm/kcmsock.c:181<br /> skb_release_head_state+0x8e/0x160 net/core/skbuff.c:841<br /> skb_release_all net/core/skbuff.c:852 [inline]<br /> __kfree_skb net/core/skbuff.c:868 [inline]<br /> kfree_skb_reason+0x5c/0x260 net/core/skbuff.c:891<br /> kfree_skb include/linux/skbuff.h:1216 [inline]<br /> kcm_recvmsg+0x226/0x2b0 net/kcm/kcmsock.c:1161<br /> ____sys_recvmsg+0x16c/0x2e0<br /> ___sys_recvmsg net/socket.c:2743 [inline]<br /> do_recvmmsg+0x2f1/0x710 net/socket.c:2837<br /> __sys_recvmmsg net/socket.c:2916 [inline]<br /> __do_sys_recvmmsg net/socket.c:2939 [inline]<br /> __se_sys_recvmmsg net/socket.c:2932 [inline]<br /> __x64_sys_recvmmsg+0xde/0x160 net/socket.c:2932<br /> do_syscall_x64 arch/x86/entry/common.c:50 [inline]<br /> do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80<br /> entry_SYSCALL_64_after_hwframe+0x63/0xcd<br /> <br /> value changed: 0xffff88812971ce00 -&gt; 0x0000000000000000<br /> <br /> Reported by Kernel Concurrency Sanitizer on:<br /> CPU: 0 PID: 5859 Comm: syz-executor.3 Not tainted 6.0.0-syzkaller-12189-g19d17ab7c68b-dirty #0<br /> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022