cb632144ae
commit 086d49058cd8471046ae9927524708820f5fd1c7 upstream. IPv6 has this hack changing sk->sk_prot when an IPv6 socket is 'converted' to an IPv4 one with IPV6_ADDRFORM option. This operation is only performed for TCP and UDP, knowing their 'struct proto' for the two network families are populated in the same way, and can not disappear while a reader might use and dereference sk->sk_prot. If we think about it all reads of sk->sk_prot while either socket lock or RTNL is not acquired should be using READ_ONCE(). Also note that other layers like MPTCP, XFRM, CHELSIO_TLS also write over sk->sk_prot. BUG: KCSAN: data-race in inet6_recvmsg / ipv6_setsockopt write to 0xffff8881386f7aa8 of 8 bytes by task 26932 on cpu 0: do_ipv6_setsockopt net/ipv6/ipv6_sockglue.c:492 [inline] ipv6_setsockopt+0x3758/0x3910 net/ipv6/ipv6_sockglue.c:1019 udpv6_setsockopt+0x85/0x90 net/ipv6/udp.c:1649 sock_common_setsockopt+0x5d/0x70 net/core/sock.c:3489 __sys_setsockopt+0x209/0x2a0 net/socket.c:2180 __do_sys_setsockopt net/socket.c:2191 [inline] __se_sys_setsockopt net/socket.c:2188 [inline] __x64_sys_setsockopt+0x62/0x70 net/socket.c:2188 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff8881386f7aa8 of 8 bytes by task 26911 on cpu 1: inet6_recvmsg+0x7a/0x210 net/ipv6/af_inet6.c:659 ____sys_recvmsg+0x16c/0x320 ___sys_recvmsg net/socket.c:2674 [inline] do_recvmmsg+0x3f5/0xae0 net/socket.c:2768 __sys_recvmmsg net/socket.c:2847 [inline] __do_sys_recvmmsg net/socket.c:2870 [inline] __se_sys_recvmmsg net/socket.c:2863 [inline] __x64_sys_recvmmsg+0xde/0x160 net/socket.c:2863 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0xffffffff85e0e980 -> 0xffffffff85e01580 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 26911 Comm: syz-executor.3 Not tainted 5.17.0-rc2-syzkaller-00316-g0457e5153e0e-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.