| From foo@baz Wed Apr 11 10:26:56 CEST 2018 |
| From: Eric Dumazet <edumazet@google.com> |
| Date: Sun, 8 Apr 2018 07:52:08 -0700 |
| Subject: sctp: sctp_sockaddr_af must check minimal addr length for AF_INET6 |
| |
| From: Eric Dumazet <edumazet@google.com> |
| |
| |
| [ Upstream commit 81e98370293afcb58340ce8bd71af7b97f925c26 ] |
| |
| Check must happen before call to ipv6_addr_v4mapped() |
| |
| syzbot report was : |
| |
| BUG: KMSAN: uninit-value in sctp_sockaddr_af net/sctp/socket.c:359 [inline] |
| BUG: KMSAN: uninit-value in sctp_do_bind+0x60f/0xdc0 net/sctp/socket.c:384 |
| CPU: 0 PID: 3576 Comm: syzkaller968804 Not tainted 4.16.0+ #82 |
| Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 |
| Call Trace: |
| __dump_stack lib/dump_stack.c:17 [inline] |
| dump_stack+0x185/0x1d0 lib/dump_stack.c:53 |
| kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 |
| __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676 |
| sctp_sockaddr_af net/sctp/socket.c:359 [inline] |
| sctp_do_bind+0x60f/0xdc0 net/sctp/socket.c:384 |
| sctp_bind+0x149/0x190 net/sctp/socket.c:332 |
| inet6_bind+0x1fd/0x1820 net/ipv6/af_inet6.c:293 |
| SYSC_bind+0x3f2/0x4b0 net/socket.c:1474 |
| SyS_bind+0x54/0x80 net/socket.c:1460 |
| do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 |
| entry_SYSCALL_64_after_hwframe+0x3d/0xa2 |
| RIP: 0033:0x43fd49 |
| RSP: 002b:00007ffe99df3d28 EFLAGS: 00000213 ORIG_RAX: 0000000000000031 |
| RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fd49 |
| RDX: 0000000000000010 RSI: 0000000020000000 RDI: 0000000000000003 |
| RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 |
| R10: 00000000004002c8 R11: 0000000000000213 R12: 0000000000401670 |
| R13: 0000000000401700 R14: 0000000000000000 R15: 0000000000000000 |
| |
| Local variable description: ----address@SYSC_bind |
| Variable was created at: |
| SYSC_bind+0x6f/0x4b0 net/socket.c:1461 |
| SyS_bind+0x54/0x80 net/socket.c:1460 |
| |
| Signed-off-by: Eric Dumazet <edumazet@google.com> |
| Cc: Vlad Yasevich <vyasevich@gmail.com> |
| Cc: Neil Horman <nhorman@tuxdriver.com> |
| Reported-by: syzbot <syzkaller@googlegroups.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/sctp/socket.c | 13 ++++++++----- |
| 1 file changed, 8 insertions(+), 5 deletions(-) |
| |
| --- a/net/sctp/socket.c |
| +++ b/net/sctp/socket.c |
| @@ -335,11 +335,14 @@ static struct sctp_af *sctp_sockaddr_af( |
| if (!opt->pf->af_supported(addr->sa.sa_family, opt)) |
| return NULL; |
| |
| - /* V4 mapped address are really of AF_INET family */ |
| - if (addr->sa.sa_family == AF_INET6 && |
| - ipv6_addr_v4mapped(&addr->v6.sin6_addr) && |
| - !opt->pf->af_supported(AF_INET, opt)) |
| - return NULL; |
| + if (addr->sa.sa_family == AF_INET6) { |
| + if (len < SIN6_LEN_RFC2133) |
| + return NULL; |
| + /* V4 mapped address are really of AF_INET family */ |
| + if (ipv6_addr_v4mapped(&addr->v6.sin6_addr) && |
| + !opt->pf->af_supported(AF_INET, opt)) |
| + return NULL; |
| + } |
| |
| /* If we get this far, af is valid. */ |
| af = sctp_get_af_specific(addr->sa.sa_family); |