| Message ID | 20180408145208.228542-1-edumazet@google.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] sctp: sctp_sockaddr_af must check minimal addr length for AF_INET6 | expand |
From: Eric Dumazet <edumazet@google.com> Date: Sun, 8 Apr 2018 07:52:08 -0700 > Check must happen before call to ipv6_addr_v4mapped() > > syzbot report was : ... > 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> Applied and queued up for -stable, thanks Eric.
On Sun, Apr 08, 2018 at 07:52:08AM -0700, Eric Dumazet wrote:
> Check must happen before call to ipv6_addr_v4mapped()
Please don't forget to also Cc linux-sctp@vger.kernel.org on sctp
patches.
Thanks!
diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 7a10ae3c3d8293abecd955ff6a5a19e60dcc6f95..eb712df7156eda7124cd88b4034359b088c2c475 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -357,11 +357,14 @@ static struct sctp_af *sctp_sockaddr_af(struct sctp_sock *opt, 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);
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> --- net/sctp/socket.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)