4.9-stable review patch. If anyone has any objections, please let me know.
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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);