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Subject[PATCH v2] sctp: fully initialize the IPv6 address in sctp_v6_to_addr()
Date
KMSAN reported use of uninitialized sctp_addr->v4.sin_addr.s_addr and
sctp_addr->v6.sin6_scope_id in sctp_v6_cmp_addr() (see below).
Make sure all fields of an IPv6 address are initialized, which
guarantees that the IPv4 fields are also initialized.

==================================================================
BUG: KMSAN: use of uninitialized memory in sctp_v6_cmp_addr+0x8d4/0x9f0
net/sctp/ipv6.c:517
CPU: 2 PID: 31056 Comm: syz-executor1 Not tainted 4.11.0-rc5+ #2944
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
01/01/2011
Call Trace:
dump_stack+0x172/0x1c0 lib/dump_stack.c:42
is_logbuf_locked mm/kmsan/kmsan.c:59 [inline]
kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:938
native_save_fl arch/x86/include/asm/irqflags.h:18 [inline]
arch_local_save_flags arch/x86/include/asm/irqflags.h:72 [inline]
arch_local_irq_save arch/x86/include/asm/irqflags.h:113 [inline]
__msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:467
sctp_v6_cmp_addr+0x8d4/0x9f0 net/sctp/ipv6.c:517
sctp_v6_get_dst+0x8c7/0x1630 net/sctp/ipv6.c:290
sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
sctp_assoc_add_peer+0x66d/0x16f0 net/sctp/associola.c:651
sctp_sendmsg+0x35a5/0x4f90 net/sctp/socket.c:1871
inet_sendmsg+0x498/0x670 net/ipv4/af_inet.c:762
sock_sendmsg_nosec net/socket.c:633 [inline]
sock_sendmsg net/socket.c:643 [inline]
SYSC_sendto+0x608/0x710 net/socket.c:1696
SyS_sendto+0x8a/0xb0 net/socket.c:1664
entry_SYSCALL_64_fastpath+0x13/0x94
RIP: 0033:0x44b479
RSP: 002b:00007f6213f21c08 EFLAGS: 00000286 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 000000000044b479
RDX: 0000000000000041 RSI: 0000000020edd000 RDI: 0000000000000006
RBP: 00000000007080a8 R08: 0000000020b85fe4 R09: 000000000000001c
R10: 0000000000040005 R11: 0000000000000286 R12: 00000000ffffffff
R13: 0000000000003760 R14: 00000000006e5820 R15: 0000000000ff8000
origin description: ----dst_saddr@sctp_v6_get_dst
local variable created at:
sk_fullsock include/net/sock.h:2321 [inline]
inet6_sk include/linux/ipv6.h:309 [inline]
sctp_v6_get_dst+0x91/0x1630 net/sctp/ipv6.c:241
sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
==================================================================
BUG: KMSAN: use of uninitialized memory in sctp_v6_cmp_addr+0x8d4/0x9f0
net/sctp/ipv6.c:517
CPU: 2 PID: 31056 Comm: syz-executor1 Not tainted 4.11.0-rc5+ #2944
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
01/01/2011
Call Trace:
dump_stack+0x172/0x1c0 lib/dump_stack.c:42
is_logbuf_locked mm/kmsan/kmsan.c:59 [inline]
kmsan_report+0x12a/0x180 mm/kmsan/kmsan.c:938
native_save_fl arch/x86/include/asm/irqflags.h:18 [inline]
arch_local_save_flags arch/x86/include/asm/irqflags.h:72 [inline]
arch_local_irq_save arch/x86/include/asm/irqflags.h:113 [inline]
__msan_warning_32+0x61/0xb0 mm/kmsan/kmsan_instr.c:467
sctp_v6_cmp_addr+0x8d4/0x9f0 net/sctp/ipv6.c:517
sctp_v6_get_dst+0x8c7/0x1630 net/sctp/ipv6.c:290
sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
sctp_assoc_add_peer+0x66d/0x16f0 net/sctp/associola.c:651
sctp_sendmsg+0x35a5/0x4f90 net/sctp/socket.c:1871
inet_sendmsg+0x498/0x670 net/ipv4/af_inet.c:762
sock_sendmsg_nosec net/socket.c:633 [inline]
sock_sendmsg net/socket.c:643 [inline]
SYSC_sendto+0x608/0x710 net/socket.c:1696
SyS_sendto+0x8a/0xb0 net/socket.c:1664
entry_SYSCALL_64_fastpath+0x13/0x94
RIP: 0033:0x44b479
RSP: 002b:00007f6213f21c08 EFLAGS: 00000286 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 000000000044b479
RDX: 0000000000000041 RSI: 0000000020edd000 RDI: 0000000000000006
RBP: 00000000007080a8 R08: 0000000020b85fe4 R09: 000000000000001c
R10: 0000000000040005 R11: 0000000000000286 R12: 00000000ffffffff
R13: 0000000000003760 R14: 00000000006e5820 R15: 0000000000ff8000
origin description: ----dst_saddr@sctp_v6_get_dst
local variable created at:
sk_fullsock include/net/sock.h:2321 [inline]
inet6_sk include/linux/ipv6.h:309 [inline]
sctp_v6_get_dst+0x91/0x1630 net/sctp/ipv6.c:241
sctp_transport_route+0x101/0x570 net/sctp/transport.c:292
==================================================================

Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
---
v2 is identical to v1, resending per request by Marcelo Ricardo Leitner.
---
net/sctp/ipv6.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 2a186b201ad2..a15d691829c6 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -513,6 +513,8 @@ static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr,
addr->sa.sa_family = AF_INET6;
addr->v6.sin6_port = port;
addr->v6.sin6_addr = *saddr;
+ addr->v6.sin6_flowinfo = 0;
+ addr->v6.sin6_scope_id = 0;
}

/* Compare addresses exactly.
--
2.14.0.434.g98096fd7a8-goog
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