[PATCH 5.4 016/434] sctp: fully initialize v4 addr in some functions

Greg Kroah-Hartman
2019-12-29T17:42:02Z

From: Xin Long <lucien.xin@gmail.com>

[ Upstream commit b6f3320b1d5267e7b583a6d0c88dda518101740c ]

Syzbot found a crash:

BUG: KMSAN: uninit-value in crc32_body lib/crc32.c:112 [inline]
BUG: KMSAN: uninit-value in crc32_le_generic lib/crc32.c:179 [inline]
BUG: KMSAN: uninit-value in __crc32c_le_base+0x4fa/0xd30 lib/crc32.c:202
Call Trace:
crc32_body lib/crc32.c:112 [inline]
crc32_le_generic lib/crc32.c:179 [inline]
__crc32c_le_base+0x4fa/0xd30 lib/crc32.c:202
chksum_update+0xb2/0x110 crypto/crc32c_generic.c:90
crypto_shash_update+0x4c5/0x530 crypto/shash.c:107
crc32c+0x150/0x220 lib/libcrc32c.c:47
sctp_csum_update+0x89/0xa0 include/net/sctp/checksum.h:36
__skb_checksum+0x1297/0x12a0 net/core/skbuff.c:2640
sctp_compute_cksum include/net/sctp/checksum.h:59 [inline]
sctp_packet_pack net/sctp/output.c:528 [inline]
sctp_packet_transmit+0x40fb/0x4250 net/sctp/output.c:597
sctp_outq_flush_transports net/sctp/outqueue.c:1146 [inline]
sctp_outq_flush+0x1823/0x5d80 net/sctp/outqueue.c:1194
sctp_outq_uncork+0xd0/0xf0 net/sctp/outqueue.c:757
sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1781 [inline]
sctp_side_effects net/sctp/sm_sideeffect.c:1184 [inline]
sctp_do_sm+0x8fe1/0x9720 net/sctp/sm_sideeffect.c:1155
sctp_primitive_REQUESTHEARTBEAT+0x175/0x1a0 net/sctp/primitive.c:185
sctp_apply_peer_addr_params+0x212/0x1d40 net/sctp/socket.c:2433
sctp_setsockopt_peer_addr_params net/sctp/socket.c:2686 [inline]
sctp_setsockopt+0x189bb/0x19090 net/sctp/socket.c:4672

The issue was caused by transport->ipaddr set with uninit addr param, which
was passed by:

sctp_transport_init net/sctp/transport.c:47 [inline]
sctp_transport_new+0x248/0xa00 net/sctp/transport.c:100
sctp_assoc_add_peer+0x5ba/0x2030 net/sctp/associola.c:611
sctp_process_param net/sctp/sm_make_chunk.c:2524 [inline]

where 'addr' is set by sctp_v4_from_addr_param(), and it doesn't initialize
the padding of addr->v4.

Later when calling sctp_make_heartbeat(), hbinfo.daddr(=transport->ipaddr)
will become the part of skb, and the issue occurs.

This patch is to fix it by initializing the padding of addr->v4 in
sctp_v4_from_addr_param(), as well as other functions that do the similar
thing, and these functions shouldn't trust that the caller initializes the
memory, as Marcelo suggested.

Reported-by: syzbot+6dcbfea81cd3d4dd0b02@syzkaller.appspotmail.com
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/sctp/protocol.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -227,6 +227,7 @@ static void sctp_v4_from_skb(union sctp_
sa->sin_port = sh->dest;
sa->sin_addr.s_addr = ip_hdr(skb)->daddr;
}
+ memset(sa->sin_zero, 0, sizeof(sa->sin_zero));
}

/* Initialize an sctp_addr from a socket. */
@@ -235,6 +236,7 @@ static void sctp_v4_from_sk(union sctp_a
addr->v4.sin_family = AF_INET;
addr->v4.sin_port = 0;
addr->v4.sin_addr.s_addr = inet_sk(sk)->inet_rcv_saddr;
+ memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
}

/* Initialize sk->sk_rcv_saddr from sctp_addr. */
@@ -257,6 +259,7 @@ static void sctp_v4_from_addr_param(unio
addr->v4.sin_family = AF_INET;
addr->v4.sin_port = port;
addr->v4.sin_addr.s_addr = param->v4.addr.s_addr;
+ memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
}

/* Initialize an address parameter from a sctp_addr and return the length
@@ -281,6 +284,7 @@ static void sctp_v4_dst_saddr(union sctp
saddr->v4.sin_family = AF_INET;
saddr->v4.sin_port = port;
saddr->v4.sin_addr.s_addr = fl4->saddr;
+ memset(saddr->v4.sin_zero, 0, sizeof(saddr->v4.sin_zero));
}

/* Compare two addresses exactly. */
@@ -303,6 +307,7 @@ static void sctp_v4_inaddr_any(union sct
addr->v4.sin_family = AF_INET;
addr->v4.sin_addr.s_addr = htonl(INADDR_ANY);
addr->v4.sin_port = port;
+ memset(addr->v4.sin_zero, 0, sizeof(addr->v4.sin_zero));
}

/* Is this a wildcard address? */