[PATCH 5.13 172/266] sctp: validate from_addr_param return

Greg Kroah-Hartman
2021-07-15T19:38:13Z

From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

[ Upstream commit 0c5dc070ff3d6246d22ddd931f23a6266249e3db ]

Ilja reported that, simply putting it, nothing was validating that
from_addr_param functions were operating on initialized memory. That is,
the parameter itself was being validated by sctp_walk_params, but it
doesn't check for types and their specific sizes and it could be a 0-length
one, causing from_addr_param to potentially work over the next parameter or
even uninitialized memory.

The fix here is to, in all calls to from_addr_param, check if enough space
is there for the wanted IP address type.

Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/net/sctp/structs.h | 2 +-
net/sctp/bind_addr.c | 19 +++++++++++--------
net/sctp/input.c | 6 ++++--
net/sctp/ipv6.c | 7 ++++++-
net/sctp/protocol.c | 7 ++++++-
net/sctp/sm_make_chunk.c | 29 ++++++++++++++++-------------
6 files changed, 44 insertions(+), 26 deletions(-)

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 1aa585216f34..d49593c72a55 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -461,7 +461,7 @@ struct sctp_af {
int saddr);
void (*from_sk) (union sctp_addr *,
struct sock *sk);
- void (*from_addr_param) (union sctp_addr *,
+ bool (*from_addr_param) (union sctp_addr *,
union sctp_addr_param *,
__be16 port, int iif);
int (*to_addr_param) (const union sctp_addr *,
diff --git a/net/sctp/bind_addr.c b/net/sctp/bind_addr.c
index 53e5ed79f63f..59e653b528b1 100644
--- a/net/sctp/bind_addr.c
+++ b/net/sctp/bind_addr.c
@@ -270,22 +270,19 @@ int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw_addr_list,
rawaddr = (union sctp_addr_param *)raw_addr_list;

af = sctp_get_af_specific(param_type2af(param->type));
- if (unlikely(!af)) {
+ if (unlikely(!af) ||
+ !af->from_addr_param(&addr, rawaddr, htons(port), 0)) {
retval = -EINVAL;
- sctp_bind_addr_clean(bp);
- break;
+ goto out_err;
}

- af->from_addr_param(&addr, rawaddr, htons(port), 0);
if (sctp_bind_addr_state(bp, &addr) != -1)
goto next;
retval = sctp_add_bind_addr(bp, &addr, sizeof(addr),
SCTP_ADDR_SRC, gfp);
- if (retval) {
+ if (retval)
/* Can't finish building the list, clean up. */
- sctp_bind_addr_clean(bp);
- break;
- }
+ goto out_err;

next:
len = ntohs(param->length);
@@ -294,6 +291,12 @@ next:
}

return retval;
+
+out_err:
+ if (retval)
+ sctp_bind_addr_clean(bp);
+
+ return retval;
}

/********************************************************************
diff --git a/net/sctp/input.c b/net/sctp/input.c
index d508f6f3dd08..8924e2e142c8 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -1131,7 +1131,8 @@ static struct sctp_association *__sctp_rcv_init_lookup(struct net *net,
if (!af)
continue;

- af->from_addr_param(paddr, params.addr, sh->source, 0);
+ if (!af->from_addr_param(paddr, params.addr, sh->source, 0))
+ continue;

asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
if (asoc)
@@ -1174,7 +1175,8 @@ static struct sctp_association *__sctp_rcv_asconf_lookup(
if (unlikely(!af))
return NULL;

- af->from_addr_param(&paddr, param, peer_port, 0);
+ if (af->from_addr_param(&paddr, param, peer_port, 0))
+ return NULL;

return __sctp_lookup_association(net, laddr, &paddr, transportp);
}
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index bd08807c9e44..5c6f5ced9cfa 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -551,15 +551,20 @@ static void sctp_v6_to_sk_daddr(union sctp_addr *addr, struct sock *sk)
}

/* Initialize a sctp_addr from an address parameter. */
-static void sctp_v6_from_addr_param(union sctp_addr *addr,
+static bool sctp_v6_from_addr_param(union sctp_addr *addr,
union sctp_addr_param *param,
__be16 port, int iif)
{
+ if (ntohs(param->v6.param_hdr.length) < sizeof(struct sctp_ipv6addr_param))
+ return false;
+
addr->v6.sin6_family = AF_INET6;
addr->v6.sin6_port = port;
addr->v6.sin6_flowinfo = 0; /* BUG */
addr->v6.sin6_addr = param->v6.addr;
addr->v6.sin6_scope_id = iif;
+
+ return true;
}

/* Initialize an address parameter from a sctp_addr and return the length
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 6f2bbfeec3a4..25192b378e2e 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -254,14 +254,19 @@ static void sctp_v4_to_sk_daddr(union sctp_addr *addr, struct sock *sk)
}

/* Initialize a sctp_addr from an address parameter. */
-static void sctp_v4_from_addr_param(union sctp_addr *addr,
+static bool sctp_v4_from_addr_param(union sctp_addr *addr,
union sctp_addr_param *param,
__be16 port, int iif)
{
+ if (ntohs(param->v4.param_hdr.length) < sizeof(struct sctp_ipv4addr_param))
+ return false;
+
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));
+
+ return true;
}

/* Initialize an address parameter from a sctp_addr and return the length
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 5b44d228b6ca..f33a870b483d 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -2346,11 +2346,13 @@ int sctp_process_init(struct sctp_association *asoc, struct sctp_chunk *chunk,

/* Process the initialization parameters. */
sctp_walk_params(param, peer_init, init_hdr.params) {
- if (!src_match && (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
- param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
+ if (!src_match &&
+ (param.p->type == SCTP_PARAM_IPV4_ADDRESS ||
+ param.p->type == SCTP_PARAM_IPV6_ADDRESS)) {
af = sctp_get_af_specific(param_type2af(param.p->type));
- af->from_addr_param(&addr, param.addr,
- chunk->sctp_hdr->source, 0);
+ if (!af->from_addr_param(&addr, param.addr,
+ chunk->sctp_hdr->source, 0))
+ continue;
if (sctp_cmp_addr_exact(sctp_source(chunk), &addr))
src_match = 1;
}
@@ -2531,7 +2533,8 @@ static int sctp_process_param(struct sctp_association *asoc,
break;
do_addr_param:
af = sctp_get_af_specific(param_type2af(param.p->type));
- af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0);
+ if (!af->from_addr_param(&addr, param.addr, htons(asoc->peer.port), 0))
+ break;
scope = sctp_scope(peer_addr);
if (sctp_in_scope(net, &addr, scope))
if (!sctp_assoc_add_peer(asoc, &addr, gfp, SCTP_UNCONFIRMED))
@@ -2632,15 +2635,13 @@ do_addr_param:
addr_param = param.v + sizeof(struct sctp_addip_param);

af = sctp_get_af_specific(param_type2af(addr_param->p.type));
- if (af == NULL)
+ if (!af)
break;

- af->from_addr_param(&addr, addr_param,
- htons(asoc->peer.port), 0);
+ if (!af->from_addr_param(&addr, addr_param,
+ htons(asoc->peer.port), 0))
+ break;

- /* if the address is invalid, we can't process it.
- * XXX: see spec for what to do.
- */
if (!af->addr_valid(&addr, NULL, NULL))
break;

@@ -3054,7 +3055,8 @@ static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
if (unlikely(!af))
return SCTP_ERROR_DNS_FAILED;

- af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0);
+ if (!af->from_addr_param(&addr, addr_param, htons(asoc->peer.port), 0))
+ return SCTP_ERROR_DNS_FAILED;

/* ADDIP 4.2.1 This parameter MUST NOT contain a broadcast
* or multicast address.
@@ -3331,7 +3333,8 @@ static void sctp_asconf_param_success(struct sctp_association *asoc,

/* We have checked the packet before, so we do not check again. */
af = sctp_get_af_specific(param_type2af(addr_param->p.type));
- af->from_addr_param(&addr, addr_param, htons(bp->port), 0);
+ if (!af->from_addr_param(&addr, addr_param, htons(bp->port), 0))
+ return;

switch (asconf_param->param_hdr.type) {
case SCTP_PARAM_ADD_IP:
--
2.30.2