[PATCH AUTOSEL 5.4 71/74] sctp: validate from_addr_param return

[PATCH AUTOSEL 5.4 71/74] sctp: validate from_addr_param return

[Sasha Levin]

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 3e8f87a3c52f..fd7c3f76040c 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -466,7 +466,7 @@ 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 701c5a4e441d..a825e74d01fc 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 @@ int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw_addr_list,
 	}
 
 	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 7807754f69c5..a84523284777 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 52c92b8d827f..fae6157e837a 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -530,15 +530,20 @@ 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 981c7cbca46a..7f8702abc7bf 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -253,14 +253,19 @@ 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 4ffb9116b6f2..38ca7ce8a44e 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -2337,11 +2337,13 @@ 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;
 		}
@@ -2522,7 +2524,8 @@ 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))
@@ -2623,15 +2626,13 @@ static int sctp_process_param(struct sctp_association *asoc,
 		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;
 
@@ -3045,7 +3046,8 @@ 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.
@@ -3322,7 +3324,8 @@ 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

[PATCH AUTOSEL 5.4 72/74] sctp: add size validation when walking chunks

[Sasha Levin]

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

[ Upstream commit 50619dbf8db77e98d821d615af4f634d08e22698 ]

The first chunk in a packet is ensured to be present at the beginning of
sctp_rcv(), as a packet needs to have at least 1 chunk. But the second
one, may not be completely available and ch->length can be over
uninitialized memory.

Fix here is by only trying to walk on the next chunk if there is enough to
hold at least the header, and then proceed with the ch->length validation
that is already there.

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>
---
 net/sctp/input.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sctp/input.c b/net/sctp/input.c
index a84523284777..ab84ebf1af4a 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -1247,7 +1247,7 @@ static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net,
 
 		ch = (struct sctp_chunkhdr *)ch_end;
 		chunk_num++;
-	} while (ch_end < skb_tail_pointer(skb));
+	} while (ch_end + sizeof(*ch) < skb_tail_pointer(skb));
 
 	return asoc;
 }
-- 
2.30.2