[PATCH AUTOSEL 5.13 185/189] sctp: validate from_addr_param return

[PATCH AUTOSEL 5.13 185/189] 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 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 @@ 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 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 @@ 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;
 
@@ -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

[PATCH AUTOSEL 5.13 186/189] 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 8924e2e142c8..f72bff93745c 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