[PATCH 4.9 26/26] sctp: validate from_addr_param return

Greg Kroah-Hartman
2021-09-24T12:47:59Z

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

commit 0c5dc070ff3d6246d22ddd931f23a6266249e3db upstream.

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/net/sctp/structs.h | 2 +-
net/sctp/bind_addr.c | 20 +++++++++++---------
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(+), 27 deletions(-)

--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -470,7 +470,7 @@ 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 *,
--- a/net/sctp/bind_addr.c
+++ b/net/sctp/bind_addr.c
@@ -285,20 +285,16 @@ int sctp_raw_to_bind_addrs(struct sctp_b
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);
retval = sctp_add_bind_addr(bp, &addr, sizeof(addr),
SCTP_ADDR_SRC, gfp);
- if (retval) {
- /* Can't finish building the list, clean up. */
- sctp_bind_addr_clean(bp);
- break;
- }
+ if (retval)
+ goto out_err;

len = ntohs(param->length);
addrs_len -= len;
@@ -306,6 +302,12 @@ int sctp_raw_to_bind_addrs(struct sctp_b
}

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

/********************************************************************
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -1051,7 +1051,8 @@ static struct sctp_association *__sctp_r
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)
@@ -1097,7 +1098,8 @@ static struct sctp_association *__sctp_r
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);
}
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -490,15 +490,20 @@ static void sctp_v6_to_sk_daddr(union sc
}

/* 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
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -274,14 +274,19 @@ static void sctp_v4_to_sk_daddr(union sc
}

/* 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
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -2342,11 +2342,13 @@ int sctp_process_init(struct sctp_associ

/* 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;
}
@@ -2540,7 +2542,8 @@ static int sctp_process_param(struct sct
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))
@@ -2633,15 +2636,13 @@ do_addr_param:
addr_param = param.v + sizeof(sctp_addip_param_t);

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;

@@ -3053,7 +3054,8 @@ static __be16 sctp_process_asconf_param(
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.
@@ -3318,7 +3320,8 @@ static void sctp_asconf_param_success(st

/* 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) {