From 0c5dc070ff3d6246d22ddd931f23a6266249e3db Mon Sep 17 00:00:00 2001 From: Marcelo Ricardo Leitner Date: Mon, 28 Jun 2021 16:13:41 -0300 Subject: sctp: validate from_addr_param return 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 Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller --- 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 ++++++++++++++++------------- 5 files changed, 43 insertions(+), 25 deletions(-) (limited to 'net/sctp') 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: -- cgit v1.2.3 From 50619dbf8db77e98d821d615af4f634d08e22698 Mon Sep 17 00:00:00 2001 From: Marcelo Ricardo Leitner Date: Mon, 28 Jun 2021 16:13:42 -0300 Subject: sctp: add size validation when walking chunks 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 Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller --- net/sctp/input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/sctp') 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; } -- cgit v1.2.3 From b6ffe7671b24689c09faa5675dd58f93758a97ae Mon Sep 17 00:00:00 2001 From: Marcelo Ricardo Leitner Date: Mon, 28 Jun 2021 16:13:43 -0300 Subject: sctp: validate chunk size in __rcv_asconf_lookup In one of the fallbacks that SCTP has for identifying an association for an incoming packet, it looks for AddIp chunk (from ASCONF) and take a peek. Thing is, at this stage nothing was validating that the chunk actually had enough content for that, allowing the peek to happen over uninitialized memory. Similar check already exists in actual asconf handling in sctp_verify_asconf(). Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller --- net/sctp/input.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/sctp') diff --git a/net/sctp/input.c b/net/sctp/input.c index f72bff93745c..96dea8097dbe 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -1168,6 +1168,9 @@ static struct sctp_association *__sctp_rcv_asconf_lookup( union sctp_addr_param *param; union sctp_addr paddr; + if (ntohs(ch->length) < sizeof(*asconf) + sizeof(struct sctp_paramhdr)) + return NULL; + /* Skip over the ADDIP header and find the Address parameter */ param = (union sctp_addr_param *)(asconf + 1); -- cgit v1.2.3 From ef6c8d6ccf0c1dccdda092ebe8782777cd7803c9 Mon Sep 17 00:00:00 2001 From: Marcelo Ricardo Leitner Date: Mon, 28 Jun 2021 16:13:44 -0300 Subject: sctp: add param size validation for SCTP_PARAM_SET_PRIMARY When SCTP handles an INIT chunk, it calls for example: sctp_sf_do_5_1B_init sctp_verify_init sctp_verify_param sctp_process_init sctp_process_param handling of SCTP_PARAM_SET_PRIMARY sctp_verify_init() wasn't doing proper size validation and neither the later handling, allowing it to work over the chunk itself, possibly being uninitialized memory. Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller --- net/sctp/sm_make_chunk.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'net/sctp') diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c index f33a870b483d..587fb3cb88e2 100644 --- a/net/sctp/sm_make_chunk.c +++ b/net/sctp/sm_make_chunk.c @@ -2166,9 +2166,16 @@ static enum sctp_ierror sctp_verify_param(struct net *net, break; case SCTP_PARAM_SET_PRIMARY: - if (ep->asconf_enable) - break; - goto unhandled; + if (!ep->asconf_enable) + goto unhandled; + + if (ntohs(param.p->length) < sizeof(struct sctp_addip_param) + + sizeof(struct sctp_paramhdr)) { + sctp_process_inv_paramlength(asoc, param.p, + chunk, err_chunk); + retval = SCTP_IERROR_ABORT; + } + break; case SCTP_PARAM_HOST_NAME_ADDRESS: /* Tell the peer, we won't support this param. */ -- cgit v1.2.3