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

stable inclusion from linux-4.19.198 commit c7a03ebace4f9cd40d9cd9dd5fb2af558025583c CVE: CVE-2021-3655

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[ 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 Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Xiu Jianfeng xiujianfeng@huawei.com Reviewed-by: Yue Haibing yuehaibing@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- 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 19f8d5881b08d..2882bc7a5b4b8 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -474,7 +474,7 @@ 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 38d01cfb313e5..f8a2832456728 100644 --- a/net/sctp/bind_addr.c +++ b/net/sctp/bind_addr.c @@ -285,22 +285,19 @@ 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); @@ -309,6 +306,12 @@ 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 ee922867a5e02..81b4f091760eb 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -1088,7 +1088,8 @@ 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) @@ -1131,7 +1132,8 @@ 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 4cc5739244935..fc82617b60765 100644 --- a/net/sctp/ipv6.c +++ b/net/sctp/ipv6.c @@ -542,15 +542,20 @@ 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 af054f38341b9..dd51256582556 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -268,14 +268,19 @@ 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 dc51e14f568ee..a1ca070e36b0a 100644 --- a/net/sctp/sm_make_chunk.c +++ b/net/sctp/sm_make_chunk.c @@ -2352,11 +2352,13 @@ 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; } @@ -2537,7 +2539,8 @@ 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)) @@ -2634,15 +2637,13 @@ 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;

@@ -3059,7 +3060,8 @@ 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. @@ -3336,7 +3338,8 @@ 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: