From 584eab291c67894cb17cc87544b9d086228ea70f Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Thu, 22 Nov 2018 19:59:46 +0900 Subject: netfilter: add missing error handling code for register functions register_{netdevice/inetaddr/inet6addr}_notifier may return an error value, this patch adds the code to handle these error paths. Signed-off-by: Taehee Yoo Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/ipv4/nf_nat_masquerade.h | 2 +- include/net/netfilter/ipv6/nf_nat_masquerade.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'include/net') diff --git a/include/net/netfilter/ipv4/nf_nat_masquerade.h b/include/net/netfilter/ipv4/nf_nat_masquerade.h index cd24be4c4a99..13d55206bb9f 100644 --- a/include/net/netfilter/ipv4/nf_nat_masquerade.h +++ b/include/net/netfilter/ipv4/nf_nat_masquerade.h @@ -9,7 +9,7 @@ nf_nat_masquerade_ipv4(struct sk_buff *skb, unsigned int hooknum, const struct nf_nat_range2 *range, const struct net_device *out); -void nf_nat_masquerade_ipv4_register_notifier(void); +int nf_nat_masquerade_ipv4_register_notifier(void); void nf_nat_masquerade_ipv4_unregister_notifier(void); #endif /*_NF_NAT_MASQUERADE_IPV4_H_ */ diff --git a/include/net/netfilter/ipv6/nf_nat_masquerade.h b/include/net/netfilter/ipv6/nf_nat_masquerade.h index 0c3b5ebf0bb8..2917bf95c437 100644 --- a/include/net/netfilter/ipv6/nf_nat_masquerade.h +++ b/include/net/netfilter/ipv6/nf_nat_masquerade.h @@ -5,7 +5,7 @@ unsigned int nf_nat_masquerade_ipv6(struct sk_buff *skb, const struct nf_nat_range2 *range, const struct net_device *out); -void nf_nat_masquerade_ipv6_register_notifier(void); +int nf_nat_masquerade_ipv6_register_notifier(void); void nf_nat_masquerade_ipv6_unregister_notifier(void); #endif /* _NF_NAT_MASQUERADE_IPV6_H_ */ -- cgit v1.2.3 From fb6df5a6234c38a9c551559506a49a677ac6f07a Mon Sep 17 00:00:00 2001 From: Xin Long Date: Sat, 1 Dec 2018 01:36:59 +0800 Subject: sctp: kfree_rcu asoc In sctp_hash_transport/sctp_epaddr_lookup_transport, it dereferences a transport's asoc under rcu_read_lock while asoc is freed not after a grace period, which leads to a use-after-free panic. This patch fixes it by calling kfree_rcu to make asoc be freed after a grace period. Note that only the asoc's memory is delayed to free in the patch, it won't cause sk to linger longer. Thanks Neil and Marcelo to make this clear. Fixes: 7fda702f9315 ("sctp: use new rhlist interface on sctp transport rhashtable") Fixes: cd2b70875058 ("sctp: check duplicate node before inserting a new transport") Reported-by: syzbot+0b05d8aa7cb185107483@syzkaller.appspotmail.com Reported-by: syzbot+aad231d51b1923158444@syzkaller.appspotmail.com Suggested-by: Neil Horman Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Acked-by: Neil Horman Signed-off-by: David S. Miller --- include/net/sctp/structs.h | 2 ++ net/sctp/associola.c | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-) (limited to 'include/net') diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index a11f93790476..feada358d872 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -2075,6 +2075,8 @@ struct sctp_association { __u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1]; __u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1]; + + struct rcu_head rcu; }; diff --git a/net/sctp/associola.c b/net/sctp/associola.c index dd77ec3892b6..914750b819b2 100644 --- a/net/sctp/associola.c +++ b/net/sctp/associola.c @@ -435,7 +435,7 @@ static void sctp_association_destroy(struct sctp_association *asoc) WARN_ON(atomic_read(&asoc->rmem_alloc)); - kfree(asoc); + kfree_rcu(asoc, rcu); SCTP_DBG_OBJCNT_DEC(assoc); } -- cgit v1.2.3 From afd0a8006e98b1890908f81746c94ca5dae29d7c Mon Sep 17 00:00:00 2001 From: Jakub Audykowicz Date: Tue, 4 Dec 2018 20:27:41 +0100 Subject: sctp: frag_point sanity check If for some reason an association's fragmentation point is zero, sctp_datamsg_from_user will try to endlessly try to divide a message into zero-sized chunks. This eventually causes kernel panic due to running out of memory. Although this situation is quite unlikely, it has occurred before as reported. I propose to add this simple last-ditch sanity check due to the severity of the potential consequences. Signed-off-by: Jakub Audykowicz Acked-by: Neil Horman Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller --- include/net/sctp/sctp.h | 5 +++++ net/sctp/chunk.c | 6 ++++++ net/sctp/socket.c | 3 +-- 3 files changed, 12 insertions(+), 2 deletions(-) (limited to 'include/net') diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h index ab9242e51d9e..2abbc15824af 100644 --- a/include/net/sctp/sctp.h +++ b/include/net/sctp/sctp.h @@ -620,4 +620,9 @@ static inline bool sctp_transport_pmtu_check(struct sctp_transport *t) return false; } +static inline __u32 sctp_min_frag_point(struct sctp_sock *sp, __u16 datasize) +{ + return sctp_mtu_payload(sp, SCTP_DEFAULT_MINSEGMENT, datasize); +} + #endif /* __net_sctp_h__ */ diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c index ce8087846f05..d2048de86e7c 100644 --- a/net/sctp/chunk.c +++ b/net/sctp/chunk.c @@ -191,6 +191,12 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, * the packet */ max_data = asoc->frag_point; + if (unlikely(!max_data)) { + max_data = sctp_min_frag_point(sctp_sk(asoc->base.sk), + sctp_datachk_len(&asoc->stream)); + pr_warn_ratelimited("%s: asoc:%p frag_point is zero, forcing max_data to default minimum (%Zu)", + __func__, asoc, max_data); + } /* If the the peer requested that we authenticate DATA chunks * we need to account for bundling of the AUTH chunks along with diff --git a/net/sctp/socket.c b/net/sctp/socket.c index bf618d1b41fd..b8cebd5a87e5 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -3324,8 +3324,7 @@ static int sctp_setsockopt_maxseg(struct sock *sk, char __user *optval, unsigned __u16 datasize = asoc ? sctp_datachk_len(&asoc->stream) : sizeof(struct sctp_data_chunk); - min_len = sctp_mtu_payload(sp, SCTP_DEFAULT_MINSEGMENT, - datasize); + min_len = sctp_min_frag_point(sp, datasize); max_len = SCTP_MAX_CHUNK_LEN - datasize; if (val < min_len || val > max_len) -- cgit v1.2.3 From e6ac64d4c4d095085d7dd71cbd05704ac99829b2 Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Thu, 6 Dec 2018 19:30:37 +0100 Subject: neighbour: Avoid writing before skb->head in neigh_hh_output() While skb_push() makes the kernel panic if the skb headroom is less than the unaligned hardware header size, it will proceed normally in case we copy more than that because of alignment, and we'll silently corrupt adjacent slabs. In the case fixed by the previous patch, "ipv6: Check available headroom in ip6_xmit() even without options", we end up in neigh_hh_output() with 14 bytes headroom, 14 bytes hardware header and write 16 bytes, starting 2 bytes before the allocated buffer. Always check we're not writing before skb->head and, if the headroom is not enough, warn and drop the packet. v2: - instead of panicking with BUG_ON(), WARN_ON_ONCE() and drop the packet (Eric Dumazet) - if we avoid the panic, though, we need to explicitly check the headroom before the memcpy(), otherwise we'll have corrupted slabs on a running kernel, after we warn - use __skb_push() instead of skb_push(), as the headroom check is already implemented here explicitly (Eric Dumazet) Signed-off-by: Stefano Brivio Signed-off-by: David S. Miller --- include/net/neighbour.h | 28 +++++++++++++++++++++++----- 1 file changed, 23 insertions(+), 5 deletions(-) (limited to 'include/net') diff --git a/include/net/neighbour.h b/include/net/neighbour.h index f58b384aa6c9..665990c7dec8 100644 --- a/include/net/neighbour.h +++ b/include/net/neighbour.h @@ -454,6 +454,7 @@ static inline int neigh_hh_bridge(struct hh_cache *hh, struct sk_buff *skb) static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb) { + unsigned int hh_alen = 0; unsigned int seq; unsigned int hh_len; @@ -461,16 +462,33 @@ static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb seq = read_seqbegin(&hh->hh_lock); hh_len = hh->hh_len; if (likely(hh_len <= HH_DATA_MOD)) { - /* this is inlined by gcc */ - memcpy(skb->data - HH_DATA_MOD, hh->hh_data, HH_DATA_MOD); + hh_alen = HH_DATA_MOD; + + /* skb_push() would proceed silently if we have room for + * the unaligned size but not for the aligned size: + * check headroom explicitly. + */ + if (likely(skb_headroom(skb) >= HH_DATA_MOD)) { + /* this is inlined by gcc */ + memcpy(skb->data - HH_DATA_MOD, hh->hh_data, + HH_DATA_MOD); + } } else { - unsigned int hh_alen = HH_DATA_ALIGN(hh_len); + hh_alen = HH_DATA_ALIGN(hh_len); - memcpy(skb->data - hh_alen, hh->hh_data, hh_alen); + if (likely(skb_headroom(skb) >= hh_alen)) { + memcpy(skb->data - hh_alen, hh->hh_data, + hh_alen); + } } } while (read_seqretry(&hh->hh_lock, seq)); - skb_push(skb, hh_len); + if (WARN_ON_ONCE(skb_headroom(skb) < hh_alen)) { + kfree_skb(skb); + return NET_XMIT_DROP; + } + + __skb_push(skb, hh_len); return dev_queue_xmit(skb); } -- cgit v1.2.3