diff options
| author | Ross Lagerwall <ross.lagerwall@citrix.com> | 2019-01-17 18:34:38 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-31 10:13:41 +0300 |
| commit | 66a011d153c67599c0dc11704ce4ef3f387b1e22 (patch) | |
| tree | e19327ab0145836bef1074e92ef7e285499c2388 | |
| parent | 1ae7a7cb7ab8016e84781dd9cddd705d9e794248 (diff) | |
| download | linux-66a011d153c67599c0dc11704ce4ef3f387b1e22.tar.xz | |
net: Fix usage of pskb_trim_rcsum
[ Upstream commit 6c57f0458022298e4da1729c67bd33ce41c14e7a ]
In certain cases, pskb_trim_rcsum() may change skb pointers.
Reinitialize header pointers afterwards to avoid potential
use-after-frees. Add a note in the documentation of
pskb_trim_rcsum(). Found by KASAN.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/net/ppp/pppoe.c | 1 | ||||
| -rw-r--r-- | include/linux/skbuff.h | 1 | ||||
| -rw-r--r-- | net/bridge/br_netfilter_ipv6.c | 1 | ||||
| -rw-r--r-- | net/bridge/netfilter/nft_reject_bridge.c | 1 | ||||
| -rw-r--r-- | net/ipv4/ip_input.c | 1 |
5 files changed, 5 insertions, 0 deletions
diff --git a/drivers/net/ppp/pppoe.c b/drivers/net/ppp/pppoe.c index 951892da3352..c37ef5287caa 100644 --- a/drivers/net/ppp/pppoe.c +++ b/drivers/net/ppp/pppoe.c @@ -445,6 +445,7 @@ static int pppoe_rcv(struct sk_buff *skb, struct net_device *dev, if (pskb_trim_rcsum(skb, len)) goto drop; + ph = pppoe_hdr(skb); pn = pppoe_pernet(dev_net(dev)); /* Note that get_item does a sock_hold(), so sk_pppox(po) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index f6250555ce7d..39c2570ddcf6 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3163,6 +3163,7 @@ int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len); * * This is exactly the same as pskb_trim except that it ensures the * checksum of received packets are still valid after the operation. + * It can change skb pointers. */ static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len) diff --git a/net/bridge/br_netfilter_ipv6.c b/net/bridge/br_netfilter_ipv6.c index 96c072e71ea2..5811208863b7 100644 --- a/net/bridge/br_netfilter_ipv6.c +++ b/net/bridge/br_netfilter_ipv6.c @@ -131,6 +131,7 @@ int br_validate_ipv6(struct net *net, struct sk_buff *skb) IPSTATS_MIB_INDISCARDS); goto drop; } + hdr = ipv6_hdr(skb); } if (hdr->nexthdr == NEXTHDR_HOP && br_nf_check_hbh_len(skb)) goto drop; diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c index eaf05de37f75..b09ec869c913 100644 --- a/net/bridge/netfilter/nft_reject_bridge.c +++ b/net/bridge/netfilter/nft_reject_bridge.c @@ -230,6 +230,7 @@ static bool reject6_br_csum_ok(struct sk_buff *skb, int hook) pskb_trim_rcsum(skb, ntohs(ip6h->payload_len) + sizeof(*ip6h))) return false; + ip6h = ipv6_hdr(skb); thoff = ipv6_skip_exthdr(skb, ((u8*)(ip6h+1) - skb->data), &proto, &fo); if (thoff < 0 || thoff >= skb->len || (fo & htons(~0x7)) != 0) return false; diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c index 57fc13c6ab2b..1b160378ea9c 100644 --- a/net/ipv4/ip_input.c +++ b/net/ipv4/ip_input.c @@ -481,6 +481,7 @@ int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, goto drop; } + iph = ip_hdr(skb); skb->transport_header = skb->network_header + iph->ihl*4; /* Remove any debris in the socket control block */ |