3.16.72-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Steffen Klassert <[email protected]> commit 1a14f1e5550a341f76e5c8f596e9b5f8a886dfbc upstream. We skip the header informations if the data pointer points already behind the header in question for some protocols. This is because we call pskb_may_pull with a negative value converted to unsigened int from pskb_may_pull in this case. Skipping the header informations can lead to incorrect policy lookups, so fix it by a check of the data pointer position before we call pskb_may_pull. Signed-off-by: Steffen Klassert <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> --- net/ipv4/xfrm4_policy.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) --- a/net/ipv4/xfrm4_policy.c +++ b/net/ipv4/xfrm4_policy.c @@ -131,7 +131,8 @@ _decode_session4(struct sk_buff *skb, st break; case IPPROTO_ICMP: - if (pskb_may_pull(skb, xprth + 2 - skb->data)) { + if (xprth + 2 < skb->data || + pskb_may_pull(skb, xprth + 2 - skb->data)) { u8 *icmp = xprth; fl4->fl4_icmp_type = icmp[0]; @@ -140,7 +141,8 @@ _decode_session4(struct sk_buff *skb, st break; case IPPROTO_ESP: - if (pskb_may_pull(skb, xprth + 4 - skb->data)) { + if (xprth + 4 < skb->data || + pskb_may_pull(skb, xprth + 4 - skb->data)) { __be32 *ehdr = (__be32 *)xprth; fl4->fl4_ipsec_spi = ehdr[0]; @@ -148,7 +150,8 @@ _decode_session4(struct sk_buff *skb, st break; case IPPROTO_AH: - if (pskb_may_pull(skb, xprth + 8 - skb->data)) { + if (xprth + 8 < skb->data || + pskb_may_pull(skb, xprth + 8 - skb->data)) { __be32 *ah_hdr = (__be32 *)xprth; fl4->fl4_ipsec_spi = ah_hdr[1]; @@ -156,7 +159,8 @@ _decode_session4(struct sk_buff *skb, st break; case IPPROTO_COMP: - if (pskb_may_pull(skb, xprth + 4 - skb->data)) { + if (xprth + 4 < skb->data || + pskb_may_pull(skb, xprth + 4 - skb->data)) { __be16 *ipcomp_hdr = (__be16 *)xprth; fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1])); @@ -164,7 +168,8 @@ _decode_session4(struct sk_buff *skb, st break; case IPPROTO_GRE: - if (pskb_may_pull(skb, xprth + 12 - skb->data)) { + if (xprth + 12 < skb->data || + pskb_may_pull(skb, xprth + 12 - skb->data)) { __be16 *greflags = (__be16 *)xprth; __be32 *gre_hdr = (__be32 *)xprth;
