diff options
| -rw-r--r-- | include/net/ipv6.h | 2 | ||||
| -rw-r--r-- | net/ipv6/netfilter/nf_conntrack_reasm.c | 9 | ||||
| -rw-r--r-- | net/ipv6/reassembly.c | 55 |
3 files changed, 46 insertions, 20 deletions
diff --git a/include/net/ipv6.h b/include/net/ipv6.h index bd1f396cc9c7..637cc6dd12b7 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -1064,6 +1064,8 @@ int ipv6_skip_exthdr(const struct sk_buff *, int start, u8 *nexthdrp, bool ipv6_ext_hdr(u8 nexthdr); +bool ipv6_frag_thdr_truncated(struct sk_buff *skb, int start, u8 *nexthdrp); + enum { IP6_FH_F_FRAG = (1 << 0), IP6_FH_F_AUTH = (1 << 1), diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c index 054d287eb13d..b9cc0b330dbe 100644 --- a/net/ipv6/netfilter/nf_conntrack_reasm.c +++ b/net/ipv6/netfilter/nf_conntrack_reasm.c @@ -440,6 +440,7 @@ find_prev_fhdr(struct sk_buff *skb, u8 *prevhdrp, int *prevhoff, int *fhoff) int nf_ct_frag6_gather(struct net *net, struct sk_buff *skb, u32 user) { u16 savethdr = skb->transport_header; + u8 nexthdr = NEXTHDR_FRAGMENT; int fhoff, nhoff, ret; struct frag_hdr *fhdr; struct frag_queue *fq; @@ -455,6 +456,14 @@ int nf_ct_frag6_gather(struct net *net, struct sk_buff *skb, u32 user) if (find_prev_fhdr(skb, &prevhdr, &nhoff, &fhoff) < 0) return 0; + /* Discard the first fragment if it does not include all headers + * RFC 8200, Section 4.5 + */ + if (ipv6_frag_thdr_truncated(skb, fhoff, &nexthdr)) { + pr_debug("Drop incomplete fragment\n"); + return 0; + } + if (!pskb_may_pull(skb, fhoff + sizeof(*fhdr))) return -ENOMEM; diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c index c8cf1bbad74a..e3869bac9c88 100644 --- a/net/ipv6/reassembly.c +++ b/net/ipv6/reassembly.c @@ -318,15 +318,43 @@ out_fail: return -1; } +/* Check if the upper layer header is truncated in the first fragment. */ +bool ipv6_frag_thdr_truncated(struct sk_buff *skb, int start, u8 *nexthdrp) +{ + u8 nexthdr = *nexthdrp; + __be16 frag_off; + int offset; + + offset = ipv6_skip_exthdr(skb, start, &nexthdr, &frag_off); + if (offset < 0 || (frag_off & htons(IP6_OFFSET))) + return false; + switch (nexthdr) { + case NEXTHDR_TCP: + offset += sizeof(struct tcphdr); + break; + case NEXTHDR_UDP: + offset += sizeof(struct udphdr); + break; + case NEXTHDR_ICMP: + offset += sizeof(struct icmp6hdr); + break; + default: + offset += 1; + } + if (offset > skb->len) + return true; + return false; +} +EXPORT_SYMBOL(ipv6_frag_thdr_truncated); + static int ipv6_frag_rcv(struct sk_buff *skb) { struct frag_hdr *fhdr; struct frag_queue *fq; const struct ipv6hdr *hdr = ipv6_hdr(skb); struct net *net = dev_net(skb_dst(skb)->dev); - __be16 frag_off; - int iif, offset; u8 nexthdr; + int iif; if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED) goto fail_hdr; @@ -362,24 +390,11 @@ static int ipv6_frag_rcv(struct sk_buff *skb) * the source of the fragment, with the Pointer field set to zero. */ nexthdr = hdr->nexthdr; - offset = ipv6_skip_exthdr(skb, skb_transport_offset(skb), &nexthdr, &frag_off); - if (offset >= 0) { - /* Check some common protocols' header */ - if (nexthdr == IPPROTO_TCP) - offset += sizeof(struct tcphdr); - else if (nexthdr == IPPROTO_UDP) - offset += sizeof(struct udphdr); - else if (nexthdr == IPPROTO_ICMPV6) - offset += sizeof(struct icmp6hdr); - else - offset += 1; - - if (!(frag_off & htons(IP6_OFFSET)) && offset > skb->len) { - __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev), - IPSTATS_MIB_INHDRERRORS); - icmpv6_param_prob(skb, ICMPV6_HDR_INCOMP, 0); - return -1; - } + if (ipv6_frag_thdr_truncated(skb, skb_transport_offset(skb), &nexthdr)) { + __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev), + IPSTATS_MIB_INHDRERRORS); + icmpv6_param_prob(skb, ICMPV6_HDR_INCOMP, 0); + return -1; } iif = skb->dev ? skb->dev->ifindex : 0; |