diff options
| -rw-r--r-- | net/ipv6/ip6_output.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index a8a919520090..5cb18c8ba9b2 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1246,7 +1246,7 @@ static int __ip6_append_data(struct sock *sk, const struct sockcm_cookie *sockc) { struct sk_buff *skb, *skb_prev = NULL; - unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu; + unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu; int exthdrlen = 0; int dst_exthdrlen = 0; int hh_len; @@ -1282,6 +1282,12 @@ static int __ip6_append_data(struct sock *sk, sizeof(struct frag_hdr) : 0) + rt->rt6i_nfheader_len; + /* as per RFC 7112 section 5, the entire IPv6 Header Chain must fit + * the first fragment + */ + if (headersize + transhdrlen > mtu) + goto emsgsize; + if (cork->length + length > mtu - headersize && ipc6->dontfrag && (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_RAW)) { @@ -1297,9 +1303,8 @@ static int __ip6_append_data(struct sock *sk, if (cork->length + length > maxnonfragsize - headersize) { emsgsize: - ipv6_local_error(sk, EMSGSIZE, fl6, - mtu - headersize + - sizeof(struct ipv6hdr)); + pmtu = max_t(int, mtu - headersize + sizeof(struct ipv6hdr), 0); + ipv6_local_error(sk, EMSGSIZE, fl6, pmtu); return -EMSGSIZE; } |