From: Olivier Matz olivier.matz@6wind.com
[ Upstream commit b9aa52c4cb457e7416cc0c95f475e72ef4a61336 ]
The following code returns EFAULT (Bad address):
s = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6); setsockopt(s, SOL_IPV6, IPV6_HDRINCL, 1); sendto(ipv6_icmp6_packet, addr); /* returns -1, errno = EFAULT */
The IPv4 equivalent code works. A workaround is to use IPPROTO_RAW instead of IPPROTO_ICMPV6.
The failure happens because 2 bytes are eaten from the msghdr by rawv6_probe_proto_opt() starting from commit 19e3c66b52ca ("ipv6 equivalent of "ipv4: Avoid reading user iov twice after raw_probe_proto_opt""), but at that time it was not a problem because IPV6_HDRINCL was not yet introduced.
Only eat these 2 bytes if hdrincl == 0.
Fixes: 715f504b1189 ("ipv6: add IPV6_HDRINCL option for raw sockets") Signed-off-by: Olivier Matz olivier.matz@6wind.com Acked-by: Nicolas Dichtel nicolas.dichtel@6wind.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/raw.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
--- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -895,11 +895,14 @@ static int rawv6_sendmsg(struct sock *sk opt = ipv6_fixup_options(&opt_space, opt);
fl6.flowi6_proto = proto; - rfv.msg = msg; - rfv.hlen = 0; - err = rawv6_probe_proto_opt(&rfv, &fl6); - if (err) - goto out; + + if (!hdrincl) { + rfv.msg = msg; + rfv.hlen = 0; + err = rawv6_probe_proto_opt(&rfv, &fl6); + if (err) + goto out; + }
if (!ipv6_addr_any(daddr)) fl6.daddr = *daddr;