From: Muhammad Usama Anjum musamaanjum@gmail.com
commit 864db232dc7036aa2de19749c3d5be0143b24f8f upstream.
nlh is being checked for validtity two times when it is dereferenced in this function. Check for validity again when updating the flags through nlh pointer to make the dereferencing safe.
CC: stable@vger.kernel.org Addresses-Coverity: ("NULL pointer dereference") Signed-off-by: Muhammad Usama Anjum musamaanjum@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/route.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -3283,9 +3283,11 @@ static int ip6_route_multipath_add(struc * nexthops have been replaced by first new, the rest should * be added to it. */ - cfg->fc_nlinfo.nlh->nlmsg_flags &= ~(NLM_F_EXCL | - NLM_F_REPLACE); - cfg->fc_nlinfo.nlh->nlmsg_flags |= NLM_F_CREATE; + if (cfg->fc_nlinfo.nlh) { + cfg->fc_nlinfo.nlh->nlmsg_flags &= ~(NLM_F_EXCL | + NLM_F_REPLACE); + cfg->fc_nlinfo.nlh->nlmsg_flags |= NLM_F_CREATE; + } nhn++; }