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net: ipv6: check for validity before dereferencing cfg->fc_nlinfo.nlh

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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>
This commit is contained in:
Muhammad Usama Anjum 2021-04-09 03:01:29 +05:00 committed by Greg Kroah-Hartman
parent 005c5afa9f
commit 40375bc3d0
1 changed files with 5 additions and 3 deletions
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8
net/ipv6/route.c
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@ -5203,9 +5203,11 @@ static int ip6_route_multipath_add(struct fib6_config *cfg,
* nexthops have been replaced by first new, the rest should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++;
}