[patch 20/37] IPV6 OOPSer triggerable by any user

[Greg KH <gregkh@suse.de>]

-stable review patch.  If anyone has any objections, please let us know.

------------------
From: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

[IPV6]: Fix kernel OOPs when setting sticky socket options.

Bug noticed by Remi Denis-Courmont <rdenis@simphalempin.com>.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 net/ipv6/exthdrs.c |   29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

--- linux-2.6.17.11.orig/net/ipv6/exthdrs.c
+++ linux-2.6.17.11/net/ipv6/exthdrs.c
@@ -635,14 +635,17 @@ ipv6_renew_options(struct sock *sk, stru
 	struct ipv6_txoptions *opt2;
 	int err;
 
-	if (newtype != IPV6_HOPOPTS && opt->hopopt)
-		tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
-	if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
-		tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
-	if (newtype != IPV6_RTHDR && opt->srcrt)
-		tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
-	if (newtype != IPV6_DSTOPTS && opt->dst1opt)
-		tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
+	if (opt) {
+		if (newtype != IPV6_HOPOPTS && opt->hopopt)
+			tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
+		if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
+			tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
+		if (newtype != IPV6_RTHDR && opt->srcrt)
+			tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
+		if (newtype != IPV6_DSTOPTS && opt->dst1opt)
+			tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
+	}
+
 	if (newopt && newoptlen)
 		tot_len += CMSG_ALIGN(newoptlen);
 
@@ -659,25 +662,25 @@ ipv6_renew_options(struct sock *sk, stru
 	opt2->tot_len = tot_len;
 	p = (char *)(opt2 + 1);
 
-	err = ipv6_renew_option(opt->hopopt, newopt, newoptlen,
+	err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
 				newtype != IPV6_HOPOPTS,
 				&opt2->hopopt, &p);
 	if (err)
 		goto out;
 
-	err = ipv6_renew_option(opt->dst0opt, newopt, newoptlen,
+	err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
 				newtype != IPV6_RTHDRDSTOPTS,
 				&opt2->dst0opt, &p);
 	if (err)
 		goto out;
 
-	err = ipv6_renew_option(opt->srcrt, newopt, newoptlen,
+	err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
 				newtype != IPV6_RTHDR,
-				(struct ipv6_opt_hdr **)opt2->srcrt, &p);
+				(struct ipv6_opt_hdr **)&opt2->srcrt, &p);
 	if (err)
 		goto out;
 
-	err = ipv6_renew_option(opt->dst1opt, newopt, newoptlen,
+	err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
 				newtype != IPV6_DSTOPTS,
 				&opt2->dst1opt, &p);
 	if (err)

--
-
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