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From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org
Subject: [PATCH 5/9] netfilter: ip6t_srh: fix NULL pointer dereferences
Date: Thu, 21 Mar 2019 12:28:41 +0100
Message-ID: <20190321112845.10627-6-pablo@netfilter.org> (raw)
In-Reply-To: <20190321112845.10627-1-pablo@netfilter.org>

From: Kangjie Lu <kjlu@umn.edu>

skb_header_pointer may return NULL. The current code dereference
its return values without a NULL check.

The fix inserts the checks to avoid NULL pointer dereferences.

Fixes: 202a8ff545cc ("netfilter: add IPv6 segment routing header 'srh' match")
Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/ipv6/netfilter/ip6t_srh.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/ipv6/netfilter/ip6t_srh.c b/net/ipv6/netfilter/ip6t_srh.c
index 1059894a6f4c..4cb83fb69844 100644
--- a/net/ipv6/netfilter/ip6t_srh.c
+++ b/net/ipv6/netfilter/ip6t_srh.c
@@ -210,6 +210,8 @@ static bool srh1_mt6(const struct sk_buff *skb, struct xt_action_param *par)
 		psidoff = srhoff + sizeof(struct ipv6_sr_hdr) +
 			  ((srh->segments_left + 1) * sizeof(struct in6_addr));
 		psid = skb_header_pointer(skb, psidoff, sizeof(_psid), &_psid);
+		if (!psid)
+			return false;
 		if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_PSID,
 				ipv6_masked_addr_cmp(psid, &srhinfo->psid_msk,
 						     &srhinfo->psid_addr)))
@@ -223,6 +225,8 @@ static bool srh1_mt6(const struct sk_buff *skb, struct xt_action_param *par)
 		nsidoff = srhoff + sizeof(struct ipv6_sr_hdr) +
 			  ((srh->segments_left - 1) * sizeof(struct in6_addr));
 		nsid = skb_header_pointer(skb, nsidoff, sizeof(_nsid), &_nsid);
+		if (!nsid)
+			return false;
 		if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_NSID,
 				ipv6_masked_addr_cmp(nsid, &srhinfo->nsid_msk,
 						     &srhinfo->nsid_addr)))
@@ -233,6 +237,8 @@ static bool srh1_mt6(const struct sk_buff *skb, struct xt_action_param *par)
 	if (srhinfo->mt_flags & IP6T_SRH_LSID) {
 		lsidoff = srhoff + sizeof(struct ipv6_sr_hdr);
 		lsid = skb_header_pointer(skb, lsidoff, sizeof(_lsid), &_lsid);
+		if (!lsid)
+			return false;
 		if (NF_SRH_INVF(srhinfo, IP6T_SRH_INV_LSID,
 				ipv6_masked_addr_cmp(lsid, &srhinfo->lsid_msk,
 						     &srhinfo->lsid_addr)))
-- 
2.11.0


  parent reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-21 11:28 [PATCH 0/9] Netfilter fixes for net Pablo Neira Ayuso
2019-03-21 11:28 ` [PATCH 1/9] netfilter: nf_conntrack_sip: remove direct dependency on IPv6 Pablo Neira Ayuso
2019-03-21 11:28 ` [PATCH 2/9] netfilter: nft_set_rbtree: check for inactive element after flag mismatch Pablo Neira Ayuso
2019-03-21 11:28 ` [PATCH 3/9] netfilter: bridge: set skb transport_header before entering NF_INET_PRE_ROUTING Pablo Neira Ayuso
2019-03-21 11:28 ` [PATCH 4/9] netfilter: fix NETFILTER_XT_TARGET_TEE dependencies Pablo Neira Ayuso
2019-03-21 11:28 ` Pablo Neira Ayuso [this message]
2019-03-21 11:28 ` [PATCH 6/9] netfilter: nf_tables: bogus EBUSY in helper removal from transaction Pablo Neira Ayuso
2019-03-21 11:28 ` [PATCH 7/9] netfilter: nft_redir: fix module autoload with ip4 Pablo Neira Ayuso
2019-03-21 11:28 ` [PATCH 8/9] netfilter: nf_flowtable: remove duplicated transition in diagram Pablo Neira Ayuso
2019-03-21 11:28 ` [PATCH 9/9] netfilter: nf_tables: add missing ->release_ops() in error path of newrule() Pablo Neira Ayuso
2019-03-21 17:07 ` [PATCH 0/9] Netfilter fixes for net David Miller

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