[linux] 01/01: ipv6: Check ip6_find_1stfragopt() return value properly.

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benh pushed a commit to branch stretch-security
in repository linux.

commit 2da7c17a3ddf84be9a1c24ba340d0d54b33f44a0
Author: Ben Hutchings <ben at decadent.org.uk>
Date:   Wed Jun 7 23:34:12 2017 +0100

    ipv6: Check ip6_find_1stfragopt() return value properly.
    
    Follow-up to the fix for CVE-2017-9074.
---
 debian/changelog                                   |  6 ++
 ...ip6_find_1stfragopt-return-value-properly.patch | 84 ++++++++++++++++++++++
 debian/patches/series                              |  1 +
 3 files changed, 91 insertions(+)

diff --git a/debian/changelog b/debian/changelog
index a0365b6..3b02ccb 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+linux (4.9.30-1+deb9u1) UNRELEASED; urgency=medium
+
+  * ipv6: Check ip6_find_1stfragopt() return value properly.
+
+ -- Ben Hutchings <ben at decadent.org.uk>  Wed, 07 Jun 2017 23:31:14 +0100
+
 linux (4.9.30-1) unstable; urgency=medium
 
   * New upstream stable update:
diff --git a/debian/patches/bugfix/all/ipv6-check-ip6_find_1stfragopt-return-value-properly.patch b/debian/patches/bugfix/all/ipv6-check-ip6_find_1stfragopt-return-value-properly.patch
new file mode 100644
index 0000000..e6649a9
--- /dev/null
+++ b/debian/patches/bugfix/all/ipv6-check-ip6_find_1stfragopt-return-value-properly.patch
@@ -0,0 +1,84 @@
+From: "David S. Miller" <davem at davemloft.net>
+Date: Wed, 17 May 2017 22:54:11 -0400
+Subject: ipv6: Check ip6_find_1stfragopt() return value properly.
+Origin: https://git.kernel.org/linus/7dd7eb9513bd02184d45f000ab69d78cb1fa1531
+Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-9074
+
+Do not use unsigned variables to see if it returns a negative
+error or not.
+
+Fixes: 2423496af35d ("ipv6: Prevent overrun when parsing v6 header options")
+Reported-by: Julia Lawall <julia.lawall at lip6.fr>
+Signed-off-by: David S. Miller <davem at davemloft.net>
+---
+ net/ipv6/ip6_offload.c | 9 ++++-----
+ net/ipv6/ip6_output.c  | 7 +++----
+ net/ipv6/udp_offload.c | 8 +++++---
+ 3 files changed, 12 insertions(+), 12 deletions(-)
+
+--- a/net/ipv6/ip6_offload.c
++++ b/net/ipv6/ip6_offload.c
+@@ -63,7 +63,6 @@ static struct sk_buff *ipv6_gso_segment(
+ 	const struct net_offload *ops;
+ 	int proto;
+ 	struct frag_hdr *fptr;
+-	unsigned int unfrag_ip6hlen;
+ 	unsigned int payload_len;
+ 	u8 *prevhdr;
+ 	int offset = 0;
+@@ -116,10 +115,10 @@ static struct sk_buff *ipv6_gso_segment(
+ 		skb->network_header = (u8 *)ipv6h - skb->head;
+ 
+ 		if (udpfrag) {
+-			unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
+-			if (unfrag_ip6hlen < 0)
+-				return ERR_PTR(unfrag_ip6hlen);
+-			fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen);
++			int err = ip6_find_1stfragopt(skb, &prevhdr);
++			if (err < 0)
++				return ERR_PTR(err);
++			fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
+ 			fptr->frag_off = htons(offset);
+ 			if (skb->next)
+ 				fptr->frag_off |= htons(IP6_MF);
+--- a/net/ipv6/ip6_output.c
++++ b/net/ipv6/ip6_output.c
+@@ -586,11 +586,10 @@ int ip6_fragment(struct net *net, struct
+ 	int ptr, offset = 0, err = 0;
+ 	u8 *prevhdr, nexthdr = 0;
+ 
+-	hlen = ip6_find_1stfragopt(skb, &prevhdr);
+-	if (hlen < 0) {
+-		err = hlen;
++	err = ip6_find_1stfragopt(skb, &prevhdr);
++	if (err < 0)
+ 		goto fail;
+-	}
++	hlen = err;
+ 	nexthdr = *prevhdr;
+ 
+ 	mtu = ip6_skb_dst_mtu(skb);
+--- a/net/ipv6/udp_offload.c
++++ b/net/ipv6/udp_offload.c
+@@ -29,6 +29,7 @@ static struct sk_buff *udp6_ufo_fragment
+ 	u8 frag_hdr_sz = sizeof(struct frag_hdr);
+ 	__wsum csum;
+ 	int tnl_hlen;
++	int err;
+ 
+ 	mss = skb_shinfo(skb)->gso_size;
+ 	if (unlikely(skb->len <= mss))
+@@ -90,9 +91,10 @@ static struct sk_buff *udp6_ufo_fragment
+ 		/* Find the unfragmentable header and shift it left by frag_hdr_sz
+ 		 * bytes to insert fragment header.
+ 		 */
+-		unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
+-		if (unfrag_ip6hlen < 0)
+-			return ERR_PTR(unfrag_ip6hlen);
++		err = ip6_find_1stfragopt(skb, &prevhdr);
++		if (err < 0)
++			return ERR_PTR(err);
++		unfrag_ip6hlen = err;
+ 		nexthdr = *prevhdr;
+ 		*prevhdr = NEXTHDR_FRAGMENT;
+ 		unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
diff --git a/debian/patches/series b/debian/patches/series
index 227998e..f6e3d0e 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -113,6 +113,7 @@ bugfix/all/dccp-tcp-do-not-inherit-mc_list-from-parent.patch
 bugfix/all/sunrpc-refactor-svc_set_num_threads.patch
 bugfix/all/nfsv4-fix-callback-server-shutdown.patch
 bugfix/all/ipv6-prevent-overrun-when-parsing-v6-header-options.patch
+bugfix/all/ipv6-check-ip6_find_1stfragopt-return-value-properly.patch
 bugfix/all/sctp-do-not-inherit-ipv6_-mc-ac-fl-_list-from-parent.patch
 bugfix/all/ipv6-dccp-do-not-inherit-ipv6_mc_list-from-parent.patch
 bugfix/all/crypto-skcipher-Add-missing-api-setkey-checks.patch

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