[kernel/f14] Fix NULL dereference in udp6_ufo_fragment(), caused by fix for CVE-2011-2699.
Chuck Ebbert
cebbert at fedoraproject.org
Tue Oct 25 14:21:49 UTC 2011
commit 4d20e68f2cbe4a2f10f54c1a68f9556771a5268f
Author: Chuck Ebbert <cebbert at redhat.com>
Date: Tue Oct 25 10:22:06 2011 -0400
Fix NULL dereference in udp6_ufo_fragment(), caused by fix for CVE-2011-2699.
...fix-null-dereference-in-udp6_ufo_fragment.patch | 103 ++++++++++++++++++++
kernel.spec | 7 ++
2 files changed, 110 insertions(+), 0 deletions(-)
---
diff --git a/ipv6-fix-null-dereference-in-udp6_ufo_fragment.patch b/ipv6-fix-null-dereference-in-udp6_ufo_fragment.patch
new file mode 100644
index 0000000..5d6a20f
--- /dev/null
+++ b/ipv6-fix-null-dereference-in-udp6_ufo_fragment.patch
@@ -0,0 +1,103 @@
+From jasowang at redhat.com Sat Oct 8 20:56:54 2011
+Subject: ipv6: fix NULL dereference in udp6_ufo_fragment()
+To: gregkh at suse.de, stable at kernel.org
+From: Jason Wang <jasowang at redhat.com>
+Cc: davem at davemloft.net, eric.dumazet at gmail.com
+Date: Sun, 09 Oct 2011 10:56:44 +0800
+Message-ID: <20111009025644.9437.53281.stgit at dhcp-8-146.nay.redhat.com>
+
+From: Jason Wang <jasowang at redhat.com>
+
+This patch fixes the issue caused by ef81bb40bf15f350fe865f31fa42f1082772a576
+which is a backport of upstream 87c48fa3b4630905f98268dde838ee43626a060c. The
+problem does not exist in upstream.
+
+We do not check whether route is attached before trying to assign ip
+identification through route dest which lead NULL pointer dereference. This
+happens when host bridge transmit a packet from guest.
+
+This patch changes ipv6_select_ident() to accept in6_addr as its paramter and
+fix the issue by using the destination address in ipv6 header when no route is
+attached.
+
+Signed-off-by: Jason Wang <jasowang at redhat.com>
+Acked-by: David S. Miller <davem at davemloft.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>
+---
+ include/net/ipv6.h | 2 +-
+ net/ipv6/ip6_output.c | 10 +++++-----
+ net/ipv6/udp.c | 4 +++-
+ 3 files changed, 9 insertions(+), 7 deletions(-)
+
+--- a/include/net/ipv6.h
++++ b/include/net/ipv6.h
+@@ -463,7 +463,7 @@ static inline int ipv6_addr_diff(const s
+ return __ipv6_addr_diff(a1, a2, sizeof(struct in6_addr));
+ }
+
+-extern void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt);
++extern void ipv6_select_ident(struct frag_hdr *fhdr, struct in6_addr *addr);
+
+ /*
+ * Prototypes exported by ipv6
+--- a/net/ipv6/ip6_output.c
++++ b/net/ipv6/ip6_output.c
+@@ -620,9 +620,9 @@ static u32 __ipv6_select_ident(const str
+ return hash + newid;
+ }
+
+-void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt)
++void ipv6_select_ident(struct frag_hdr *fhdr, struct in6_addr *addr)
+ {
+- fhdr->identification = htonl(__ipv6_select_ident(&rt->rt6i_dst.addr));
++ fhdr->identification = htonl(__ipv6_select_ident(addr));
+ }
+
+ static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
+@@ -709,7 +709,7 @@ int ip6_fragment(struct sk_buff *skb, in
+ skb_reset_network_header(skb);
+ memcpy(skb_network_header(skb), tmp_hdr, hlen);
+
+- ipv6_select_ident(fh, rt);
++ ipv6_select_ident(fh, &rt->rt6i_dst.addr);
+ fh->nexthdr = nexthdr;
+ fh->reserved = 0;
+ fh->frag_off = htons(IP6_MF);
+@@ -855,7 +855,7 @@ slow_path:
+ fh->nexthdr = nexthdr;
+ fh->reserved = 0;
+ if (!frag_id) {
+- ipv6_select_ident(fh, rt);
++ ipv6_select_ident(fh, &rt->rt6i_dst.addr);
+ frag_id = fh->identification;
+ } else
+ fh->identification = frag_id;
+@@ -1146,7 +1146,7 @@ static inline int ip6_ufo_append_data(st
+ skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
+ sizeof(struct frag_hdr)) & ~7;
+ skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
+- ipv6_select_ident(&fhdr, rt);
++ ipv6_select_ident(&fhdr, &rt->rt6i_dst.addr);
+ skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
+ __skb_queue_tail(&sk->sk_write_queue, skb);
+
+--- a/net/ipv6/udp.c
++++ b/net/ipv6/udp.c
+@@ -1309,6 +1309,7 @@ static struct sk_buff *udp6_ufo_fragment
+ u8 frag_hdr_sz = sizeof(struct frag_hdr);
+ int offset;
+ __wsum csum;
++ struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
+
+ mss = skb_shinfo(skb)->gso_size;
+ if (unlikely(skb->len <= mss))
+@@ -1359,7 +1360,8 @@ static struct sk_buff *udp6_ufo_fragment
+ fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
+ fptr->nexthdr = nexthdr;
+ fptr->reserved = 0;
+- ipv6_select_ident(fptr, (struct rt6_info *)skb_dst(skb));
++ ipv6_select_ident(fptr,
++ rt ? &rt->rt6i_dst.addr : &ipv6_hdr(skb)->daddr);
+
+ /* Fragment the skb. ipv6 header and the remaining fields of the
+ * fragment header are updated in ipv6_gso_segment()
diff --git a/kernel.spec b/kernel.spec
index f6da1ef..98ca031 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -852,6 +852,8 @@ Patch14012: bluetooth-prevent-buffer-overflow-in-l2cap-config-request.patch
Patch14013: nl80211-fix-overflow-in-ssid_len.patch.patch
# CVE-2011-2699
Patch14014: ipv6-make-fragment-identifications-less-predictable.patch
+# fix possible null dereference in above fix
+Patch14015: ipv6-fix-null-dereference-in-udp6_ufo_fragment.patch
# RHBZ #699684
Patch14020: x86-mm-fix-pgd_lock-deadlock.patch
@@ -1657,6 +1659,7 @@ ApplyPatch bluetooth-prevent-buffer-overflow-in-l2cap-config-request.patch
ApplyPatch nl80211-fix-overflow-in-ssid_len.patch.patch
# CVE-2011-2699
ApplyPatch ipv6-make-fragment-identifications-less-predictable.patch
+ApplyPatch ipv6-fix-null-dereference-in-udp6_ufo_fragment.patch
# RHBZ #699684
ApplyPatch x86-mm-fix-pgd_lock-deadlock.patch
@@ -2292,6 +2295,10 @@ fi
# and build.
%changelog
+* Tue Oct 25 2011 Chuck Ebbert <cebbert at redhat.com>
+- Fix NULL dereference in udp6_ufo_fragment(), caused by
+ fix for CVE-2011-2699.
+
* Fri Oct 21 2011 Dave Jones <davej at redhat.com> 2.6.35.14-100
- Lower severity of Radeon lockup messages.
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