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authorThorsten Leemhuis <fedora@leemhuis.info>2017-02-07 17:39:29 +0100
committerThorsten Leemhuis <fedora@leemhuis.info>2017-02-07 17:39:29 +0100
commit454e7e6cc8f6ec1ca49611972d9f024bb3128db8 (patch)
treebecd5a1fa97b93f0b8788087a0acd2283b181c43 /ip6_gre-fix-ip6gre_err-invalid-reads.patch
parent721a7ba6a26425f5c9af350f92005d89155d09f1 (diff)
parentcbf9a4853ae920d61ed056da9d90f6e679c74308 (diff)
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Diffstat (limited to 'ip6_gre-fix-ip6gre_err-invalid-reads.patch')
-rw-r--r--ip6_gre-fix-ip6gre_err-invalid-reads.patch91
1 files changed, 91 insertions, 0 deletions
diff --git a/ip6_gre-fix-ip6gre_err-invalid-reads.patch b/ip6_gre-fix-ip6gre_err-invalid-reads.patch
new file mode 100644
index 000000000..756663c11
--- /dev/null
+++ b/ip6_gre-fix-ip6gre_err-invalid-reads.patch
@@ -0,0 +1,91 @@
+From 7892032cfe67f4bde6fc2ee967e45a8fbaf33756 Mon Sep 17 00:00:00 2001
+From: Eric Dumazet <edumazet@google.com>
+Date: Sat, 4 Feb 2017 23:18:55 -0800
+Subject: ip6_gre: fix ip6gre_err() invalid reads
+
+Andrey Konovalov reported out of bound accesses in ip6gre_err()
+
+If GRE flags contains GRE_KEY, the following expression
+*(((__be32 *)p) + (grehlen / 4) - 1)
+
+accesses data ~40 bytes after the expected point, since
+grehlen includes the size of IPv6 headers.
+
+Let's use a "struct gre_base_hdr *greh" pointer to make this
+code more readable.
+
+p[1] becomes greh->protocol.
+grhlen is the GRE header length.
+
+Fixes: c12b395a4664 ("gre: Support GRE over IPv6")
+Signed-off-by: Eric Dumazet <edumazet@google.com>
+Reported-by: Andrey Konovalov <andreyknvl@google.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ net/ipv6/ip6_gre.c | 40 +++++++++++++++++++++-------------------
+ 1 file changed, 21 insertions(+), 19 deletions(-)
+
+diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
+index 5586318..630b73b 100644
+--- a/net/ipv6/ip6_gre.c
++++ b/net/ipv6/ip6_gre.c
+@@ -367,35 +367,37 @@ static void ip6gre_tunnel_uninit(struct net_device *dev)
+
+
+ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+- u8 type, u8 code, int offset, __be32 info)
++ u8 type, u8 code, int offset, __be32 info)
+ {
+- const struct ipv6hdr *ipv6h = (const struct ipv6hdr *)skb->data;
+- __be16 *p = (__be16 *)(skb->data + offset);
+- int grehlen = offset + 4;
++ const struct gre_base_hdr *greh;
++ const struct ipv6hdr *ipv6h;
++ int grehlen = sizeof(*greh);
+ struct ip6_tnl *t;
++ int key_off = 0;
+ __be16 flags;
++ __be32 key;
+
+- flags = p[0];
+- if (flags&(GRE_CSUM|GRE_KEY|GRE_SEQ|GRE_ROUTING|GRE_VERSION)) {
+- if (flags&(GRE_VERSION|GRE_ROUTING))
+- return;
+- if (flags&GRE_KEY) {
+- grehlen += 4;
+- if (flags&GRE_CSUM)
+- grehlen += 4;
+- }
++ if (!pskb_may_pull(skb, offset + grehlen))
++ return;
++ greh = (const struct gre_base_hdr *)(skb->data + offset);
++ flags = greh->flags;
++ if (flags & (GRE_VERSION | GRE_ROUTING))
++ return;
++ if (flags & GRE_CSUM)
++ grehlen += 4;
++ if (flags & GRE_KEY) {
++ key_off = grehlen + offset;
++ grehlen += 4;
+ }
+
+- /* If only 8 bytes returned, keyed message will be dropped here */
+- if (!pskb_may_pull(skb, grehlen))
++ if (!pskb_may_pull(skb, offset + grehlen))
+ return;
+ ipv6h = (const struct ipv6hdr *)skb->data;
+- p = (__be16 *)(skb->data + offset);
++ greh = (const struct gre_base_hdr *)(skb->data + offset);
++ key = key_off ? *(__be32 *)(skb->data + key_off) : 0;
+
+ t = ip6gre_tunnel_lookup(skb->dev, &ipv6h->daddr, &ipv6h->saddr,
+- flags & GRE_KEY ?
+- *(((__be32 *)p) + (grehlen / 4) - 1) : 0,
+- p[1]);
++ key, greh->protocol);
+ if (!t)
+ return;
+
+--
+cgit v0.12
+