mirror of
https://github.com/Divested-Mobile/DivestOS-Build.git
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92 lines
2.7 KiB
Diff
92 lines
2.7 KiB
Diff
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From 7892032cfe67f4bde6fc2ee967e45a8fbaf33756 Mon Sep 17 00:00:00 2001
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From: Eric Dumazet <edumazet@google.com>
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Date: Sat, 4 Feb 2017 23:18:55 -0800
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Subject: ip6_gre: fix ip6gre_err() invalid reads
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Andrey Konovalov reported out of bound accesses in ip6gre_err()
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If GRE flags contains GRE_KEY, the following expression
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*(((__be32 *)p) + (grehlen / 4) - 1)
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accesses data ~40 bytes after the expected point, since
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grehlen includes the size of IPv6 headers.
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Let's use a "struct gre_base_hdr *greh" pointer to make this
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code more readable.
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p[1] becomes greh->protocol.
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grhlen is the GRE header length.
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Fixes: c12b395a4664 ("gre: Support GRE over IPv6")
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Signed-off-by: Eric Dumazet <edumazet@google.com>
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Reported-by: Andrey Konovalov <andreyknvl@google.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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net/ipv6/ip6_gre.c | 40 +++++++++++++++++++++-------------------
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1 file changed, 21 insertions(+), 19 deletions(-)
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diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
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index 5586318..630b73b 100644
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--- a/net/ipv6/ip6_gre.c
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+++ b/net/ipv6/ip6_gre.c
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@@ -367,35 +367,37 @@ static void ip6gre_tunnel_uninit(struct net_device *dev)
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static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
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- u8 type, u8 code, int offset, __be32 info)
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+ u8 type, u8 code, int offset, __be32 info)
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{
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- const struct ipv6hdr *ipv6h = (const struct ipv6hdr *)skb->data;
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- __be16 *p = (__be16 *)(skb->data + offset);
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- int grehlen = offset + 4;
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+ const struct gre_base_hdr *greh;
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+ const struct ipv6hdr *ipv6h;
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+ int grehlen = sizeof(*greh);
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struct ip6_tnl *t;
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+ int key_off = 0;
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__be16 flags;
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+ __be32 key;
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- flags = p[0];
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- if (flags&(GRE_CSUM|GRE_KEY|GRE_SEQ|GRE_ROUTING|GRE_VERSION)) {
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- if (flags&(GRE_VERSION|GRE_ROUTING))
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- return;
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- if (flags&GRE_KEY) {
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- grehlen += 4;
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- if (flags&GRE_CSUM)
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- grehlen += 4;
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- }
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+ if (!pskb_may_pull(skb, offset + grehlen))
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+ return;
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+ greh = (const struct gre_base_hdr *)(skb->data + offset);
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+ flags = greh->flags;
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+ if (flags & (GRE_VERSION | GRE_ROUTING))
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+ return;
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+ if (flags & GRE_CSUM)
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+ grehlen += 4;
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+ if (flags & GRE_KEY) {
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+ key_off = grehlen + offset;
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+ grehlen += 4;
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}
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- /* If only 8 bytes returned, keyed message will be dropped here */
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- if (!pskb_may_pull(skb, grehlen))
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+ if (!pskb_may_pull(skb, offset + grehlen))
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return;
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ipv6h = (const struct ipv6hdr *)skb->data;
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- p = (__be16 *)(skb->data + offset);
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+ greh = (const struct gre_base_hdr *)(skb->data + offset);
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+ key = key_off ? *(__be32 *)(skb->data + key_off) : 0;
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t = ip6gre_tunnel_lookup(skb->dev, &ipv6h->daddr, &ipv6h->saddr,
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- flags & GRE_KEY ?
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- *(((__be32 *)p) + (grehlen / 4) - 1) : 0,
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- p[1]);
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+ key, greh->protocol);
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if (!t)
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return;
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--
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cgit v1.1
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