This is a note to let you know that I've just added the patch titled
ip6_gre: fix ip6gre_err() invalid reads
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ip6_gre-fix-ip6gre_err-invalid-reads.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Feb 14 16:29:59 PST 2017
From: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Sat, 4 Feb 2017 23:18:55 -0800
Subject: ip6_gre: fix ip6gre_err() invalid reads
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 7892032cfe67f4bde6fc2ee967e45a8fbaf33756 ]
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@xxxxxxxxxx>
Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/ip6_gre.c | 41 ++++++++++++++++++++++-------------------
1 file changed, 22 insertions(+), 19 deletions(-)
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -55,6 +55,7 @@
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
#include <net/ip6_tunnel.h>
+#include <net/gre.h>
static bool log_ecn_error = true;
@@ -367,35 +368,37 @@ static void ip6gre_tunnel_uninit(struct
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;
Patches currently in stable-queue which might be from edumazet@xxxxxxxxxx are
queue-4.4/ipv6-pointer-math-error-in-ip6_tnl_parse_tlv_enc_lim.patch
queue-4.4/netlabel-out-of-bound-access-in-cipso_v4_validate.patch
queue-4.4/packet-round-up-linear-to-header-len.patch
queue-4.4/tun-read-vnet_hdr_sz-once.patch
queue-4.4/ipv6-fix-ip6_tnl_parse_tlv_enc_lim.patch
queue-4.4/l2tp-do-not-use-udp_ioctl.patch
queue-4.4/tcp-fix-0-divide-in-__tcp_select_window.patch
queue-4.4/can-fix-kernel-panic-at-security_sock_rcv_skb.patch
queue-4.4/net-introduce-device-min_header_len.patch
queue-4.4/macvtap-read-vnet_hdr_size-once.patch
queue-4.4/tcp-avoid-infinite-loop-in-tcp_splice_read.patch
queue-4.4/mlx4-invoke-softirqs-after-napi_reschedule.patch
queue-4.4/ipv6-tcp-add-a-missing-tcp_v6_restore_cb.patch
queue-4.4/ipv4-keep-skb-dst-around-in-presence-of-ip-options.patch
queue-4.4/net-use-a-work-queue-to-defer-net_disable_timestamp-work.patch
queue-4.4/ip6_gre-fix-ip6gre_err-invalid-reads.patch