[maverick/ti-omap4 CVE 1/2] gro: Reset dev pointer on reuse

Andy Whitcroft apw at canonical.com
Wed Jul 27 15:20:54 UTC 2011

From: Herbert Xu <herbert at gondor.apana.org.au>

commit 66c46d741e2e60f0e8b625b80edb0ab820c46d7a upstream.

On older kernels the VLAN code may zero skb->dev before dropping
it and causing it to be reused by GRO.

Unfortunately we didn't reset skb->dev in that case which causes
the next GRO user to get a bogus skb->dev pointer.

This particular problem no longer happens with the current upstream
kernel due to changes in VLAN processing.

However, for correctness we should still reset the skb->dev pointer
in the GRO reuse function in case a future user does the same thing.

Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Brandon Philips <bphilips at suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>
Signed-off-by: Andi Kleen <ak at linux.intel.com>
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>

BugLink: http://bugs.launchpad.net/bugs/816549
Signed-off-by: Andy Whitcroft <apw at canonical.com>
 net/core/dev.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index d11a74d..d64bb2b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3222,6 +3222,7 @@ void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
 	__skb_pull(skb, skb_headlen(skb));
 	skb_reserve(skb, NET_IP_ALIGN - skb_headroom(skb));
+	skb->dev = napi->dev;
 	napi->skb = skb;

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