Commit 4909122f authored Jun 08, 2009 by Herbert Xu Committed by David S. Miller Jun 08, 2009

tun: Optimise handling of bogus gso->hdr_len



As all current versions of virtio_net generate a value for the
header length that's too small, we should optimise this so that
we don't copy it twice.  This can be done by ensuring that it is
at least as large as the place where we'll write the checksum.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent b82f08ea

drivers/net/tun.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -565,6 +565,10 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun,
		if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
		return -EFAULT;

		if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
		gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
		gso.hdr_len = gso.csum_start + gso.csum_offset + 2;

		if (gso.hdr_len > len)
		return -EINVAL;
		offset += sizeof(pi);