lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

[NET]: Fix incorrect sg_mark_end() calls.

Browse Source 
This fixes scatterlist corruptions added by

	commit 68e3f5dd4d
	[CRYPTO] users: Fix up scatterlist conversion errors

The issue is that the code calls sg_mark_end() which clobbers the
sg_page() pointer of the final scatterlist entry.

The first part fo the fix makes skb_to_sgvec() do __sg_mark_end().

After considering all skb_to_sgvec() call sites the most correct
solution is to call __sg_mark_end() in skb_to_sgvec() since that is
what all of the callers would end up doing anyways.

I suspect this might have fixed some problems in virtio_net which is
the sole non-crypto user of skb_to_sgvec().

Other similar sg_mark_end() cases were converted over to
__sg_mark_end() as well.

Arguably sg_mark_end() is a poorly named function because it doesn't
just "mark", it clears out the page pointer as a side effect, which is
what led to these bugs in the first place.

The one remaining plain sg_mark_end() call is in scsi_alloc_sgtable()
and arguably it could be converted to __sg_mark_end() if only so that
we can delete this confusing interface from linux/scatterlist.h

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller
2007-10-30 21:29:29 -07:00
parent 07afa04025
commit 51c739d1f4
7 changed files with 37 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
net/ipv4/esp4.c
View File

@@ -111,9 +111,10 @@ static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
goto unlock;
}
sg_init_table(sg, nfrags);
sg_mark_end(sg, skb_to_sgvec(skb, sg, esph->enc_data +
esp->conf.ivlen -
skb->data, clen));
skb_to_sgvec(skb, sg,
esph->enc_data +
esp->conf.ivlen -
skb->data, clen);
err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
if (unlikely(sg != &esp->sgbuf[0]))
kfree(sg);
@@ -205,8 +206,9 @@ static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
goto out;
}
sg_init_table(sg, nfrags);
sg_mark_end(sg, skb_to_sgvec(skb, sg, sizeof(*esph) + esp->conf.ivlen,
elen));
skb_to_sgvec(skb, sg,
sizeof(*esph) + esp->conf.ivlen,
elen);
err = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
if (unlikely(sg != &esp->sgbuf[0]))
kfree(sg);