[NET]: Fix incorrect sg_mark_end() calls.

This fixes scatterlist corruptions added by

	commit 68e3f5dd4db62619fdbe520d36c9ebf62e672256
	[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>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c
index 91cd8f0d1e10..ab7cbd6575c4 100644
--- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
+++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
@@ -211,8 +211,8 @@ encryptor(struct scatterlist *sg, void *data)
 	if (thislen == 0)
 		return 0;
 
-	sg_mark_end(desc->infrags, desc->fragno);
-	sg_mark_end(desc->outfrags, desc->fragno);
+	__sg_mark_end(&desc->infrags[desc->fragno - 1]);
+	__sg_mark_end(&desc->outfrags[desc->fragno - 1]);
 
 	ret = crypto_blkcipher_encrypt_iv(&desc->desc, desc->outfrags,
 					  desc->infrags, thislen);
@@ -293,7 +293,7 @@ decryptor(struct scatterlist *sg, void *data)
 	if (thislen == 0)
 		return 0;
 
-	sg_mark_end(desc->frags, desc->fragno);
+	__sg_mark_end(&desc->frags[desc->fragno - 1]);
 
 	ret = crypto_blkcipher_decrypt_iv(&desc->desc, desc->frags,
 					  desc->frags, thislen);