RE: [PATCH 3.4 01/25] crypto: scatterwalk - Set the chain pointerindication bit

[Lendacky, Thomas]

Hi Greg,

This patch is probably not needed in any of the stable branches, but if
you do add it you'll need to also include a patch that changes the use
of an sg_page to an sg_chain_ptr to prevent a BUG_ON when CONFIG_DEBUG_SG
is enabled (http://marc.info/?l=linux-crypto-vger&m=138627061905651&w=2).

Thanks,
Tom


-----Original Message-----
From: Greg Kroah-Hartman [mailto:gregkh@xxxxxxxxxxxxxxxxxxx] 
Sent: Tuesday, December 10, 2013 2:00 AM
To: linux-kernel@xxxxxxxxxxxxxxx
Cc: Greg Kroah-Hartman; stable@xxxxxxxxxxxxxxx; Lendacky, Thomas; Herbert Xu
Subject: [PATCH 3.4 01/25] crypto: scatterwalk - Set the chain pointer indication bit

3.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tom Lendacky <thomas.lendacky@xxxxxxx>

commit 41da8b5adba77e22584f8b45f9641504fa885308 upstream.

The scatterwalk_crypto_chain function invokes the scatterwalk_sg_chain function to chain two scatterlists, but the chain pointer indication bit is not set.  When the resulting scatterlist is used, for example, by sg_nents to count the number of scatterlist entries, a segfault occurs because sg_nents does not follow the chain pointer to the chained scatterlist.

Update scatterwalk_sg_chain to set the chain pointer indication bit as is done by the sg_chain function.

Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 include/crypto/scatterwalk.h |    1 +
 1 file changed, 1 insertion(+)

--- a/include/crypto/scatterwalk.h
+++ b/include/crypto/scatterwalk.h
@@ -36,6 +36,7 @@ static inline void scatterwalk_sg_chain(  {
 	sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0);
 	sg1[num - 1].page_link &= ~0x02;
+	sg1[num - 1].page_link |= 0x01;
 }
 
 static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)




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