[PATCH 6/9] [CRYPTO] Fix boundary check in standard multi-block cipher processors

[Chris Wright]

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

[CRYPTO] Fix boundary check in standard multi-block cipher processors

Fixes Bug 5194 (IPSec related Oops in 2.6.13).

The boundary check in the standard multi-block cipher processors are
broken when nbytes is not a multiple of bsize.  In those cases it will
always process an extra block.

This patch corrects the check so that it processes at most nbytes of data.

Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxx>
---
 crypto/cipher.c |   12 +++++++++---
 1 files changed, 9 insertions(+), 3 deletions(-)

Index: linux-2.6.13.y/crypto/cipher.c
===================================================================
--- linux-2.6.13.y.orig/crypto/cipher.c
+++ linux-2.6.13.y/crypto/cipher.c
@@ -191,6 +191,8 @@ static unsigned int cbc_process_encrypt(
 	u8 *iv = desc->info;
 	unsigned int done = 0;
 
+	nbytes -= bsize;
+
 	do {
 		xor(iv, src);
 		fn(crypto_tfm_ctx(tfm), dst, iv);
@@ -198,7 +200,7 @@ static unsigned int cbc_process_encrypt(
 
 		src += bsize;
 		dst += bsize;
-	} while ((done += bsize) < nbytes);
+	} while ((done += bsize) <= nbytes);
 
 	return done;
 }
@@ -219,6 +221,8 @@ static unsigned int cbc_process_decrypt(
 	u8 *iv = desc->info;
 	unsigned int done = 0;
 
+	nbytes -= bsize;
+
 	do {
 		u8 *tmp_dst = *dst_p;
 
@@ -230,7 +234,7 @@ static unsigned int cbc_process_decrypt(
 
 		src += bsize;
 		dst += bsize;
-	} while ((done += bsize) < nbytes);
+	} while ((done += bsize) <= nbytes);
 
 	return done;
 }
@@ -243,12 +247,14 @@ static unsigned int ecb_process(const st
 	void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
 	unsigned int done = 0;
 
+	nbytes -= bsize;
+
 	do {
 		fn(crypto_tfm_ctx(tfm), dst, src);
 
 		src += bsize;
 		dst += bsize;
-	} while ((done += bsize) < nbytes);
+	} while ((done += bsize) <= nbytes);
 
 	return done;
 }

--
-
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