[PATCH] crypto: eseqiv - fix IV generation for sync algorithms

[PATCH] crypto: eseqiv - fix IV generation for sync algorithms

[Steffen Klassert]

If crypto_ablkcipher_encrypt() returns synchronous,
eseqiv_complete2() is called even if req->giv is already the
pointer to the generated IV. The generated IV is overwritten
with some random data in this case. This patch fixes this by
calling eseqiv_complete2() just in the case where an asynchronous
algorithm would call eseqiv_complete() as the complete function.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 crypto/eseqiv.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/crypto/eseqiv.c b/crypto/eseqiv.c
index 2a342c8..2fa53b0 100644
--- a/crypto/eseqiv.c
+++ b/crypto/eseqiv.c
@@ -153,7 +153,8 @@ static int eseqiv_givencrypt(struct skcipher_givcrypt_request *req)
 	if (err)
 		goto out;
 
-	eseqiv_complete2(req);
+	if (complete == eseqiv_complete)
+		eseqiv_complete2(req);
 
 out:
 	return err;
-- 
1.5.4.2

Re: [PATCH] crypto: eseqiv - fix IV generation for sync algorithms

[Herbert Xu]

On Tue, Apr 14, 2009 at 03:23:51PM +0200, Steffen Klassert wrote:
> If crypto_ablkcipher_encrypt() returns synchronous,
> eseqiv_complete2() is called even if req->giv is already the
> pointer to the generated IV. The generated IV is overwritten
> with some random data in this case. This patch fixes this by
> calling eseqiv_complete2() just in the case where an asynchronous
> algorithm would call eseqiv_complete() as the complete function.
> 
> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

Well caught! Clearly no one has ever tried this before :)

> diff --git a/crypto/eseqiv.c b/crypto/eseqiv.c
> index 2a342c8..2fa53b0 100644
> --- a/crypto/eseqiv.c
> +++ b/crypto/eseqiv.c
> @@ -153,7 +153,8 @@ static int eseqiv_givencrypt(struct skcipher_givcrypt_request *req)
>  	if (err)
>  		goto out;
>  
> -	eseqiv_complete2(req);
> +	if (complete == eseqiv_complete)
> +		eseqiv_complete2(req);

Being paranoid it may just be possible for our caller (or one if
its ancestors) to be eseqiv, in which case this test will give a
false positive.

So how about doing what seqiv does and check

	if (giv != req->giv)

Thanks,
-- 
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Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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Re: [PATCH] crypto: eseqiv - fix IV generation for sync algorithms

[Steffen Klassert]

On Wed, Apr 15, 2009 at 07:15:49PM +0800, Herbert Xu wrote:
> 
> Well caught! Clearly no one has ever tried this before :)
> 

I thought so :)

> 
> So how about doing what seqiv does and check
> 
> 	if (giv != req->giv)
> 

Yes, that's probaply the better check.
An updated patch is below.


crypto: eseqiv - fix IV generation for sync algorithms

If crypto_ablkcipher_encrypt() returns synchronous,
eseqiv_complete2() is called even if req->giv is already the
pointer to the generated IV. The generated IV is overwritten
with some random data in this case. This patch fixes this by
calling eseqiv_complete2() just if the generated IV has to be
copied to req->giv.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 crypto/eseqiv.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/crypto/eseqiv.c b/crypto/eseqiv.c
index 2a342c8..3ca3b66 100644
--- a/crypto/eseqiv.c
+++ b/crypto/eseqiv.c
@@ -153,7 +153,8 @@ static int eseqiv_givencrypt(struct skcipher_givcrypt_request *req)
 	if (err)
 		goto out;
 
-	eseqiv_complete2(req);
+	if (giv != req->giv)
+		eseqiv_complete2(req);
 
 out:
 	return err;
-- 
1.5.4.2

Re: [PATCH] crypto: eseqiv - fix IV generation for sync algorithms

[Herbert Xu]

On Wed, Apr 15, 2009 at 02:19:02PM +0200, Steffen Klassert wrote:
> 
> crypto: eseqiv - fix IV generation for sync algorithms

Applied to crypt-2.6.  Thanks a lot!
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Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt