2009-04-14 13:21:52

by Steffen Klassert

[permalink] [raw]
Subject: [PATCH] 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 in the case where an asynchronous
algorithm would call eseqiv_complete() as the complete function.

Signed-off-by: Steffen Klassert <[email protected]>
---
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



2009-04-15 11:15:53

by Herbert Xu

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

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 <[email protected]>

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,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

2009-04-15 12:17:03

by Steffen Klassert

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

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 <[email protected]>
---
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


2009-04-15 12:45:50

by Herbert Xu

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

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!
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt