2020-08-12 12:59:09

by Ondrej Mosnacek

Subject: [PATCH v2] crypto: algif_aead - fix uninitialized ctx->init

In skcipher_accept_parent_nokey() the whole af_alg_ctx structure is
cleared by memset() after allocation, so add such memset() also to
aead_accept_parent_nokey() so that the new "init" field is also
initialized to zero. Without that the initial ctx->init checks might
randomly return true and cause errors.

While there, also remove the redundant zero assignments in both
functions.

Found via libkcapi testsuite.

Cc: Stephan Mueller <[email protected]>
Fixes: f3c802a1f300 ("crypto: algif_aead - Only wake up when ctx->more is zero")
Suggested-by: Herbert Xu <[email protected]>
Signed-off-by: Ondrej Mosnacek <[email protected]>
---

v2:
- intead add missing memset() to algif_aead and remove the redundant
zero assignments (suggested by Herbert)

crypto/algif_aead.c | 6 ------
crypto/algif_skcipher.c | 7 +------
2 files changed, 1 insertion(+), 12 deletions(-)

diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index d48d2156e6210..43c6aa784858b 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -558,12 +558,6 @@ static int aead_accept_parent_nokey(void *private, struct sock *sk)

INIT_LIST_HEAD(&ctx->tsgl_list);
ctx->len = len;
- ctx->used = 0;
- atomic_set(&ctx->rcvused, 0);
- ctx->more = 0;
- ctx->merge = 0;
- ctx->enc = 0;
- ctx->aead_assoclen = 0;
crypto_init_wait(&ctx->wait);

ask->private = ctx;
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index a51ba22fef58f..81c4022285a7c 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -333,6 +333,7 @@ static int skcipher_accept_parent_nokey(void *private, struct sock *sk)
ctx = sock_kmalloc(sk, len, GFP_KERNEL);
if (!ctx)
return -ENOMEM;
+ memset(ctx, 0, len);

ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(tfm),
GFP_KERNEL);
@@ -340,16 +341,10 @@ static int skcipher_accept_parent_nokey(void *private, struct sock *sk)
sock_kfree_s(sk, ctx, len);
return -ENOMEM;
}
-
memset(ctx->iv, 0, crypto_skcipher_ivsize(tfm));

INIT_LIST_HEAD(&ctx->tsgl_list);
ctx->len = len;
- ctx->used = 0;
- atomic_set(&ctx->rcvused, 0);
- ctx->more = 0;
- ctx->merge = 0;
- ctx->enc = 0;
crypto_init_wait(&ctx->wait);

ask->private = ctx;
--
2.26.2

2020-08-13 07:12:33

by Herbert Xu

Subject: Re: [PATCH v2] crypto: algif_aead - fix uninitialized ctx->init

On Wed, Aug 12, 2020 at 02:58:25PM +0200, Ondrej Mosnacek wrote:
> In skcipher_accept_parent_nokey() the whole af_alg_ctx structure is
> cleared by memset() after allocation, so add such memset() also to
> aead_accept_parent_nokey() so that the new "init" field is also
> initialized to zero. Without that the initial ctx->init checks might
> randomly return true and cause errors.
>
> While there, also remove the redundant zero assignments in both
> functions.
>
> Found via libkcapi testsuite.
>
> Cc: Stephan Mueller <[email protected]>
> Fixes: f3c802a1f300 ("crypto: algif_aead - Only wake up when ctx->more is zero")
> Suggested-by: Herbert Xu <[email protected]>
> Signed-off-by: Ondrej Mosnacek <[email protected]>
> ---
>
> v2:
> - intead add missing memset() to algif_aead and remove the redundant
> zero assignments (suggested by Herbert)
>
> crypto/algif_aead.c | 6 ------
> crypto/algif_skcipher.c | 7 +------
> 2 files changed, 1 insertion(+), 12 deletions(-)

Patch applied. Thanks.
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt