2023-01-13 10:34:14

by Herbert Xu

Subject: [PATCH] crypto: essiv - Handle EBUSY correctly

As it is essiv only handles the special return value of EINPROGERSS,
which means that in all other cases it will free data related to the
request.

However, as the caller of essiv may specify MAY_BACKLOG, we also need
to expect EBUSY and treat it in the same way. Otherwise backlogged
requests will trigger a use-after-free.

Fixes: be1eb7f78aa8 ("crypto: essiv - create wrapper template...")
Signed-off-by: Herbert Xu <[email protected]>

diff --git a/crypto/essiv.c b/crypto/essiv.c
index e33369df9034..307eba74b901 100644
--- a/crypto/essiv.c
+++ b/crypto/essiv.c
@@ -171,7 +171,12 @@ static void essiv_aead_done(struct crypto_async_request *areq, int err)
struct aead_request *req = areq->data;
struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);

+ if (err == -EINPROGRESS)
+ goto out;
+
kfree(rctx->assoc);
+
+out:
aead_request_complete(req, err);
}

@@ -247,7 +252,7 @@ static int essiv_aead_crypt(struct aead_request *req, bool enc)
err = enc ? crypto_aead_encrypt(subreq) :
crypto_aead_decrypt(subreq);

- if (rctx->assoc && err != -EINPROGRESS)
+ if (rctx->assoc && err != -EINPROGRESS && err != -EBUSY)
kfree(rctx->assoc);
return err;
}
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

2023-01-13 11:15:02

by Ard Biesheuvel

Subject: Re: [PATCH] crypto: essiv - Handle EBUSY correctly

On Fri, 13 Jan 2023 at 11:24, Herbert Xu <[email protected]> wrote:
>
> As it is essiv only handles the special return value of EINPROGERSS,
> which means that in all other cases it will free data related to the
> request.
>
> However, as the caller of essiv may specify MAY_BACKLOG, we also need
> to expect EBUSY and treat it in the same way. Otherwise backlogged
> requests will trigger a use-after-free.
>
> Fixes: be1eb7f78aa8 ("crypto: essiv - create wrapper template...")
> Signed-off-by: Herbert Xu <[email protected]>

Acked-by: Ard Biesheuvel <[email protected]>

>
> diff --git a/crypto/essiv.c b/crypto/essiv.c
> index e33369df9034..307eba74b901 100644
> --- a/crypto/essiv.c
> +++ b/crypto/essiv.c
> @@ -171,7 +171,12 @@ static void essiv_aead_done(struct crypto_async_request *areq, int err)
> struct aead_request *req = areq->data;
> struct essiv_aead_request_ctx *rctx = aead_request_ctx(req);
>
> + if (err == -EINPROGRESS)
> + goto out;
> +
> kfree(rctx->assoc);
> +
> +out:
> aead_request_complete(req, err);
> }
>
> @@ -247,7 +252,7 @@ static int essiv_aead_crypt(struct aead_request *req, bool enc)
> err = enc ? crypto_aead_encrypt(subreq) :
> crypto_aead_decrypt(subreq);
>
> - if (rctx->assoc && err != -EINPROGRESS)
> + if (rctx->assoc && err != -EINPROGRESS && err != -EBUSY)
> kfree(rctx->assoc);
> return err;
> }
> --
> Email: Herbert Xu <[email protected]>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt