2022-02-25 10:20:20

by Jia-Ju Bai

Subject: [PATCH] crypto: drbg: check the return value of crypto_shash_init()

Then function crypto_shash_init() in drbg_kcapi_hash() can fail, but
there is no check of its return value. To fix this bug, its return value
should be checked with new error handling code.

Fixes: 541af946fe13 ("crypto: drbg - SP800-90A Deterministic Random Bit Generator")
Reported-by: TOTE Robot <[email protected]>
Signed-off-by: Jia-Ju Bai <[email protected]>
---
crypto/drbg.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/crypto/drbg.c b/crypto/drbg.c
index 177983b6ae38..51feb9538701 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -1725,8 +1725,11 @@ static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
{
struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
struct drbg_string *input = NULL;
+ int ret = 0;

- crypto_shash_init(&sdesc->shash);
+ ret = crypto_shash_init(&sdesc->shash);
+ if (ret)
+ return ret;
list_for_each_entry(input, in, list)
crypto_shash_update(&sdesc->shash, input->buf, input->len);
return crypto_shash_final(&sdesc->shash, outval);
--
2.17.1

2022-02-25 23:44:44

by Eric Biggers

Subject: Re: [PATCH] crypto: drbg: check the return value of crypto_shash_init()

On Thu, Feb 24, 2022 at 11:46:23PM -0800, Jia-Ju Bai wrote:
> Then function crypto_shash_init() in drbg_kcapi_hash() can fail, but
> there is no check of its return value. To fix this bug, its return value
> should be checked with new error handling code.
>
> Fixes: 541af946fe13 ("crypto: drbg - SP800-90A Deterministic Random Bit Generator")
> Reported-by: TOTE Robot <[email protected]>
> Signed-off-by: Jia-Ju Bai <[email protected]>
> ---
> crypto/drbg.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/crypto/drbg.c b/crypto/drbg.c
> index 177983b6ae38..51feb9538701 100644
> --- a/crypto/drbg.c
> +++ b/crypto/drbg.c
> @@ -1725,8 +1725,11 @@ static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
> {
> struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
> struct drbg_string *input = NULL;
> + int ret = 0;
>
> - crypto_shash_init(&sdesc->shash);
> + ret = crypto_shash_init(&sdesc->shash);
> + if (ret)
> + return ret;
> list_for_each_entry(input, in, list)
> crypto_shash_update(&sdesc->shash, input->buf, input->len);
> return crypto_shash_final(&sdesc->shash, outval);

What about the call to crypto_shash_update() right below it?

- Eric