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[PATCH] s390/crypto: initialize ret to zero to avoid returning garbage value

Started byColin King <colin.king@canonical.com>
First post2016-09-05 18:30 +0200
Last post2016-09-06 09:20 +0200
Articles 2 — 2 participants

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  [PATCH] s390/crypto: initialize ret to zero to avoid returning garbage value Colin King <colin.king@canonical.com> - 2016-09-05 18:30 +0200
    Re: [PATCH] s390/crypto: initialize ret to zero to avoid returning  garbage value Martin Schwidefsky <schwidefsky@de.ibm.com> - 2016-09-06 09:20 +0200

#1476585 — [PATCH] s390/crypto: initialize ret to zero to avoid returning garbage value

FromColin King <colin.king@canonical.com>
Date2016-09-05 18:30 +0200
Subject[PATCH] s390/crypto: initialize ret to zero to avoid returning garbage value
Message-ID<se4Wu-68Q-27@gated-at.bofh.it>
From: Colin Ian King <colin.king@canonical.com>

static analysis with cppcheck detected that ret is not initialized
and hence garbage is potentially being returned in the case where
prng_data->ppnows.reseed_counter <= prng_reseed_limit.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 arch/s390/crypto/prng.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/crypto/prng.c b/arch/s390/crypto/prng.c
index 79e3a1f..a21fdf4 100644
--- a/arch/s390/crypto/prng.c
+++ b/arch/s390/crypto/prng.c
@@ -412,7 +412,7 @@ static int prng_sha512_reseed(void)
 
 static int prng_sha512_generate(u8 *buf, size_t nbytes)
 {
-	int ret;
+	int ret = 0;
 
 	/* reseed needed ? */
 	if (prng_data->ppnows.reseed_counter > prng_reseed_limit) {
-- 
2.9.3

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#1477110 — Re: [PATCH] s390/crypto: initialize ret to zero to avoid returning garbage value

FromMartin Schwidefsky <schwidefsky@de.ibm.com>
Date2016-09-06 09:20 +0200
SubjectRe: [PATCH] s390/crypto: initialize ret to zero to avoid returning garbage value
Message-ID<seiPL-7bK-3@gated-at.bofh.it>
In reply to#1476585
On Mon,  5 Sep 2016 17:21:18 +0100
Colin King <colin.king@canonical.com> wrote:

> From: Colin Ian King <colin.king@canonical.com>
> 
> static analysis with cppcheck detected that ret is not initialized
> and hence garbage is potentially being returned in the case where
> prng_data->ppnows.reseed_counter <= prng_reseed_limit.
> 
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  arch/s390/crypto/prng.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/s390/crypto/prng.c b/arch/s390/crypto/prng.c
> index 79e3a1f..a21fdf4 100644
> --- a/arch/s390/crypto/prng.c
> +++ b/arch/s390/crypto/prng.c
> @@ -412,7 +412,7 @@ static int prng_sha512_reseed(void)
> 
>  static int prng_sha512_generate(u8 *buf, size_t nbytes)
>  {
> -	int ret;
> +	int ret = 0;
> 
>  	/* reseed needed ? */
>  	if (prng_data->ppnows.reseed_counter > prng_reseed_limit) {

This issue has been introduced by git commit 0177db01adf26cf9
"s390/crypto: simplify return code handling" which is only on
the features branch right now. And to set ret=0 does not fix
the problem. The correct fix is to return nbytes.

Still a good catch though.

-- 
blue skies,
   Martin.

"Reality continues to ruin my life." - Calvin.

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