[PATCH 0/2] crypto-testmgr: Fine-tuning for drbg_cavs_test()

[PATCH 0/2] crypto-testmgr: Fine-tuning for drbg_cavs_test()

[SF Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sat, 21 Oct 2017 19:47:43 +0200

Two update suggestions were taken into account
from static source code analysis.

Markus Elfring (2):
  Use common error handling code
  Delete an unnecessary variable initialisation

 crypto/testmgr.c | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

-- 
2.14.2

[PATCH 1/2] crypto-testmgr: Use common error handling code in drbg_cavs_test()

[SF Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sat, 21 Oct 2017 19:29:11 +0200

Adjust jump targets so that a bit of exception handling can be better
reused at the end of this function.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 crypto/testmgr.c | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index dd9c7f1c1c7b..76c5128284f8 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -1914,8 +1914,8 @@ static int drbg_cavs_test(const struct drbg_testvec *test, int pr,
 	if (IS_ERR(drng)) {
 		printk(KERN_ERR "alg: drbg: could not allocate DRNG handle for "
 		       "%s\n", driver);
-		kzfree(buf);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto free_buffer;
 	}
 
 	test_data.testentropy = &testentropy;
@@ -1924,7 +1924,7 @@ static int drbg_cavs_test(const struct drbg_testvec *test, int pr,
 	ret = crypto_drbg_reset_test(drng, &pers, &test_data);
 	if (ret) {
 		printk(KERN_ERR "alg: drbg: Failed to reset rng\n");
-		goto outbuf;
+		goto free_rng;
 	}
 
 	drbg_string_fill(&addtl, test->addtla, test->addtllen);
@@ -1936,11 +1936,9 @@ static int drbg_cavs_test(const struct drbg_testvec *test, int pr,
 		ret = crypto_drbg_get_bytes_addtl(drng,
 			buf, test->expectedlen, &addtl);
 	}
-	if (ret < 0) {
-		printk(KERN_ERR "alg: drbg: could not obtain random data for "
-		       "driver %s\n", driver);
-		goto outbuf;
-	}
+
+	if (ret < 0)
+		goto report_failure;
 
 	drbg_string_fill(&addtl, test->addtlb, test->addtllen);
 	if (pr) {
@@ -1951,18 +1949,21 @@ static int drbg_cavs_test(const struct drbg_testvec *test, int pr,
 		ret = crypto_drbg_get_bytes_addtl(drng,
 			buf, test->expectedlen, &addtl);
 	}
-	if (ret < 0) {
-		printk(KERN_ERR "alg: drbg: could not obtain random data for "
-		       "driver %s\n", driver);
-		goto outbuf;
-	}
 
-	ret = memcmp(test->expected, buf, test->expectedlen);
+	if (ret < 0)
+		goto report_failure;
 
-outbuf:
+	ret = memcmp(test->expected, buf, test->expectedlen);
+free_rng:
 	crypto_free_rng(drng);
+free_buffer:
 	kzfree(buf);
 	return ret;
+
+report_failure:
+	pr_err("alg: drbg: could not obtain random data for driver %s\n",
+	       driver);
+	goto free_rng;
 }
 
 
-- 
2.14.2

Re: [PATCH 1/2] crypto-testmgr: Use common error handling code in drbg_cavs_test()

[Stephan Mueller]

Am Samstag, 21. Oktober 2017, 19:53:54 CEST schrieb SF Markus Elfring:

Hi Markus,

> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Sat, 21 Oct 2017 19:29:11 +0200
> 
> Adjust jump targets so that a bit of exception handling can be better
> reused at the end of this function.
> 
> This issue was detected by using the Coccinelle software.

Thank you for this patch.

> -outbuf:
> +	ret = memcmp(test->expected, buf, test->expectedlen);
> +free_rng:
>  	crypto_free_rng(drng);
> +free_buffer:
>  	kzfree(buf);
>  	return ret;
> +
> +report_failure:
> +	pr_err("alg: drbg: could not obtain random data for driver %s\n",
> +	       driver);
> +	goto free_rng;

Though, jumping back and forth like this with goto directives is something 
that looks a bit strange. At least to my taste, may I suggest to have gotos 
pointing only downwards and not up again? (Note, the same applies to the 
ansi_cprng patch set).

What about something like following:

...
    memcmp
    goto free_rng;

report_failure:
    <failure report>

free_rng:
    <the deallocation code>

Ciao
Stephan

Re: crypto-testmgr: Use common error handling code in drbg_cavs_test()

[SF Markus Elfring]

> Though, jumping back and forth like this with goto directives is something 
> that looks a bit strange. At least to my taste, may I suggest to have gotos 
> pointing only downwards and not up again? (Note, the same applies to the 
> ansi_cprng patch set).
> 
> What about something like following:
> 
> ...
>     memcmp
>     goto free_rng;

Do you find an additional jump really acceptable at such a source code place?


> report_failure:
>     <failure report>
> 
> free_rng:
>     <the deallocation code>

I am curious on how feedback will evolve also for the other design approach.

Regards,
Markus

[PATCH 2/2] crypto-testmgr: Delete an unnecessary variable initialisation in drbg_cavs_test()

[SF Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sat, 21 Oct 2017 19:33:45 +0200

The variable "ret" will eventually be set to an error code a bit later.
Thus omit the explicit initialisation at the beginning.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 crypto/testmgr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index 76c5128284f8..e46cf2c92497 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -1901,7 +1901,7 @@ static int alg_test_cprng(const struct alg_test_desc *desc, const char *driver,
 static int drbg_cavs_test(const struct drbg_testvec *test, int pr,
 			  const char *driver, u32 type, u32 mask)
 {
-	int ret = -EAGAIN;
+	int ret;
 	struct crypto_rng *drng;
 	struct drbg_test_data test_data;
 	struct drbg_string addtl, pers, testentropy;
-- 
2.14.2