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From: Denis Efremov <efremov@linux.com>
To: Joe Perches <joe@perches.com>,
	Julia Lawall <Julia.Lawall@lip6.fr>,
	Dan Carpenter <dan.carpenter@oracle.com>
Cc: cocci@systeme.lip6.fr, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] coccinelle: api: add kzfree script
Date: Sun, 14 Jun 2020 22:42:54 +0300	[thread overview]
Message-ID: <345c783b-a8cf-9dd1-29c6-d32b9b29053f@linux.com> (raw)
In-Reply-To: <e4981fd76a88e18376c4e634c235501b57d321e7.camel@perches.com>

On 6/4/20 7:27 PM, Joe Perches wrote:
> On Thu, 2020-06-04 at 17:08 +0300, Denis Efremov wrote:
>> Check for memset() with 0 followed by kfree().
> 
> Perhaps those uses should be memzero_explicit or kvfree_sensitive.
> 

Is it safe to suggest to use kzfree instead of memzero_explicit && kfree?
Or it would be better to use kvfree_sensitive in this case.

kzfree uses memset(0) with no barrier_data.

For example:
diff -u -p a/drivers/crypto/inside-secure/safexcel_hash.c b/drivers/crypto/inside-secure/safexcel_hash.c
--- a/drivers/crypto/inside-secure/safexcel_hash.c
+++ b/drivers/crypto/inside-secure/safexcel_hash.c
@@ -1081,8 +1081,7 @@ static int safexcel_hmac_init_pad(struct
                }
 
                /* Avoid leaking */
-               memzero_explicit(keydup, keylen);
-               kfree(keydup);
+               kzfree(keydup);
 
                if (ret)
                        return ret;

Thanks,
Denis

WARNING: multiple messages have this Message-ID (diff)
From: Denis Efremov <efremov@linux.com>
To: Joe Perches <joe@perches.com>,
	Julia Lawall <Julia.Lawall@lip6.fr>,
	Dan Carpenter <dan.carpenter@oracle.com>
Cc: cocci@systeme.lip6.fr, linux-kernel@vger.kernel.org
Subject: Re: [Cocci] [PATCH] coccinelle: api: add kzfree script
Date: Sun, 14 Jun 2020 22:42:54 +0300	[thread overview]
Message-ID: <345c783b-a8cf-9dd1-29c6-d32b9b29053f@linux.com> (raw)
In-Reply-To: <e4981fd76a88e18376c4e634c235501b57d321e7.camel@perches.com>

On 6/4/20 7:27 PM, Joe Perches wrote:
> On Thu, 2020-06-04 at 17:08 +0300, Denis Efremov wrote:
>> Check for memset() with 0 followed by kfree().
> 
> Perhaps those uses should be memzero_explicit or kvfree_sensitive.
> 

Is it safe to suggest to use kzfree instead of memzero_explicit && kfree?
Or it would be better to use kvfree_sensitive in this case.

kzfree uses memset(0) with no barrier_data.

For example:
diff -u -p a/drivers/crypto/inside-secure/safexcel_hash.c b/drivers/crypto/inside-secure/safexcel_hash.c
--- a/drivers/crypto/inside-secure/safexcel_hash.c
+++ b/drivers/crypto/inside-secure/safexcel_hash.c
@@ -1081,8 +1081,7 @@ static int safexcel_hmac_init_pad(struct
                }
 
                /* Avoid leaking */
-               memzero_explicit(keydup, keylen);
-               kfree(keydup);
+               kzfree(keydup);
 
                if (ret)
                        return ret;

Thanks,
Denis
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  parent reply	other threads:[~2020-06-14 19:42 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-04 14:08 [PATCH] coccinelle: api: add kzfree script Denis Efremov
2020-06-04 14:08 ` [Cocci] " Denis Efremov
2020-06-04 14:15 ` Julia Lawall
2020-06-04 14:15   ` [Cocci] " Julia Lawall
2020-06-04 15:39   ` Denis Efremov
2020-06-04 15:39     ` [Cocci] " Denis Efremov
2020-06-04 15:51     ` Julia Lawall
2020-06-04 15:51       ` [Cocci] " Julia Lawall
2020-06-04 17:22       ` Denis Efremov
2020-06-04 17:22         ` [Cocci] " Denis Efremov
2020-06-04 17:28         ` Julia Lawall
2020-06-04 17:28           ` [Cocci] " Julia Lawall
2020-06-04 16:27 ` Joe Perches
2020-06-04 16:27   ` [Cocci] " Joe Perches
2020-06-04 17:30   ` Denis Efremov
2020-06-04 17:30     ` [Cocci] " Denis Efremov
2020-06-04 17:36     ` Joe Perches
2020-06-04 17:36       ` [Cocci] " Joe Perches
2020-06-14 19:42   ` Denis Efremov [this message]
2020-06-14 19:42     ` Denis Efremov
2020-06-14 20:01     ` Joe Perches
2020-06-14 20:01       ` [Cocci] " Joe Perches
2020-06-15 12:03     ` Dan Carpenter
2020-06-15 12:03       ` [Cocci] " Dan Carpenter
2020-06-15 13:51       ` Denis Efremov
2020-06-15 13:51         ` [Cocci] " Denis Efremov
2020-06-04 20:48 ` [PATCH v2] " Denis Efremov
2020-06-04 20:48   ` [Cocci] " Denis Efremov
2020-06-04 20:57   ` Julia Lawall
2020-06-04 20:57     ` Julia Lawall
2020-06-04 21:03     ` Denis Efremov
2020-06-04 21:03       ` Denis Efremov
2020-06-04 21:25     ` Denis Efremov
2020-06-04 21:25       ` Denis Efremov
2020-06-06  8:16       ` Julia Lawall
2020-06-06  8:16         ` Julia Lawall
2020-06-14 21:54 ` [PATCH v3] " Denis Efremov
2020-06-14 21:54   ` [Cocci] " Denis Efremov
2020-06-17 20:42   ` Julia Lawall
2020-06-17 20:42     ` Julia Lawall
2020-06-17 21:42     ` Denis Efremov
2020-06-17 21:42       ` Denis Efremov
2020-07-07 21:35   ` Julia Lawall
2020-07-07 21:35     ` Julia Lawall
2020-07-17 11:57 ` [PATCH v4] " Denis Efremov
2020-07-17 11:57   ` [Cocci] " Denis Efremov
2020-07-17 20:39   ` Julia Lawall
2020-07-17 20:39     ` [Cocci] " Julia Lawall
2020-08-10 23:45     ` Eric Biggers
2020-08-10 23:45       ` [Cocci] " Eric Biggers
2020-08-11  7:12       ` Denis Efremov
2020-08-11  7:12         ` [Cocci] " Denis Efremov
2020-08-11  7:49 ` [PATCH] coccinelle: api: update kzfree script to kfree_sensitive Denis Efremov
2020-08-11  7:49   ` [Cocci] " Denis Efremov
2020-08-26  8:12   ` Denis Efremov
2020-08-26  8:12     ` [Cocci] " Denis Efremov
2020-09-12 15:08   ` Julia Lawall
2020-09-12 15:08     ` [Cocci] " Julia Lawall
2020-06-04 15:20 [PATCH] coccinelle: api: add kzfree script Markus Elfring
2020-06-04 15:20 ` Markus Elfring
2020-06-04 15:56 ` Julia Lawall
2020-06-04 15:56   ` Julia Lawall

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