[PATCH v2] KEYS: use kfree_sensitive with key

[PATCH v2] KEYS: use kfree_sensitive with key

[Mahmoud Adam]

key might contain private part of the key, so better use
kfree_sensitive to free it

Signed-off-by: Mahmoud Adam <mngyadam@amazon.com>
---
v2: kfree_sensitive only private key

 crypto/asymmetric_keys/public_key.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
index eca5671ad3f2..cd8c4123d936 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -43,7 +43,10 @@ static void public_key_describe(const struct key *asymmetric_key,
 void public_key_free(struct public_key *key)
 {
 	if (key) {
-		kfree(key->key);
+		if(key->key_is_private)
+			kfree_sensitive(key->key);
+		else
+			kfree(key->key);
 		kfree(key->params);
 		kfree(key);
 	}
@@ -218,7 +221,7 @@ static int software_key_query(const struct kernel_pkey_params *params,
 	ret = 0;

 error_free_key:
-	kfree(key);
+	kfree_sensitive(key);
 error_free_tfm:
 	crypto_free_akcipher(tfm);
 	pr_devel("<==%s() = %d\n", __func__, ret);
@@ -303,7 +306,7 @@ static int software_key_eds_op(struct kernel_pkey_params *params,
 		ret = req->dst_len;

 error_free_key:
-	kfree(key);
+	kfree_sensitive(key);
 error_free_req:
 	akcipher_request_free(req);
 error_free_tfm:
@@ -456,7 +459,7 @@ int public_key_verify_signature(const struct public_key *pkey,
 	ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait);

 error_free_key:
-	kfree(key);
+	kfree_sensitive(key);
 error_free_req:
 	akcipher_request_free(req);
 error_free_tfm:
--
2.40.1

Re: [PATCH v2] KEYS: use kfree_sensitive with key

[Herbert Xu]

On Thu, Jun 15, 2023 at 12:57:13PM +0000, Mahmoud Adam wrote:
> key might contain private part of the key, so better use
> kfree_sensitive to free it
> 
> Signed-off-by: Mahmoud Adam <mngyadam@amazon.com>
> ---
> v2: kfree_sensitive only private key
> 
>  crypto/asymmetric_keys/public_key.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)

Sorry, I was confused by the naming in this file.  These public_keys
can indeed be private.  So I'll just take your original patch.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH v2] KEYS: use kfree_sensitive with key

[Adam, Mahmoud]

> On 16. Jun 2023, at 12:31, Herbert Xu <herbert@gondor.apana.org.au> wrote:
> 
> On Thu, Jun 15, 2023 at 12:57:13PM +0000, Mahmoud Adam wrote:
>> key might contain private part of the key, so better use
>> kfree_sensitive to free it
>> 
>> Signed-off-by: Mahmoud Adam <mngyadam@amazon.com>
>> ---
>> v2: kfree_sensitive only private key
>> 
>> crypto/asymmetric_keys/public_key.c | 11 +++++++----
>> 1 file changed, 7 insertions(+), 4 deletions(-)
> 
> Sorry, I was confused by the naming in this file.  These public_keys
> can indeed be private.  So I'll just take your original patch.

It’s indeed very confusing.

Thanks for the review.

Mahmoud Adam



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