2023-06-15 12:59:58

by Mahmoud Adam

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

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

Signed-off-by: Mahmoud Adam <[email protected]>
---
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

2023-06-16 11:03:45

by Adam, Mahmoud

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

> On 16. Jun 2023, at 12:31, Herbert Xu <[email protected]> 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 <[email protected]>
>> ---
>> 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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2023-06-16 11:13:45

by Herbert Xu

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

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 <[email protected]>
> ---
> 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 <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt