linux-kernel - [PATCH 2/2] crypto: aead,cipher - zeroize key buffer after use

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Date: Thu, 11 Apr 2024 23:51:57 +0000
From: Hailey Mothershead <hailmo@...zon.com>
To: <herbert@...dor.apana.org.au>
CC: <davem@...emloft.net>, <linux-crypto@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <hailmo@...zon.com>
Subject: [PATCH 2/2] crypto: aead,cipher - zeroize key buffer after use

I.G 9.7.B for FIPS 140-3 specifies that variables temporarily holding
cryptographic information should be zeroized once they are no longer
needed. Accomplish this by using kfree_sensitive for buffers that
previously held the private key.

Signed-off-by: Hailey Mothershead <hailmo@...zon.com>
---
 crypto/aead.c   | 2 +-
 crypto/cipher.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/crypto/aead.c b/crypto/aead.c
index 16991095270d..2592d5375de5 100644
--- a/crypto/aead.c
+++ b/crypto/aead.c
@@ -36,7 +36,7 @@ static int setkey_unaligned(struct crypto_aead *tfm, const u8 *key,
 	memcpy(alignbuffer, key, keylen);
 	ret = crypto_aead_alg(tfm)->setkey(tfm, alignbuffer, keylen);
 	memset(alignbuffer, 0, keylen);
-	kfree(buffer);
+	kfree_sensitive(buffer);
 	return ret;
 }
 
diff --git a/crypto/cipher.c b/crypto/cipher.c
index b47141ed4a9f..efb87fa417e7 100644
--- a/crypto/cipher.c
+++ b/crypto/cipher.c
@@ -35,7 +35,7 @@ static int setkey_unaligned(struct crypto_cipher *tfm, const u8 *key,
 	memcpy(alignbuffer, key, keylen);
 	ret = cia->cia_setkey(crypto_cipher_tfm(tfm), alignbuffer, keylen);
 	memset(alignbuffer, 0, keylen);
-	kfree(buffer);
+	kfree_sensitive(buffer);
 	return ret;
 
 }
-- 
2.40.1