[PATCH] KEYS: encrypted: fix key instantiation with user-provided data

From: Nikolaus Voss <nv@vosn.de>
To: Mimi Zohar <zohar@linux.ibm.com>,
	David Howells <dhowells@redhat.com>,
	Jarkko Sakkinen <jarkko@kernel.org>,
	James Morris <jmorris@namei.org>,
	"Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-integrity@vger.kernel.org, keyrings@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH] KEYS: encrypted: fix key instantiation with user-provided data
Date: Fri, 16 Sep 2022 07:45:29 +0200	[thread overview]
Message-ID: <20220919072317.E41421357@mail.steuer-voss.de> (raw)

Commit cd3bc044af48 ("KEYS: encrypted: Instantiate key with user-provided
decrypted data") added key instantiation with user provided decrypted data.
The user data is hex-ascii-encoded but was just memcpy'ed to the binary buffer.
Fix this to use hex2bin instead.

Fixes: cd3bc044af48 ("KEYS: encrypted: Instantiate key with user-provided decrypted data")
Cc: stable <stable@kernel.org>
Signed-off-by: Nikolaus Voss <nikolaus.voss@haag-streit.com>
---
 security/keys/encrypted-keys/encrypted.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c
index e05cfc2e49ae..1e313982af02 100644
--- a/security/keys/encrypted-keys/encrypted.c
+++ b/security/keys/encrypted-keys/encrypted.c
@@ -627,7 +627,7 @@ static struct encrypted_key_payload *encrypted_key_alloc(struct key *key,
 			pr_err("encrypted key: instantiation of keys using provided decrypted data is disabled since CONFIG_USER_DECRYPTED_DATA is set to false\n");
 			return ERR_PTR(-EINVAL);
 		}
-		if (strlen(decrypted_data) != decrypted_datalen) {
+		if (strlen(decrypted_data) != decrypted_datalen * 2) {
 			pr_err("encrypted key: decrypted data provided does not match decrypted data length provided\n");
 			return ERR_PTR(-EINVAL);
 		}
@@ -791,8 +791,8 @@ static int encrypted_init(struct encrypted_key_payload *epayload,
 		ret = encrypted_key_decrypt(epayload, format, hex_encoded_iv);
 	} else if (decrypted_data) {
 		get_random_bytes(epayload->iv, ivsize);
-		memcpy(epayload->decrypted_data, decrypted_data,
-				   epayload->decrypted_datalen);
+		ret = hex2bin(epayload->decrypted_data, decrypted_data,
+			      epayload->decrypted_datalen);
 	} else {
 		get_random_bytes(epayload->iv, ivsize);
 		get_random_bytes(epayload->decrypted_data, epayload->decrypted_datalen);
-- 
2.34.1

