Thread (13 messages) 13 messages, 3 authors, 2022-10-05

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

From: Jarkko Sakkinen <jarkko@kernel.org>
Date: 2022-09-20 05:06:31
Also in: keyrings, linux-integrity, lkml

On Fri, Sep 16, 2022 at 07:45:29AM +0200, Nikolaus Voss wrote:
quoted hunk ↗ jump to hunk
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 <redacted>
---
 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) {
This looks wrong. What does cap decrypted_data, and why strnlen()
is not used?
 			pr_err("encrypted key: decrypted data provided does not match decrypted data length provided\n");
Using pr_err() is probably wrong here and has different prefix
than elsewhere in the file (also most of other uses of pr_err()
are wrong apparently). Nothing bad is really happening.

And who does make any sense of that error message anyway?

For one, I don't understand it.
quoted hunk ↗ jump to hunk
 			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

BR, Jarkko
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