From e7c87bef7de2417b219d4dbfe8d33a0098a8df54 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 25 Sep 2015 16:31:46 +0100 Subject: [PATCH] X.509: Don't strip leading 00's from key ID when constructing key description Don't strip leading zeros from the crypto key ID when using it to construct the struct key description as the signature in kernels up to and including 4.2 matched this aspect of the key. This means that 1 in 256 keys won't actually match if their key ID begins with 00. The key ID is stored in the module signature as binary and so must be converted to text in order to invoke request_key() - but it isn't stripped at this point. Something like this is likely to be observed in dmesg when the key is loaded: [ 1.572423] Loaded X.509 cert 'Build time autogenerated kernel key: 62a7c3d2da278be024da4af8652c071f3fea33' followed by this when we try and use it: [ 1.646153] Request for unknown module key 'Build time autogenerated kernel key: 0062a7c3d2da278be024da4af8652c071f3fea33' err -11 The 'Loaded' line should show an extra '00' on the front of the hex string. This problem should not affect 4.3-rc1 and onwards because there the key should be matched on one of its auxiliary identities rather than the key struct's description string. Reported-by: Arjan van de Ven Reported-by: Andy Whitcroft Signed-off-by: David Howells --- crypto/asymmetric_keys/x509_public_key.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c index 6d88dd15c98d..197096632412 100644 --- a/crypto/asymmetric_keys/x509_public_key.c +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -332,10 +332,6 @@ static int x509_key_preparse(struct key_preparsed_payload *prep) srlen = cert->raw_serial_size; q = cert->raw_serial; } - if (srlen > 1 && *q == 0) { - srlen--; - q++; - } ret = -ENOMEM; desc = kmalloc(sulen + 2 + srlen * 2 + 1, GFP_KERNEL); -- 2.20.1