linux/crypto/asymmetric_keys
Chun-Yi Lee 04b00bdb41 X.509: Support parse long form of length octets in Authority Key Identifier
Per X.509 spec in 4.2.1.1 section, the structure of Authority Key
Identifier Extension is:

   AuthorityKeyIdentifier ::= SEQUENCE {
      keyIdentifier             [0] KeyIdentifier           OPTIONAL,
      authorityCertIssuer       [1] GeneralNames            OPTIONAL,
      authorityCertSerialNumber [2] CertificateSerialNumber OPTIONAL  }

   KeyIdentifier ::= OCTET STRING

When a certificate also provides
authorityCertIssuer and authorityCertSerialNumber then the length of
AuthorityKeyIdentifier SEQUENCE is likely to long form format.
e.g.
   The example certificate demos/tunala/A-server.pem in openssl source:

X509v3 Authority Key Identifier:
    keyid:49:FB:45:72:12:C4:CC:E1:45:A1:D3:08:9E:95:C4:2C:6D:55:3F:17
    DirName:/C=NZ/L=Wellington/O=Really Irresponsible Authorisation Authority (RIAA)/OU=Cert-stamping/CN=Jackov al-Trades/emailAddress=none@fake.domain
    serial:00

Current parsing rule of OID_authorityKeyIdentifier only take care the
short form format, it causes load certificate to modsign_keyring fail:

[   12.061147] X.509: Extension: 47
[   12.075121] MODSIGN: Problem loading in-kernel X.509 certificate (-74)

So, this patch add the parsing rule for support long form format against
Authority Key Identifier.

v3:
Changed the size check in "Short Form length" case, we allow v[3] smaller
then (vlen - 4) because authorityCertIssuer and authorityCertSerialNumber
are also possible attach in AuthorityKeyIdentifier sequence.

v2:
 - Removed comma from author's name.
 - Moved 'Short Form length' comment inside the if-body.
 - Changed the type of sub to size_t.
 - Use ASN1_INDEFINITE_LENGTH rather than writing 0x80 and 127.
 - Moved the key_len's value assignment before alter v.
 - Fixed the typo of octets.
 - Add 2 to v before entering the loop for calculate the length.
 - Removed the comment of check vlen.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Chun-Yi Lee <jlee@suse.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-04-22 11:32:19 +09:30
..
.gitignore X.509: Add a crypto key parser for binary (DER) X.509 certificates 2012-10-08 13:50:22 +10:30
asymmetric_keys.h
asymmetric_type.c
Kconfig X.509: Add a crypto key parser for binary (DER) X.509 certificates 2012-10-08 13:50:22 +10:30
Makefile X.509: Add a crypto key parser for binary (DER) X.509 certificates 2012-10-08 13:50:22 +10:30
public_key.c KEYS: Asymmetric public-key algorithm crypto key subtype 2012-10-08 13:50:14 +10:30
public_key.h RSA: Implement signature verification algorithm [PKCS#1 / RFC3447] 2012-10-08 13:50:16 +10:30
rsa.c RSA: Fix signature verification for shorter signatures 2012-10-08 13:50:17 +10:30
signature.c KEYS: Provide signature verification with an asymmetric key 2012-10-08 13:50:15 +10:30
x509_cert_parser.c X.509: Support parse long form of length octets in Authority Key Identifier 2013-04-22 11:32:19 +09:30
x509_parser.h MODSIGN: Fix 32-bit overflow in X.509 certificate validity date checking 2012-10-10 20:06:37 +10:30
x509_public_key.c X.509: Convert some printk calls to pr_devel 2012-10-10 20:06:38 +10:30
x509_rsakey.asn1 X.509: Add a crypto key parser for binary (DER) X.509 certificates 2012-10-08 13:50:22 +10:30
x509.asn1 X.509: Add a crypto key parser for binary (DER) X.509 certificates 2012-10-08 13:50:22 +10:30