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authorDavid Howells <dhowells@redhat.com>2014-09-16 20:36:13 +0400
committerDavid Howells <dhowells@redhat.com>2014-09-16 20:36:13 +0400
commit46963b774d441c833afc1535f6d84b3df2a94204 (patch)
tree335cbd163ef2581b72d462f49984a6809609a58b /crypto/asymmetric_keys/x509_cert_parser.c
parent7901c1a8effbe5f89673bfc09d6e37b8f334f1a7 (diff)
downloadlinux-46963b774d441c833afc1535f6d84b3df2a94204.tar.xz
KEYS: Overhaul key identification when searching for asymmetric keys
Make use of the new match string preparsing to overhaul key identification when searching for asymmetric keys. The following changes are made: (1) Use the previously created asymmetric_key_id struct to hold the following key IDs derived from the X.509 certificate or PKCS#7 message: id: serial number + issuer skid: subjKeyId + subject authority: authKeyId + issuer (2) Replace the hex fingerprint attached to key->type_data[1] with an asymmetric_key_ids struct containing the id and the skid (if present). (3) Make the asymmetric_type match data preparse select one of two searches: (a) An iterative search for the key ID given if prefixed with "id:". The prefix is expected to be followed by a hex string giving the ID to search for. The criterion key ID is checked against all key IDs recorded on the key. (b) A direct search if the key ID is not prefixed with "id:". This will look for an exact match on the key description. (4) Make x509_request_asymmetric_key() take a key ID. This is then converted into "id:<hex>" and passed into keyring_search() where match preparsing will turn it back into a binary ID. (5) X.509 certificate verification then takes the authority key ID and looks up a key that matches it to find the public key for the certificate signature. (6) PKCS#7 certificate verification then takes the id key ID and looks up a key that matches it to find the public key for the signed information block signature. Additional changes: (1) Multiple subjKeyId and authKeyId values on an X.509 certificate cause the cert to be rejected with -EBADMSG. (2) The 'fingerprint' ID is gone. This was primarily intended to convey PGP public key fingerprints. If PGP is supported in future, this should generate a key ID that carries the fingerprint. (3) Th ca_keyid= kernel command line option is now converted to a key ID and used to match the authority key ID. Possibly this should only match the actual authKeyId part and not the issuer as well. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com>
Diffstat (limited to 'crypto/asymmetric_keys/x509_cert_parser.c')
-rw-r--r--crypto/asymmetric_keys/x509_cert_parser.c55
1 files changed, 33 insertions, 22 deletions
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index ac72348c186a..96151b2b91a2 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -46,7 +46,8 @@ void x509_free_certificate(struct x509_certificate *cert)
public_key_destroy(cert->pub);
kfree(cert->issuer);
kfree(cert->subject);
- kfree(cert->fingerprint);
+ kfree(cert->id);
+ kfree(cert->skid);
kfree(cert->authority);
kfree(cert->sig.digest);
mpi_free(cert->sig.rsa.s);
@@ -62,6 +63,7 @@ struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
{
struct x509_certificate *cert;
struct x509_parse_context *ctx;
+ struct asymmetric_key_id *kid;
long ret;
ret = -ENOMEM;
@@ -89,6 +91,17 @@ struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
if (ret < 0)
goto error_decode;
+ /* Generate cert issuer + serial number key ID */
+ kid = asymmetric_key_generate_id(cert->raw_serial,
+ cert->raw_serial_size,
+ cert->raw_issuer,
+ cert->raw_issuer_size);
+ if (IS_ERR(kid)) {
+ ret = PTR_ERR(kid);
+ goto error_decode;
+ }
+ cert->id = kid;
+
kfree(ctx);
return cert;
@@ -407,36 +420,34 @@ int x509_process_extension(void *context, size_t hdrlen,
const void *value, size_t vlen)
{
struct x509_parse_context *ctx = context;
+ struct asymmetric_key_id *kid;
const unsigned char *v = value;
- char *f;
int i;
pr_debug("Extension: %u\n", ctx->last_oid);
if (ctx->last_oid == OID_subjectKeyIdentifier) {
/* Get hold of the key fingerprint */
- if (vlen < 3)
+ if (ctx->cert->skid || vlen < 3)
return -EBADMSG;
if (v[0] != ASN1_OTS || v[1] != vlen - 2)
return -EBADMSG;
v += 2;
vlen -= 2;
- f = kmalloc(vlen * 2 + 1, GFP_KERNEL);
- if (!f)
- return -ENOMEM;
- for (i = 0; i < vlen; i++)
- sprintf(f + i * 2, "%02x", v[i]);
- pr_debug("fingerprint %s\n", f);
- ctx->cert->fingerprint = f;
+ kid = asymmetric_key_generate_id(v, vlen,
+ ctx->cert->raw_subject,
+ ctx->cert->raw_subject_size);
+ if (IS_ERR(kid))
+ return PTR_ERR(kid);
+ ctx->cert->skid = kid;
+ pr_debug("subjkeyid %*phN\n", kid->len, kid->data);
return 0;
}
if (ctx->last_oid == OID_authorityKeyIdentifier) {
- size_t key_len;
-
/* Get hold of the CA key fingerprint */
- if (vlen < 5)
+ if (ctx->cert->authority || vlen < 5)
return -EBADMSG;
/* Authority Key Identifier must be a Constructed SEQUENCE */
@@ -454,7 +465,7 @@ int x509_process_extension(void *context, size_t hdrlen,
v[3] > vlen - 4)
return -EBADMSG;
- key_len = v[3];
+ vlen = v[3];
v += 4;
} else {
/* Long Form length */
@@ -476,17 +487,17 @@ int x509_process_extension(void *context, size_t hdrlen,
v[sub + 1] > vlen - 4 - sub)
return -EBADMSG;
- key_len = v[sub + 1];
+ vlen = v[sub + 1];
v += (sub + 2);
}
- f = kmalloc(key_len * 2 + 1, GFP_KERNEL);
- if (!f)
- return -ENOMEM;
- for (i = 0; i < key_len; i++)
- sprintf(f + i * 2, "%02x", v[i]);
- pr_debug("authority %s\n", f);
- ctx->cert->authority = f;
+ kid = asymmetric_key_generate_id(v, vlen,
+ ctx->cert->raw_issuer,
+ ctx->cert->raw_issuer_size);
+ if (IS_ERR(kid))
+ return PTR_ERR(kid);
+ pr_debug("authkeyid %*phN\n", kid->len, kid->data);
+ ctx->cert->authority = kid;
return 0;
}