PKCS#7: Support CMS messages also [RFC5652]
Since CMS is an evolution of PKCS#7, with much of the ASN.1 being
compatible, add support for CMS signed-data messages also [RFC5652 sec 5].
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-By: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/crypto/asymmetric_keys/pkcs7.asn1 b/crypto/asymmetric_keys/pkcs7.asn1
index 0550443..6bf8ff4 100644
--- a/crypto/asymmetric_keys/pkcs7.asn1
+++ b/crypto/asymmetric_keys/pkcs7.asn1
@@ -69,7 +69,7 @@
SignerInfo ::= SEQUENCE {
version INTEGER ({ pkcs7_note_signerinfo_version }),
- issuerAndSerialNumber IssuerAndSerialNumber,
+ sid SignerIdentifier, -- CMS variant, not PKCS#7
digestAlgorithm DigestAlgorithmIdentifier ({ pkcs7_sig_note_digest_algo }),
authenticatedAttributes CHOICE {
aaSet [0] IMPLICIT SetOfAuthenticatedAttribute
@@ -88,6 +88,12 @@
} OPTIONAL
} ({ pkcs7_note_signed_info })
+SignerIdentifier ::= CHOICE {
+ -- RFC5652 sec 5.3
+ issuerAndSerialNumber IssuerAndSerialNumber,
+ subjectKeyIdentifier [0] IMPLICIT SubjectKeyIdentifier
+}
+
IssuerAndSerialNumber ::= SEQUENCE {
issuer Name ({ pkcs7_sig_note_issuer }),
serialNumber CertificateSerialNumber ({ pkcs7_sig_note_serial })
@@ -95,6 +101,8 @@
CertificateSerialNumber ::= INTEGER
+SubjectKeyIdentifier ::= OCTET STRING ({ pkcs7_sig_note_skid })
+
SetOfAuthenticatedAttribute ::= SET OF AuthenticatedAttribute
AuthenticatedAttribute ::= SEQUENCE {
diff --git a/crypto/asymmetric_keys/pkcs7_parser.c b/crypto/asymmetric_keys/pkcs7_parser.c
index ab427f0..826e2f3 100644
--- a/crypto/asymmetric_keys/pkcs7_parser.c
+++ b/crypto/asymmetric_keys/pkcs7_parser.c
@@ -33,6 +33,9 @@
unsigned raw_serial_size;
unsigned raw_issuer_size;
const void *raw_issuer;
+ const void *raw_skid;
+ unsigned raw_skid_size;
+ bool expect_skid;
};
/*
@@ -249,15 +252,21 @@
unsigned char tag,
const void *value, size_t vlen)
{
+ struct pkcs7_parse_context *ctx = context;
unsigned version;
if (vlen != 1)
goto unsupported;
- version = *(const u8 *)value;
+ ctx->msg->version = version = *(const u8 *)value;
switch (version) {
case 1:
- /* PKCS#7 SignedData [RFC2315 sec 9.1] */
+ /* PKCS#7 SignedData [RFC2315 sec 9.1]
+ * CMS ver 1 SignedData [RFC5652 sec 5.1]
+ */
+ break;
+ case 3:
+ /* CMS ver 3 SignedData [RFC2315 sec 5.1] */
break;
default:
goto unsupported;
@@ -277,6 +286,7 @@
unsigned char tag,
const void *value, size_t vlen)
{
+ struct pkcs7_parse_context *ctx = context;
unsigned version;
if (vlen != 1)
@@ -285,7 +295,18 @@
version = *(const u8 *)value;
switch (version) {
case 1:
- /* PKCS#7 SignerInfo [RFC2315 sec 9.2] */
+ /* PKCS#7 SignerInfo [RFC2315 sec 9.2]
+ * CMS ver 1 SignerInfo [RFC5652 sec 5.3]
+ */
+ if (ctx->msg->version != 1)
+ goto version_mismatch;
+ ctx->expect_skid = false;
+ break;
+ case 3:
+ /* CMS ver 3 SignerInfo [RFC2315 sec 5.3] */
+ if (ctx->msg->version == 1)
+ goto version_mismatch;
+ ctx->expect_skid = true;
break;
default:
goto unsupported;
@@ -296,6 +317,9 @@
unsupported:
pr_warn("Unsupported SignerInfo version\n");
return -EINVAL;
+version_mismatch:
+ pr_warn("SignedData-SignerInfo version mismatch\n");
+ return -EBADMSG;
}
/*
@@ -440,6 +464,22 @@
}
/*
+ * Note the issuing cert's subjectKeyIdentifier
+ */
+int pkcs7_sig_note_skid(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+
+ pr_devel("SKID: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
+
+ ctx->raw_skid = value;
+ ctx->raw_skid_size = vlen;
+ return 0;
+}
+
+/*
* Note the signature data
*/
int pkcs7_sig_note_signature(void *context, size_t hdrlen,
@@ -472,13 +512,21 @@
struct asymmetric_key_id *kid;
/* Generate cert issuer + serial number key ID */
- kid = asymmetric_key_generate_id(ctx->raw_serial,
- ctx->raw_serial_size,
- ctx->raw_issuer,
- ctx->raw_issuer_size);
+ if (!ctx->expect_skid) {
+ kid = asymmetric_key_generate_id(ctx->raw_serial,
+ ctx->raw_serial_size,
+ ctx->raw_issuer,
+ ctx->raw_issuer_size);
+ } else {
+ kid = asymmetric_key_generate_id(ctx->raw_skid,
+ ctx->raw_skid_size,
+ "", 0);
+ }
if (IS_ERR(kid))
return PTR_ERR(kid);
+ pr_devel("SINFO KID: %u [%*phN]\n", kid->len, kid->len, kid->data);
+
sinfo->signing_cert_id = kid;
sinfo->index = ++ctx->sinfo_index;
*ctx->ppsinfo = sinfo;
diff --git a/crypto/asymmetric_keys/pkcs7_parser.h b/crypto/asymmetric_keys/pkcs7_parser.h
index efc7dc9..790dd7c 100644
--- a/crypto/asymmetric_keys/pkcs7_parser.h
+++ b/crypto/asymmetric_keys/pkcs7_parser.h
@@ -33,7 +33,9 @@
unsigned authattrs_len;
const void *authattrs;
- /* Issuing cert serial number and issuer's name */
+ /* Issuing cert serial number and issuer's name [PKCS#7 or CMS ver 1]
+ * or issuing cert's SKID [CMS ver 3].
+ */
struct asymmetric_key_id *signing_cert_id;
/* Message signature.
@@ -50,6 +52,7 @@
struct x509_certificate *certs; /* Certificate list */
struct x509_certificate *crl; /* Revocation list */
struct pkcs7_signed_info *signed_infos;
+ u8 version; /* Version of cert (1 -> PKCS#7 or CMS; 3 -> CMS) */
/* Content Data (or NULL) */
enum OID data_type; /* Type of Data */