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PKCS#7: Support CMS messages also [RFC5652]

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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>
This commit is contained in:
David Howells 2015-07-20 21:16:33 +01:00
parent a4c6e57f4f
commit 60d65cacd7
3 changed files with 68 additions and 9 deletions
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10
crypto/asymmetric_keys/pkcs7.asn1
View file

@ -69,7 +69,7 @@ SignerInfos ::= CHOICE {
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 @@ SignerInfo ::= SEQUENCE {
} 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 @@ IssuerAndSerialNumber ::= SEQUENCE {
CertificateSerialNumber ::= INTEGER
SubjectKeyIdentifier ::= OCTET STRING ({ pkcs7_sig_note_skid })
SetOfAuthenticatedAttribute ::= SET OF AuthenticatedAttribute
AuthenticatedAttribute ::= SEQUENCE {

62
crypto/asymmetric_keys/pkcs7_parser.c
View file

@ -33,6 +33,9 @@ struct pkcs7_parse_context {
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 @@ int pkcs7_note_signeddata_version(void *context, size_t hdrlen,
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 @@ int pkcs7_note_signerinfo_version(void *context, size_t hdrlen,
unsigned char tag,
const void *value, size_t vlen)
{
struct pkcs7_parse_context *ctx = context;
unsigned version;
if (vlen != 1)
@ -285,7 +295,18 @@ int pkcs7_note_signerinfo_version(void *context, size_t hdrlen,
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 @@ int pkcs7_note_signerinfo_version(void *context, size_t hdrlen,
unsupported:
pr_warn("Unsupported SignerInfo version\n");
return -EINVAL;
version_mismatch:
pr_warn("SignedData-SignerInfo version mismatch\n");
return -EBADMSG;
}
/*
@ -439,6 +463,22 @@ int pkcs7_sig_note_issuer(void *context, size_t hdrlen,
return 0;
}
/*
* 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
*/
@ -472,13 +512,21 @@ int pkcs7_note_signed_info(void *context, size_t hdrlen,
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;

5
crypto/asymmetric_keys/pkcs7_parser.h
View file

@ -33,7 +33,9 @@ struct pkcs7_signed_info {
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 pkcs7_message {
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 */