PKCS#7: Check content type and versions
We only support PKCS#7 signed-data [RFC2315 sec 9] content at the top level,
so reject anything else. Further, check that the version numbers in
SignedData and SignerInfo are 1 in both cases.
Note that we don't restrict the inner content type. In the PKCS#7 code we
don't parse the data attached there, but merely verify the signature over
it.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-By: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/crypto/asymmetric_keys/pkcs7_parser.c b/crypto/asymmetric_keys/pkcs7_parser.c
index 3bd5a1e..ab427f0 100644
--- a/crypto/asymmetric_keys/pkcs7_parser.c
+++ b/crypto/asymmetric_keys/pkcs7_parser.c
@@ -226,6 +226,79 @@
}
/*
+ * We only support signed data [RFC2315 sec 9].
+ */
+int pkcs7_check_content_type(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+
+ if (ctx->last_oid != OID_signed_data) {
+ pr_warn("Only support pkcs7_signedData type\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * Note the SignedData version
+ */
+int pkcs7_note_signeddata_version(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ unsigned version;
+
+ if (vlen != 1)
+ goto unsupported;
+
+ version = *(const u8 *)value;
+ switch (version) {
+ case 1:
+ /* PKCS#7 SignedData [RFC2315 sec 9.1] */
+ break;
+ default:
+ goto unsupported;
+ }
+
+ return 0;
+
+unsupported:
+ pr_warn("Unsupported SignedData version\n");
+ return -EINVAL;
+}
+
+/*
+ * Note the SignerInfo version
+ */
+int pkcs7_note_signerinfo_version(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ unsigned version;
+
+ if (vlen != 1)
+ goto unsupported;
+
+ version = *(const u8 *)value;
+ switch (version) {
+ case 1:
+ /* PKCS#7 SignerInfo [RFC2315 sec 9.2] */
+ break;
+ default:
+ goto unsupported;
+ }
+
+ return 0;
+
+unsupported:
+ pr_warn("Unsupported SignerInfo version\n");
+ return -EINVAL;
+}
+
+/*
* Extract a certificate and store it in the context.
*/
int pkcs7_extract_cert(void *context, size_t hdrlen,
@@ -326,7 +399,7 @@
}
/*
- * Note the set of auth attributes for digestion purposes [RFC2315 9.3]
+ * Note the set of auth attributes for digestion purposes [RFC2315 sec 9.3]
*/
int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen,
unsigned char tag,