KEYS: Generalise system_verify_data() to provide access to internal content

Generalise system_verify_data() to provide access to internal content
through a callback.  This allows all the PKCS#7 stuff to be hidden inside
this function and removed from the PE file parser and the PKCS#7 test key.

If external content is not required, NULL should be passed as data to the
function.  If the callback is not required, that can be set to NULL.

The function is now called verify_pkcs7_signature() to contrast with
verify_pefile_signature() and the definitions of both have been moved into
linux/verification.h along with the key_being_used_for enum.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 9 insertions, 31 deletions

diff --git a/crypto/asymmetric_keys/verify_pefile.c b/crypto/asymmetric_keys/verify_pefile.c
index 7e8c2338ae25..265351075b0e 100644
--- a/crypto/asymmetric_keys/verify_pefile.c
+++ b/crypto/asymmetric_keys/verify_pefile.c
@@ -16,7 +16,7 @@
 #include <linux/err.h>
 #include <linux/pe.h>
 #include <linux/asn1.h>
-#include <crypto/pkcs7.h>
+#include <linux/verification.h>
 #include <crypto/hash.h>
 #include "verify_pefile.h"
 
@@ -392,9 +392,8 @@ error_no_desc:
  * verify_pefile_signature - Verify the signature on a PE binary image
  * @pebuf: Buffer containing the PE binary image
  * @pelen: Length of the binary image
- * @trust_keyring: Signing certificates to use as starting points
+ * @trust_keys: Signing certificate(s) to use as starting points
  * @usage: The use to which the key is being put.
- * @_trusted: Set to true if trustworth, false otherwise
  *
  * Validate that the certificate chain inside the PKCS#7 message inside the PE
  * binary image intersects keys we already know and trust.
@@ -418,14 +417,10 @@ error_no_desc:
  * May also return -ENOMEM.
  */
 int verify_pefile_signature(const void *pebuf, unsigned pelen,
-			    struct key *trusted_keyring,
-			    enum key_being_used_for usage,
-			    bool *_trusted)
+			    struct key *trusted_keys,
+			    enum key_being_used_for usage)
 {
-	struct pkcs7_message *pkcs7;
 	struct pefile_context ctx;
-	const void *data;
-	size_t datalen;
 	int ret;
 
 	kenter("");
@@ -439,19 +434,10 @@ int verify_pefile_signature(const void *pebuf, unsigned pelen,
 	if (ret < 0)
 		return ret;
 
-	pkcs7 = pkcs7_parse_message(pebuf + ctx.sig_offset, ctx.sig_len);
-	if (IS_ERR(pkcs7))
-		return PTR_ERR(pkcs7);
-	ctx.pkcs7 = pkcs7;
-
-	ret = pkcs7_get_content_data(ctx.pkcs7, &data, &datalen, false);
-	if (ret < 0 || datalen == 0) {
-		pr_devel("PKCS#7 message does not contain data\n");
-		ret = -EBADMSG;
-		goto error;
-	}
-
-	ret = mscode_parse(&ctx);
+	ret = verify_pkcs7_signature(NULL, 0,
+				     pebuf + ctx.sig_offset, ctx.sig_len,
+				     trusted_keys, -EKEYREJECTED, usage,
+				     mscode_parse, &ctx);
 	if (ret < 0)
 		goto error;
 
@@ -462,16 +448,8 @@ int verify_pefile_signature(const void *pebuf, unsigned pelen,
 	 * contents.
 	 */
 	ret = pefile_digest_pe(pebuf, pelen, &ctx);
-	if (ret < 0)
-		goto error;
-
-	ret = pkcs7_verify(pkcs7, usage);
-	if (ret < 0)
-		goto error;
-
-	ret = pkcs7_validate_trust(pkcs7, trusted_keyring, _trusted);
 
 error:
-	pkcs7_free_message(ctx.pkcs7);
+	kfree(ctx.digest);
 	return ret;
 }