1 files changed, 62 insertions, 28 deletions

diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
index e666eb011a85..1d29376072da 100644
--- a/crypto/asymmetric_keys/pkcs7_trust.c
+++ b/crypto/asymmetric_keys/pkcs7_trust.c
@@ -23,9 +23,9 @@
 /**
  * Check the trust on one PKCS#7 SignedInfo block.
  */
-int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
-			     struct pkcs7_signed_info *sinfo,
-			     struct key *trust_keyring)
+static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
+				    struct pkcs7_signed_info *sinfo,
+				    struct key *trust_keyring)
 {
 	struct public_key_signature *sig = &sinfo->sig;
 	struct x509_certificate *x509, *last = NULL, *p;
@@ -35,6 +35,11 @@ int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
 
 	kenter(",%u,", sinfo->index);
 
+	if (sinfo->unsupported_crypto) {
+		kleave(" = -ENOPKG [cached]");
+		return -ENOPKG;
+	}
+
 	for (x509 = sinfo->signer; x509; x509 = x509->signer) {
 		if (x509->seen) {
 			if (x509->verified) {
@@ -49,15 +54,18 @@ int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
 		/* Look to see if this certificate is present in the trusted
 		 * keys.
 		 */
-		key = x509_request_asymmetric_key(trust_keyring, x509->subject,
-						  x509->fingerprint);
-		if (!IS_ERR(key))
+		key = x509_request_asymmetric_key(trust_keyring, x509->id,
+						  false);
+		if (!IS_ERR(key)) {
 			/* One of the X.509 certificates in the PKCS#7 message
 			 * is apparently the same as one we already trust.
 			 * Verify that the trusted variant can also validate
 			 * the signature on the descendant.
 			 */
+			pr_devel("sinfo %u: Cert %u as key %x\n",
+				 sinfo->index, x509->index, key_serial(key));
 			goto matched;
+		}
 		if (key == ERR_PTR(-ENOMEM))
 			return -ENOMEM;
 
@@ -77,16 +85,36 @@ int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
 	/* No match - see if the root certificate has a signer amongst the
 	 * trusted keys.
 	 */
-	if (!last || !last->issuer || !last->authority) {
-		kleave(" = -ENOKEY [no backref]");
-		return -ENOKEY;
+	if (last && last->authority) {
+		key = x509_request_asymmetric_key(trust_keyring, last->authority,
+						  false);
+		if (!IS_ERR(key)) {
+			x509 = last;
+			pr_devel("sinfo %u: Root cert %u signer is key %x\n",
+				 sinfo->index, x509->index, key_serial(key));
+			goto matched;
+		}
+		if (PTR_ERR(key) != -ENOKEY)
+			return PTR_ERR(key);
+	}
+
+	/* As a last resort, see if we have a trusted public key that matches
+	 * the signed info directly.
+	 */
+	key = x509_request_asymmetric_key(trust_keyring,
+					  sinfo->signing_cert_id,
+					  false);
+	if (!IS_ERR(key)) {
+		pr_devel("sinfo %u: Direct signer is key %x\n",
+			 sinfo->index, key_serial(key));
+		x509 = NULL;
+		goto matched;
 	}
+	if (PTR_ERR(key) != -ENOKEY)
+		return PTR_ERR(key);
 
-	key = x509_request_asymmetric_key(trust_keyring, last->issuer,
-					  last->authority);
-	if (IS_ERR(key))
-		return PTR_ERR(key) == -ENOMEM ? -ENOMEM : -ENOKEY;
-	x509 = last;
+	kleave(" = -ENOKEY [no backref]");
+	return -ENOKEY;
 
 matched:
 	ret = verify_signature(key, sig);
@@ -100,10 +128,12 @@ matched:
 	}
 
 verified:
-	x509->verified = true;
-	for (p = sinfo->signer; p != x509; p = p->signer) {
-		p->verified = true;
-		p->trusted = trusted;
+	if (x509) {
+		x509->verified = true;
+		for (p = sinfo->signer; p != x509; p = p->signer) {
+			p->verified = true;
+			p->trusted = trusted;
+		}
 	}
 	sinfo->trusted = trusted;
 	kleave(" = 0");
@@ -141,24 +171,28 @@ int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
 {
 	struct pkcs7_signed_info *sinfo;
 	struct x509_certificate *p;
-	int cached_ret = 0, ret;
+	int cached_ret = -ENOKEY;
+	int ret;
 
 	for (p = pkcs7->certs; p; p = p->next)
 		p->seen = false;
 
 	for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) {
 		ret = pkcs7_validate_trust_one(pkcs7, sinfo, trust_keyring);
-		if (ret < 0) {
-			if (ret == -ENOPKG) {
+		switch (ret) {
+		case -ENOKEY:
+			continue;
+		case -ENOPKG:
+			if (cached_ret == -ENOKEY)
 				cached_ret = -ENOPKG;
-			} else if (ret == -ENOKEY) {
-				if (cached_ret == 0)
-					cached_ret = -ENOKEY;
-			} else {
-				return ret;
-			}
+			continue;
+		case 0:
+			*_trusted |= sinfo->trusted;
+			cached_ret = 0;
+			continue;
+		default:
+			return ret;
 		}
-		*_trusted |= sinfo->trusted;
 	}
 
 	return cached_ret;