Make the determination of the trustworthiness of a key dependent on whether
a key that can verify it is present in the supplied ring of trusted keys
rather than whether or not the verifying key has KEY_FLAG_TRUSTED set.

verify_pkcs7_signature() will return -ENOKEY if the PKCS#7 message trust
chain cannot be verified.

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

 certs/system_keyring.c                  |   13 ++++---------
 crypto/asymmetric_keys/pkcs7_key_type.c |    2 +-
 crypto/asymmetric_keys/pkcs7_parser.h   |    1 -
 crypto/asymmetric_keys/pkcs7_trust.c    |   16 +++-------------
 crypto/asymmetric_keys/verify_pefile.c  |    2 +-
 crypto/asymmetric_keys/x509_parser.h    |    1 -
 include/crypto/pkcs7.h                  |    3 +--
 include/linux/verification.h            |    1 -
 kernel/module_signing.c                 |    2 +-
 9 files changed, 11 insertions(+), 30 deletions(-)

diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index a83bffedc0aa..dc18869ff680 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -121,7 +121,6 @@ late_initcall(load_system_certificate_list);
 int verify_pkcs7_signature(const void *data, size_t len,
                           const void *raw_pkcs7, size_t pkcs7_len,
                           struct key *trusted_keys,
-                          int untrusted_error,
                           enum key_being_used_for usage,
                           int (*view_content)(void *ctx,
                                               const void *data, size_t len,
@@ -129,7 +128,6 @@ int verify_pkcs7_signature(const void *data, size_t len,
                           void *ctx)
 {
        struct pkcs7_message *pkcs7;
-       bool trusted;
        int ret;
 
        pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
@@ -149,13 +147,10 @@ int verify_pkcs7_signature(const void *data, size_t len,
 
        if (!trusted_keys)
                trusted_keys = system_trusted_keyring;
-       ret = pkcs7_validate_trust(pkcs7, trusted_keys, &trusted);
-       if (ret < 0)
-               goto error;
-
-       if (!trusted && untrusted_error) {
-               pr_err("PKCS#7 signature not signed with a trusted key\n");
-               ret = untrusted_error;
+       ret = pkcs7_validate_trust(pkcs7, trusted_keys);
+       if (ret < 0) {
+               if (ret == -ENOKEY)
+                       pr_err("PKCS#7 signature not signed with a trusted 
key\n");
                goto error;
        }
 
diff --git a/crypto/asymmetric_keys/pkcs7_key_type.c 
b/crypto/asymmetric_keys/pkcs7_key_type.c
index ab9bf5363ecd..3b92523882e5 100644
--- a/crypto/asymmetric_keys/pkcs7_key_type.c
+++ b/crypto/asymmetric_keys/pkcs7_key_type.c
@@ -62,7 +62,7 @@ static int pkcs7_preparse(struct key_preparsed_payload *prep)
 
        return verify_pkcs7_signature(NULL, 0,
                                      prep->data, prep->datalen,
-                                     NULL, -ENOKEY, usage,
+                                     NULL, usage,
                                      pkcs7_view_content, prep);
 }
 
diff --git a/crypto/asymmetric_keys/pkcs7_parser.h 
b/crypto/asymmetric_keys/pkcs7_parser.h
index d5eec31e95b6..f4e81074f5e0 100644
--- a/crypto/asymmetric_keys/pkcs7_parser.h
+++ b/crypto/asymmetric_keys/pkcs7_parser.h
@@ -22,7 +22,6 @@ struct pkcs7_signed_info {
        struct pkcs7_signed_info *next;
        struct x509_certificate *signer; /* Signing certificate (in msg->certs) 
*/
        unsigned        index;
-       bool            trusted;
        bool            unsupported_crypto;     /* T if not usable due to 
missing crypto */
 
        /* Message digest - the digest of the Content Data (or NULL) */
diff --git a/crypto/asymmetric_keys/pkcs7_trust.c 
b/crypto/asymmetric_keys/pkcs7_trust.c
index 554200284ea8..36e77cb07bd0 100644
--- a/crypto/asymmetric_keys/pkcs7_trust.c
+++ b/crypto/asymmetric_keys/pkcs7_trust.c
@@ -30,7 +30,6 @@ static int pkcs7_validate_trust_one(struct pkcs7_message 
*pkcs7,
        struct public_key_signature *sig = sinfo->sig;
        struct x509_certificate *x509, *last = NULL, *p;
        struct key *key;
-       bool trusted;
        int ret;
 
        kenter(",%u,", sinfo->index);
@@ -42,10 +41,8 @@ static int pkcs7_validate_trust_one(struct pkcs7_message 
*pkcs7,
 
        for (x509 = sinfo->signer; x509; x509 = x509->signer) {
                if (x509->seen) {
-                       if (x509->verified) {
-                               trusted = x509->trusted;
+                       if (x509->verified)
                                goto verified;
-                       }
                        kleave(" = -ENOKEY [cached]");
                        return -ENOKEY;
                }
@@ -122,7 +119,6 @@ static int pkcs7_validate_trust_one(struct pkcs7_message 
*pkcs7,
 
 matched:
        ret = verify_signature(key, sig);
-       trusted = test_bit(KEY_FLAG_TRUSTED, &key->flags);
        key_put(key);
        if (ret < 0) {
                if (ret == -ENOMEM)
@@ -134,12 +130,9 @@ matched:
 verified:
        if (x509) {
                x509->verified = true;
-               for (p = sinfo->signer; p != x509; p = p->signer) {
+               for (p = sinfo->signer; p != x509; p = p->signer)
                        p->verified = true;
-                       p->trusted = trusted;
-               }
        }
-       sinfo->trusted = trusted;
        kleave(" = 0");
        return 0;
 }
@@ -148,7 +141,6 @@ verified:
  * pkcs7_validate_trust - Validate PKCS#7 trust chain
  * @pkcs7: The PKCS#7 certificate to validate
  * @trust_keyring: Signing certificates to use as starting points
- * @_trusted: Set to true if trustworth, false otherwise
  *
  * Validate that the certificate chain inside the PKCS#7 message intersects
  * keys we already know and trust.
@@ -170,8 +162,7 @@ verified:
  * May also return -ENOMEM.
  */
 int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
-                        struct key *trust_keyring,
-                        bool *_trusted)
+                        struct key *trust_keyring)
 {
        struct pkcs7_signed_info *sinfo;
        struct x509_certificate *p;
@@ -191,7 +182,6 @@ int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
                                cached_ret = -ENOPKG;
                        continue;
                case 0:
-                       *_trusted |= sinfo->trusted;
                        cached_ret = 0;
                        continue;
                default:
diff --git a/crypto/asymmetric_keys/verify_pefile.c 
b/crypto/asymmetric_keys/verify_pefile.c
index 265351075b0e..672a94c2c3ff 100644
--- a/crypto/asymmetric_keys/verify_pefile.c
+++ b/crypto/asymmetric_keys/verify_pefile.c
@@ -436,7 +436,7 @@ int verify_pefile_signature(const void *pebuf, unsigned 
pelen,
 
        ret = verify_pkcs7_signature(NULL, 0,
                                     pebuf + ctx.sig_offset, ctx.sig_len,
-                                    trusted_keys, -EKEYREJECTED, usage,
+                                    trusted_keys, usage,
                                     mscode_parse, &ctx);
        if (ret < 0)
                goto error;
diff --git a/crypto/asymmetric_keys/x509_parser.h 
b/crypto/asymmetric_keys/x509_parser.h
index f24f4d808e7f..05eef1c68881 100644
--- a/crypto/asymmetric_keys/x509_parser.h
+++ b/crypto/asymmetric_keys/x509_parser.h
@@ -39,7 +39,6 @@ struct x509_certificate {
        unsigned        index;
        bool            seen;                   /* Infinite recursion 
prevention */
        bool            verified;
-       bool            trusted;
        bool            self_signed;            /* T if self-signed (check 
unsupported_sig too) */
        bool            unsupported_key;        /* T if key uses unsupported 
crypto */
        bool            unsupported_sig;        /* T if signature uses 
unsupported crypto */
diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h
index 8323e3e57131..583f199400a3 100644
--- a/include/crypto/pkcs7.h
+++ b/include/crypto/pkcs7.h
@@ -33,8 +33,7 @@ extern int pkcs7_get_content_data(const struct pkcs7_message 
*pkcs7,
  * pkcs7_trust.c
  */
 extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
-                               struct key *trust_keyring,
-                               bool *_trusted);
+                               struct key *trust_keyring);
 
 /*
  * pkcs7_verify.c
diff --git a/include/linux/verification.h b/include/linux/verification.h
index bb0fcf941cb7..a10549a6c7cd 100644
--- a/include/linux/verification.h
+++ b/include/linux/verification.h
@@ -33,7 +33,6 @@ struct key;
 extern int verify_pkcs7_signature(const void *data, size_t len,
                                  const void *raw_pkcs7, size_t pkcs7_len,
                                  struct key *trusted_keys,
-                                 int untrusted_error,
                                  enum key_being_used_for usage,
                                  int (*view_content)(void *ctx,
                                                      const void *data, size_t 
len,
diff --git a/kernel/module_signing.c b/kernel/module_signing.c
index 593aace88a02..6a64e03b9f44 100644
--- a/kernel/module_signing.c
+++ b/kernel/module_signing.c
@@ -81,6 +81,6 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen)
        }
 
        return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len,
-                                     NULL, -ENOKEY, VERIFYING_MODULE_SIGNATURE,
+                                     NULL, VERIFYING_MODULE_SIGNATURE,
                                      NULL, NULL);
 }

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