ipe: fallback to platform keyring also if key in trusted keyring is rejected

If enabled, we fallback to the platform keyring if the trusted keyring
doesn't have the key used to sign the ipe policy. But if pkcs7_verify()
rejects the key for other reasons, such as usage restrictions, we do not
fallback. Do so, following the same change in dm-verity.

Signed-off-by: Luca Boccassi <[email protected]>
Suggested-by: Serge Hallyn <[email protected]>
[FW: fixed some line length issues and a typo in the commit message]
Signed-off-by: Fan Wu <[email protected]>

Author: bluca

security/ipe/policy.c

@@ -178,7 +178,7 @@ struct ipe_policy *ipe_new_policy(const char *text, size_t textlen,
 					    VERIFYING_UNSPECIFIED_SIGNATURE,
 					    set_pkcs7_data, new);
 #ifdef CONFIG_IPE_POLICY_SIG_PLATFORM_KEYRING
-		if (rc == -ENOKEY)
+		if (rc == -ENOKEY || rc == -EKEYREJECTED)
 			rc = verify_pkcs7_signature(NULL, 0, new->pkcs7, pkcs7len,
 						    VERIFY_USE_PLATFORM_KEYRING,
 						    VERIFYING_UNSPECIFIED_SIGNATURE,