From 0ad2c3da34827b68c4f524c0c50f223746af91a5 Mon Sep 17 00:00:00 2001
From: pcarana <pc.moreno2099@gmail.com>
Date: Tue, 24 Mar 2020 18:39:01 -0600
Subject: [PATCH] Add new incidences regarding manifest validation.

-Related to #28.
-'incid-file-at_mft-not-found': when a file listed in a manifest isn't found at the manifest publication point.
-'incid-file-at-mft-hash-not-match': the file hash doesn't match the hash listed at the manifest.
-Both incidences will be an error by default.
---
 src/crypto/hash.c         | 32 +++++++++++++++++++++++++++-----
 src/incidence/incidence.c | 12 ++++++++++++
 src/incidence/incidence.h |  2 ++
 src/object/manifest.c     | 16 +++++++++++++++-
 4 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/src/crypto/hash.c b/src/crypto/hash.c
index 1e7143eb..6a8366b2 100644
--- a/src/crypto/hash.c
+++ b/src/crypto/hash.c
@@ -5,6 +5,7 @@
 #include <sys/stat.h>
 #include <sys/types.h> /* For blksize_t */
 
+#include "common.h"
 #include "file.h"
 #include "log.h"
 #include "asn1/oid.h"
@@ -101,7 +102,14 @@ end1:
 
 /**
  * Computes the hash of the file @uri, and compares it to @expected (The
- * "expected" hash). Returns 0 if no errors happened and the hashes match.
+ * "expected" hash).
+ *
+ * Returns:
+ *   0 if no errors happened and the hashes match, or the hash doesn't match
+ *     but there's an incidence to ignore such error.
+ * < 0 if there was an error that can't be ignored.
+ * > 0 if there was an error but it can be ignored (file not found and there's
+ *     an incidence to ignore this).
  */
 int
 hash_validate_mft_file(char const *algorithm, struct rpki_uri *uri,
@@ -114,12 +122,26 @@ hash_validate_mft_file(char const *algorithm, struct rpki_uri *uri,
 	if (expected->bits_unused != 0)
 		return pr_err("Hash string has unused bits.");
 
-	error = hash_file(algorithm, uri, actual, &actual_len);
-	if (error)
-		return error;
+	do {
+		error = hash_file(algorithm, uri, actual, &actual_len);
+		if (!error)
+			break;
+
+		if (error == EACCES || error == ENOENT) {
+			if (incidence(INID_MFT_FILE_NOT_FOUND,
+			    "File '%s' listed at manifest doesn't exist",
+			    uri_get_printable(uri)))
+				return -EINVAL;
+
+			return error;
+		}
+		/* Any other error (crypto, enomem, file read) */
+		return ENSURE_NEGATIVE(error);
+	} while (0);
 
 	if (!hash_matches(expected->buf, expected->size, actual, actual_len)) {
-		return pr_err("File '%s' does not match its manifest hash.",
+		return incidence(INID_MFT_FILE_HASH_NOT_MATCH,
+		    "File '%s' does not match its manifest hash.",
 		    uri_get_printable(uri));
 	}
 
diff --git a/src/incidence/incidence.c b/src/incidence/incidence.c
index 74f8effa..b916395a 100644
--- a/src/incidence/incidence.c
+++ b/src/incidence/incidence.c
@@ -29,6 +29,18 @@ static struct incidence incidences[__INID_MAX] = {
 		"Object isn't DER encoded",
 		INAC_IGNORE,
 	},
+	{
+		INID_MFT_FILE_NOT_FOUND,
+		"incid-file-at_mft-not-found",
+		"File listed at manifest doesn't exist",
+		INAC_ERROR
+	},
+	{
+		INID_MFT_FILE_HASH_NOT_MATCH,
+		"incid-file-at-mft-hash-not-match",
+		"File hash listed at manifest doesn't match the actual file hash",
+		INAC_ERROR
+	},
 };
 
 static int
diff --git a/src/incidence/incidence.h b/src/incidence/incidence.h
index 3656a9c7..cba80d8e 100644
--- a/src/incidence/incidence.h
+++ b/src/incidence/incidence.h
@@ -10,6 +10,8 @@
 enum incidence_id {
 	INID_HASHALG_HAS_PARAMS,
 	INID_OBJ_NOT_DER,
+	INID_MFT_FILE_NOT_FOUND,
+	INID_MFT_FILE_HASH_NOT_MATCH,
 
 	__INID_MAX,
 };
diff --git a/src/object/manifest.c b/src/object/manifest.c
index 677d79c9..bacbfce4 100644
--- a/src/object/manifest.c
+++ b/src/object/manifest.c
@@ -170,8 +170,22 @@ build_rpp(struct Manifest *mft, struct rpki_uri *mft_uri, struct rpp **pp)
 		if (error)
 			goto fail;
 
+		/*
+		 * Expect:
+		 * - Negative value: an error not to be ignored, the whole
+		 *   manifest will be discarded.
+		 * - Zero value: hash at manifest matches file's hash, or it
+		 *   doesn't match its hash but there's an incidence to ignore
+		 *   such error.
+		 * - Positive value: file doesn't exist and keep validating
+		 *   manifest.
+		 */
 		error = hash_validate_mft_file("sha256", uri, &fah->hash);
-		if (error) {
+		if (error < 0) {
+			uri_refput(uri);
+			goto fail;
+		}
+		if (error > 0) {
 			uri_refput(uri);
 			continue;
 		}
-- 
2.47.3