From 45de1eb6e3d31ac3ece6b02671ddcc9dfab06e76 Mon Sep 17 00:00:00 2001
From: Ondrej Kozina <okozina@redhat.com>
Date: Tue, 25 Aug 2020 19:23:21 +0200
Subject: [PATCH 6/6] Simplify validation code a bit.

Keep it simple. If there's not enough memory we can't validate
segments. The LUKS2 specification does not recommend to continue
processing LUKS2 metadata if it can not be properly validated.

(cherry picked from commit 752c9a52798f11d3b765b673ebaa3058eb25316e)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
---
 lib/luks2/luks2_json_metadata.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/lib/luks2/luks2_json_metadata.c b/lib/luks2/luks2_json_metadata.c
index cd28400c..66ee0b91 100644
--- a/lib/luks2/luks2_json_metadata.c
+++ b/lib/luks2/luks2_json_metadata.c
@@ -594,9 +594,9 @@ static bool validate_segment_intervals(struct crypt_device *cd,
 static int hdr_validate_segments(struct crypt_device *cd, json_object *hdr_jobj)
 {
 	json_object *jobj_segments, *jobj_digests, *jobj_offset, *jobj_size, *jobj_type, *jobj_flags, *jobj;
-	struct interval *intervals;
 	uint64_t offset, size;
 	int i, r, count, first_backup = -1;
+	struct interval *intervals = NULL;
 
 	if (!json_object_object_get_ex(hdr_jobj, "segments", &jobj_segments)) {
 		log_dbg(cd, "Missing segments section.");
@@ -687,8 +687,11 @@ static int hdr_validate_segments(struct crypt_device *cd, json_object *hdr_jobj)
 
 	if ((size_t)first_backup < SIZE_MAX / sizeof(*intervals))
 		intervals = malloc(first_backup * sizeof(*intervals));
-	else
-		intervals = NULL;
+
+	if (!intervals) {
+		log_dbg(cd, "Not enough memory.");
+		return 1;
+	}
 
 	for (i = 0; i < first_backup; i++) {
 		jobj = json_segments_get_segment(jobj_segments, i);
@@ -697,14 +700,8 @@ static int hdr_validate_segments(struct crypt_device *cd, json_object *hdr_jobj)
 			free(intervals);
 			return 1;
 		}
-		if (intervals != NULL) {
-			intervals[i].offset = json_segment_get_offset(jobj, 0);
-			intervals[i].length = json_segment_get_size(jobj, 0) ?: UINT64_MAX;
-		}
-	}
-	if (intervals == NULL) {
-		log_dbg(cd, "Not enough memory.");
-		return 1;
+		intervals[i].offset = json_segment_get_offset(jobj, 0);
+		intervals[i].length = json_segment_get_size(jobj, 0) ?: UINT64_MAX;
 	}
 
 	r = !validate_segment_intervals(cd, first_backup, intervals);
-- 
2.20.1