From e8e71e43c3ff2dca951d30af48708bcb411e47d2 Mon Sep 17 00:00:00 2001 From: Tobias Stoeckmann Date: Mon, 24 Aug 2020 19:21:43 +0200 Subject: [PATCH 3/5] Check segment gaps regardless of heap space. Segments are validated in hdr_validate_segments. Gaps in segment keys are detected when collecting offsets. But if an invalid segment is very large, larger than count, it could happen that cryptsetup is unable to allocate enough memory, not giving a clue about what actually is the problem. Therefore check for gaps even if not enough memory is available. This gives much more information with debug output enabled. Obviously cryptsetup still fails if segments are perfectly fine but not enough RAM available. But at that stage, the user knows that it's the fault of the system, not of an invalid segment. --- lib/luks2/luks2_json_metadata.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff --git a/lib/luks2/luks2_json_metadata.c b/lib/luks2/luks2_json_metadata.c index e346067..e4e1424 100644 --- a/lib/luks2/luks2_json_metadata.c +++ b/lib/luks2/luks2_json_metadata.c @@ -679,11 +679,10 @@ static int hdr_validate_segments(struct crypt_device *cd, json_object *hdr_jobj) if (first_backup < 0) first_backup = count; - intervals = malloc(first_backup * sizeof(*intervals)); - if (!intervals) { - log_dbg(cd, "Not enough memory."); - return 1; - } + if (first_backup <= count && (size_t)first_backup < SIZE_MAX / sizeof(*intervals)) + intervals = malloc(first_backup * sizeof(*intervals)); + else + intervals = NULL; for (i = 0; i < first_backup; i++) { jobj = json_segments_get_segment(jobj_segments, i); @@ -692,8 +691,14 @@ static int hdr_validate_segments(struct crypt_device *cd, json_object *hdr_jobj) free(intervals); return 1; } - intervals[i].offset = json_segment_get_offset(jobj, 0); - intervals[i].length = json_segment_get_size(jobj, 0) ?: UINT64_MAX; + 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; } r = !validate_segment_intervals(cd, first_backup, intervals); -- 1.8.3.1