From 81c8bbee46ad6ebacf72eae70ba5147f376205a4 Mon Sep 17 00:00:00 2001
From: Rod Smith <rodsmith@rodsbooks.com>
Date: Mon, 14 Sep 2020 10:08:18 -0400
Subject: [PATCH] Fix segfault on some weird data structures

---
 NEWS      |  6 ++++++
 gpt.cc    | 13 ++++++++++++-
 support.h |  2 +-
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/NEWS b/NEWS
index 54c865e..bac3da3 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,9 @@
+1.0.6 (?/??/2020):
+------------------
+
+- Fixed bug that could cause segfault if GPT header claimed partition
+  entries are oversized.
+
 1.0.5 (2/17/2020):
 ------------------
 
diff --git a/gpt.cc b/gpt.cc
index fe8e956..1b4e10f 100644
--- a/gpt.cc
+++ b/gpt.cc
@@ -1041,6 +1041,14 @@ int GPTData::LoadHeader(struct GPTHeader *header, DiskIO & disk, uint64_t sector
    } // if
    *crcOk = CheckHeaderCRC(&tempHeader);
 
+   if (tempHeader.sizeOfPartitionEntries != sizeof(GPTPart)) {
+       cerr << "Warning: Partition table header claims that the size of partition table\n";
+       cerr << "entries is " << tempHeader.sizeOfPartitionEntries << " bytes, but this program ";
+       cerr << " supports only " << sizeof(GPTPart) << "-byte entries.\n";
+       cerr << "Adjusting accordingly, but partition table may be garbage.\n";
+       tempHeader.sizeOfPartitionEntries = sizeof(GPTPart);
+   }
+
    if (allOK && (numParts != tempHeader.numParts) && *crcOk) {
       allOK = SetGPTSize(tempHeader.numParts, 0);
    }
@@ -1058,7 +1066,10 @@ int GPTData::LoadPartitionTable(const struct GPTHeader & header, DiskIO & disk,
    uint32_t sizeOfParts, newCRC;
    int retval;
 
-   if (disk.OpenForRead()) {
+   if (header.sizeOfPartitionEntries != sizeof(GPTPart)) {
+      cerr << "Error! GPT header contains invalid partition entry size!\n";
+      retval = 0;
+   } else if (disk.OpenForRead()) {
       if (sector == 0) {
          retval = disk.Seek(header.partitionEntriesLBA);
       } else {
diff --git a/support.h b/support.h
index 9a79b95..978bfe1 100644
--- a/support.h
+++ b/support.h
@@ -8,7 +8,7 @@
 #ifndef __GPTSUPPORT
 #define __GPTSUPPORT
 
-#define GPTFDISK_VERSION "1.0.5"
+#define GPTFDISK_VERSION "1.0.5.1"
 
 #if defined (__FreeBSD__) || defined (__FreeBSD_kernel__) || defined (__APPLE__)
 // Darwin (Mac OS) & FreeBSD: disk IOCTLs are different, and there is no lseek64
-- 
1.8.3.1