VeraCrypt
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authorMounir IDRASSI <mounir.idrassi@idrix.fr>2019-11-26 09:55:56 +0100
committerMounir IDRASSI <mounir.idrassi@idrix.fr>2019-11-27 00:15:43 +0100
commit79eea6e5b1fd1300729d31b7ccda6a4718b4b81b (patch)
tree0854c74d26e0fe63d2d573de168bd0adb922b8ec
parent9741c9209d0deedcc5d60434e5e7df3c531ff192 (diff)
downloadVeraCrypt-79eea6e5b1fd1300729d31b7ccda6a4718b4b81b.tar.gz
VeraCrypt-79eea6e5b1fd1300729d31b7ccda6a4718b4b81b.zip
Windows: Don't restore MBR to VeraCrypt value if it is coming from a loader different from us or different from Microsoft one.
-rw-r--r--src/Common/BootEncryption.cpp27
1 files changed, 25 insertions, 2 deletions
diff --git a/src/Common/BootEncryption.cpp b/src/Common/BootEncryption.cpp
index 3ad7320c..ccf3ac2f 100644
--- a/src/Common/BootEncryption.cpp
+++ b/src/Common/BootEncryption.cpp
@@ -275,6 +275,27 @@ bool ZipAdd (zip_t *z, const char* name, const unsigned char* pbData, DWORD cbDa
return true;
}
+static BOOL IsWindowsMBR (const byte *buffer, size_t bufferSize)
+{
+ BOOL bRet = FALSE;
+ byte g_pbMsSignature[4] = {0x33, 0xc0, 0x8e, 0xd0};
+ const char* g_szStr1 = "Invalid partition table";
+ const char* g_szStr2 = "Error loading operating system";
+ const char* g_szStr3 = "Missing operating system";
+
+ if ((0 == memcmp (buffer, g_pbMsSignature, 4)) &&
+ (BufferContainsString (buffer, bufferSize, g_szStr1)
+ || BufferContainsString (buffer, bufferSize, g_szStr2)
+ || BufferContainsString (buffer, bufferSize, g_szStr3)
+ )
+ )
+ {
+ bRet = TRUE;
+ }
+
+ return bRet;
+}
+
namespace VeraCrypt
{
#if !defined (SETUP)
@@ -3546,8 +3567,10 @@ namespace VeraCrypt
}
}
- // perform actual write only if content is different
- if (memcmp (mbr, bootLoaderBuf, TC_MAX_MBR_BOOT_CODE_SIZE))
+ // perform actual write only if content is different and either we are not in PostOOBE mode or the MBR contains VeraCrypt/Windows signature.
+ // this last check is done to avoid interfering with multi-boot configuration where MBR belongs to a boot manager like Grub
+ if (memcmp (mbr, bootLoaderBuf, TC_MAX_MBR_BOOT_CODE_SIZE)
+ && (!PostOOBEMode || BufferContainsString (mbr, sizeof (mbr), TC_APP_NAME) || IsWindowsMBR (mbr, sizeof (mbr))))
{
memcpy (mbr, bootLoaderBuf, TC_MAX_MBR_BOOT_CODE_SIZE);