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| author | Mounir IDRASSI <mounir.idrassi@idrix.fr> | 2019-01-31 01:10:38 +0100 |
|---|---|---|
| committer | Mounir IDRASSI <mounir.idrassi@idrix.fr> | 2019-02-01 00:36:19 +0100 |
| commit | 5571a8ba6b258decb9c9a109d3a8562e3d2ea5fa (patch) | |
| tree | f5e52ea212bb8e2a9cec5e0b8ea532e6b8cce494 /src/Driver/DriveFilter.c | |
| parent | 61c1baa4bf5a97675187a37cf203e1937a060daa (diff) | |
| download | VeraCrypt-5571a8ba6b258decb9c9a109d3a8562e3d2ea5fa.tar.gz VeraCrypt-5571a8ba6b258decb9c9a109d3a8562e3d2ea5fa.zip | |
Windows driver: better randomness for wipe bytes by always using Whirlpool hash of current time and random bytes retrieved using CPU RDRAND/RDSEED if available.
Diffstat (limited to 'src/Driver/DriveFilter.c')
| -rw-r--r-- | src/Driver/DriveFilter.c | 47 |
1 files changed, 28 insertions, 19 deletions
diff --git a/src/Driver/DriveFilter.c b/src/Driver/DriveFilter.c index c17410df..a02ca3e5 100644 --- a/src/Driver/DriveFilter.c +++ b/src/Driver/DriveFilter.c @@ -28,6 +28,7 @@ #include "DriveFilter.h" #include "Boot/Windows/BootCommon.h" #include "cpu.h" +#include "rdrand.h" static BOOL DeviceFilterActive = FALSE; @@ -1521,30 +1522,38 @@ static VOID SetupThreadProc (PVOID threadArg) // generate real random values for wipeRandChars and // wipeRandCharsUpdate instead of relying on uninitialized stack memory LARGE_INTEGER iSeed; + byte digest[WHIRLPOOL_DIGESTSIZE]; + WHIRLPOOL_CTX tctx; + +#ifndef _WIN64 + KFLOATING_SAVE floatingPointState; + NTSTATUS saveStatus = STATUS_INVALID_PARAMETER; + if (HasISSE()) + saveStatus = KeSaveFloatingPointState (&floatingPointState); +#endif + KeQuerySystemTime( &iSeed ); - if (KeGetCurrentIrql() < DISPATCH_LEVEL) + WHIRLPOOL_init (&tctx); + WHIRLPOOL_add ((unsigned char *) &(iSeed.QuadPart), sizeof(iSeed.QuadPart), &tctx); + // use RDSEED or RDRAND from CPU as source of entropy if present + if ( (HasRDSEED() && RDSEED_getBytes (digest, sizeof (digest))) + || (HasRDRAND() && RDRAND_getBytes (digest, sizeof (digest))) + ) { - ULONG ulRandom; - ulRandom = RtlRandomEx( &iSeed.LowPart ); - memcpy (wipeRandChars, &ulRandom, TC_WIPE_RAND_CHAR_COUNT); - ulRandom = RtlRandomEx( &ulRandom ); - memcpy (wipeRandCharsUpdate, &ulRandom, TC_WIPE_RAND_CHAR_COUNT); - burn (&ulRandom, sizeof(ulRandom)); + WHIRLPOOL_add (digest, sizeof(digest), &tctx); } - else - { - byte digest[SHA512_DIGESTSIZE]; - sha512_ctx tctx; - sha512_begin (&tctx); - sha512_hash ((unsigned char *) &(iSeed.QuadPart), sizeof(iSeed.QuadPart), &tctx); - sha512_end (digest, &tctx); + WHIRLPOOL_finalize (&tctx, digest); + +#if !defined (_WIN64) + if (NT_SUCCESS (saveStatus)) + KeRestoreFloatingPointState (&floatingPointState); +#endif - memcpy (wipeRandChars, digest, TC_WIPE_RAND_CHAR_COUNT); - memcpy (wipeRandCharsUpdate, &digest[SHA512_DIGESTSIZE - TC_WIPE_RAND_CHAR_COUNT], TC_WIPE_RAND_CHAR_COUNT); + memcpy (wipeRandChars, digest, TC_WIPE_RAND_CHAR_COUNT); + memcpy (wipeRandCharsUpdate, &digest[WHIRLPOOL_DIGESTSIZE - TC_WIPE_RAND_CHAR_COUNT], TC_WIPE_RAND_CHAR_COUNT); - burn (digest, SHA512_DIGESTSIZE); - burn (&tctx, sizeof (tctx)); - } + burn (digest, WHIRLPOOL_DIGESTSIZE); + burn (&tctx, sizeof (tctx)); burn (&iSeed, sizeof(iSeed)); |