REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4648
The SavePasswordToVariable function takes in the password, generates a salt,
generates a SHA256 hash of the
password and saves the password hash to a variable. The KeyLipGenerateSalt
function calls RandomSeed with
NULL as the first argument. The RandomSeed function comes from CryptRandTsc.c.
When NULL is used as the
first argument, the default seed "UEFI Crypto Library default seed" is used
this is concatenated with the TSC
Added a logic to shuffle the default seed string characters
Signed-off-by: V V Pranav <pranav....@intel.com>
---
.../Library/BaseCryptLib/Rand/CryptRandTsc.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/CryptoPkg/Library/BaseCryptLib/Rand/CryptRandTsc.c
b/CryptoPkg/Library/BaseCryptLib/Rand/CryptRandTsc.c
index 30454bf10f..8b699ba20d 100644
--- a/CryptoPkg/Library/BaseCryptLib/Rand/CryptRandTsc.c
+++ b/CryptoPkg/Library/BaseCryptLib/Rand/CryptRandTsc.c
@@ -35,6 +35,17 @@ RandomSeed (
)
{
CHAR8 DefaultSeed[128];
+ UINT8 temp = 0;
+ CHAR8 DefaultSeedString[64] = "UEFI Crypto Library default seed";
+ UINT8 CharCounter = 0;
+ UINTN Random = 0;
+
+ for (CharCounter = 0; CharCounter < (strlen(DefaultSeedString)-1);
CharCounter++) {
+ Random = AsmReadTsc () % 10;
+ temp = DefaultSeedString[Random];
+ DefaultSeedString[Random] = DefaultSeedString[CharCounter];
+ DefaultSeedString[CharCounter] = temp;
+ }
if (SeedSize > INT_MAX) {
return FALSE;
@@ -61,8 +72,8 @@ RandomSeed (
AsciiSPrint (
DefaultSeed,
sizeof (DefaultSeed),
- "UEFI Crypto Library default seed (%ld)",
- AsmReadTsc ()
+ "%s (%ld)",
+ DefaultSeedString, AsmReadTsc ()
);
RAND_seed (DefaultSeed, sizeof (DefaultSeed));
--
2.39.1.windows.1
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