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CryptEncrypt() fixed to support zero-length reserved buffers

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This commit is contained in:
Simon Rozman 2016-06-20 14:51:14 +02:00
parent 7510410b56
commit 5d47a19972
1 changed files with 21 additions and 11 deletions
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16
include/WinStd/Crypt.h
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@ -232,17 +232,27 @@ inline BOOL CryptEncrypt(_In_ HCRYPTKEY hKey, _In_opt_ HCRYPTHASH hHash, _In_ BO
DWORD
dwDataLen = (DWORD)(aData.size() * sizeof(_Ty)),
dwBufLen = (DWORD)(aData.capacity() * sizeof(_Ty)),
dwEncLen;
dwEncLen = dwDataLen,
dwResult;
if (dwBufLen) {
aData.resize(dwBufLen);
dwEncLen = dwDataLen;
if (CryptEncrypt(hKey, hHash, Final, dwFlags, (BYTE*)aData.data(), &dwEncLen, dwBufLen)) {
// Encryption succeeded.
assert(dwEncLen <= dwBufLen);
if (dwEncLen < dwBufLen)
aData.resize((dwEncLen + sizeof(_Ty) - 1) / sizeof(_Ty));
return TRUE;
} else if (GetLastError() == ERROR_MORE_DATA) {
} else
dwResult = GetLastError();
} else if (CryptEncrypt(hKey, NULL, Final, dwFlags, NULL, &dwEncLen, 0)) {
// CryptEncrypt() always succeeds for output data size queries.
// dwEncLen contains required output data size. Continue as if the buffer was to small. Actually, the output buffer _was_ too small!
dwResult = ERROR_MORE_DATA;
} else
dwResult = GetLastError();
if (dwResult == ERROR_MORE_DATA) {
// Encrypted data will be longer. Reserve more space and retry.
aData.resize(((dwBufLen = dwEncLen) + sizeof(_Ty) - 1) / sizeof(_Ty));
dwEncLen = dwDataLen;