[PATCH 3/3] crypt32: Make CryptBinaryToStringA fill short base64 buffer correctly.
Jeff Smith
whydoubt at gmail.com
Wed Oct 9 12:53:55 CDT 2019
Signed-off-by: Jeff Smith <whydoubt at gmail.com>
---
dlls/crypt32/base64.c | 105 +++++++++++++++++++-----------------
dlls/crypt32/tests/base64.c | 2 -
2 files changed, 56 insertions(+), 51 deletions(-)
diff --git a/dlls/crypt32/base64.c b/dlls/crypt32/base64.c
index acd05ec1a5..ac60c6efbd 100644
--- a/dlls/crypt32/base64.c
+++ b/dlls/crypt32/base64.c
@@ -93,50 +93,53 @@ static BOOL EncodeBinaryToBinaryA(const BYTE *pbBinary,
return ret;
}
-static LONG encodeBase64A(const BYTE *in_buf, int in_len, LPCSTR sep,
+static DWORD stradd(LPSTR ptr, LPCSTR end, LPCSTR s, DWORD slen)
+{
+ if (ptr + slen > end)
+ slen = end - ptr;
+ memcpy(ptr, s, slen);
+ return slen;
+}
+
+static DWORD encodeBase64A(const BYTE *in_buf, int in_len, LPCSTR sep,
char* out_buf, DWORD *out_len)
{
int div, i;
const BYTE *d = in_buf;
int bytes = (in_len*8 + 5)/6, pad_bytes = (bytes % 4) ? 4 - (bytes % 4) : 0;
- DWORD needed;
LPSTR ptr;
+ LPCSTR end;
+ char chunk[4];
- TRACE("bytes is %d, pad bytes is %d\n", bytes, pad_bytes);
- needed = bytes + pad_bytes;
- needed += (needed / 64 + (needed % 64 ? 1 : 0)) * strlen(sep);
- needed++;
-
- if (needed > *out_len)
+ if (!out_buf)
{
- *out_len = needed;
- return ERROR_INSUFFICIENT_BUFFER;
+ TRACE("bytes is %d, pad bytes is %d\n", bytes, pad_bytes);
+ *out_len = bytes + pad_bytes;
+ *out_len += (*out_len / 64 + (*out_len % 64 ? 1 : 0)) * strlen(sep) + 1;
+ return 0;
}
- else
- *out_len = needed;
/* Three bytes of input give 4 chars of output */
div = in_len / 3;
ptr = out_buf;
+ end = ptr + *out_len;
i = 0;
- while (div > 0)
+ while (div > 0 && ptr < end)
{
if (i && i % 64 == 0)
- {
- strcpy(ptr, sep);
- ptr += strlen(sep);
- }
+ ptr += stradd(ptr, end, sep, strlen(sep));
/* first char is the first 6 bits of the first byte*/
- *ptr++ = b64[ ( d[0] >> 2) & 0x3f ];
+ chunk[0] = b64[ ( d[0] >> 2) & 0x3f ];
/* second char is the last 2 bits of the first byte and the first 4
* bits of the second byte */
- *ptr++ = b64[ ((d[0] << 4) & 0x30) | (d[1] >> 4 & 0x0f)];
+ chunk[1] = b64[ ((d[0] << 4) & 0x30) | (d[1] >> 4 & 0x0f)];
/* third char is the last 4 bits of the second byte and the first 2
* bits of the third byte */
- *ptr++ = b64[ ((d[1] << 2) & 0x3c) | (d[2] >> 6 & 0x03)];
+ chunk[2] = b64[ ((d[1] << 2) & 0x3c) | (d[2] >> 6 & 0x03)];
/* fourth char is the remaining 6 bits of the third byte */
- *ptr++ = b64[ d[2] & 0x3f];
+ chunk[3] = b64[ d[2] & 0x3f];
+ ptr += stradd(ptr, end, chunk, 4);
i += 4;
d += 3;
div--;
@@ -146,31 +149,33 @@ static LONG encodeBase64A(const BYTE *in_buf, int in_len, LPCSTR sep,
{
case 1:
/* first char is the first 6 bits of the first byte*/
- *ptr++ = b64[ ( d[0] >> 2) & 0x3f ];
+ chunk[0] = b64[ ( d[0] >> 2) & 0x3f ];
/* second char is the last 2 bits of the first byte and the first 4
* bits of the second byte */
- *ptr++ = b64[ ((d[0] << 4) & 0x30) | (d[1] >> 4 & 0x0f)];
+ chunk[1] = b64[ ((d[0] << 4) & 0x30) | (d[1] >> 4 & 0x0f)];
/* third char is the last 4 bits of the second byte padded with
* two zeroes */
- *ptr++ = b64[ ((d[1] << 2) & 0x3c) ];
+ chunk[2] = b64[ ((d[1] << 2) & 0x3c) ];
/* fourth char is a = to indicate one byte of padding */
- *ptr++ = '=';
+ chunk[3] = '=';
+ ptr += stradd(ptr, end, chunk, 4);
break;
case 2:
/* first char is the first 6 bits of the first byte*/
- *ptr++ = b64[ ( d[0] >> 2) & 0x3f ];
+ chunk[0] = b64[ ( d[0] >> 2) & 0x3f ];
/* second char is the last 2 bits of the first byte padded with
* four zeroes*/
- *ptr++ = b64[ ((d[0] << 4) & 0x30)];
+ chunk[1] = b64[ ((d[0] << 4) & 0x30)];
/* third char is = to indicate padding */
- *ptr++ = '=';
+ chunk[2] = '=';
/* fourth char is = to indicate padding */
- *ptr++ = '=';
+ chunk[3] = '=';
+ ptr += stradd(ptr, end, chunk, 4);
break;
}
- strcpy(ptr, sep);
+ ptr += stradd(ptr, end, sep, strlen(sep));
- return ERROR_SUCCESS;
+ return ptr - out_buf;
}
static BOOL BinaryToBase64A(const BYTE *pbBinary,
@@ -215,26 +220,28 @@ static BOOL BinaryToBase64A(const BYTE *pbBinary,
if (pszString)
{
- if (charsNeeded <= *pcchString)
+ LPSTR ptr = pszString;
+ DWORD size = *pcchString;
+ LPSTR end = ptr + size;
+
+ if (header)
{
- LPSTR ptr = pszString;
- DWORD size = charsNeeded;
+ ptr += stradd(ptr, end, header, strlen(header));
+ ptr += stradd(ptr, end, sep, strlen(sep));
+ size = end - ptr;
+ }
+ ptr += encodeBase64A(pbBinary, cbBinary, sep, ptr, &size);
+ if (trailer)
+ {
+ ptr += stradd(ptr, end, trailer, strlen(trailer));
+ ptr += stradd(ptr, end, sep, strlen(sep));
+ }
- if (header)
- {
- strcpy(ptr, header);
- ptr += strlen(ptr);
- strcpy(ptr, sep);
- ptr += strlen(sep);
- }
- encodeBase64A(pbBinary, cbBinary, sep, ptr, &size);
- ptr += size - 1;
- if (trailer)
- {
- strcpy(ptr, trailer);
- ptr += strlen(ptr);
- strcpy(ptr, sep);
- }
+ if (ptr < end)
+ *ptr = '\0';
+
+ if (charsNeeded <= *pcchString)
+ {
*pcchString = charsNeeded - 1;
}
else
diff --git a/dlls/crypt32/tests/base64.c b/dlls/crypt32/tests/base64.c
index f2d16735ab..31605fe6b9 100644
--- a/dlls/crypt32/tests/base64.c
+++ b/dlls/crypt32/tests/base64.c
@@ -137,12 +137,10 @@ static void encodeAndCompareBase64_A(const BYTE *toEncode, DWORD toEncodeLen,
ok((!ret && GetLastError() == ERROR_MORE_DATA) || broken(ret) /* XP */, "CryptBinaryToStringA failed %d, error %d.\n",
ret, GetLastError());
ok(strLen2 == strLen || broken(strLen2 == strLen - 1), "Expected length %d, got %d\n", strLen, strLen2);
-todo_wine {
if (header)
ok(str[0] == header[0], "Unexpected buffer contents %#x.\n", str[0]);
else
ok(str[0] == expected[0], "Unexpected buffer contents %#x.\n", str[0]);
-}
strLen2 = strLen;
ret = CryptBinaryToStringA(toEncode, toEncodeLen, format, str, &strLen2);
ok(ret, "CryptBinaryToStringA failed: %d\n", GetLastError());
--
2.21.0
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