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Corrections to base64 encoding and decoding functions (#1804)

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* Allow base64 encoding of blobs

* Fix typo error on base64 encoding resulting in unterminated string being returned.

* Limit padding characters to maximum of two

* Tidy up padding characters

* Add detection of UTF8 format when decoding base64
This commit is contained in:
apjarvis
2019-03-28 22:38:22 +00:00
committed by Manuel
parent ea2aa495b3
commit c44286bc2b
1 changed files with 68 additions and 18 deletions
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86
src/extensions/extension-formats.c
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@@ -627,12 +627,6 @@ int encodeBase64(char **result, const unsigned char *data, int dataLength)
while (out < dataLength) {
d = data[out++];
if (d > 0x3F) {
if (d == 0x80)
continue;
free(encoded);
return ERROR_INVALID_CHARACTER;
}
switch (bitsLeft) {
case 0:
encoded[in++] = map[d >> 2];
@@ -653,19 +647,24 @@ int encodeBase64(char **result, const unsigned char *data, int dataLength)
break;
}
}
/* Flush remaining bits */
switch (bitsLeft) {
case 2:
encoded[in++] = map[b << 4];
encoded[in++] = '=';
encoded[in++] = '=';
break;
case 4:
encoded[in++] = map[b << 2];
encoded[in++] = '=';
break;
default:
break;
}
for (int i=0; i < (in & 0x03); i++)
encoded[in++] = '=';
encoded[in] == '\0';
/* Terminate as string */
encoded[in] = '\0';
return ERROR_NONE;
}
@@ -800,22 +799,32 @@ static void plistFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
static void encodeBase64Func(sqlite3_context *context, int argc, sqlite3_value **argv){
int resultLength;
int errno = 0;
int dataLength;
const unsigned char *data;
char *result = NULL;
assert( argc==1 );
switch( sqlite3_value_type(argv[0]) ){
case SQLITE_BLOB:
case SQLITE_TEXT: {
const unsigned char *data = sqlite3_value_text(argv[0]);
int dataLength = sqlite3_value_bytes(argv[0]);
data = sqlite3_value_blob(argv[0]);
dataLength = sqlite3_value_bytes(argv[0]);
errno = encodeBase64(&result, data, dataLength);
if (errno == ERROR_NONE) {
resultLength = strlen(result);
sqlite3_result_text(context, result, resultLength, &freeResult);
sqlite3_result_text(context, result, resultLength, &freeResult);
} else {
if (sqlite3_value_type(argv[0]) == SQLITE_TEXT)
sqlite3_result_text(context, data, dataLength, NULL);
else
sqlite3_result_blob(context, data, dataLength, NULL);
sqlite3_result_blob(context, data, dataLength, NULL);
}
break;
case SQLITE_TEXT: {
data = sqlite3_value_text(argv[0]);
dataLength = sqlite3_value_bytes(argv[0]);
sqlite3_result_text(context, data, dataLength, NULL);
errno = encodeBase64(&result, data, dataLength);
if (errno == ERROR_NONE) {
resultLength = strlen(result);
sqlite3_result_text(context, result, resultLength, &freeResult);
} else {
sqlite3_result_text(context, data, dataLength, NULL);
}
break;
}
@@ -859,6 +868,47 @@ int isText(unsigned char *data, int dataLength)
return result;
}
/** isUTF8
*
* Returns one if the characters conform to UTF8 format in so
* far as all the byte lengths are consistent. It does not
* check for overlong encodings or invalid characters. A zero
* is returned if the format is not consistent.
* Note that a file of all zeros will be returned as UTF8.
*/
int isUTF8(unsigned char *data, int length)
{
int count = 0;
while (length-- > 0) {
unsigned char d = *(data++);
switch (count) {
case 0: /* First character */
if ((d & 0x80) == 0)
continue; /* 7 bit ASCII */
if ((d & 0xE0) == 0xC0) {
count = 1; /* 2 byte code */
break;
}
if ((d & 0xF0) == 0xE0) {
count = 2; /* 3 byte code */
break;
}
if ((d & 0xF8) == 0xF0) {
count = 3; /* 4 byte code */
break;
}
return 0;
default:
count--;
if ((d & 0xC0) != 0x80)
return 0;
break;
}
}
return (count == 0) ? 1 : 0;
}
static void decodeBase64Func(sqlite3_context *context, int argc, sqlite3_value **argv){
int resultLength;
int errno = 0;
@@ -871,7 +921,7 @@ static void decodeBase64Func(sqlite3_context *context, int argc, sqlite3_value *
int dataLength = sqlite3_value_bytes(argv[0]);
errno = decodeBase64(&result, &resultLength, data, dataLength);
if (errno == ERROR_NONE) {
if (isText(result, resultLength) == 0)
if (isUTF8(result, resultLength))
sqlite3_result_text(context, result, resultLength, &freeResult);
else
sqlite3_result_blob(context, result, resultLength, &freeResult);