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/*
* Copyright (c) 2015, Intel Corporation
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Intel Corporation nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "utf8_validate.h"
#include "ue2common.h"
#include "util/unicode_def.h"
#include <cstring>
namespace ue2 {
static
bool hasValidContBytes(const u8 *s, size_t num) {
/* continuer bytes must all be of the form 10xx xxxx */
for (size_t i = 0; i < num; i++) {
if ((s[i] & 0xc0) != UTF_CONT_BYTE_HEADER) {
return false;
}
}
return true;
}
static
bool isAllowedCodepoint(u32 val) {
if (val >= 0xd800 && val <= 0xdfff) {
return false; // High and low surrogate halves
}
if (val > 0x10ffff) {
return false; // As per limit in RFC 3629
}
return true;
}
bool isValidUtf8(const char *expression, const size_t len) {
if (!expression) {
return true;
}
const u8 *s = (const u8 *)expression;
u32 val;
size_t i = 0;
while (i < len) {
DEBUG_PRINTF("byte %zu: 0x%02x\n", i, s[i]);
// One octet.
if (s[i] < 0x7f) {
DEBUG_PRINTF("one octet\n");
i++;
continue;
}
// Two octets.
if ((s[i] & 0xe0) == UTF_TWO_BYTE_HEADER) {
DEBUG_PRINTF("two octets\n");
if (i + 2 > len) {
break;
}
if (!hasValidContBytes(&s[i] + 1, 1)) {
break;
}
val = ((s[i] & 0x1f) << 6) | (s[i + 1] & UTF_CONT_BYTE_VALUE_MASK);
DEBUG_PRINTF("val=0x%x\n", val);
if (val < 1U << 7) {
DEBUG_PRINTF("overlong encoding\n");
break;
}
if (!isAllowedCodepoint(val)) {
DEBUG_PRINTF("codepoint not allowed\n");
break;
}
i += 2;
continue;
}
// Three octets.
if ((s[i] & 0xf0) == UTF_THREE_BYTE_HEADER) {
DEBUG_PRINTF("three octets\n");
if (i + 3 > len) {
break;
}
if (!hasValidContBytes(&s[i] + 1, 2)) {
break;
}
val = ((s[i] & 0xf) << 12) |
((s[i + 1] & UTF_CONT_BYTE_VALUE_MASK) << 6) |
(s[i + 2] & UTF_CONT_BYTE_VALUE_MASK);
if (val < 1U << 11) {
DEBUG_PRINTF("overlong encoding\n");
break;
}
if (!isAllowedCodepoint(val)) {
DEBUG_PRINTF("codepoint not allowed\n");
break;
}
i += 3;
continue;
}
// Four octets.
if ((s[i] & 0xf8) == UTF_FOUR_BYTE_HEADER) {
DEBUG_PRINTF("four octets\n");
if (i + 4 > len) {
break;
}
if (!hasValidContBytes(&s[i] + 1, 3)) {
break;
}
val = ((s[i] & 0xf) << 18) |
((s[i + 1] & UTF_CONT_BYTE_VALUE_MASK) << 12) |
((s[i + 2] & UTF_CONT_BYTE_VALUE_MASK) << 6) |
(s[i + 3] & UTF_CONT_BYTE_VALUE_MASK);
if (val < 1U << 16) {
DEBUG_PRINTF("overlong encoding\n");
break;
}
if (!isAllowedCodepoint(val)) {
DEBUG_PRINTF("codepoint not allowed\n");
break;
}
i += 4;
continue;
}
// Something else?
DEBUG_PRINTF("bad byte 0x%02x\n", s[i]);
break;
}
DEBUG_PRINTF("i=%zu, len=%zu\n", i, len);
return i == len;
}
} // namespace ue2
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