Initial commit of Hyperscan

src/parser/utf8_validate.cpp

@@ -0,0 +1,163 @@
+/*
+ * 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) {
+    if (!expression) {
+        return true;
+    }
+
+    const size_t len = strlen(expression);
+    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