- Fixed bug #49687 (utf8_decode vulnerabilities and deficiencies in the number

  of reported malformed sequences). (Gustavo)
#Made a public interface for get_next_char/utf-8 in trunk to use in utf8_decode.
#In PHP 5.3, trunk's get_next_char was copied to xml.c because 5.3's
#get_next_char is different and is not prepared to recover appropriately from
#errors.

diff --git a/NEWS b/NEWS
index 3c6a354a3ac16e0a4d53a0a2ca1e5bc1690359bc..952cb708752f67096cf36b52e33b402ba8028b13 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -152,6 +152,8 @@
   other platforms). (Pierre)
 - Fixed bug #50345 (nanosleep not detected properly on some solaris versions).
   (Ulf, Tony)
+- Fixed bug #49687 (utf8_decode vulnerabilities and deficiencies in the number
+  of reported malformed sequences). (Gustavo)
 - Fixed bug #49407 (get_html_translation_table doesn't handle UTF-8). (Gustavo)
 - Fixed bug #49215 (make fails on glob_wrapper). (Felipe)
 - Fixed bug #48831 (php -i has different output to php --ini). (Richard, 

diff --git a/ext/xml/tests/bug49687.phpt b/ext/xml/tests/bug49687.phpt
new file mode 100644 (file)
index 0000000..3ff19ce
--- /dev/null
+++ b/ext/xml/tests/bug49687.phpt
@@ -0,0 +1,24 @@
+--TEST--\r
+Bug #49687 Several utf8_decode deficiencies and vulnerabilities\r
+--SKIPIF--\r
+<?php\r
+require_once("skipif.inc");\r
+if (!extension_loaded('xml')) die ("skip xml extension not available");\r
+?>\r
+--FILE--\r
+<?php\r
+\r
+$tests = array(\r
+    "\x41\xC2\x3E\x42",\r
+    "\xE3\x80\x22",\r
+    "\x41\x98\xBA\x42\xE2\x98\x43\xE2\x98\xBA\xE2\x98",\r
+);\r
+foreach ($tests as $t) {\r
+    echo bin2hex(utf8_decode($t)), "\n";\r
+}\r
+echo "Done.\n";\r
+--EXPECT--\r
+413f3e42\r
+3f22\r
+413f3f423f433f3f\r
+Done.\r

diff --git a/ext/xml/xml.c b/ext/xml/xml.c
index 72729d6de5c9540951fd6c851f60f2343a363d28..c05e1e6539064484715201df33e419c8f481975f 100644 (file)
--- a/ext/xml/xml.c
+++ b/ext/xml/xml.c
@@ -659,10 +659,111 @@ PHPAPI char *xml_utf8_encode(const char *s, int len, int *newlen, const XML_Char
 }
 /* }}} */
 
+/* copied from trunk's implementation of get_next_char in ext/standard/html.c */
+#define MB_FAILURE(pos, advance) do { \
+       *cursor = pos + (advance); \
+       *status = FAILURE; \
+       return 0; \
+} while (0)
+
+#define CHECK_LEN(pos, chars_need) ((str_len - (pos)) >= (chars_need))
+#define utf8_lead(c)  ((c) < 0x80 || ((c) >= 0xC2 && (c) <= 0xF4))
+#define utf8_trail(c) ((c) >= 0x80 && (c) <= 0xBF)
+
+/* {{{ php_next_utf8_char
+ */
+static inline unsigned int php_next_utf8_char(
+               const unsigned char *str,
+               size_t str_len,
+               size_t *cursor,
+               int *status)
+{
+       size_t pos = *cursor;
+       unsigned int this_char = 0;
+       unsigned char c;
+
+       *status = SUCCESS;
+
+       if (!CHECK_LEN(pos, 1))
+               MB_FAILURE(pos, 1);
+
+       /* We'll follow strategy 2. from section 3.6.1 of UTR #36:
+               * "In a reported illegal byte sequence, do not include any
+               *  non-initial byte that encodes a valid character or is a leading
+               *  byte for a valid sequence.» */
+       c = str[pos];
+       if (c < 0x80) {
+               this_char = c;
+               pos++;
+       } else if (c < 0xc2) {
+               MB_FAILURE(pos, 1);
+       } else if (c < 0xe0) {
+               if (!CHECK_LEN(pos, 2))
+                       MB_FAILURE(pos, 1);
+
+               if (!utf8_trail(str[pos + 1])) {
+                       MB_FAILURE(pos, utf8_lead(str[pos + 1]) ? 1 : 2);
+               }
+               this_char = ((c & 0x1f) << 6) | (str[pos + 1] & 0x3f);
+               if (this_char < 0x80) { /* non-shortest form */
+                       MB_FAILURE(pos, 2);
+               }
+               pos += 2;
+       } else if (c < 0xf0) {
+               size_t avail = str_len - pos;
+
+               if (avail < 3 ||
+                               !utf8_trail(str[pos + 1]) || !utf8_trail(str[pos + 2])) {
+                       if (avail < 2 || utf8_lead(str[pos + 1]))
+                               MB_FAILURE(pos, 1);
+                       else if (avail < 3 || utf8_lead(str[pos + 2]))
+                               MB_FAILURE(pos, 2);
+                       else
+                               MB_FAILURE(pos, 3);
+               }
+
+               this_char = ((c & 0x0f) << 12) | ((str[pos + 1] & 0x3f) << 6) | (str[pos + 2] & 0x3f);
+               if (this_char < 0x800) { /* non-shortest form */
+                       MB_FAILURE(pos, 3);
+               } else if (this_char >= 0xd800 && this_char <= 0xdfff) { /* surrogate */
+                       MB_FAILURE(pos, 3);
+               }
+               pos += 3;
+       } else if (c < 0xf5) {
+               size_t avail = str_len - pos;
+
+               if (avail < 4 ||
+                               !utf8_trail(str[pos + 1]) || !utf8_trail(str[pos + 2]) ||
+                               !utf8_trail(str[pos + 3])) {
+                       if (avail < 2 || utf8_lead(str[pos + 1]))
+                               MB_FAILURE(pos, 1);
+                       else if (avail < 3 || utf8_lead(str[pos + 2]))
+                               MB_FAILURE(pos, 2);
+                       else if (avail < 4 || utf8_lead(str[pos + 3]))
+                               MB_FAILURE(pos, 3);
+                       else
+                               MB_FAILURE(pos, 4);
+               }
+                               
+               this_char = ((c & 0x07) << 18) | ((str[pos + 1] & 0x3f) << 12) | ((str[pos + 2] & 0x3f) << 6) | (str[pos + 3] & 0x3f);
+               if (this_char < 0x10000 || this_char > 0x10FFFF) { /* non-shortest form or outside range */
+                       MB_FAILURE(pos, 4);
+               }
+               pos += 4;
+       } else {
+               MB_FAILURE(pos, 1);
+       }
+       
+       *cursor = pos;
+       return this_char;
+}
+/* }}} */
+
+
 /* {{{ xml_utf8_decode */
 PHPAPI char *xml_utf8_decode(const XML_Char *s, int len, int *newlen, const XML_Char *encoding)
 {
-       int pos = len;
+       size_t pos = 0;
        char *newbuf = emalloc(len + 1);
        unsigned int c;
        char (*decoder)(unsigned short) = NULL;
@@ -681,36 +782,15 @@ PHPAPI char *xml_utf8_decode(const XML_Char *s, int len, int *newlen, const XML_
                newbuf[*newlen] = '\0';
                return newbuf;
        }
-       while (pos > 0) {
-               c = (unsigned char)(*s);
-               if (c >= 0xf0) { /* four bytes encoded, 21 bits */
-                       if(pos-4 >= 0) {
-                               c = ((s[0]&7)<<18) | ((s[1]&63)<<12) | ((s[2]&63)<<6) | (s[3]&63);
-                       } else {
-                               c = '?';        
-                       }
-                       s += 4;
-                       pos -= 4;
-               } else if (c >= 0xe0) { /* three bytes encoded, 16 bits */
-                       if(pos-3 >= 0) {
-                               c = ((s[0]&63)<<12) | ((s[1]&63)<<6) | (s[2]&63);
-                       } else {
-                               c = '?';
-                       }
-                       s += 3;
-                       pos -= 3;
-               } else if (c >= 0xc0) { /* two bytes encoded, 11 bits */
-                       if(pos-2 >= 0) {
-                               c = ((s[0]&63)<<6) | (s[1]&63);
-                       } else {
-                               c = '?';
-                       }
-                       s += 2;
-                       pos -= 2;
-               } else {
-                       s++;
-                       pos--;
+
+       while (pos < (size_t)len) {
+               int status = FAILURE;
+               c = php_next_utf8_char((const unsigned char*)s, (size_t) len, &pos, &status);
+
+               if (status == FAILURE || c > 0xFFU) {
+                       c = '?';
                }
+
                newbuf[*newlen] = decoder ? decoder(c) : c;
                ++*newlen;
        }