From: Alexander Borisov <alexander.borisov@nginx.com>
Date: Tue, 28 May 2019 17:49:58 +0000 (+0300)
Subject: Improved processing of invalid surrogate pairs in strings.
X-Git-Tag: 0.3.3~25
X-Git-Url: http://git.kaiwu.me/postgresql/log/contrib/postgres_fdw/static/gitweb.js?a=commitdiff_plain;h=721af4cc5ec2470a69f0c680b0027b4d1339aff9;p=njs.git

Improved processing of invalid surrogate pairs in strings.

Previously, an exception was thrown on invalid surrogate pairs.
Now, all such pairs are converted to replacement character.

This closes #170 issue on GitHub.
---

diff --git a/njs/njs_parser_terminal.c b/njs/njs_parser_terminal.c
index 7f1122b7..3c85ccda 100644
--- a/njs/njs_parser_terminal.c
+++ b/njs/njs_parser_terminal.c
@@ -1049,12 +1049,27 @@ njs_parser_escape_string_create(njs_vm_t *vm, njs_parser_t *parser,
         }
 
         if (cp_pair != 0) {
-            cp = njs_string_surrogate_pair(cp_pair, cp);
+            if (nxt_fast_path(cp >= 0xdc00 && cp <= 0xdfff)) {
+                cp = njs_string_surrogate_pair(cp_pair, cp);
+
+            } else if (nxt_slow_path(cp >= 0xd800 && cp <= 0xdbff)) {
+                cp = NXT_UTF8_REPLACEMENT;
+
+                dst = nxt_utf8_encode(dst, (uint32_t) cp);
+
+            } else {
+                dst = nxt_utf8_encode(dst, NXT_UTF8_REPLACEMENT);
+            }
+
             cp_pair = 0;
 
         } else if (cp >= 0xd800 && cp <= 0xdfff) {
-            cp_pair = cp;
-            continue;
+            if (cp <= 0xdbff && src[0] == '\\' && src[1] == 'u') {
+                cp_pair = cp;
+                continue;
+            }
+
+            cp = NXT_UTF8_REPLACEMENT;
         }
 
         dst = nxt_utf8_encode(dst, (uint32_t) cp);
@@ -1183,20 +1198,29 @@ njs_parser_escape_string_calc_length(njs_vm_t *vm, njs_parser_t *parser,
         }
 
         if (cp_pair != 0) {
-            if (nxt_slow_path(cp < 0xdc00 || cp > 0xdfff)) {
-                goto invalid_pair;
+            if (nxt_fast_path(cp >= 0xdc00 && cp <= 0xdfff)) {
+                cp = njs_string_surrogate_pair(cp_pair, cp);
+
+            } else if (nxt_slow_path(cp >= 0xd800 && cp <= 0xdbff)) {
+                cp = NXT_UTF8_REPLACEMENT;
+
+                size += nxt_utf8_size(cp);
+                length++;
+
+            } else {
+                size += nxt_utf8_size(NXT_UTF8_REPLACEMENT);
+                length++;
             }
 
-            cp = njs_string_surrogate_pair(cp_pair, cp);
             cp_pair = 0;
 
         } else if (cp >= 0xd800 && cp <= 0xdfff) {
-            if (nxt_slow_path(cp > 0xdbff || src[0] != '\\' || src[1] != 'u')) {
-                goto invalid_pair;
+            if (cp <= 0xdbff && src[0] == '\\' && src[1] == 'u') {
+                cp_pair = cp;
+                continue;
             }
 
-            cp_pair = cp;
-            continue;
+            cp = NXT_UTF8_REPLACEMENT;
         }
 
         size += nxt_utf8_size(cp);
@@ -1214,11 +1238,4 @@ invalid:
                             njs_parser_text(parser));
 
     return NJS_ERROR;
-
-invalid_pair:
-
-    njs_parser_syntax_error(vm, parser, "Invalid surrogate pair \"%V\"",
-                            njs_parser_text(parser));
-
-    return NJS_ERROR;
 }
diff --git a/njs/test/njs_unit_test.c b/njs/test/njs_unit_test.c
index 458dc8ff..921e98a3 100644
--- a/njs/test/njs_unit_test.c
+++ b/njs/test/njs_unit_test.c
@@ -4448,15 +4448,25 @@ static njs_unit_test_t  njs_test[] =
       nxt_string("1") },
 
     { nxt_string("'\\ud83d abc \\udc4d'"),
-      nxt_string("SyntaxError: Invalid surrogate pair "
-                 "\"\\ud83d abc \\udc4d\" in 1") },
+      nxt_string("� abc �") },
 
     { nxt_string("'\\ud83d'"),
-      nxt_string("SyntaxError: Invalid surrogate pair \"\\ud83d\" in 1") },
+      nxt_string("�") },
 
     { nxt_string("'\\ud83d\\uabcd'"),
-      nxt_string("SyntaxError: Invalid surrogate pair "
-                 "\"\\ud83d\\uabcd\" in 1") },
+      nxt_string("�ꯍ") },
+
+    { nxt_string("'\\u{d800}\\u{dB00}'"),
+      nxt_string("��") },
+
+    { nxt_string("'\\u{d800}\\u{d7ff}'"),
+      nxt_string("�퟿") },
+
+    { nxt_string("'\\u{d800}['"),
+      nxt_string("�[") },
+
+    { nxt_string("'\\u{D800}\\u{'"),
+      nxt_string("SyntaxError: Invalid Unicode code point \"\\u{D800}\\u{\" in 1") },
 
     { nxt_string("''.hasOwnProperty('length')"),
       nxt_string("true") },
diff --git a/nxt/nxt_utf8.h b/nxt/nxt_utf8.h
index 8362b40a..dc77f02e 100644
--- a/nxt/nxt_utf8.h
+++ b/nxt/nxt_utf8.h
@@ -15,6 +15,8 @@
  */
 #define NXT_UTF8_SORT_INVALID  0x0EEE0EEE
 
+#define NXT_UTF8_REPLACEMENT   0xFFFD
+
 
 NXT_EXPORT u_char *nxt_utf8_encode(u_char *p, uint32_t u);
 NXT_EXPORT uint32_t nxt_utf8_decode(const u_char **start, const u_char *end);