Fix bogus handling of control characters in json_lex_string().

The original coding misbehaved if "char" is signed, and also made the
extremely poor decision to print control characters literally when trying
to complain about them.  Report and patch by Shigeru Hanada.

In passing, also fix core dump risk in report_parse_error() should the
parse state be something other than what it expects.

diff --git a/src/backend/utils/adt/json.c b/src/backend/utils/adt/json.c
index 8ab47defbe47075728235c0e1c06d4d69b46118f..61ae62eb8a9c61cbc4d2d2f6828c59ac1ece5fe6 100644 (file)
--- a/src/backend/utils/adt/json.c
+++ b/src/backend/utils/adt/json.c
@@ -419,7 +419,7 @@ json_lex_string(JsonLexContext *lex)
        for (s = lex->token_start + 1; *s != '"'; ++s)
        {
                /* Per RFC4627, these characters MUST be escaped. */
-               if (*s < 32)
+               if ((unsigned char) *s < 32)
                {
                        /* A NUL byte marks the (premature) end of the string. */
                        if (*s == '\0')
@@ -430,8 +430,8 @@ json_lex_string(JsonLexContext *lex)
                        ereport(ERROR,
                                        (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
                                         errmsg("invalid input syntax for type json"),
-                                        errdetail_internal("line %d: Character \"%c\" must be escaped.",
-                                               lex->line_number, *s)));
+                                        errdetail_internal("line %d: Character with value \"0x%02x\" must be escaped.",
+                                               lex->line_number, (unsigned char) *s)));
                }
                else if (*s == '\\')
                {
@@ -637,7 +637,7 @@ report_parse_error(JsonParseStack *stack, JsonLexContext *lex)
                        (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
                         errmsg("invalid input syntax for type json: \"%s\"",
                                lex->input),
-                        errdetail_internal(detail, lex->line_number, token)));
+                        detail ? errdetail_internal(detail, lex->line_number, token) : 0));
 }
 
 /*

diff --git a/src/test/regress/expected/json.out b/src/test/regress/expected/json.out
index ed8b237076270087f1e5a93c7adf0d8fd3e2d003..4b1ad89de6e6b73bdfcd3fb6fb2ef4dbbab0a3d5 100644 (file)
--- a/src/test/regress/expected/json.out
+++ b/src/test/regress/expected/json.out
@@ -26,8 +26,7 @@ def"'::json;                                  -- ERROR, unescaped newline in string constant
 ERROR:  invalid input syntax for type json
 LINE 1: SELECT '"abc
                ^
-DETAIL:  line 1: Character "
-" must be escaped.
+DETAIL:  line 1: Character with value "0x0a" must be escaped.
 SELECT '"\n\"\\"'::json;               -- OK, legal escapes
    json   
 ----------