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authorMarkus Armbruster <armbru@redhat.com>2018-08-23 18:39:53 +0200
committerMarkus Armbruster <armbru@redhat.com>2018-08-24 20:26:37 +0200
commitb2da4a4d7537567b44db60b7b79cd14f64e48f2f (patch)
treeb4a2f02e72bb87c160592a9ec2b42dc67b44c393 /qobject/json-parser.c
parent4b1c0cd7c7f9f9cf2e46c0a9c9cd88b2cba3decd (diff)
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json: Leave rejecting invalid escape sequences to parser
Both lexer and parser reject invalid escape sequences in strings. The parser's check is useless. The lexer ends the token right after the first non-well-formed byte. This tends to lead to suboptimal error reporting. For instance, input {"abc\@ijk": 1} produces the tokens JSON_LCURLY { JSON_ERROR "abc\@ JSON_KEYWORD ijk JSON_ERROR ": 1}\n The parser then reports three errors Invalid JSON syntax JSON parse error, invalid keyword 'ijk' Invalid JSON syntax before it recovers at the newline. Drop the lexer's escape sequence checking, and make it accept the same characters after backslash it accepts elsewhere in strings. It now produces JSON_LCURLY { JSON_STRING "abc\@ijk" JSON_COLON : JSON_INTEGER 1 JSON_RCURLY and the parser reports just JSON parse error, invalid escape sequence in string While there, fix parse_string()'s inaccurate function comment. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180823164025.12553-27-armbru@redhat.com>
Diffstat (limited to 'qobject/json-parser.c')
-rw-r--r--qobject/json-parser.c56
1 files changed, 33 insertions, 23 deletions
diff --git a/qobject/json-parser.c b/qobject/json-parser.c
index a9b227f..7437827 100644
--- a/qobject/json-parser.c
+++ b/qobject/json-parser.c
@@ -106,30 +106,40 @@ static int hex2decimal(char ch)
}
/**
- * parse_string(): Parse a json string and return a QObject
+ * parse_string(): Parse a JSON string
*
- * string
- * ""
- * " chars "
- * chars
- * char
- * char chars
- * char
- * any-Unicode-character-
- * except-"-or-\-or-
- * control-character
- * \"
- * \\
- * \/
- * \b
- * \f
- * \n
- * \r
- * \t
- * \u four-hex-digits
+ * From RFC 8259 "The JavaScript Object Notation (JSON) Data
+ * Interchange Format":
+ *
+ * char = unescaped /
+ * escape (
+ * %x22 / ; " quotation mark U+0022
+ * %x5C / ; \ reverse solidus U+005C
+ * %x2F / ; / solidus U+002F
+ * %x62 / ; b backspace U+0008
+ * %x66 / ; f form feed U+000C
+ * %x6E / ; n line feed U+000A
+ * %x72 / ; r carriage return U+000D
+ * %x74 / ; t tab U+0009
+ * %x75 4HEXDIG ) ; uXXXX U+XXXX
+ * escape = %x5C ; \
+ * quotation-mark = %x22 ; "
+ * unescaped = %x20-21 / %x23-5B / %x5D-10FFFF
+ *
+ * Extensions over RFC 8259:
+ * - Extra escape sequence in strings:
+ * 0x27 (apostrophe) is recognized after escape, too
+ * - Single-quoted strings:
+ * Like double-quoted strings, except they're delimited by %x27
+ * (apostrophe) instead of %x22 (quotation mark), and can't contain
+ * unescaped apostrophe, but can contain unescaped quotation mark.
+ *
+ * Note:
+ * - Encoding is modified UTF-8.
+ * - Invalid Unicode characters are rejected.
+ * - Control characters \x00..\x1F are rejected by the lexer.
*/
-static QString *qstring_from_escaped_str(JSONParserContext *ctxt,
- JSONToken *token)
+static QString *parse_string(JSONParserContext *ctxt, JSONToken *token)
{
const char *ptr = token->str;
QString *str;
@@ -495,7 +505,7 @@ static QObject *parse_literal(JSONParserContext *ctxt)
switch (token->type) {
case JSON_STRING:
- return QOBJECT(qstring_from_escaped_str(ctxt, token));
+ return QOBJECT(parse_string(ctxt, token));
case JSON_INTEGER: {
/*
* Represent JSON_INTEGER as QNUM_I64 if possible, else as