json: Reject invalid UTF-8 sequences

We reject bytes that can't occur in valid UTF-8 (\xC0..\xC1,
\xF5..\xFF in the lexer.  That's insufficient; there's plenty of
invalid UTF-8 not containing these bytes, as demonstrated by
check-qjson:

* Malformed sequences

  - Unexpected continuation bytes

  - Missing continuation bytes after start bytes other than
    \xC0..\xC1, \xF5..\xFD.

* Overlong sequences with start bytes other than \xC0..\xC1,
  \xF5..\xFD.

* Invalid code points

Fixing this in the lexer would be bothersome.  Fixing it in the parser
is straightforward, so do that.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-23-armbru@redhat.com>
This commit is contained in:
Markus Armbruster 2018-08-23 18:39:49 +02:00
parent a89d3104a2
commit e59f39d403
4 changed files with 122 additions and 105 deletions

View file

@ -2,5 +2,6 @@
#define QEMU_UNICODE_H
int mod_utf8_codepoint(const char *s, size_t n, char **end);
ssize_t mod_utf8_encode(char buf[], size_t bufsz, int codepoint);
#endif