RFC 8259 on string contents:
All Unicode characters may be placed within the quotation marks,
except for the characters that MUST be escaped: quotation mark,
reverse solidus, and the control characters (U+0000 through
U+001F).
The QAPI schema parser accepts both less and more than JSON: it
accepts only ASCII with \u (less), and accepts control characters
other than LF (new line) unescaped. How it treats unescaped non-ASCII
input differs between Python 2 and Python 3.
Make it accept strictly less: require printable ASCII. Drop support
for \b, \f, \n, \r, \t.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190913201349.24332-7-armbru@redhat.com>
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