Fix bad libbxo format strings in jls

The existing format string for the empty case was trying to read varargs
values that weren't passed to xo_emit. This appears to work on x86 (since
the next argument is probably a pointer an empty string), but for CHERI
we can bound variadic arguments and detect a read past the end.

While touching these lines also use the libxo 'a' modifier to avoid having to
construct the libxo format string using asprintf.

Found by:	CHERI
Reviewed By:	allanjude
Differential Revision: https://reviews.freebsd.org/D26885
This commit is contained in:
Alex Richardson 2020-11-04 14:31:52 +00:00
parent 4c18532bd0
commit d24f17df96

View File

@ -505,17 +505,13 @@ quoted_print(int pflags, char *name, char *value)
{
int qc;
char *p = value;
char *param_name_value;
/* An empty string needs quoting. */
if (!*p) {
asprintf(&param_name_value, "{k:%s}{d:%s/\"\"}", name, name);
xo_emit(param_name_value);
free(param_name_value);
xo_emit("{ea:/%s}{da:/\"\"}", name, value, name);
return;
}
asprintf(&param_name_value, "{:%s/%%s}", name);
/*
* The value will be surrounded by quotes if it contains spaces
* or quotes.
@ -528,9 +524,7 @@ quoted_print(int pflags, char *name, char *value)
if (qc && pflags & PRINT_QUOTED)
xo_emit("{P:/%c}", qc);
xo_emit(param_name_value, value);
free(param_name_value);
xo_emit("{a:/%s}", name, value);
if (qc && pflags & PRINT_QUOTED)
xo_emit("{P:/%c}", qc);