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

1 files changed, 2 insertions, 8 deletions

diff --git a/usr.sbin/jls/jls.c b/usr.sbin/jls/jls.c
index 4c968fdc76df..3621de849bda 100644
--- a/usr.sbin/jls/jls.c
+++ b/usr.sbin/jls/jls.c
@@ -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);