wc: sandbox wc using capsicum

Reviewed by:	AllanJude, emaste
Differential Revision:	https://reviews.freebsd.org/D14409

2 files changed, 37 insertions, 1 deletions

diff --git a/usr.bin/wc/Makefile b/usr.bin/wc/Makefile
index 540e33d15c926..550b718e1478a 100644
--- a/usr.bin/wc/Makefile
+++ b/usr.bin/wc/Makefile
@@ -1,7 +1,15 @@
 #	@(#)Makefile	8.1 (Berkeley) 6/6/93
 # $FreeBSD$
 
+.include <src.opts.mk>
+
 PROG=	wc
 LIBADD=	xo
 
+.if ${MK_CASPER} != "no"
+LIBADD+=        casper
+LIBADD+=        cap_fileargs
+CFLAGS+=-DWITH_CASPER
+.endif
+
 .include <bsd.prog.mk>
diff --git a/usr.bin/wc/wc.c b/usr.bin/wc/wc.c
index c2990035c0c7e..196d6f488a815 100644
--- a/usr.bin/wc/wc.c
+++ b/usr.bin/wc/wc.c
@@ -44,9 +44,11 @@ static char sccsid[] = "@(#)wc.c	8.1 (Berkeley) 6/6/93";
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include <sys/capsicum.h>
 #include <sys/param.h>
 #include <sys/stat.h>
 
+#include <capsicum_helpers.h>
 #include <ctype.h>
 #include <err.h>
 #include <errno.h>
@@ -61,6 +63,10 @@ __FBSDID("$FreeBSD$");
 #include <wctype.h>
 #include <libxo/xo.h>
 
+#include <libcasper.h>
+#include <casper/cap_fileargs.h>
+
+static fileargs_t *fa;
 static uintmax_t tlinect, twordct, tcharct, tlongline;
 static int doline, doword, dochar, domulti, dolongline;
 static volatile sig_atomic_t siginfo;
@@ -90,6 +96,7 @@ int
 main(int argc, char *argv[])
 {
 	int ch, errors, total;
+	cap_rights_t rights;
 
 	(void) setlocale(LC_CTYPE, "");
 
@@ -125,6 +132,26 @@ main(int argc, char *argv[])
 
 	(void)signal(SIGINFO, siginfo_handler);
 
+	fa = fileargs_init(argc, argv, O_RDONLY, 0,
+	    cap_rights_init(&rights, CAP_READ, CAP_FSTAT));
+	if (fa == NULL) {
+		xo_warn("Unable to init casper");
+		exit(1);
+	}
+
+	caph_cache_catpages();
+	if (caph_limit_stdio() < 0) {
+		xo_warn("Unable to limit stdio");
+		fileargs_free(fa);
+		exit(1);
+	}
+
+	if (caph_enter() < 0) {
+		xo_warn("Unable to enter capability mode");
+		fileargs_free(fa);
+		exit(1);
+	}
+
 	/* Wc's flags are on by default. */
 	if (doline + doword + dochar + domulti + dolongline == 0)
 		doline = doword = dochar = 1;
@@ -158,6 +185,7 @@ main(int argc, char *argv[])
 		xo_close_container("total");
 	}
 
+	fileargs_free(fa);
 	xo_close_container("wc");
 	xo_finish();
 	exit(errors == 0 ? 0 : 1);
@@ -206,7 +234,7 @@ cnt(const char *file)
 	linect = wordct = charct = llct = tmpll = 0;
 	if (file == NULL)
 		fd = STDIN_FILENO;
-	else if ((fd = open(file, O_RDONLY, 0)) < 0) {
+	else if ((fd = fileargs_open(fa, file)) < 0) {
 		xo_warn("%s: open", file);
 		return (1);
 	}