[PATCH] policycoreutils: handle argument counter of zero

["Christian Göttsche" <cgzones@googlemail.com>]

The number of arguments passed to main(), argc, can be zero if the
pathname passed to execve(2) is NULL, e.g. via:

    execve("/path/to/exe", {NULL}, {NULL});

Also avoid NULL pointer dereferences on the argument value.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
---
 policycoreutils/run_init/open_init_pty.c | 2 +-
 policycoreutils/secon/secon.c            | 3 +++
 policycoreutils/setfiles/setfiles.c      | 6 +++++-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/policycoreutils/run_init/open_init_pty.c b/policycoreutils/run_init/open_init_pty.c
index 150cb45e..19101c50 100644
--- a/policycoreutils/run_init/open_init_pty.c
+++ b/policycoreutils/run_init/open_init_pty.c
@@ -244,7 +244,7 @@ int main(int argc, char *argv[])
 	rb_init(&inbuf, inbuf_mem, sizeof(inbuf_mem));
 	rb_init(&outbuf, outbuf_mem, sizeof(outbuf_mem));
 
-	if (argc == 1) {
+	if (argc < 2) {
 		printf("usage: %s PROGRAM [ARGS]...\n", argv[0]);
 		exit(1);
 	}
diff --git a/policycoreutils/secon/secon.c b/policycoreutils/secon/secon.c
index a0957d09..d624fa13 100644
--- a/policycoreutils/secon/secon.c
+++ b/policycoreutils/secon/secon.c
@@ -333,6 +333,9 @@ static void cmd_line(int argc, char *argv[])
 		opts->from_type = OPTS_FROM_CUR;
 
 	if (opts->from_type == OPTS_FROM_ARG) {
+		if (!argv[0])
+			errx(EXIT_FAILURE, "No argument given");
+
 		opts->f.arg = argv[0];
 
 		if (xstreq(argv[0], "-"))
diff --git a/policycoreutils/setfiles/setfiles.c b/policycoreutils/setfiles/setfiles.c
index 44cab46d..ab7016ac 100644
--- a/policycoreutils/setfiles/setfiles.c
+++ b/policycoreutils/setfiles/setfiles.c
@@ -163,6 +163,10 @@ int main(int argc, char **argv)
 	policyfile = NULL;
 
 	r_opts.abort_on_error = 0;
+	if (!argv[0]) {
+		fprintf(stderr, "Called without required program name!\n");
+		exit(-1);
+	}
 	r_opts.progname = strdup(argv[0]);
 	if (!r_opts.progname) {
 		fprintf(stderr, "%s:  Out of memory!\n", argv[0]);
@@ -423,7 +427,7 @@ int main(int argc, char **argv)
 
 		altpath = argv[optind];
 		optind++;
-	} else if (argc == 1)
+	} else if (argc < 2)
 		usage(argv[0]);
 
 	/* Set selabel_open options. */
-- 
2.34.1