Commit eed09ad2 authored by Kees Cook's avatar Kees Cook
Browse files

samples/seccomp: Adjust sample to also provide kill option 



As a quick way to test SECCOMP_RET_KILL, have a negative errno mean to
kill the process.

While we're in here, also swap the arch and syscall arguments so they're
ordered more like how seccomp filters order them.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 495ac306

samples/seccomp/dropper.c

+7 −2
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ 
#include <sys/prctl.h>

#include <unistd.h>



static int install_filter(int nr, int arch, int error)

static int install_filter(int arch, int nr, int error)

{

	struct sock_filter filter[] = {

		BPF_STMT(BPF_LD+BPF_W+BPF_ABS,
@@ -42,6 +42,10 @@ static int install_filter(int nr, int arch, int error) 
		.len = (unsigned short)(sizeof(filter)/sizeof(filter[0])),

		.filter = filter,

	};

	if (error == -1) {

		struct sock_filter kill = BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL);

		filter[4] = kill;

	}

	if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {

		perror("prctl(NO_NEW_PRIVS)");

		return 1;
@@ -57,9 +61,10 @@ int main(int argc, char **argv) 
{

	if (argc < 5) {

		fprintf(stderr, "Usage:\n"

			"dropper <syscall_nr> <arch> <errno> <prog> [<args>]\n"

			"dropper <arch> <syscall_nr> <errno> <prog> [<args>]\n"

			"Hint:	AUDIT_ARCH_I386: 0x%X\n"

			"	AUDIT_ARCH_X86_64: 0x%X\n"

			"	errno == -1 means SECCOMP_RET_KILL\n"

			"\n", AUDIT_ARCH_I386, AUDIT_ARCH_X86_64);

		return 1;

	}