seccomp_export_bpf (3)

#include <seccomp.h>

typedef void * scmp_filter_ctx;

int seccomp_export_bpf(const scmp_filter_ctx ctx, int fd);
int seccomp_export_pfc(const scmp_filter_ctx ctx, int fd);

Link with -lseccomp.

The seccomp_export_bpf() and seccomp_export_pfc() functions generate and output the current seccomp filter in either BPF (Berkley Packet Filter) or PFC (Pseudo Filter Code). The output of seccomp_export_bpf() is suitable for loading into the kernel, while the output of seccomp_export_pfc() is human readable and is intended primarily as a debugging tool for developers using libseccomp. Both functions write the filter to the fd file descriptor.

The filter context ctx is the value returned by the call to seccomp_init(3).

While the two output formats are guaranteed to be functionally equivalent for the given seccomp filter configuration, the filter instructions, and their ordering, are not guaranteed to be the same in both the BPF and PFC formats.

Returns zero on success, negative errno values on failure.

#include <seccomp.h>

int main(int argc, char *argv[])
{
	int rc = -1;
	scmp_filter_ctx ctx;
	int filter_fd;

	ctx = seccomp_init(SCMP_ACT_KILL);
	if (ctx == NULL)
		goto out;

	/* ... */

	filter_fd = open("/tmp/seccomp_filter.bpf", O_WRONLY);
	if (filter_fd == -1) {
		rc = -errno;
		goto out;
	}

	rc = seccomp_export_bpf(ctx, filter_fd);
	if (rc < 0) {
		close(filter_fd);
		goto out;
	}
	close(filter_fd);

	/* ... */

out:
	seccomp_release(ctx);
	return -rc;
}

While the seccomp filter can be generated independent of the kernel, kernel support is required to load and enforce the seccomp filter generated by libseccomp.

The libseccomp project site, with more information and the source code repository, can be found at http://libseccomp.sf.net. This library is currently under development, please report any bugs at the project site or directly to the author.

Paul Moore <[email protected]>

seccomp_init(3), seccomp_release(3)