1 files changed, 165 insertions, 0 deletions
diff --git a/tools/testing/selftests/netfilter/audit_logread.c b/tools/testing/selftests/netfilter/audit_logread.c
new file mode 100644
index 000000000000..a0a880fc2d9d
--- /dev/null
+++ b/tools/testing/selftests/netfilter/audit_logread.c
@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <linux/audit.h>
+#include <linux/netlink.h>
+
+static int fd;
+
+#define MAX_AUDIT_MESSAGE_LENGTH	8970
+struct audit_message {
+	struct nlmsghdr nlh;
+	union {
+		struct audit_status s;
+		char data[MAX_AUDIT_MESSAGE_LENGTH];
+	} u;
+};
+
+int audit_recv(int fd, struct audit_message *rep)
+{
+	struct sockaddr_nl addr;
+	socklen_t addrlen = sizeof(addr);
+	int ret;
+
+	do {
+		ret = recvfrom(fd, rep, sizeof(*rep), 0,
+			       (struct sockaddr *)&addr, &addrlen);
+	} while (ret < 0 && errno == EINTR);
+
+	if (ret < 0 ||
+	    addrlen != sizeof(addr) ||
+	    addr.nl_pid != 0 ||
+	    rep->nlh.nlmsg_type == NLMSG_ERROR) /* short-cut for now */
+		return -1;
+
+	return ret;
+}
+
+int audit_send(int fd, uint16_t type, uint32_t key, uint32_t val)
+{
+	static int seq = 0;
+	struct audit_message msg = {
+		.nlh = {
+			.nlmsg_len   = NLMSG_SPACE(sizeof(msg.u.s)),
+			.nlmsg_type  = type,
+			.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK,
+			.nlmsg_seq   = ++seq,
+		},
+		.u.s = {
+			.mask    = key,
+			.enabled = key == AUDIT_STATUS_ENABLED ? val : 0,
+			.pid     = key == AUDIT_STATUS_PID ? val : 0,
+		}
+	};
+	struct sockaddr_nl addr = {
+		.nl_family = AF_NETLINK,
+	};
+	int ret;
+
+	do {
+		ret = sendto(fd, &msg, msg.nlh.nlmsg_len, 0,
+			     (struct sockaddr *)&addr, sizeof(addr));
+	} while (ret < 0 && errno == EINTR);
+
+	if (ret != (int)msg.nlh.nlmsg_len)
+		return -1;
+	return 0;
+}
+
+int audit_set(int fd, uint32_t key, uint32_t val)
+{
+	struct audit_message rep = { 0 };
+	int ret;
+
+	ret = audit_send(fd, AUDIT_SET, key, val);
+	if (ret)
+		return ret;
+
+	ret = audit_recv(fd, &rep);
+	if (ret < 0)
+		return ret;
+	return 0;
+}
+
+int readlog(int fd)
+{
+	struct audit_message rep = { 0 };
+	int ret = audit_recv(fd, &rep);
+	const char *sep = "";
+	char *k, *v;
+
+	if (ret < 0)
+		return ret;
+
+	if (rep.nlh.nlmsg_type != AUDIT_NETFILTER_CFG)
+		return 0;
+
+	/* skip the initial "audit(...): " part */
+	strtok(rep.u.data, " ");
+
+	while ((k = strtok(NULL, "="))) {
+		v = strtok(NULL, " ");
+
+		/* these vary and/or are uninteresting, ignore */
+		if (!strcmp(k, "pid") ||
+		    !strcmp(k, "comm") ||
+		    !strcmp(k, "subj"))
+			continue;
+
+		/* strip the varying sequence number */
+		if (!strcmp(k, "table"))
+			*strchrnul(v, ':') = '\0';
+
+		printf("%s%s=%s", sep, k, v);
+		sep = " ";
+	}
+	if (*sep) {
+		printf("\n");
+		fflush(stdout);
+	}
+	return 0;
+}
+
+void cleanup(int sig)
+{
+	audit_set(fd, AUDIT_STATUS_ENABLED, 0);
+	close(fd);
+	if (sig)
+		exit(0);
+}
+
+int main(int argc, char **argv)
+{
+	struct sigaction act = {
+		.sa_handler = cleanup,
+	};
+
+	fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_AUDIT);
+	if (fd < 0) {
+		perror("Can't open netlink socket");
+		return -1;
+	}
+
+	if (sigaction(SIGTERM, &act, NULL) < 0 ||
+	    sigaction(SIGINT, &act, NULL) < 0) {
+		perror("Can't set signal handler");
+		close(fd);
+		return -1;
+	}
+
+	audit_set(fd, AUDIT_STATUS_ENABLED, 1);
+	audit_set(fd, AUDIT_STATUS_PID, getpid());
+
+	while (1)
+		readlog(fd);
+}