zdtm: Check CapAmb is restored correctly after C/R

This test sets CapAmb according to CapPrm and CapInh and check CapAmb
after C/R.

Signed-off-by: Liu Chao <liuchao173@huawei.com>

test/zdtm/static/Makefile

@@ -8,6 +8,7 @@ TST_NOFILE	:=				\
 		sleeping00			\
 		pid00				\
 		caps00				\
+		caps01				\
 		wait00				\
 		zombie00			\
 		zombie01			\

test/zdtm/static/caps01.c

@@ -0,0 +1,168 @@
+#include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/prctl.h>
+#include <linux/capability.h>
+
+#include "zdtmtst.h"
+
+const char *test_doc = "Check that CapAmb are preserved";
+const char *test_author = "Liu Chao <liuchao173@huawei.com>";
+
+struct cap_hdr {
+	unsigned int version;
+	int pid;
+};
+
+struct cap_data {
+	unsigned int eff;
+	unsigned int prm;
+	unsigned int inh;
+}; 
+
+#define _LINUX_CAPABILITY_VERSION_3 0x20080522
+#define _LINUX_CAPABILITY_U32S_3    2
+#define CAP_DAC_OVERRIDE	    1
+#define PR_CAP_AMBIENT		    47
+#define PR_CAP_AMBIENT_IS_SET	    1
+#define PR_CAP_AMBIENT_RAISE	    2
+#define PR_CAP_AMBIENT_LOWER	    3
+
+int capget(struct cap_hdr *hdrp, struct cap_data *datap);
+int capset(struct cap_hdr *hdrp, const struct cap_data *datap);
+
+static int cap_last_cap = 63;
+
+int main(int argc, char **argv)
+{
+	task_waiter_t t;
+	int pid, result_pipe[2];
+	unsigned int amb[_LINUX_CAPABILITY_U32S_3];
+	unsigned int amb_2[_LINUX_CAPABILITY_U32S_3];
+	char res = 'x';
+	FILE *f;
+
+	test_init(argc, argv);
+	task_waiter_init(&t);
+
+	f = fopen("/proc/sys/kernel/cap_last_cap", "r");
+	if (f) {
+		if (fscanf(f, "%d", &cap_last_cap) != 1) {
+			pr_perror("Unable to read cal_last_cap");
+			fclose(f);
+			return 1;
+		}
+		fclose(f);
+	} else
+		test_msg("/proc/sys/kernel/cap_last_cap is not available\n");
+
+	if (pipe(result_pipe)) {
+		pr_perror("Can't create pipe");
+		return 1;
+	}
+
+	pid = test_fork();
+	if (pid == 0) {
+		int b, i, ret;
+		struct cap_hdr hdr;
+		struct cap_data data[_LINUX_CAPABILITY_U32S_3];
+
+		hdr.version = _LINUX_CAPABILITY_VERSION_3;
+		hdr.pid = 0;
+
+		if (capget(&hdr, data) < 0) {
+			pr_perror("capget");
+			return -1;
+		}
+
+		hdr.version = _LINUX_CAPABILITY_VERSION_3;
+		hdr.pid = 0;
+
+		data[0].eff &= ~((1 << CAP_CHOWN) | (1 << CAP_DAC_OVERRIDE));
+		data[0].prm &= ~(1 << CAP_DAC_OVERRIDE);
+		data[0].inh = data[0].prm;
+		data[1].inh = data[1].prm;
+
+		if (capset(&hdr, data) < 0) {
+			pr_perror("capset");
+			return -1;
+		}
+
+		for (b = 0; b < _LINUX_CAPABILITY_U32S_3; b++) {
+			amb[b] = data[b].prm;
+			for (i = 0; i < 32; i++) {
+				if (b * 32 + i > cap_last_cap)
+					break;
+				if ((amb[b] & (1 << i)) > 0)
+					ret = prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, i + b * 32, 0, 0);
+				else
+					ret = prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_LOWER, i + b * 32, 0, 0);
+				if (ret) {
+					pr_perror("Unable to set ambient capability %d to %d: %d", i + b * 32, amb[b] & (1 << i), ret);
+					return -1;
+				}
+			}
+		}
+
+		task_waiter_complete_current(&t);
+		task_waiter_wait4(&t, getppid());
+
+		for (b = 0; b < _LINUX_CAPABILITY_U32S_3; b++) {
+			amb_2[b] = 0;
+			for (i = 0; i < 32; i++) {
+				if (b * 32 + i > cap_last_cap)
+					break;
+				ret = prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, i + b * 32, 0, 0);
+				if (ret < 0) {
+					pr_perror("Unable to read ambient capability %d: %d", i + b * 32, ret);
+					goto bad;
+				}
+
+				amb_2[b] |= (ret << i);
+			}
+		}
+
+		for (b = 0; b < _LINUX_CAPABILITY_U32S_3; b++) {
+			if (amb[b] != amb_2[b]) {
+				res = '1';
+				goto bad;
+			}
+		}
+
+		res = '0';
+	bad:
+		write(result_pipe[1], &res, 1);
+
+		if (res != '0') {
+			write(result_pipe[1], amb, sizeof(amb));
+			write(result_pipe[1], amb_2, sizeof(amb_2));
+		}
+
+		close(result_pipe[0]);
+		close(result_pipe[1]);
+		_exit(0);
+	}
+
+	task_waiter_wait4(&t, pid);
+
+	test_daemon();
+	test_waitsig();
+
+	task_waiter_complete_current(&t);
+
+	read(result_pipe[0], &res, 1);
+
+	if (res == '0')
+		pass();
+	else {
+		read(result_pipe[0], amb, sizeof(amb));
+		read(result_pipe[0], amb_2, sizeof(amb_2));
+		test_msg("amb[]=%08x, %08x\n", amb[0], amb[1]);
+		test_msg("amb[]=%08x, %08x\n", amb_2[0], amb_2[1]);
+		fail("Fail: %c", res);
+	}
+	close(result_pipe[0]);
+	close(result_pipe[1]);
+
+	return 0;
+}

test/zdtm/static/caps01.desc

@@ -0,0 +1 @@
+{'flags': 'suid'}