[LTP] [PATCH] syscalls/prctl04.c: New test for prctl() with PR_{SET, GET}_SECCOMP

* [LTP] [PATCH] syscalls/prctl04.c: New test for prctl() with PR_{SET, GET}_SECCOMP
@ 2019-05-06 11:14 Yang Xu
  2019-05-20 13:04 ` Cyril Hrubis
  0 siblings, 1 reply; 7+ messages in thread
From: Yang Xu @ 2019-05-06 11:14 UTC (permalink / raw)
  To: ltp

Signed-off-by: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
---
 configure.ac                               |   1 +
 include/lapi/prctl.h                       |   5 +
 include/lapi/seccomp.h                     |  36 +++
 runtest/syscalls                           |   1 +
 testcases/kernel/syscalls/prctl/.gitignore |   1 +
 testcases/kernel/syscalls/prctl/prctl04.c  | 262 +++++++++++++++++++++
 6 files changed, 306 insertions(+)
 create mode 100644 include/lapi/seccomp.h
 create mode 100644 testcases/kernel/syscalls/prctl/prctl04.c

diff --git a/configure.ac b/configure.ac
index fad8f8396..c858aff42 100644
--- a/configure.ac
+++ b/configure.ac
@@ -46,6 +46,7 @@ AC_CHECK_HEADERS([ \
     linux/mempolicy.h \
     linux/module.h \
     linux/netlink.h \
+    linux/seccomp.h \
     linux/userfaultfd.h \
     mm.h \
     netinet/sctp.h \
diff --git a/include/lapi/prctl.h b/include/lapi/prctl.h
index 6db8a6480..c3612e643 100644
--- a/include/lapi/prctl.h
+++ b/include/lapi/prctl.h
@@ -14,4 +14,9 @@
 # define PR_GET_CHILD_SUBREAPER	37
 #endif
 
+#ifndef PR_SET_SECCOMP
+# define PR_GET_SECCOMP  21
+# define PR_SET_SECCOMP  22
+#endif
+
 #endif /* LAPI_PRCTL_H__ */
diff --git a/include/lapi/seccomp.h b/include/lapi/seccomp.h
new file mode 100644
index 000000000..1e5bc3933
--- /dev/null
+++ b/include/lapi/seccomp.h
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019 FUJITSU LIMITED. All rights reserved.
+ * Author: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
+ */
+#ifndef LAPI_SECCOMP_H__
+# define _LAPI_SECCOMP_H
+
+#include <linux/types.h>
+
+/* Valid values for seccomp.mode and prctl(PR_SET_SECCOMP, <mode>) */
+#define SECCOMP_MODE_DISABLED   0
+#define SECCOMP_MODE_STRICT     1
+#define SECCOMP_MODE_FILTER     2
+
+#define SECCOMP_RET_KILL_THREAD  0x00000000U /* kill the thread */
+#define SECCOMP_RET_KILL         SECCOMP_RET_KILL_THREAD
+#define SECCOMP_RET_ALLOW        0x7fff0000U /* allow */
+
+/**
+ * struct seccomp_data - the format the BPF program executes over.
+ * @nr: the system call number
+ * @arch: indicates system call convention as an AUDIT_ARCH_* value
+ *        as defined in <linux/audit.h>.
+ * @instruction_pointer: at the time of the system call.
+ * @args: up to 6 system call arguments always stored as 64-bit values
+ * regardless of the architecture.
+ */
+struct seccomp_data {
+	int nr;
+	__u32 arch;
+	__u64 instruction_pointer;
+	__u64 args[6];
+};
+
+#endif /* _LAPI_SECCOMP_H */
diff --git a/runtest/syscalls b/runtest/syscalls
index 2b8ca719b..51bff2990 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -863,6 +863,7 @@ ppoll01 ppoll01
 prctl01 prctl01
 prctl02 prctl02
 prctl03 prctl03
+prctl04 prctl04
 
 pread01 pread01
 pread01_64 pread01_64
diff --git a/testcases/kernel/syscalls/prctl/.gitignore b/testcases/kernel/syscalls/prctl/.gitignore
index 2f46a9a12..1c3da3052 100644
--- a/testcases/kernel/syscalls/prctl/.gitignore
+++ b/testcases/kernel/syscalls/prctl/.gitignore
@@ -1,3 +1,4 @@
 /prctl01
 /prctl02
 /prctl03
+/prctl04
diff --git a/testcases/kernel/syscalls/prctl/prctl04.c b/testcases/kernel/syscalls/prctl/prctl04.c
new file mode 100644
index 000000000..e3ba69af3
--- /dev/null
+++ b/testcases/kernel/syscalls/prctl/prctl04.c
@@ -0,0 +1,262 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2019 FUJITSU LIMITED. All rights reserved.
+ * Author: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
+ *
+ * Test PR_GET_SECCOMP and PR_SET_SECCOMP of prctl(2).
+ * 1) If PR_SET_SECCOMP sets the SECCOMP_MODE_STRICT for the calling thread,
+ *    the only system call that the thread is permitted to make are read(2),
+ *    write(2),_exit(2)(but not exit_group(2)), and sigreturn(2).  Other
+ *    system calls result in the delivery of a SIGKILL signal. This operation
+ *    is available only if the kernel is configured with CONFIG_SECCOMP enabled.
+ * 2) If PR_SET_SECCOMP sets the SECCOMP_MODE_FILTER for the calling thread,
+ *    the system calls allowed are defined by a pointer to a Berkeley Packet
+ *    Filter. Other system calls result int the delivery of a SIGSYS signal
+ *    with SECCOMP_RET_KILL. The SECCOMP_SET_MODE_FILTER operation is available
+ *    only if the kernel is configured with CONFIG_SECCOMP_FILTER enabled.
+ * 3) If SECCOMP_MODE_FILTER filters permit fork(2), then the seccomp mode
+ *    is inherited by children created by fork(2).
+ */
+
+#include <errno.h>
+#include <signal.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+#include <linux/filter.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include "tst_test.h"
+#include "lapi/syscalls.h"
+#include "lapi/prctl.h"
+#include "config.h"
+#ifdef HAVE_LINUX_SECCOMP_H
+#include <linux/seccomp.h>
+#else
+#include <lapi/seccomp.h>
+#endif
+
+#define FNAME "filename"
+
+static const struct sock_filter  strict_filter[] = {
+	BPF_STMT(BPF_LD | BPF_W | BPF_ABS, (offsetof (struct seccomp_data, nr))),
+
+	BPF_JUMP(BPF_JMP | BPF_JEQ, __NR_close, 5, 0),
+	BPF_JUMP(BPF_JMP | BPF_JEQ, __NR_exit,  4, 0),
+	BPF_JUMP(BPF_JMP | BPF_JEQ, __NR_wait4, 3, 0),
+	BPF_JUMP(BPF_JMP | BPF_JEQ, __NR_write, 2, 0),
+	BPF_JUMP(BPF_JMP | BPF_JEQ, __NR_clone, 1, 0),
+
+	BPF_STMT(BPF_RET | BPF_K, SECCOMP_RET_KILL),
+	BPF_STMT(BPF_RET | BPF_K, SECCOMP_RET_ALLOW)
+};
+
+static const struct sock_fprog  strict = {
+	.len = (unsigned short)ARRAY_SIZE(strict_filter),
+	.filter = (struct sock_filter *)strict_filter
+};
+
+static void check_strict_mode(int val)
+{
+	int fd;
+	char buf[2];
+
+	fd = SAFE_OPEN(FNAME, O_RDWR | O_CREAT, 0666);
+
+	TEST(prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT));
+	if (TST_RET == -1) {
+		if (TST_ERR == EINVAL) {
+			tst_res(TCONF,
+				"prctl(PR_SET_SECCOMP) doesn't support "
+				"SECCOMP_MODE_STRICT");
+		} else {
+			tst_res(TFAIL | TTERRNO,
+				"prctl(PR_SET_SECCOMP) sets "
+				"SECCOMP_MODE_STRICT failed");
+		}
+		return;
+	}
+	if (val == 1) {
+		tst_res(TPASS,
+			"prctl(PR_SET_SECCOMP) sets SECCOMP_MODE_STRICT "
+			"succeed");
+		prctl(PR_GET_SECCOMP);
+		tst_res(TFAIL, "prctl(PR_GET_SECCOMP) succeed unexpectedly");
+	}
+	if (val == 2) {
+		SAFE_WRITE(1, fd, "a", 1);
+		SAFE_READ(0, fd, buf, 1);
+		tst_res(TPASS,
+			"SECCOMP_MODE_STRICT permits read(2) write(2) "
+			"and _exit(2)");
+	}
+	if (val == 3) {
+		close(fd);
+		tst_res(TFAIL,
+			"SECCOMP_MODE_STRICT permits close(2) unexpectdly");
+	}
+
+	tst_syscall(__NR_exit, 0);
+}
+
+static void check_filter_mode(int val)
+{
+	int childpid;
+	int childstatus;
+	int fd;
+
+	fd = SAFE_OPEN(FNAME, O_RDWR | O_CREAT, 0666);
+
+	TEST(prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &strict));
+	if (TST_RET == -1) {
+		if (TST_ERR == EFAULT)
+			tst_res(TFAIL, "the strict prog is an invalid address");
+		else
+			tst_res(TFAIL | TERRNO,
+				"prctl(PR_SET_SECCOMP) sets strict filter "
+				"failed");
+		return;
+	}
+	if (val == 1) {
+		tst_res(TPASS,
+			"prctl(PR_SET_SECCOMP) sets strict filter succeed");
+		prctl(PR_GET_SECCOMP);
+		tst_res(TFAIL, "prctl(PR_GET_SECCOMP) succeed unexpectedly");
+	}
+	if (val == 2) {
+		close(fd);
+		tst_res(TPASS, "SECCOMP_MODE_FILTER permits close(2)");
+	}
+	if (val == 3)
+		exit(0);
+	if (val == 4) {
+		childpid = fork();
+		if (childpid == 0) {
+			tst_res(TPASS, "SECCOMP_MODE_FILTER permits fork(2)");
+			exit(0);
+		} else {
+			wait4(childpid, &childstatus, 0, NULL);
+			if (WIFSIGNALED(childstatus) &&
+					WTERMSIG(childstatus) == SIGSYS)
+				tst_res(TPASS,
+					"SECCOMP_MODE_FILTER has been "
+					"inherited by child");
+			else
+				tst_res(TFAIL,
+					"SECCOMP_MODE_FILTER isn't been "
+					"inherited by child");
+		}
+	}
+	tst_syscall(__NR_exit, 0);
+}
+
+static void verify_prctl(void)
+{
+	int pid;
+	int status;
+
+	TEST(prctl(PR_GET_SECCOMP));
+	if (TST_RET == -1) {
+		if (TST_ERR == EINVAL) {
+			tst_res(TCONF,
+				"prctl() doesn't support PR_GET_SECCOMP");
+		} else {
+			tst_res(TFAIL | TTERRNO,
+				"prctl(PR_GET_SECCOMP) failed");
+		}
+		return;
+	}
+	tst_res(TPASS, "prctl(PR_GET_SECCOMP) succeed");
+
+	/*call get_seccomp when in stric mode ,it should be killed*/
+	pid = SAFE_FORK();
+	if (pid == 0) {
+		check_strict_mode(1);
+	} else {
+		SAFE_WAITPID(pid, &status, 0);
+		if (WIFSIGNALED(status) && WTERMSIG(status) == SIGKILL)
+			tst_res(TPASS,
+				"SECCOMP_MODE_STRICT doesn't permit "
+				"GET_SECCOMP call");
+	}
+
+	/*positive check in secure computing mode*/
+	pid = SAFE_FORK();
+	if (pid == 0) {
+		check_strict_mode(2);
+	} else {
+		SAFE_WAITPID(pid, &status, 0);
+		if (WIFSIGNALED(status) && WTERMSIG(status) == SIGKILL)
+			tst_res(TFAIL,
+				"SECCOMP_MODE_STRICT doesn't permit "
+				"read(2) write(2) and _exit(2)");
+	}
+
+	/*negative check in secure computing mode*/
+	pid = SAFE_FORK();
+	if (pid == 0) {
+		check_strict_mode(3);
+	} else {
+		SAFE_WAITPID(pid, &status, 0);
+		if (WIFSIGNALED(status) && WTERMSIG(status) == SIGKILL)
+			tst_res(TPASS,
+				"SECCOMP_MODE_STRICT doesn't permit close(2)");
+	}
+
+	/*call get_seccomp in filter mode should be killed by SIGSYS signal*/
+	pid = SAFE_FORK();
+	if (pid == 0) {
+		check_filter_mode(1);
+	} else {
+		SAFE_WAITPID(pid, &status, 0);
+		if (WIFSIGNALED(status) && WTERMSIG(status) == SIGSYS)
+			tst_res(TPASS,
+				"SECCOMP_MODE_FILTER doestn't permit "
+				"GET_SECCOMP call");
+	}
+
+	/*positive check in SECCOMP_MODE_FILTER*/
+	pid = SAFE_FORK();
+	if (pid == 0) {
+		check_filter_mode(2);
+	} else {
+		SAFE_WAITPID(pid, &status, 0);
+		if (WIFSIGNALED(status) && WTERMSIG(status) == SIGSYS)
+			tst_res(TFAIL,
+				"SECCOMP_MODE_FILTER doesn't permit close(2)");
+	}
+
+	/*negative check in SECCOMP_MODE_FILTER*/
+	pid = SAFE_FORK();
+	if (pid == 0) {
+		check_filter_mode(3);
+	} else {
+		SAFE_WAITPID(pid, &status, 0);
+		if (WIFSIGNALED(status) && WTERMSIG(status) == SIGSYS)
+			tst_res(TPASS,
+				"SECCOMP_MODE_FILTER doesn't permit exit()");
+		else
+			tst_res(TFAIL,
+				"SECCOMP_MODE_FILTER permits exit() "
+				"unexpectdly");
+	}
+
+	pid = SAFE_FORK();
+	if (pid == 0) {
+		check_filter_mode(4);
+	} else {
+		SAFE_WAITPID(pid, &status, 0);
+		if (WIFSIGNALED(status) && WTERMSIG(status) == SIGSYS)
+			tst_res(TFAIL,
+				"SECCOMP_MODE_FILTER fork failed "
+				"unexpectdly");
+	}
+}
+
+static struct tst_test test = {
+	.test_all = verify_prctl,
+	.forks_child = 1,
+	.needs_tmpdir = 1,
+	.needs_root = 1,
+};
-- 
2.18.1




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