[PATCH] Implement decoding of NS_* ioctl commands

Nikolay Marchuk marchuk.nikolay.a at gmail.com
Thu Apr 13 15:10:11 UTC 2017


* configure.ac (AC_CHECK_HEADERS): Add linux/nsfs.h.
* defs.h (DECL_IOCTL(nsfs)): New prototype.
(setns_types): Make global.
* ioctl.c (ioctl_decode): Call nsfs_ioctl for 0xb7 code.
* nsfs.c: New file.
* nsfs.h: Likewise.
* Makefile.am (strace_SOURCES): Add them.
* tests/ioctl_nsfs.c: New file.
* tests/ioctl_nsfs.test: Likewise.
* tests/.gitignore: Add ioctl_nsfs.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(DECODER_TESTS): Add ioctl_nsfs.test.
* NEWS: Mention this change.
---
 Makefile.am           |   2 +
 NEWS                  |   1 +
 configure.ac          |   1 +
 defs.h                |   2 +
 ioctl.c               |   2 +
 nsfs.c                |  65 +++++++++++++++++++++++
 nsfs.h                |  21 ++++++++
 tests/.gitignore      |   1 +
 tests/Makefile.am     |   2 +
 tests/ioctl_nsfs.c    | 140 ++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/ioctl_nsfs.test |  11 ++++
 11 files changed, 248 insertions(+)
 create mode 100644 nsfs.c
 create mode 100644 nsfs.h
 create mode 100644 tests/ioctl_nsfs.c
 create mode 100755 tests/ioctl_nsfs.test

diff --git a/Makefile.am b/Makefile.am
index 8af709b..7435e27 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -171,6 +171,8 @@ strace_SOURCES =	\
 	native_defs.h	\
 	net.c		\
 	netlink.c       \
+	nsfs.c          \
+	nsfs.h          \
 	nsig.h		\
 	numa.c		\
 	oldstat.c	\
diff --git a/NEWS b/NEWS
index 7bbd221..a150742 100644
--- a/NEWS
+++ b/NEWS
@@ -19,6 +19,7 @@ Noteworthy changes in release ?.?? (????-??-??)
     architectures.
   * Implemented decoding of statx syscall.
   * Updated lists of ioctl commands from Linux 4.11.
+  * Implemented decoding of NS_* ioctl commands.
 
 * Bug fixes
   * Fixed decoding of flags argument of preadv2 and pwritev2 syscalls on x32.
diff --git a/configure.ac b/configure.ac
index 9e5087b..dc49fdc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -366,6 +366,7 @@ AC_CHECK_HEADERS(m4_normalize([
 	linux/ipc.h
 	linux/mmtimer.h
 	linux/msg.h
+	linux/nsfs.h
 	linux/perf_event.h
 	linux/quota.h
 	linux/seccomp.h
diff --git a/defs.h b/defs.h
index 54f6417..9c0518d 100644
--- a/defs.h
+++ b/defs.h
@@ -301,6 +301,7 @@ extern const struct xlat netlink_protocols[];
 extern const struct xlat open_access_modes[];
 extern const struct xlat open_mode_flags[];
 extern const struct xlat resource_flags[];
+extern const struct xlat setns_types[];
 extern const struct xlat sg_io_info[];
 extern const struct xlat socketlayers[];
 extern const struct xlat whence_codes[];
@@ -642,6 +643,7 @@ name ## _ioctl(struct tcb *, unsigned int request, kernel_ulong_t arg)
 DECL_IOCTL(dm);
 DECL_IOCTL(file);
 DECL_IOCTL(fs_x);
+DECL_IOCTL(nsfs);
 DECL_IOCTL(ptp);
 DECL_IOCTL(scsi);
 DECL_IOCTL(term);
diff --git a/ioctl.c b/ioctl.c
index aa1880f..4511e0b 100644
--- a/ioctl.c
+++ b/ioctl.c
@@ -280,6 +280,8 @@ ioctl_decode(struct tcb *tcp)
 	case 0x94:
 		return btrfs_ioctl(tcp, code, arg);
 #endif
+	case 0xb7:
+		return nsfs_ioctl(tcp, code, arg);
 #ifdef HAVE_LINUX_DM_IOCTL_H
 	case 0xfd:
 		return dm_ioctl(tcp, code, arg);
diff --git a/nsfs.c b/nsfs.c
new file mode 100644
index 0000000..1048f9a
--- /dev/null
+++ b/nsfs.c
@@ -0,0 +1,65 @@
+/*
+ * Support for decoding of NS_* ioctl commands.
+ *
+ * Copyright (c) 2017 Nikolay Marchuk <marchuk.nikolay.a at gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "defs.h"
+#include "nsfs.h"
+
+int
+nsfs_ioctl(struct tcb *tcp, unsigned int code, kernel_ulong_t arg)
+{
+	unsigned int uid;
+	switch (code) {
+	case NS_GET_USERNS:
+	case NS_GET_PARENT:
+		return 1 + RVAL_FD + RVAL_DECODED;
+	case NS_GET_NSTYPE:
+		if (entering(tcp))
+			return 0;
+		if (!syserror(tcp)) {
+			const char *outstr;
+			outstr = xlookup(setns_types, tcp->u_rval);
+			if (outstr) {
+				tcp->auxstr = outstr;
+				return 1 + RVAL_STR;
+			}
+		}
+		return 1;
+	case NS_GET_OWNER_UID:
+		if (entering(tcp))
+			return 0;
+		tprints(", ");
+		if (!umove_or_printaddr(tcp, arg, &uid)) {
+			printuid("[", uid);
+			tprints("]");
+		}
+		return 1;
+	default:
+		return RVAL_DECODED;
+	}
+}
diff --git a/nsfs.h b/nsfs.h
new file mode 100644
index 0000000..3e17c53
--- /dev/null
+++ b/nsfs.h
@@ -0,0 +1,21 @@
+#ifndef STRACE_NSFS_H
+#define STRACE_NSFS_H
+
+#include <linux/ioctl.h>
+
+#ifdef HAVE_LINUX_NSFS_H
+# include <linux/nsfs.h>
+#else
+# define NSIO    0xb7
+# define NS_GET_USERNS   _IO(NSIO, 0x1)
+# define NS_GET_PARENT   _IO(NSIO, 0x2)
+#endif
+
+#ifndef NS_GET_NSTYPE
+# define NS_GET_NSTYPE    _IO(NSIO, 0x3)
+#endif
+#ifndef NS_GET_OWNER_UID
+# define NS_GET_OWNER_UID _IO(NSIO, 0x4)
+#endif
+
+#endif /* !STRACE_NSFS_H */
diff --git a/tests/.gitignore b/tests/.gitignore
index 1b03984..03b221e 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -124,6 +124,7 @@ ioctl_loop
 ioctl_loop-nv
 ioctl_loop-v
 ioctl_mtd
+ioctl_nsfs
 ioctl_rtc
 ioctl_rtc-v
 ioctl_scsi
diff --git a/tests/Makefile.am b/tests/Makefile.am
index ce75196..3533b59 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -188,6 +188,7 @@ check_PROGRAMS = \
 	ioctl_loop-nv \
 	ioctl_loop-v \
 	ioctl_mtd \
+	ioctl_nsfs \
 	ioctl_rtc \
 	ioctl_rtc-v \
 	ioctl_scsi \
@@ -507,6 +508,7 @@ DECODER_TESTS = \
 	ioctl_dm-v.test \
 	ioctl_dm.test \
 	ioctl_loop-nv.test \
+	ioctl_nsfs.test \
 	ioctl_sock_gifconf.test \
 	ipc_msgbuf.test \
 	llseek.test \
diff --git a/tests/ioctl_nsfs.c b/tests/ioctl_nsfs.c
new file mode 100644
index 0000000..112b8a9
--- /dev/null
+++ b/tests/ioctl_nsfs.c
@@ -0,0 +1,140 @@
+/*
+ * Check decoding of NS_* commands of ioctl syscall.
+ *
+ * Copyright (c) 2017 Nikolay Marchuk <marchuk.nikolay.a at gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "tests.h"
+
+#include <fcntl.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include "nsfs.h"
+
+#ifndef CLONE_NEWUSER
+# define CLONE_NEWUSER 0x10000000
+#endif
+
+static void
+test_no_namespace(void)
+{
+	ioctl(-1, NS_GET_USERNS);
+	printf("ioctl(-1, NS_GET_USERNS) = -1 EBADF (%m)\n");
+	ioctl(-1, NS_GET_PARENT);
+	printf("ioctl(-1, NS_GET_PARENT) = -1 EBADF (%m)\n");
+	ioctl(-1, NS_GET_NSTYPE);
+	printf("ioctl(-1, NS_GET_NSTYPE) = -1 EBADF (%m)\n");
+	ioctl(-1, NS_GET_OWNER_UID, NULL);
+	printf("ioctl(-1, NS_GET_OWNER_UID, NULL) = -1 EBADF (%m)\n");
+}
+
+static void
+test_clone(pid_t pid)
+{
+	char path[sizeof("/proc/%d/ns/user") + sizeof(int)*3];
+	snprintf(path, sizeof(path), "/proc/%d/ns/user", pid);
+
+	int ns_fd = open(path, O_RDONLY);
+	if (ns_fd == -1)
+		perror_msg_and_skip("open: %s", path);
+
+	int userns_fd = ioctl(ns_fd, NS_GET_USERNS);
+	printf("ioctl(%d, NS_GET_USERNS) = %s\n", ns_fd, sprintrc(userns_fd));
+
+	int parent_ns_fd = ioctl(userns_fd, NS_GET_PARENT);
+	printf("ioctl(%d, NS_GET_PARENT) = %s\n",
+	       userns_fd, sprintrc(parent_ns_fd));
+
+	int nstype = ioctl(userns_fd, NS_GET_NSTYPE);
+	if (nstype == -1) {
+		printf("ioctl(%d, NS_GET_NSTYPE) = %s\n",
+		       userns_fd, sprintrc(nstype));
+	} else {
+		printf("ioctl(%d, NS_GET_NSTYPE) = %d (CLONE_NEWUSER)\n",
+		       userns_fd, nstype);
+	}
+
+	TAIL_ALLOC_OBJECT_CONST_PTR(unsigned int, uid);
+	int rc = ioctl(userns_fd, NS_GET_OWNER_UID, uid);
+	if (rc == -1) {
+		printf("ioctl(%d, NS_GET_OWNER_UID, %p) = %s\n",
+		       userns_fd, uid, sprintrc(rc));
+	} else {
+		printf("ioctl(%d, NS_GET_OWNER_UID, [%u]) = %d\n",
+		       userns_fd, *uid, rc);
+	}
+}
+
+static int
+child(void *arg)
+{
+	int *pipefd = (int *) arg;
+	close(pipefd[1]);
+	/* Wait for EOF from pipe. */
+	if (read(pipefd[0], &pipefd[1], 1))
+		perror_msg_and_fail("read");
+	return 0;
+}
+
+static void
+test_user_namespace(void)
+{
+	pid_t pid;
+	int pipefd[2];
+	int rc, status;
+
+	rc = pipe(pipefd);
+	if (rc == -1)
+		perror_msg_and_fail("pipe");
+
+	pid = clone(child, tail_alloc(1) + 1,
+	            CLONE_NEWUSER | CLONE_UNTRACED | SIGCHLD, pipefd);
+	if (pid == -1) {
+		perror("clone");
+		return;
+	}
+	close(pipefd[0]);
+	test_clone(pid);
+	close(pipefd[1]);
+	if (wait(&status) != pid) {
+		perror_msg_and_fail("wait");
+	} else if (status != 0){
+		error_msg_and_fail("unexpected child exit status %d", status);
+	}
+}
+
+int
+main(void)
+{
+	test_no_namespace();
+	test_user_namespace();
+	puts("+++ exited with 0 +++");
+	return 0;
+}
diff --git a/tests/ioctl_nsfs.test b/tests/ioctl_nsfs.test
new file mode 100755
index 0000000..acdfb61
--- /dev/null
+++ b/tests/ioctl_nsfs.test
@@ -0,0 +1,11 @@
+#!/bin/sh
+
+# Check decoding of NS_* ioctls.
+
+. "${srcdir=.}/init.sh"
+
+check_prog grep
+run_prog > /dev/null
+run_strace -a16 -eioctl -esignal=none $args > "$EXP"
+grep -v '^ioctl([012],' < "$LOG" > "$OUT"
+match_diff "$OUT" "$EXP"
-- 
2.1.4





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