proc: test /proc/sysvipc vs setns(CLONE_NEWIPC)

I thought that /proc/sysvipc has the same bug as /proc/net

	commit 1fde6f21d90f8ba5da3cb9c54ca991ed72696c43
	proc: fix /proc/net/* after setns(2)

However, it doesn't! /proc/sysvipc files do

	get_ipc_ns(current->nsproxy->ipc_ns);

in their open() hook and avoid the problem.

Keep the test, maybe /proc/sysvipc will become broken someday :-\

Link: http://lkml.kernel.org/r/20190706180146.GA21015@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/tools/testing/selftests/proc/.gitignore b/tools/testing/selftests/proc/.gitignore
index 444ad39d370053b008bdb3117c2ebc4a86ed2f67..66fab4c58ed4b70cb953792cf0ecd57c83e44d2a 100644 (file)
--- a/tools/testing/selftests/proc/.gitignore
+++ b/tools/testing/selftests/proc/.gitignore
@@ -12,4 +12,5 @@
 /read
 /self
 /setns-dcache
+/setns-sysvipc
 /thread-self

diff --git a/tools/testing/selftests/proc/Makefile b/tools/testing/selftests/proc/Makefile
index 9f09fcd09ea37dd71daae2efd8f5a25eb6c9d376..a8ed0f684829269c0d4ed0b8996f82a0445f21a9 100644 (file)
--- a/tools/testing/selftests/proc/Makefile
+++ b/tools/testing/selftests/proc/Makefile
@@ -17,6 +17,7 @@ TEST_GEN_PROGS += proc-uptime-002
 TEST_GEN_PROGS += read
 TEST_GEN_PROGS += self
 TEST_GEN_PROGS += setns-dcache
+TEST_GEN_PROGS += setns-sysvipc
 TEST_GEN_PROGS += thread-self
 
 include ../lib.mk

diff --git a/tools/testing/selftests/proc/setns-sysvipc.c b/tools/testing/selftests/proc/setns-sysvipc.c
new file mode 100644 (file)
index 0000000..903890c
--- /dev/null
+++ b/tools/testing/selftests/proc/setns-sysvipc.c
@@ -0,0 +1,133 @@
+/*
+ * Copyright © 2019 Alexey Dobriyan <adobriyan@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/*
+ * Test that setns(CLONE_NEWIPC) points to new /proc/sysvipc content even
+ * if old one is in dcache.
+ */
+#undef NDEBUG
+#include <assert.h>
+#include <errno.h>
+#include <stdio.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+
+static pid_t pid = -1;
+
+static void f(void)
+{
+       if (pid > 0) {
+               kill(pid, SIGTERM);
+       }
+}
+
+int main(void)
+{
+       int fd[2];
+       char _ = 0;
+       int nsfd;
+
+       atexit(f);
+
+       /* Check for priviledges and syscall availability straight away. */
+       if (unshare(CLONE_NEWIPC) == -1) {
+               if (errno == ENOSYS || errno == EPERM) {
+                       return 4;
+               }
+               return 1;
+       }
+       /* Distinguisher between two otherwise empty IPC namespaces. */
+       if (shmget(IPC_PRIVATE, 1, IPC_CREAT) == -1) {
+               return 1;
+       }
+
+       if (pipe(fd) == -1) {
+               return 1;
+       }
+
+       pid = fork();
+       if (pid == -1) {
+               return 1;
+       }
+
+       if (pid == 0) {
+               if (unshare(CLONE_NEWIPC) == -1) {
+                       return 1;
+               }
+
+               if (write(fd[1], &_, 1) != 1) {
+                       return 1;
+               }
+
+               pause();
+
+               return 0;
+       }
+
+       if (read(fd[0], &_, 1) != 1) {
+               return 1;
+       }
+
+       {
+               char buf[64];
+               snprintf(buf, sizeof(buf), "/proc/%u/ns/ipc", pid);
+               nsfd = open(buf, O_RDONLY);
+               if (nsfd == -1) {
+                       return 1;
+               }
+       }
+
+       /* Reliably pin dentry into dcache. */
+       (void)open("/proc/sysvipc/shm", O_RDONLY);
+
+       if (setns(nsfd, CLONE_NEWIPC) == -1) {
+               return 1;
+       }
+
+       kill(pid, SIGTERM);
+       pid = 0;
+
+       {
+               char buf[4096];
+               ssize_t rv;
+               int fd;
+
+               fd = open("/proc/sysvipc/shm", O_RDONLY);
+               if (fd == -1) {
+                       return 1;
+               }
+
+#define S32 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n"
+#define S64 "       key      shmid perms                  size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime                   rss                  swap\n"
+               rv = read(fd, buf, sizeof(buf));
+               if (rv == strlen(S32)) {
+                       assert(memcmp(buf, S32, strlen(S32)) == 0);
+               } else if (rv == strlen(S64)) {
+                       assert(memcmp(buf, S64, strlen(S64)) == 0);
+               } else {
+                       assert(0);
+               }
+       }
+
+       return 0;
+}