mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-30 14:19:16 +00:00
1fde6f21d9
/proc entries under /proc/net/* can't be cached into dcache because
setns(2) can change current net namespace.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: avoid vim miscolorization]
[adobriyan@gmail.com: write test, add dummy ->d_revalidate hook: necessary if /proc/net/* is pinned at setns time]
Link: http://lkml.kernel.org/r/20190108192350.GA12034@avx2
Link: http://lkml.kernel.org/r/20190107162336.GA9239@avx2
Fixes: 1da4d377f9 ("proc: revalidate misc dentries")
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reported-by: Mateusz Stępień <mateusz.stepien@netrounds.com>
Reported-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
129 lines
2.6 KiB
C
129 lines
2.6 KiB
C
/*
|
|
* 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_NEWNET) points to new /proc/net content even
|
|
* if old one is in dcache.
|
|
*
|
|
* FIXME /proc/net/unix is under CONFIG_UNIX which can be disabled.
|
|
*/
|
|
#undef NDEBUG
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
#include <sched.h>
|
|
#include <signal.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <sys/types.h>
|
|
#include <sys/stat.h>
|
|
#include <fcntl.h>
|
|
#include <sys/socket.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_NEWNET) == -1) {
|
|
if (errno == ENOSYS || errno == EPERM) {
|
|
return 4;
|
|
}
|
|
return 1;
|
|
}
|
|
/* Distinguisher between two otherwise empty net namespaces. */
|
|
if (socket(AF_UNIX, SOCK_STREAM, 0) == -1) {
|
|
return 1;
|
|
}
|
|
|
|
if (pipe(fd) == -1) {
|
|
return 1;
|
|
}
|
|
|
|
pid = fork();
|
|
if (pid == -1) {
|
|
return 1;
|
|
}
|
|
|
|
if (pid == 0) {
|
|
if (unshare(CLONE_NEWNET) == -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/net", pid);
|
|
nsfd = open(buf, O_RDONLY);
|
|
if (nsfd == -1) {
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
/* Reliably pin dentry into dcache. */
|
|
(void)open("/proc/net/unix", O_RDONLY);
|
|
|
|
if (setns(nsfd, CLONE_NEWNET) == -1) {
|
|
return 1;
|
|
}
|
|
|
|
kill(pid, SIGTERM);
|
|
pid = 0;
|
|
|
|
{
|
|
char buf[4096];
|
|
ssize_t rv;
|
|
int fd;
|
|
|
|
fd = open("/proc/net/unix", O_RDONLY);
|
|
if (fd == -1) {
|
|
return 1;
|
|
}
|
|
|
|
#define S "Num RefCount Protocol Flags Type St Inode Path\n"
|
|
rv = read(fd, buf, sizeof(buf));
|
|
|
|
assert(rv == strlen(S));
|
|
assert(memcmp(buf, S, strlen(S)) == 0);
|
|
}
|
|
|
|
return 0;
|
|
}
|