* [PATCH 0/3 v3] fs: allow to use dirfd as root for openat and other *at syscalls
@ 2016-07-20 20:42 Andrey Vagin
2016-07-20 20:42 ` [PATCH 1/3 v2] namei: add LOOKUP_DFD_ROOT to use dfd as root Andrey Vagin
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Andrey Vagin @ 2016-07-20 20:42 UTC (permalink / raw)
To: linux-fsdevel, Alexander Viro
Cc: linux-kernel, linux-api, containers, criu, Andrey Vagin,
Eric W. Biederman, Arnd Bergmann, J. Bruce Fields,
Miklos Szeredi, NeilBrown, Shuah Khan, Omar Sandoval
The problem is that a pathname can contain absolute symlinks and now
they are resolved relative to the current root.
It may be a problem if you want to open a file in another namespace.
For example, you open /proc/PID/root for a process from the target
namespace and then you use openat() to open a file from this namespace.
If a path to the file contains an absolute symlink, you will open a file
from the current namespace, because a symlink will be resolved relative
to the current root.
A proposed solution adds a new flag which means that dirfd should be
set as a root for a current system call (openat(), statat(), etc).
Here are examples how we can open a file in a contex of another process.
How we can do this without these changes:
old_root = open("/", O_PATH);
old_cwd = open(".", O_PATH);
chroot("/proc/PID/root");
fd = open(pathname, O_RDONLY);
fchdir(old_root); /* emulate fchroot() */
chroot(".");
fchdir(old_cwd);
close(old_cwd);
close(old_root);
How this code is simplified with new flags:
dirfd = open("/proc/PID/root", O_PATH);
fd = open(dirfd, pathname, O_RDONLY | O_ATROOT);
close(dirfd);
One more thing is that chroot isn't available for unprivileged users.
We met this problem, when we tryed to dump an ubuntu container and
failed to resolve /proc/PID/root/var/run/mysqld/mysqld.sock, because
/var/run was a symlink to /run.
Changes since the first version:
- change a value of O_ATROOT to not intersect with other constants.
Changes since the second version:
- initialize nd->root_seq (thanks to Omar Sandoval for reporting and
fixing this issue)
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "J. Bruce Fields" <bfields@redhat.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Andrey Vagin (3):
namei: add LOOKUP_DFD_ROOT to use dfd as root
fs: allow to use dirfd as root for openat and other *at syscalls
selftests: check O_ATROOT and AT_FDROOT flags
fs/exec.c | 4 +-
fs/namei.c | 42 +++++++++++----
fs/open.c | 6 ++-
fs/stat.c | 4 +-
fs/utimes.c | 4 +-
include/linux/namei.h | 2 +
include/uapi/asm-generic/fcntl.h | 4 ++
include/uapi/linux/fcntl.h | 1 +
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/lookup/.gitignore | 1 +
tools/testing/selftests/lookup/Makefile | 8 +++
tools/testing/selftests/lookup/lookup_at_root.c | 71 +++++++++++++++++++++++++
tools/testing/selftests/lookup/run.sh | 14 +++++
13 files changed, 148 insertions(+), 14 deletions(-)
create mode 100644 tools/testing/selftests/lookup/.gitignore
create mode 100644 tools/testing/selftests/lookup/Makefile
create mode 100644 tools/testing/selftests/lookup/lookup_at_root.c
create mode 100755 tools/testing/selftests/lookup/run.sh
--
2.5.5
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH 1/3 v2] namei: add LOOKUP_DFD_ROOT to use dfd as root
2016-07-20 20:42 [PATCH 0/3 v3] fs: allow to use dirfd as root for openat and other *at syscalls Andrey Vagin
@ 2016-07-20 20:42 ` Andrey Vagin
2016-07-20 20:42 ` [PATCH 2/3 v2] fs: allow to use dirfd as root for openat and other *at syscalls Andrey Vagin
2016-07-20 20:42 ` [PATCH 3/3] selftests: check O_ATROOT and AT_FDROOT flags Andrey Vagin
2 siblings, 0 replies; 4+ messages in thread
From: Andrey Vagin @ 2016-07-20 20:42 UTC (permalink / raw)
To: linux-fsdevel, Alexander Viro
Cc: linux-kernel, linux-api, containers, criu, Andrey Vagin,
Eric W. Biederman, Arnd Bergmann, J. Bruce Fields,
Miklos Szeredi, NeilBrown, Shuah Khan, Omar Sandoval
The problem is that a pathname can contain absolute symlinks and now
they are resolved relative to the current root.
If we want to open a file in another mount namespaces and we have a file
descriptor to its root directory, we probably want to resolve pathname
in the target mount namespace. For this we add this new flag.
If LOOKUP_DFD_ROOT is set, path_init() initializes nd->root and nd->path
to the same value.
Changes since v1:
* initialize nd->root_seq (thanks to Omar Sandoval for reporting and
fixing this issue)
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
---
fs/namei.c | 16 +++++++++++++++-
include/linux/namei.h | 2 ++
2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/fs/namei.c b/fs/namei.c
index 28cb1cd..17548b1 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2141,7 +2141,7 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
nd->path.dentry = NULL;
nd->m_seq = read_seqbegin(&mount_lock);
- if (*s == '/') {
+ if (*s == '/' && !(flags & LOOKUP_DFD_ROOT)) {
if (flags & LOOKUP_RCU)
rcu_read_lock();
set_root(nd);
@@ -2167,6 +2167,13 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
get_fs_pwd(current->fs, &nd->path);
nd->inode = nd->path.dentry->d_inode;
}
+ if (flags & LOOKUP_DFD_ROOT) {
+ nd->root = nd->path;
+ if (flags & LOOKUP_RCU)
+ nd->root_seq = nd->seq;
+ else
+ path_get(&nd->root);
+ }
return s;
} else {
/* Caller must check execute permissions on the starting path component */
@@ -2195,6 +2202,13 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
nd->inode = nd->path.dentry->d_inode;
}
fdput(f);
+ if (flags & LOOKUP_DFD_ROOT) {
+ nd->root = nd->path;
+ if (flags & LOOKUP_RCU)
+ nd->root_seq = nd->seq;
+ else
+ path_get(&nd->root);
+ }
return s;
}
}
diff --git a/include/linux/namei.h b/include/linux/namei.h
index ec5ec28..59ca78c 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -45,6 +45,8 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
#define LOOKUP_ROOT 0x2000
#define LOOKUP_EMPTY 0x4000
+#define LOOKUP_DFD_ROOT 0x8000
+
extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
static inline int user_path_at(int dfd, const char __user *name, unsigned flags,
--
2.5.5
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 2/3 v2] fs: allow to use dirfd as root for openat and other *at syscalls
2016-07-20 20:42 [PATCH 0/3 v3] fs: allow to use dirfd as root for openat and other *at syscalls Andrey Vagin
2016-07-20 20:42 ` [PATCH 1/3 v2] namei: add LOOKUP_DFD_ROOT to use dfd as root Andrey Vagin
@ 2016-07-20 20:42 ` Andrey Vagin
2016-07-20 20:42 ` [PATCH 3/3] selftests: check O_ATROOT and AT_FDROOT flags Andrey Vagin
2 siblings, 0 replies; 4+ messages in thread
From: Andrey Vagin @ 2016-07-20 20:42 UTC (permalink / raw)
To: linux-fsdevel, Alexander Viro
Cc: linux-kernel, linux-api, containers, criu, Andrey Vagin,
Eric W. Biederman, Arnd Bergmann, J. Bruce Fields,
Miklos Szeredi, NeilBrown, Shuah Khan, Omar Sandoval
The problem is that a pathname can contain absolute symlinks and now
they are resolved relative to the current root.
But if we want to open a file in another mount namespace and we have
a file descriptor to its root directory, we want that the pathname is
resolved in the target mount namespace and in this case we need these
new flags O_ATROOT or AT_FDROOT.
If O_ATROOT is set for openat() or AT_FDROOT is set for fstatat, linkat,
unlinkat, path_init is executed with the LOOKUP_DFD_ROOT flag.
v2: fix a value of O_ATROOT to not intersect with other constans
Signed-off-by: Andrey Vagin <avagin@openvz.org>
---
fs/exec.c | 4 +++-
fs/namei.c | 26 +++++++++++++++++---------
fs/open.c | 6 +++++-
fs/stat.c | 4 +++-
fs/utimes.c | 4 +++-
include/uapi/asm-generic/fcntl.h | 4 ++++
include/uapi/linux/fcntl.h | 1 +
7 files changed, 36 insertions(+), 13 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index 887c1c9..473b709 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -775,12 +775,14 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags)
.lookup_flags = LOOKUP_FOLLOW,
};
- if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
+ if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH | AT_FDROOT)) != 0)
return ERR_PTR(-EINVAL);
if (flags & AT_SYMLINK_NOFOLLOW)
open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW;
if (flags & AT_EMPTY_PATH)
open_exec_flags.lookup_flags |= LOOKUP_EMPTY;
+ if (flags & AT_FDROOT)
+ open_exec_flags.lookup_flags |= LOOKUP_DFD_ROOT;
file = do_filp_open(fd, name, &open_exec_flags);
if (IS_ERR(file))
diff --git a/fs/namei.c b/fs/namei.c
index 17548b1..068c2d2 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2550,7 +2550,8 @@ user_path_parent(int dfd, const char __user *path,
unsigned int flags)
{
/* only LOOKUP_REVAL is allowed in extra flags */
- return filename_parentat(dfd, getname(path), flags & LOOKUP_REVAL,
+ return filename_parentat(dfd, getname(path),
+ flags & (LOOKUP_REVAL | LOOKUP_DFD_ROOT),
parent, last, type);
}
@@ -3546,7 +3547,7 @@ static struct dentry *filename_create(int dfd, struct filename *name,
* Note that only LOOKUP_REVAL and LOOKUP_DIRECTORY matter here. Any
* other flags passed in are ignored!
*/
- lookup_flags &= LOOKUP_REVAL;
+ lookup_flags &= LOOKUP_REVAL | LOOKUP_DFD_ROOT;
name = filename_parentat(dfd, name, lookup_flags, path, &last, &type);
if (IS_ERR(name))
@@ -3944,7 +3945,8 @@ EXPORT_SYMBOL(vfs_unlink);
* writeout happening, and we don't want to prevent access to the directory
* while waiting on the I/O.
*/
-static long do_unlinkat(int dfd, const char __user *pathname)
+static long do_unlinkat(int dfd, const char __user *pathname,
+ unsigned int lookup_flags)
{
int error;
struct filename *name;
@@ -3954,7 +3956,6 @@ static long do_unlinkat(int dfd, const char __user *pathname)
int type;
struct inode *inode = NULL;
struct inode *delegated_inode = NULL;
- unsigned int lookup_flags = 0;
retry:
name = user_path_parent(dfd, pathname,
&path, &last, &type, lookup_flags);
@@ -4019,18 +4020,23 @@ slashes:
SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag)
{
- if ((flag & ~AT_REMOVEDIR) != 0)
+ unsigned int lookup_flags = 0;
+
+ if ((flag & ~(AT_REMOVEDIR | AT_FDROOT)) != 0)
return -EINVAL;
if (flag & AT_REMOVEDIR)
return do_rmdir(dfd, pathname);
- return do_unlinkat(dfd, pathname);
+ if (flag & AT_FDROOT)
+ lookup_flags |= LOOKUP_DFD_ROOT;
+
+ return do_unlinkat(dfd, pathname, lookup_flags);
}
SYSCALL_DEFINE1(unlink, const char __user *, pathname)
{
- return do_unlinkat(AT_FDCWD, pathname);
+ return do_unlinkat(AT_FDCWD, pathname, 0);
}
int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
@@ -4181,7 +4187,7 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
int how = 0;
int error;
- if ((flags & ~(AT_SYMLINK_FOLLOW | AT_EMPTY_PATH)) != 0)
+ if ((flags & ~(AT_SYMLINK_FOLLOW | AT_EMPTY_PATH | AT_FDROOT)) != 0)
return -EINVAL;
/*
* To use null names we require CAP_DAC_READ_SEARCH
@@ -4196,13 +4202,15 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
if (flags & AT_SYMLINK_FOLLOW)
how |= LOOKUP_FOLLOW;
+ if (flags & AT_FDROOT)
+ how |= LOOKUP_DFD_ROOT;
retry:
error = user_path_at(olddfd, oldname, how, &old_path);
if (error)
return error;
new_dentry = user_path_create(newdfd, newname, &new_path,
- (how & LOOKUP_REVAL));
+ (how & (LOOKUP_REVAL | LOOKUP_DFD_ROOT)));
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry))
goto out;
diff --git a/fs/open.c b/fs/open.c
index 93ae3cd..e0bc8d0 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -613,12 +613,14 @@ SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
int error = -EINVAL;
int lookup_flags;
- if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
+ if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH | AT_FDROOT)) != 0)
goto out;
lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
if (flag & AT_EMPTY_PATH)
lookup_flags |= LOOKUP_EMPTY;
+ if (flag & AT_FDROOT)
+ lookup_flags |= LOOKUP_DFD_ROOT;
retry:
error = user_path_at(dfd, filename, lookup_flags, &path);
if (error)
@@ -941,6 +943,8 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
lookup_flags |= LOOKUP_DIRECTORY;
if (!(flags & O_NOFOLLOW))
lookup_flags |= LOOKUP_FOLLOW;
+ if (flags & O_ATROOT)
+ lookup_flags |= LOOKUP_DFD_ROOT;
op->lookup_flags = lookup_flags;
return 0;
}
diff --git a/fs/stat.c b/fs/stat.c
index bc045c7..d71e7f2 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -95,13 +95,15 @@ int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
unsigned int lookup_flags = 0;
if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
- AT_EMPTY_PATH)) != 0)
+ AT_EMPTY_PATH | AT_FDROOT)) != 0)
goto out;
if (!(flag & AT_SYMLINK_NOFOLLOW))
lookup_flags |= LOOKUP_FOLLOW;
if (flag & AT_EMPTY_PATH)
lookup_flags |= LOOKUP_EMPTY;
+ if (flag & AT_FDROOT)
+ lookup_flags |= LOOKUP_DFD_ROOT;
retry:
error = user_path_at(dfd, filename, lookup_flags, &path);
if (error)
diff --git a/fs/utimes.c b/fs/utimes.c
index 85c40f4..78a9eb9 100644
--- a/fs/utimes.c
+++ b/fs/utimes.c
@@ -143,7 +143,7 @@ long do_utimes(int dfd, const char __user *filename, struct timespec *times,
goto out;
}
- if (flags & ~AT_SYMLINK_NOFOLLOW)
+ if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_FDROOT))
goto out;
if (filename == NULL && dfd != AT_FDCWD) {
@@ -165,6 +165,8 @@ long do_utimes(int dfd, const char __user *filename, struct timespec *times,
if (!(flags & AT_SYMLINK_NOFOLLOW))
lookup_flags |= LOOKUP_FOLLOW;
+ if (flags & AT_FDROOT)
+ lookup_flags |= LOOKUP_DFD_ROOT;
retry:
error = user_path_at(dfd, filename, lookup_flags, &path);
if (error)
diff --git a/include/uapi/asm-generic/fcntl.h b/include/uapi/asm-generic/fcntl.h
index e063eff..0436b1d 100644
--- a/include/uapi/asm-generic/fcntl.h
+++ b/include/uapi/asm-generic/fcntl.h
@@ -88,6 +88,10 @@
#define __O_TMPFILE 020000000
#endif
+#ifndef O_ATROOT
+#define O_ATROOT 040000000 /* dfd is a root */
+#endif
+
/* a horrid kludge trying to make sure that this will fail on old kernels */
#define O_TMPFILE (__O_TMPFILE | O_DIRECTORY)
#define O_TMPFILE_MASK (__O_TMPFILE | O_DIRECTORY | O_CREAT)
diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h
index beed138..4f3b631 100644
--- a/include/uapi/linux/fcntl.h
+++ b/include/uapi/linux/fcntl.h
@@ -62,6 +62,7 @@
#define AT_SYMLINK_FOLLOW 0x400 /* Follow symbolic links. */
#define AT_NO_AUTOMOUNT 0x800 /* Suppress terminal automount traversal */
#define AT_EMPTY_PATH 0x1000 /* Allow empty relative pathname */
+#define AT_FDROOT 0x2000 /* Resolve a path as if dirfd is root */
#endif /* _UAPI_LINUX_FCNTL_H */
--
2.5.5
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 3/3] selftests: check O_ATROOT and AT_FDROOT flags
2016-07-20 20:42 [PATCH 0/3 v3] fs: allow to use dirfd as root for openat and other *at syscalls Andrey Vagin
2016-07-20 20:42 ` [PATCH 1/3 v2] namei: add LOOKUP_DFD_ROOT to use dfd as root Andrey Vagin
2016-07-20 20:42 ` [PATCH 2/3 v2] fs: allow to use dirfd as root for openat and other *at syscalls Andrey Vagin
@ 2016-07-20 20:42 ` Andrey Vagin
2 siblings, 0 replies; 4+ messages in thread
From: Andrey Vagin @ 2016-07-20 20:42 UTC (permalink / raw)
To: linux-fsdevel, Alexander Viro
Cc: linux-kernel, linux-api, containers, criu, Andrey Vagin,
Eric W. Biederman, Arnd Bergmann, J. Bruce Fields,
Miklos Szeredi, NeilBrown, Shuah Khan, Omar Sandoval
These flags mean that the first argument "dirfd" of *at syscall-s set as
root for the current operation.
With these flags absolute symlinks have to be resolved relative to
dirfd.
This test create a file and an absolute symlink on it, which can be
resoled only if a proper root is set.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
---
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/lookup/.gitignore | 1 +
tools/testing/selftests/lookup/Makefile | 8 +++
tools/testing/selftests/lookup/lookup_at_root.c | 71 +++++++++++++++++++++++++
tools/testing/selftests/lookup/run.sh | 14 +++++
5 files changed, 95 insertions(+)
create mode 100644 tools/testing/selftests/lookup/.gitignore
create mode 100644 tools/testing/selftests/lookup/Makefile
create mode 100644 tools/testing/selftests/lookup/lookup_at_root.c
create mode 100755 tools/testing/selftests/lookup/run.sh
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index ff9e5f2..72555c8 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -9,6 +9,7 @@ TARGETS += futex
TARGETS += ipc
TARGETS += kcmp
TARGETS += lib
+TARGETS += lookup
TARGETS += membarrier
TARGETS += memfd
TARGETS += memory-hotplug
diff --git a/tools/testing/selftests/lookup/.gitignore b/tools/testing/selftests/lookup/.gitignore
new file mode 100644
index 0000000..c9a963f
--- /dev/null
+++ b/tools/testing/selftests/lookup/.gitignore
@@ -0,0 +1 @@
+lookup_at_root
diff --git a/tools/testing/selftests/lookup/Makefile b/tools/testing/selftests/lookup/Makefile
new file mode 100644
index 0000000..042b26f
--- /dev/null
+++ b/tools/testing/selftests/lookup/Makefile
@@ -0,0 +1,8 @@
+TEST_PROGS := run.sh
+
+all: lookup_at_root
+
+clean:
+ $(RM) lookup_at_root
+include ../lib.mk
+
diff --git a/tools/testing/selftests/lookup/lookup_at_root.c b/tools/testing/selftests/lookup/lookup_at_root.c
new file mode 100644
index 0000000..6723dc8
--- /dev/null
+++ b/tools/testing/selftests/lookup/lookup_at_root.c
@@ -0,0 +1,71 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <sys/prctl.h>
+#include <linux/limits.h>
+
+#define pr_err(fmt, ...) \
+ ({ \
+ fprintf(stderr, "%s:%d:" fmt ": %m\n", \
+ __func__, __LINE__, ##__VA_ARGS__); \
+ 1; \
+ })
+
+#ifndef O_ATROOT
+#define O_ATROOT 040000000 /* dfd is a root */
+#endif
+#ifndef AT_FDROOT
+#define AT_FDROOT 0x2000 /* Resolve a path as if dirfd is root */
+#endif
+
+int main(int argc, char **argv)
+{
+ struct stat st;
+ int fd, dfd;
+ char path[PATH_MAX];
+
+ dfd = open(argv[1], O_RDONLY);
+ if (dfd < 0)
+ return pr_err("open");
+
+ snprintf(path, sizeof(path), "%s/test", argv[1]);
+ if (mkdir(path, 755))
+ return pr_err("mkdir");
+
+ if (symlinkat("/test", dfd, "./test.link"))
+ return pr_err("symlinkat");
+
+ fd = openat(dfd, "test.link", O_RDONLY | O_ATROOT);
+ if (fd < 0)
+ return pr_err("open");
+
+ if (fchdir(dfd))
+ return pr_err("fchdir");
+
+ fd = openat(AT_FDCWD, "test.link", O_RDONLY | O_ATROOT);
+ if (fd < 0)
+ return pr_err("open");
+ close(fd);
+
+ fd = openat(AT_FDCWD, "/test.link", O_RDONLY | O_ATROOT);
+ if (fd < 0)
+ return pr_err("open");
+ close(fd);
+
+ if (fstatat(AT_FDCWD, "test.link", &st, AT_FDROOT))
+ return pr_err("fstatat");
+ if (fstatat(dfd, "test.link", &st, AT_FDROOT))
+ return pr_err("fstatat");
+ if (mknodat(dfd, "./test/test.file", 0644 | S_IFREG, 0))
+ return pr_err("mknod");
+ if (linkat(dfd, "./test.link/test.file",
+ dfd, "./test.link/test.file.link", AT_FDROOT))
+ return pr_err("linkat");
+ if (unlinkat(dfd, "./test.link/test.file.link", AT_FDROOT))
+ return pr_err("unlinkat");
+
+ return 0;
+}
diff --git a/tools/testing/selftests/lookup/run.sh b/tools/testing/selftests/lookup/run.sh
new file mode 100755
index 0000000..86cc51b
--- /dev/null
+++ b/tools/testing/selftests/lookup/run.sh
@@ -0,0 +1,14 @@
+#!/bin/sh
+
+set -e
+
+test_dir=`mktemp -d /tmp/lookup_test.XXXXXX`
+mount -t tmpfs lookup_at_root $test_dir
+
+ret=0
+./lookup_at_root $test_dir || ret=$?
+
+umount $test_dir
+rmdir $test_dir
+
+exit $ret
--
2.5.5
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-07-20 20:43 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-07-20 20:42 [PATCH 0/3 v3] fs: allow to use dirfd as root for openat and other *at syscalls Andrey Vagin
2016-07-20 20:42 ` [PATCH 1/3 v2] namei: add LOOKUP_DFD_ROOT to use dfd as root Andrey Vagin
2016-07-20 20:42 ` [PATCH 2/3 v2] fs: allow to use dirfd as root for openat and other *at syscalls Andrey Vagin
2016-07-20 20:42 ` [PATCH 3/3] selftests: check O_ATROOT and AT_FDROOT flags Andrey Vagin
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