Add a simple helper for a chroot with a kernelspace name and use it in
the early init code instead of relying on the implicit set_fs(KERNEL_DS)
there. Remove the now unused ksys_chroot.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/base/devtmpfs.c | 2 +-
fs/open.c | 15 ++++++++++-----
include/linux/fs.h | 1 +
include/linux/syscalls.h | 1 -
init/do_mounts.c | 2 +-
init/do_mounts_initrd.c | 4 ++--
6 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 2cedeb62706f18..a5126e7be34c8a 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -389,7 +389,7 @@ static int devtmpfs_setup(void *p)
if (err)
goto out;
kern_chdir("/.."); /* will traverse into overmounted root */
- ksys_chroot(".");
+ kern_chroot(".");
out:
*(int *)p = err;
complete(&setup_done);
diff --git a/fs/open.c b/fs/open.c
index 3d62f4d2604739..424db905da5f18 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -540,15 +540,15 @@ SYSCALL_DEFINE1(fchdir, unsigned int, fd)
return error;
}
-int ksys_chroot(const char __user *filename)
+static int do_chroot(struct filename *name)
{
struct path path;
int error;
unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
retry:
- error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
+ error = filename_lookup(AT_FDCWD, name, lookup_flags, &path, NULL);
if (error)
- goto out;
+ return error;
error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
if (error)
@@ -569,13 +569,18 @@ int ksys_chroot(const char __user *filename)
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
-out:
+ putname(name);
return error;
}
+int kern_chroot(const char *filename)
+{
+ return do_chroot(getname_kernel(filename));
+}
+
SYSCALL_DEFINE1(chroot, const char __user *, filename)
{
- return ksys_chroot(filename);
+ return do_chroot(getname(filename));
}
static int chmod_common(const struct path *path, umode_t mode)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index dccb37407e9bad..0205355bffb1bc 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3672,5 +3672,6 @@ static inline int inode_drain_writes(struct inode *inode)
}
int kern_chdir(const char *filename);
+int kern_chroot(const char *filename);
#endif /* _LINUX_FS_H */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index f2a181776b0409..a3176d1a521467 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1236,7 +1236,6 @@ asmlinkage long sys_ni_syscall(void);
* the ksys_xyzyyz() functions prototyped below.
*/
-int ksys_chroot(const char __user *filename);
ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
int ksys_fchown(unsigned int fd, uid_t user, gid_t group);
ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count);
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 8c3fca8e2d3c6e..31b8dedb189b57 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -629,7 +629,7 @@ void __init prepare_namespace(void)
out:
devtmpfs_mount();
do_kern_mount(".", "/", NULL, MS_MOVE, NULL);
- ksys_chroot(".");
+ kern_chroot(".");
}
static bool is_tmpfs;
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 522554d703b785..1cbc9988d2e0ad 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -63,7 +63,7 @@ static int __init init_linuxrc(struct subprocess_info *info, struct cred *new)
/* move initrd over / and chdir/chroot in initrd root */
kern_chdir("/root");
do_kern_mount(".", "/", NULL, MS_MOVE, NULL);
- ksys_chroot(".");
+ kern_chroot(".");
ksys_setsid();
return 0;
}
@@ -101,7 +101,7 @@ static void __init handle_initrd(void)
/* move initrd to rootfs' /old */
do_kern_mount("..", ".", NULL, MS_MOVE, NULL);
/* switch root and cwd back to / of rootfs */
- ksys_chroot("..");
+ kern_chroot("..");
if (new_decode_dev(real_root_dev) == Root_RAM0) {
kern_chdir("/old");
--
2.27.0
