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Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c227
1 files changed, 184 insertions, 43 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 38ab51881247..5c9f6f8e90c4 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2874,10 +2874,26 @@ void unlock_rename(struct dentry *p1, struct dentry *p2)
}
EXPORT_SYMBOL(unlock_rename);
-int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
- bool want_excl)
+/**
+ * vfs_create - create new file
+ * @mnt_userns: user namespace of the mount the inode was found from
+ * @dir: inode of @dentry
+ * @dentry: pointer to dentry of the base directory
+ * @mode: mode of the new file
+ * @want_excl: whether the file must not yet exist
+ *
+ * Create a new file.
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then take
+ * care to map the inode according to @mnt_userns before checking permissions.
+ * On non-idmapped mounts or if permission checking is to be performed on the
+ * raw inode simply passs init_user_ns.
+ */
+int vfs_create(struct user_namespace *mnt_userns, struct inode *dir,
+ struct dentry *dentry, umode_t mode, bool want_excl)
{
- int error = may_create(&init_user_ns, dir, dentry);
+ int error = may_create(mnt_userns, dir, dentry);
if (error)
return error;
@@ -3353,7 +3369,23 @@ static int do_open(struct nameidata *nd,
return error;
}
-struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode, int open_flag)
+/**
+ * vfs_tmpfile - create tmpfile
+ * @mnt_userns: user namespace of the mount the inode was found from
+ * @dentry: pointer to dentry of the base directory
+ * @mode: mode of the new tmpfile
+ * @open_flags: flags
+ *
+ * Create a temporary file.
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then take
+ * care to map the inode according to @mnt_userns before checking permissions.
+ * On non-idmapped mounts or if permission checking is to be performed on the
+ * raw inode simply passs init_user_ns.
+ */
+struct dentry *vfs_tmpfile(struct user_namespace *mnt_userns,
+ struct dentry *dentry, umode_t mode, int open_flag)
{
struct dentry *child = NULL;
struct inode *dir = dentry->d_inode;
@@ -3361,7 +3393,7 @@ struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode, int open_flag)
int error;
/* we want directory to be writable */
- error = inode_permission(&init_user_ns, dir, MAY_WRITE | MAY_EXEC);
+ error = inode_permission(mnt_userns, dir, MAY_WRITE | MAY_EXEC);
if (error)
goto out_err;
error = -EOPNOTSUPP;
@@ -3396,6 +3428,7 @@ static int do_tmpfile(struct nameidata *nd, unsigned flags,
const struct open_flags *op,
struct file *file)
{
+ struct user_namespace *mnt_userns;
struct dentry *child;
struct path path;
int error = path_lookupat(nd, flags | LOOKUP_DIRECTORY, &path);
@@ -3404,7 +3437,8 @@ static int do_tmpfile(struct nameidata *nd, unsigned flags,
error = mnt_want_write(path.mnt);
if (unlikely(error))
goto out;
- child = vfs_tmpfile(path.dentry, op->mode, op->open_flag);
+ mnt_userns = mnt_user_ns(path.mnt);
+ child = vfs_tmpfile(mnt_userns, path.dentry, op->mode, op->open_flag);
error = PTR_ERR(child);
if (IS_ERR(child))
goto out2;
@@ -3616,10 +3650,27 @@ inline struct dentry *user_path_create(int dfd, const char __user *pathname,
}
EXPORT_SYMBOL(user_path_create);
-int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
+/**
+ * vfs_mknod - create device node or file
+ * @mnt_userns: user namespace of the mount the inode was found from
+ * @dir: inode of @dentry
+ * @dentry: pointer to dentry of the base directory
+ * @mode: mode of the new device node or file
+ * @dev: device number of device to create
+ *
+ * Create a device node or file.
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then take
+ * care to map the inode according to @mnt_userns before checking permissions.
+ * On non-idmapped mounts or if permission checking is to be performed on the
+ * raw inode simply passs init_user_ns.
+ */
+int vfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+ struct dentry *dentry, umode_t mode, dev_t dev)
{
bool is_whiteout = S_ISCHR(mode) && dev == WHITEOUT_DEV;
- int error = may_create(&init_user_ns, dir, dentry);
+ int error = may_create(mnt_userns, dir, dentry);
if (error)
return error;
@@ -3666,6 +3717,7 @@ static int may_mknod(umode_t mode)
static long do_mknodat(int dfd, const char __user *filename, umode_t mode,
unsigned int dev)
{
+ struct user_namespace *mnt_userns;
struct dentry *dentry;
struct path path;
int error;
@@ -3684,18 +3736,22 @@ retry:
error = security_path_mknod(&path, dentry, mode, dev);
if (error)
goto out;
+
+ mnt_userns = mnt_user_ns(path.mnt);
switch (mode & S_IFMT) {
case 0: case S_IFREG:
- error = vfs_create(path.dentry->d_inode,dentry,mode,true);
+ error = vfs_create(mnt_userns, path.dentry->d_inode,
+ dentry, mode, true);
if (!error)
ima_post_path_mknod(dentry);
break;
case S_IFCHR: case S_IFBLK:
- error = vfs_mknod(path.dentry->d_inode,dentry,mode,
- new_decode_dev(dev));
+ error = vfs_mknod(mnt_userns, path.dentry->d_inode,
+ dentry, mode, new_decode_dev(dev));
break;
case S_IFIFO: case S_IFSOCK:
- error = vfs_mknod(path.dentry->d_inode,dentry,mode,0);
+ error = vfs_mknod(mnt_userns, path.dentry->d_inode,
+ dentry, mode, 0);
break;
}
out:
@@ -3718,9 +3774,25 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d
return do_mknodat(AT_FDCWD, filename, mode, dev);
}
-int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+/**
+ * vfs_mkdir - create directory
+ * @mnt_userns: user namespace of the mount the inode was found from
+ * @dir: inode of @dentry
+ * @dentry: pointer to dentry of the base directory
+ * @mode: mode of the new directory
+ *
+ * Create a directory.
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then take
+ * care to map the inode according to @mnt_userns before checking permissions.
+ * On non-idmapped mounts or if permission checking is to be performed on the
+ * raw inode simply passs init_user_ns.
+ */
+int vfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+ struct dentry *dentry, umode_t mode)
{
- int error = may_create(&init_user_ns, dir, dentry);
+ int error = may_create(mnt_userns, dir, dentry);
unsigned max_links = dir->i_sb->s_max_links;
if (error)
@@ -3759,8 +3831,11 @@ retry:
if (!IS_POSIXACL(path.dentry->d_inode))
mode &= ~current_umask();
error = security_path_mkdir(&path, dentry, mode);
- if (!error)
- error = vfs_mkdir(path.dentry->d_inode, dentry, mode);
+ if (!error) {
+ struct user_namespace *mnt_userns;
+ mnt_userns = mnt_user_ns(path.mnt);
+ error = vfs_mkdir(mnt_userns, path.dentry->d_inode, dentry, mode);
+ }
done_path_create(&path, dentry);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
@@ -3779,9 +3854,24 @@ SYSCALL_DEFINE2(mkdir, const char __user *, pathname, umode_t, mode)
return do_mkdirat(AT_FDCWD, pathname, mode);
}
-int vfs_rmdir(struct inode *dir, struct dentry *dentry)
+/**
+ * vfs_rmdir - remove directory
+ * @mnt_userns: user namespace of the mount the inode was found from
+ * @dir: inode of @dentry
+ * @dentry: pointer to dentry of the base directory
+ *
+ * Remove a directory.
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then take
+ * care to map the inode according to @mnt_userns before checking permissions.
+ * On non-idmapped mounts or if permission checking is to be performed on the
+ * raw inode simply passs init_user_ns.
+ */
+int vfs_rmdir(struct user_namespace *mnt_userns, struct inode *dir,
+ struct dentry *dentry)
{
- int error = may_delete(&init_user_ns, dir, dentry, 1);
+ int error = may_delete(mnt_userns, dir, dentry, 1);
if (error)
return error;
@@ -3821,6 +3911,7 @@ EXPORT_SYMBOL(vfs_rmdir);
long do_rmdir(int dfd, struct filename *name)
{
+ struct user_namespace *mnt_userns;
int error = 0;
struct dentry *dentry;
struct path path;
@@ -3861,7 +3952,8 @@ retry:
error = security_path_rmdir(&path, dentry);
if (error)
goto exit3;
- error = vfs_rmdir(path.dentry->d_inode, dentry);
+ mnt_userns = mnt_user_ns(path.mnt);
+ error = vfs_rmdir(mnt_userns, path.dentry->d_inode, dentry);
exit3:
dput(dentry);
exit2:
@@ -3884,6 +3976,7 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname)
/**
* vfs_unlink - unlink a filesystem object
+ * @mnt_userns: user namespace of the mount the inode was found from
* @dir: parent directory
* @dentry: victim
* @delegated_inode: returns victim inode, if the inode is delegated.
@@ -3899,11 +3992,18 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname)
* Alternatively, a caller may pass NULL for delegated_inode. This may
* be appropriate for callers that expect the underlying filesystem not
* to be NFS exported.
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then take
+ * care to map the inode according to @mnt_userns before checking permissions.
+ * On non-idmapped mounts or if permission checking is to be performed on the
+ * raw inode simply passs init_user_ns.
*/
-int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode)
+int vfs_unlink(struct user_namespace *mnt_userns, struct inode *dir,
+ struct dentry *dentry, struct inode **delegated_inode)
{
struct inode *target = dentry->d_inode;
- int error = may_delete(&init_user_ns, dir, dentry, 0);
+ int error = may_delete(mnt_userns, dir, dentry, 0);
if (error)
return error;
@@ -3974,6 +4074,8 @@ retry_deleg:
dentry = __lookup_hash(&last, path.dentry, lookup_flags);
error = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
+ struct user_namespace *mnt_userns;
+
/* Why not before? Because we want correct error value */
if (last.name[last.len])
goto slashes;
@@ -3984,7 +4086,8 @@ retry_deleg:
error = security_path_unlink(&path, dentry);
if (error)
goto exit2;
- error = vfs_unlink(path.dentry->d_inode, dentry, &delegated_inode);
+ mnt_userns = mnt_user_ns(path.mnt);
+ error = vfs_unlink(mnt_userns, path.dentry->d_inode, dentry, &delegated_inode);
exit2:
dput(dentry);
}
@@ -4033,9 +4136,25 @@ SYSCALL_DEFINE1(unlink, const char __user *, pathname)
return do_unlinkat(AT_FDCWD, getname(pathname));
}
-int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
+/**
+ * vfs_symlink - create symlink
+ * @mnt_userns: user namespace of the mount the inode was found from
+ * @dir: inode of @dentry
+ * @dentry: pointer to dentry of the base directory
+ * @oldname: name of the file to link to
+ *
+ * Create a symlink.
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then take
+ * care to map the inode according to @mnt_userns before checking permissions.
+ * On non-idmapped mounts or if permission checking is to be performed on the
+ * raw inode simply passs init_user_ns.
+ */
+int vfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+ struct dentry *dentry, const char *oldname)
{
- int error = may_create(&init_user_ns, dir, dentry);
+ int error = may_create(mnt_userns, dir, dentry);
if (error)
return error;
@@ -4073,8 +4192,13 @@ retry:
goto out_putname;
error = security_path_symlink(&path, dentry, from->name);
- if (!error)
- error = vfs_symlink(path.dentry->d_inode, dentry, from->name);
+ if (!error) {
+ struct user_namespace *mnt_userns;
+
+ mnt_userns = mnt_user_ns(path.mnt);
+ error = vfs_symlink(mnt_userns, path.dentry->d_inode, dentry,
+ from->name);
+ }
done_path_create(&path, dentry);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
@@ -4099,6 +4223,7 @@ SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newn
/**
* vfs_link - create a new link
* @old_dentry: object to be linked
+ * @mnt_userns: the user namespace of the mount
* @dir: new parent
* @new_dentry: where to create the new link
* @delegated_inode: returns inode needing a delegation break
@@ -4114,8 +4239,16 @@ SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newn
* Alternatively, a caller may pass NULL for delegated_inode. This may
* be appropriate for callers that expect the underlying filesystem not
* to be NFS exported.
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then take
+ * care to map the inode according to @mnt_userns before checking permissions.
+ * On non-idmapped mounts or if permission checking is to be performed on the
+ * raw inode simply passs init_user_ns.
*/
-int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry, struct inode **delegated_inode)
+int vfs_link(struct dentry *old_dentry, struct user_namespace *mnt_userns,
+ struct inode *dir, struct dentry *new_dentry,
+ struct inode **delegated_inode)
{
struct inode *inode = old_dentry->d_inode;
unsigned max_links = dir->i_sb->s_max_links;
@@ -4124,7 +4257,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
if (!inode)
return -ENOENT;
- error = may_create(&init_user_ns, dir, new_dentry);
+ error = may_create(mnt_userns, dir, new_dentry);
if (error)
return error;
@@ -4141,7 +4274,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
* be writen back improperly if their true value is unknown to
* the vfs.
*/
- if (HAS_UNMAPPED_ID(&init_user_ns, inode))
+ if (HAS_UNMAPPED_ID(mnt_userns, inode))
return -EPERM;
if (!dir->i_op->link)
return -EPERM;
@@ -4188,6 +4321,7 @@ EXPORT_SYMBOL(vfs_link);
static int do_linkat(int olddfd, const char __user *oldname, int newdfd,
const char __user *newname, int flags)
{
+ struct user_namespace *mnt_userns;
struct dentry *new_dentry;
struct path old_path, new_path;
struct inode *delegated_inode = NULL;
@@ -4229,7 +4363,9 @@ retry:
error = security_path_link(old_path.dentry, &new_path, new_dentry);
if (error)
goto out_dput;
- error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry, &delegated_inode);
+ mnt_userns = mnt_user_ns(new_path.mnt);
+ error = vfs_link(old_path.dentry, mnt_userns, new_path.dentry->d_inode,
+ new_dentry, &delegated_inode);
out_dput:
done_path_create(&new_path, new_dentry);
if (delegated_inode) {
@@ -4263,12 +4399,14 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname
/**
* vfs_rename - rename a filesystem object
- * @old_dir: parent of source
- * @old_dentry: source
- * @new_dir: parent of destination
- * @new_dentry: destination
- * @delegated_inode: returns an inode needing a delegation break
- * @flags: rename flags
+ * @old_mnt_userns: old user namespace of the mount the inode was found from
+ * @old_dir: parent of source
+ * @old_dentry: source
+ * @new_mnt_userns: new user namespace of the mount the inode was found from
+ * @new_dir: parent of destination
+ * @new_dentry: destination
+ * @delegated_inode: returns an inode needing a delegation break
+ * @flags: rename flags
*
* The caller must hold multiple mutexes--see lock_rename()).
*
@@ -4314,7 +4452,6 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname
int vfs_rename(struct renamedata *rd)
{
int error;
- struct user_namespace *mnt_userns = &init_user_ns;
struct inode *old_dir = rd->old_dir, *new_dir = rd->new_dir;
struct dentry *old_dentry = rd->old_dentry;
struct dentry *new_dentry = rd->new_dentry;
@@ -4330,19 +4467,21 @@ int vfs_rename(struct renamedata *rd)
if (source == target)
return 0;
- error = may_delete(mnt_userns, old_dir, old_dentry, is_dir);
+ error = may_delete(rd->old_mnt_userns, old_dir, old_dentry, is_dir);
if (error)
return error;
if (!target) {
- error = may_create(mnt_userns, new_dir, new_dentry);
+ error = may_create(rd->new_mnt_userns, new_dir, new_dentry);
} else {
new_is_dir = d_is_dir(new_dentry);
if (!(flags & RENAME_EXCHANGE))
- error = may_delete(mnt_userns, new_dir, new_dentry, is_dir);
+ error = may_delete(rd->new_mnt_userns, new_dir,
+ new_dentry, is_dir);
else
- error = may_delete(mnt_userns, new_dir, new_dentry, new_is_dir);
+ error = may_delete(rd->new_mnt_userns, new_dir,
+ new_dentry, new_is_dir);
}
if (error)
return error;
@@ -4356,13 +4495,13 @@ int vfs_rename(struct renamedata *rd)
*/
if (new_dir != old_dir) {
if (is_dir) {
- error = inode_permission(&init_user_ns, source,
+ error = inode_permission(rd->old_mnt_userns, source,
MAY_WRITE);
if (error)
return error;
}
if ((flags & RENAME_EXCHANGE) && new_is_dir) {
- error = inode_permission(&init_user_ns, target,
+ error = inode_permission(rd->new_mnt_userns, target,
MAY_WRITE);
if (error)
return error;
@@ -4552,8 +4691,10 @@ retry_deleg:
rd.old_dir = old_path.dentry->d_inode;
rd.old_dentry = old_dentry;
+ rd.old_mnt_userns = mnt_user_ns(old_path.mnt);
rd.new_dir = new_path.dentry->d_inode;
rd.new_dentry = new_dentry;
+ rd.new_mnt_userns = mnt_user_ns(new_path.mnt);
rd.delegated_inode = &delegated_inode;
rd.flags = flags;
error = vfs_rename(&rd);