diff options
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 227 |
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); |