diff options
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 92 |
1 files changed, 53 insertions, 39 deletions
diff --git a/fs/namei.c b/fs/namei.c index 2826db35dc25..5008f01787f5 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -137,7 +137,7 @@ static int do_getname(const char __user *filename, char *page) return retval; } -static char *getname_flags(const char __user * filename, int flags) +static char *getname_flags(const char __user *filename, int flags, int *empty) { char *tmp, *result; @@ -148,6 +148,8 @@ static char *getname_flags(const char __user * filename, int flags) result = tmp; if (retval < 0) { + if (retval == -ENOENT && empty) + *empty = 1; if (retval != -ENOENT || !(flags & LOOKUP_EMPTY)) { __putname(tmp); result = ERR_PTR(retval); @@ -160,7 +162,7 @@ static char *getname_flags(const char __user * filename, int flags) char *getname(const char __user * filename) { - return getname_flags(filename, 0); + return getname_flags(filename, 0, 0); } #ifdef CONFIG_AUDITSYSCALL @@ -221,14 +223,12 @@ static int check_acl(struct inode *inode, int mask) } /* - * This does basic POSIX ACL permission checking + * This does the basic permission checking */ static int acl_permission_check(struct inode *inode, int mask) { unsigned int mode = inode->i_mode; - mask &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_NOT_BLOCK; - if (current_user_ns() != inode_userns(inode)) goto other_perms; @@ -257,7 +257,7 @@ other_perms: /** * generic_permission - check for access rights on a Posix-like filesystem * @inode: inode to check access rights for - * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) + * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC, ...) * * Used to check for read/write/execute permissions on a file. * We use "fsuid" for this, letting us set arbitrary permissions @@ -273,7 +273,7 @@ int generic_permission(struct inode *inode, int mask) int ret; /* - * Do the basic POSIX ACL permission checks. + * Do the basic permission checks. */ ret = acl_permission_check(inode, mask); if (ret != -EACCES) @@ -331,12 +331,14 @@ static inline int do_inode_permission(struct inode *inode, int mask) /** * inode_permission - check for access rights to a given inode * @inode: inode to check permission on - * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) + * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC, ...) * * Used to check for read/write/execute permissions on an inode. * We use "fsuid" for this, letting us set arbitrary permissions * for filesystem access without changing the "normal" uids which * are used for other things. + * + * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask. */ int inode_permission(struct inode *inode, int mask) { @@ -721,31 +723,22 @@ static int follow_automount(struct path *path, unsigned flags, if (!path->dentry->d_op || !path->dentry->d_op->d_automount) return -EREMOTE; - /* We don't want to mount if someone supplied AT_NO_AUTOMOUNT - * and this is the terminal part of the path. + /* We don't want to mount if someone's just doing a stat - + * unless they're stat'ing a directory and appended a '/' to + * the name. + * + * We do, however, want to mount if someone wants to open or + * create a file of any type under the mountpoint, wants to + * traverse through the mountpoint or wants to open the + * mounted directory. Also, autofs may mark negative dentries + * as being automount points. These will need the attentions + * of the daemon to instantiate them before they can be used. */ - if ((flags & LOOKUP_NO_AUTOMOUNT) && !(flags & LOOKUP_PARENT)) - return -EISDIR; /* we actually want to stop here */ + if (!(flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY | + LOOKUP_OPEN | LOOKUP_CREATE | LOOKUP_AUTOMOUNT)) && + path->dentry->d_inode) + return -EISDIR; - /* - * We don't want to mount if someone's just doing a stat and they've - * set AT_SYMLINK_NOFOLLOW - unless they're stat'ing a directory and - * appended a '/' to the name. - */ - if (!(flags & LOOKUP_FOLLOW)) { - /* We do, however, want to mount if someone wants to open or - * create a file of any type under the mountpoint, wants to - * traverse through the mountpoint or wants to open the mounted - * directory. - * Also, autofs may mark negative dentries as being automount - * points. These will need the attentions of the daemon to - * instantiate them before they can be used. - */ - if (!(flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY | - LOOKUP_OPEN | LOOKUP_CREATE)) && - path->dentry->d_inode) - return -EISDIR; - } current->total_link_count++; if (current->total_link_count >= 40) return -ELOOP; @@ -859,7 +852,7 @@ static int follow_managed(struct path *path, unsigned flags) mntput(path->mnt); if (ret == -EISDIR) ret = 0; - return ret; + return ret < 0 ? ret : need_mntput; } int follow_down_one(struct path *path) @@ -907,6 +900,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path, break; path->mnt = mounted; path->dentry = mounted->mnt_root; + nd->flags |= LOOKUP_JUMPED; nd->seq = read_seqcount_begin(&path->dentry->d_seq); /* * Update the inode too. We don't need to re-check the @@ -1220,6 +1214,8 @@ retry: path_put_conditional(path, nd); return err; } + if (err) + nd->flags |= LOOKUP_JUMPED; *inode = path->dentry->d_inode; return 0; } @@ -1807,11 +1803,11 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) return __lookup_hash(&this, base, NULL); } -int user_path_at(int dfd, const char __user *name, unsigned flags, - struct path *path) +int user_path_at_empty(int dfd, const char __user *name, unsigned flags, + struct path *path, int *empty) { struct nameidata nd; - char *tmp = getname_flags(name, flags); + char *tmp = getname_flags(name, flags, empty); int err = PTR_ERR(tmp); if (!IS_ERR(tmp)) { @@ -1825,6 +1821,12 @@ int user_path_at(int dfd, const char __user *name, unsigned flags, return err; } +int user_path_at(int dfd, const char __user *name, unsigned flags, + struct path *path) +{ + return user_path_at_empty(dfd, name, flags, path, 0); +} + static int user_path_parent(int dfd, const char __user *path, struct nameidata *nd, char **name) { @@ -2044,10 +2046,7 @@ static int may_open(struct path *path, int acc_mode, int flag) if (flag & O_NOATIME && !inode_owner_or_capable(inode)) return -EPERM; - /* - * Ensure there are no outstanding leases on the file. - */ - return break_lease(inode, flag); + return 0; } static int handle_truncate(struct file *filp) @@ -2150,6 +2149,10 @@ static struct file *do_last(struct nameidata *nd, struct path *path, } /* create side of things */ + /* + * This will *only* deal with leaving RCU mode - LOOKUP_JUMPED has been + * cleared when we got to the last component we are about to look up + */ error = complete_walk(nd); if (error) return ERR_PTR(error); @@ -2218,6 +2221,9 @@ static struct file *do_last(struct nameidata *nd, struct path *path, if (error < 0) goto exit_dput; + if (error) + nd->flags |= LOOKUP_JUMPED; + error = -ENOENT; if (!path->dentry->d_inode) goto exit_dput; @@ -2227,6 +2233,10 @@ static struct file *do_last(struct nameidata *nd, struct path *path, path_to_nameidata(path, nd); nd->inode = path->dentry->d_inode; + /* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */ + error = complete_walk(nd); + if (error) + goto exit; error = -EISDIR; if (S_ISDIR(nd->inode->i_mode)) goto exit; @@ -2619,6 +2629,7 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry) if (!dir->i_op->rmdir) return -EPERM; + dget(dentry); mutex_lock(&dentry->d_inode->i_mutex); error = -EBUSY; @@ -2639,6 +2650,7 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry) out: mutex_unlock(&dentry->d_inode->i_mutex); + dput(dentry); if (!error) d_delete(dentry); return error; @@ -3028,6 +3040,7 @@ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, if (error) return error; + dget(new_dentry); if (target) mutex_lock(&target->i_mutex); @@ -3048,6 +3061,7 @@ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, out: if (target) mutex_unlock(&target->i_mutex); + dput(new_dentry); if (!error) if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) d_move(old_dentry,new_dentry); |