diff options
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 555 |
1 files changed, 274 insertions, 281 deletions
diff --git a/fs/namei.c b/fs/namei.c index 06abd2bf473..3d9d2f965f8 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -497,8 +497,6 @@ static int link_path_walk(const char *, struct nameidata *); static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link) { - int res = 0; - char *name; if (IS_ERR(link)) goto fail; @@ -509,22 +507,7 @@ static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *l path_get(&nd->root); } - res = link_path_walk(link, nd); - if (nd->depth || res || nd->last_type!=LAST_NORM) - return res; - /* - * If it is an iterative symlinks resolution in open_namei() we - * have to copy the last component. And all that crap because of - * bloody create() on broken symlinks. Furrfu... - */ - name = __getname(); - if (unlikely(!name)) { - path_put(&nd->path); - return -ENOMEM; - } - strcpy(name, nd->last.name); - nd->last.name = name; - return 0; + return link_path_walk(link, nd); fail: path_put(&nd->path); return PTR_ERR(link); @@ -546,10 +529,10 @@ static inline void path_to_nameidata(struct path *path, struct nameidata *nd) nd->path.dentry = path->dentry; } -static __always_inline int __do_follow_link(struct path *path, struct nameidata *nd) +static __always_inline int +__do_follow_link(struct path *path, struct nameidata *nd, void **p) { int error; - void *cookie; struct dentry *dentry = path->dentry; touch_atime(path->mnt, dentry); @@ -561,9 +544,9 @@ static __always_inline int __do_follow_link(struct path *path, struct nameidata } mntget(path->mnt); nd->last_type = LAST_BIND; - cookie = dentry->d_inode->i_op->follow_link(dentry, nd); - error = PTR_ERR(cookie); - if (!IS_ERR(cookie)) { + *p = dentry->d_inode->i_op->follow_link(dentry, nd); + error = PTR_ERR(*p); + if (!IS_ERR(*p)) { char *s = nd_get_link(nd); error = 0; if (s) @@ -573,8 +556,6 @@ static __always_inline int __do_follow_link(struct path *path, struct nameidata if (error) path_put(&nd->path); } - if (dentry->d_inode->i_op->put_link) - dentry->d_inode->i_op->put_link(dentry, nd, cookie); } return error; } @@ -588,6 +569,7 @@ static __always_inline int __do_follow_link(struct path *path, struct nameidata */ static inline int do_follow_link(struct path *path, struct nameidata *nd) { + void *cookie; int err = -ELOOP; if (current->link_count >= MAX_NESTED_LINKS) goto loop; @@ -601,7 +583,9 @@ static inline int do_follow_link(struct path *path, struct nameidata *nd) current->link_count++; current->total_link_count++; nd->depth++; - err = __do_follow_link(path, nd); + err = __do_follow_link(path, nd, &cookie); + if (!IS_ERR(cookie) && path->dentry->d_inode->i_op->put_link) + path->dentry->d_inode->i_op->put_link(path->dentry, nd, cookie); path_put(path); current->link_count--; nd->depth--; @@ -688,33 +672,20 @@ static __always_inline void follow_dotdot(struct nameidata *nd) set_root(nd); while(1) { - struct vfsmount *parent; struct dentry *old = nd->path.dentry; if (nd->path.dentry == nd->root.dentry && nd->path.mnt == nd->root.mnt) { break; } - spin_lock(&dcache_lock); if (nd->path.dentry != nd->path.mnt->mnt_root) { - nd->path.dentry = dget(nd->path.dentry->d_parent); - spin_unlock(&dcache_lock); + /* rare case of legitimate dget_parent()... */ + nd->path.dentry = dget_parent(nd->path.dentry); dput(old); break; } - spin_unlock(&dcache_lock); - spin_lock(&vfsmount_lock); - parent = nd->path.mnt->mnt_parent; - if (parent == nd->path.mnt) { - spin_unlock(&vfsmount_lock); + if (!follow_up(&nd->path)) break; - } - mntget(parent); - nd->path.dentry = dget(nd->path.mnt->mnt_mountpoint); - spin_unlock(&vfsmount_lock); - dput(old); - mntput(nd->path.mnt); - nd->path.mnt = parent; } follow_mount(&nd->path); } @@ -1346,7 +1317,7 @@ static int may_delete(struct inode *dir,struct dentry *victim,int isdir) return -ENOENT; BUG_ON(victim->d_parent->d_inode != dir); - audit_inode_child(victim->d_name.name, victim, dir); + audit_inode_child(victim, dir); error = inode_permission(dir, MAY_WRITE | MAY_EXEC); if (error) @@ -1387,22 +1358,6 @@ static inline int may_create(struct inode *dir, struct dentry *child) return inode_permission(dir, MAY_WRITE | MAY_EXEC); } -/* - * O_DIRECTORY translates into forcing a directory lookup. - */ -static inline int lookup_flags(unsigned int f) -{ - unsigned long retval = LOOKUP_FOLLOW; - - if (f & O_NOFOLLOW) - retval &= ~LOOKUP_FOLLOW; - - if (f & O_DIRECTORY) - retval |= LOOKUP_DIRECTORY; - - return retval; -} - /* * p1 and p2 should be directories on the same fs. */ @@ -1501,7 +1456,7 @@ int may_open(struct path *path, int acc_mode, int flag) * An append-only file must be opened in append mode for writing. */ if (IS_APPEND(inode)) { - if ((flag & FMODE_WRITE) && !(flag & O_APPEND)) + if ((flag & O_ACCMODE) != O_RDONLY && !(flag & O_APPEND)) return -EPERM; if (flag & O_TRUNC) return -EPERM; @@ -1545,7 +1500,7 @@ static int handle_truncate(struct path *path) * what get passed to sys_open(). */ static int __open_namei_create(struct nameidata *nd, struct path *path, - int flag, int mode) + int open_flag, int mode) { int error; struct dentry *dir = nd->path.dentry; @@ -1563,7 +1518,7 @@ out_unlock: if (error) return error; /* Don't check for write permission, don't truncate */ - return may_open(&nd->path, 0, flag & ~O_TRUNC); + return may_open(&nd->path, 0, open_flag & ~O_TRUNC); } /* @@ -1601,129 +1556,132 @@ static int open_will_truncate(int flag, struct inode *inode) return (flag & O_TRUNC); } -/* - * Note that the low bits of the passed in "open_flag" - * are not the same as in the local variable "flag". See - * open_to_namei_flags() for more details. - */ -struct file *do_filp_open(int dfd, const char *pathname, - int open_flag, int mode, int acc_mode) +static struct file *finish_open(struct nameidata *nd, + int open_flag, int acc_mode) { struct file *filp; - struct nameidata nd; - int error; - struct path path; - struct dentry *dir; - int count = 0; int will_truncate; - int flag = open_to_namei_flags(open_flag); - int force_reval = 0; + int error; + will_truncate = open_will_truncate(open_flag, nd->path.dentry->d_inode); + if (will_truncate) { + error = mnt_want_write(nd->path.mnt); + if (error) + goto exit; + } + error = may_open(&nd->path, acc_mode, open_flag); + if (error) { + if (will_truncate) + mnt_drop_write(nd->path.mnt); + goto exit; + } + filp = nameidata_to_filp(nd); + if (!IS_ERR(filp)) { + error = ima_file_check(filp, acc_mode); + if (error) { + fput(filp); + filp = ERR_PTR(error); + } + } + if (!IS_ERR(filp)) { + if (will_truncate) { + error = handle_truncate(&nd->path); + if (error) { + fput(filp); + filp = ERR_PTR(error); + } + } + } /* - * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only - * check for O_DSYNC if the need any syncing at all we enforce it's - * always set instead of having to deal with possibly weird behaviour - * for malicious applications setting only __O_SYNC. + * It is now safe to drop the mnt write + * because the filp has had a write taken + * on its behalf. */ - if (open_flag & __O_SYNC) - open_flag |= O_DSYNC; - - if (!acc_mode) - acc_mode = MAY_OPEN | ACC_MODE(open_flag); + if (will_truncate) + mnt_drop_write(nd->path.mnt); + return filp; - /* O_TRUNC implies we need access checks for write permissions */ - if (flag & O_TRUNC) - acc_mode |= MAY_WRITE; +exit: + if (!IS_ERR(nd->intent.open.file)) + release_open_intent(nd); + path_put(&nd->path); + return ERR_PTR(error); +} - /* Allow the LSM permission hook to distinguish append - access from general write access. */ - if (flag & O_APPEND) - acc_mode |= MAY_APPEND; +static struct file *do_last(struct nameidata *nd, struct path *path, + int open_flag, int acc_mode, + int mode, const char *pathname, + int *want_dir) +{ + struct dentry *dir = nd->path.dentry; + struct file *filp; + int error = -EISDIR; - /* - * The simplest case - just a plain lookup. - */ - if (!(flag & O_CREAT)) { - filp = get_empty_filp(); - - if (filp == NULL) - return ERR_PTR(-ENFILE); - nd.intent.open.file = filp; - filp->f_flags = open_flag; - nd.intent.open.flags = flag; - nd.intent.open.create_mode = 0; - error = do_path_lookup(dfd, pathname, - lookup_flags(flag)|LOOKUP_OPEN, &nd); - if (IS_ERR(nd.intent.open.file)) { - if (error == 0) { - error = PTR_ERR(nd.intent.open.file); - path_put(&nd.path); + switch (nd->last_type) { + case LAST_DOTDOT: + follow_dotdot(nd); + dir = nd->path.dentry; + if (nd->path.mnt->mnt_sb->s_type->fs_flags & FS_REVAL_DOT) { + if (!dir->d_op->d_revalidate(dir, nd)) { + error = -ESTALE; + goto exit; } - } else if (error) - release_open_intent(&nd); - if (error) - return ERR_PTR(error); + } + /* fallthrough */ + case LAST_DOT: + case LAST_ROOT: + if (open_flag & O_CREAT) + goto exit; + /* fallthrough */ + case LAST_BIND: + audit_inode(pathname, dir); goto ok; } - /* - * Create - we need to know the parent. - */ -reval: - error = path_init(dfd, pathname, LOOKUP_PARENT, &nd); - if (error) - return ERR_PTR(error); - if (force_reval) - nd.flags |= LOOKUP_REVAL; - error = path_walk(pathname, &nd); - if (error) { - if (nd.root.mnt) - path_put(&nd.root); - return ERR_PTR(error); + /* trailing slashes? */ + if (nd->last.name[nd->last.len]) { + if (open_flag & O_CREAT) + goto exit; + *want_dir = 1; } - if (unlikely(!audit_dummy_context())) - audit_inode(pathname, nd.path.dentry); - /* - * We have the parent and last component. First of all, check - * that we are not asked to creat(2) an obvious directory - that - * will not do. - */ - error = -EISDIR; - if (nd.last_type != LAST_NORM || nd.last.name[nd.last.len]) - goto exit_parent; + /* just plain open? */ + if (!(open_flag & O_CREAT)) { + error = do_lookup(nd, &nd->last, path); + if (error) + goto exit; + error = -ENOENT; + if (!path->dentry->d_inode) + goto exit_dput; + if (path->dentry->d_inode->i_op->follow_link) + return NULL; + error = -ENOTDIR; + if (*want_dir & !path->dentry->d_inode->i_op->lookup) + goto exit_dput; + path_to_nameidata(path, nd); + audit_inode(pathname, nd->path.dentry); + goto ok; + } - error = -ENFILE; - filp = get_empty_filp(); - if (filp == NULL) - goto exit_parent; - nd.intent.open.file = filp; - filp->f_flags = open_flag; - nd.intent.open.flags = flag; - nd.intent.open.create_mode = mode; - dir = nd.path.dentry; - nd.flags &= ~LOOKUP_PARENT; - nd.flags |= LOOKUP_CREATE | LOOKUP_OPEN; - if (flag & O_EXCL) - nd.flags |= LOOKUP_EXCL; + /* OK, it's O_CREAT */ mutex_lock(&dir->d_inode->i_mutex); - path.dentry = lookup_hash(&nd); - path.mnt = nd.path.mnt; -do_last: - error = PTR_ERR(path.dentry); - if (IS_ERR(path.dentry)) { + path->dentry = lookup_hash(nd); + path->mnt = nd->path.mnt; + + error = PTR_ERR(path->dentry); + if (IS_ERR(path->dentry)) { mutex_unlock(&dir->d_inode->i_mutex); goto exit; } - if (IS_ERR(nd.intent.open.file)) { - error = PTR_ERR(nd.intent.open.file); + if (IS_ERR(nd->intent.open.file)) { + error = PTR_ERR(nd->intent.open.file); goto exit_mutex_unlock; } /* Negative dentry, just create the file */ - if (!path.dentry->d_inode) { + if (!path->dentry->d_inode) { /* * This write is needed to ensure that a * ro->rw transition does not occur between @@ -1731,18 +1689,16 @@ do_last: * a permanent write count is taken through * the 'struct file' in nameidata_to_filp(). */ - error = mnt_want_write(nd.path.mnt); + error = mnt_want_write(nd->path.mnt); if (error) goto exit_mutex_unlock; - error = __open_namei_create(&nd, &path, flag, mode); + error = __open_namei_create(nd, path, open_flag, mode); if (error) { - mnt_drop_write(nd.path.mnt); + mnt_drop_write(nd->path.mnt); goto exit; } - filp = nameidata_to_filp(&nd); - mnt_drop_write(nd.path.mnt); - if (nd.root.mnt) - path_put(&nd.root); + filp = nameidata_to_filp(nd); + mnt_drop_write(nd->path.mnt); if (!IS_ERR(filp)) { error = ima_file_check(filp, acc_mode); if (error) { @@ -1757,147 +1713,181 @@ do_last: * It already exists. */ mutex_unlock(&dir->d_inode->i_mutex); - audit_inode(pathname, path.dentry); + audit_inode(pathname, path->dentry); error = -EEXIST; - if (flag & O_EXCL) + if (open_flag & O_EXCL) goto exit_dput; - if (__follow_mount(&path)) { + if (__follow_mount(path)) { error = -ELOOP; - if (flag & O_NOFOLLOW) + if (open_flag & O_NOFOLLOW) goto exit_dput; } error = -ENOENT; - if (!path.dentry->d_inode) + if (!path->dentry->d_inode) goto exit_dput; - if (path.dentry->d_inode->i_op->follow_link) - goto do_link; - path_to_nameidata(&path, &nd); + if (path->dentry->d_inode->i_op->follow_link) + return NULL; + + path_to_nameidata(path, nd); error = -EISDIR; - if (S_ISDIR(path.dentry->d_inode->i_mode)) + if (S_ISDIR(path->dentry->d_inode->i_mode)) goto exit; ok: + filp = finish_open(nd, open_flag, acc_mode); + return filp; + +exit_mutex_unlock: + mutex_unlock(&dir->d_inode->i_mutex); +exit_dput: + path_put_conditional(path, nd); +exit: + if (!IS_ERR(nd->intent.open.file)) + release_open_intent(nd); + path_put(&nd->path); + return ERR_PTR(error); +} + +/* + * Note that the low bits of the passed in "open_flag" + * are not the same as in the local variable "flag". See + * open_to_namei_flags() for more details. + */ +struct file *do_filp_open(int dfd, const char *pathname, + int open_flag, int mode, int acc_mode) +{ + struct file *filp; + struct nameidata nd; + int error; + struct path path; + int count = 0; + int flag = open_to_namei_flags(open_flag); + int force_reval = 0; + int want_dir = open_flag & O_DIRECTORY; + + if (!(open_flag & O_CREAT)) + mode = 0; + /* - * Consider: - * 1. may_open() truncates a file - * 2. a rw->ro mount transition occurs - * 3. nameidata_to_filp() fails due to - * the ro mount. - * That would be inconsistent, and should - * be avoided. Taking this mnt write here - * ensures that (2) can not occur. + * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only + * check for O_DSYNC if the need any syncing at all we enforce it's + * always set instead of having to deal with possibly weird behaviour + * for malicious applications setting only __O_SYNC. */ - will_truncate = open_will_truncate(flag, nd.path.dentry->d_inode); - if (will_truncate) { - error = mnt_want_write(nd.path.mnt); - if (error) - goto exit; - } - error = may_open(&nd.path, acc_mode, flag); + if (open_flag & __O_SYNC) + open_flag |= O_DSYNC; + + if (!acc_mode) + acc_mode = MAY_OPEN | ACC_MODE(open_flag); + + /* O_TRUNC implies we need access checks for write permissions */ + if (open_flag & O_TRUNC) + acc_mode |= MAY_WRITE; + + /* Allow the LSM permission hook to distinguish append + access from general write access. */ + if (open_flag & O_APPEND) + acc_mode |= MAY_APPEND; + + /* find the parent */ +reval: + error = path_init(dfd, pathname, LOOKUP_PARENT, &nd); + if (error) + return ERR_PTR(error); + if (force_reval) + nd.flags |= LOOKUP_REVAL; + + current->total_link_count = 0; + error = link_path_walk(pathname, &nd); if (error) { - if (will_truncate) - mnt_drop_write(nd.path.mnt); - goto exit; + filp = ERR_PTR(error); + goto out; } - filp = nameidata_to_filp(&nd); - if (!IS_ERR(filp)) { - error = ima_file_check(filp, acc_mode); - if (error) { - fput(filp); + if (unlikely(!audit_dummy_context()) && (open_flag & O_CREAT)) + audit_inode(pathname, nd.path.dentry); + + /* + * We have the parent and last component. + */ + + error = -ENFILE; + filp = get_empty_filp(); + if (filp == NULL) + goto exit_parent; + nd.intent.open.file = filp; + filp->f_flags = open_flag; + nd.intent.open.flags = flag; + nd.intent.open.create_mode = mode; + nd.flags &= ~LOOKUP_PARENT; + nd.flags |= LOOKUP_OPEN; + if (open_flag & O_CREAT) { + nd.flags |= LOOKUP_CREATE; + if (open_flag & O_EXCL) + nd.flags |= LOOKUP_EXCL; + } + filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname, &want_dir); + while (unlikely(!filp)) { /* trailing symlink */ + struct path holder; + struct inode *inode = path.dentry->d_inode; + void *cookie; + error = -ELOOP; + /* S_ISDIR part is a temporary automount kludge */ + if ((open_flag & O_NOFOLLOW) && !S_ISDIR(inode->i_mode)) + goto exit_dput; + if (count++ == 32) + goto exit_dput; + /* + * This is subtle. Instead of calling do_follow_link() we do + * the thing by hands. The reason is that this way we have zero + * link_count and path_walk() (called from ->follow_link) + * honoring LOOKUP_PARENT. After that we have the parent and + * last component, i.e. we are in the same situation as after + * the first path_walk(). Well, almost - if the last component + * is normal we get its copy stored in nd->last.name and we will + * have to putname() it when we are done. Procfs-like symlinks + * just set LAST_BIND. + */ + nd.flags |= LOOKUP_PARENT; + error = security_inode_follow_link(path.dentry, &nd); + if (error) + goto exit_dput; + error = __do_follow_link(&path, &nd, &cookie); + if (unlikely(error)) { + /* nd.path had been dropped */ + if (!IS_ERR(cookie) && inode->i_op->put_link) + inode->i_op->put_link(path.dentry, &nd, cookie); + path_put(&path); + release_open_intent(&nd); filp = ERR_PTR(error); + goto out; } + holder = path; + nd.flags &= ~LOOKUP_PARENT; + filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname, &want_dir); + if (inode->i_op->put_link) + inode->i_op->put_link(holder.dentry, &nd, cookie); + path_put(&holder); } - if (!IS_ERR(filp)) { - if (will_truncate) { - error = handle_truncate(&nd.path); - if (error) { - fput(filp); - filp = ERR_PTR(error); - } - } - } - /* - * It is now safe to drop the mnt write - * because the filp has had a write taken - * on its behalf. - */ - if (will_truncate) - mnt_drop_write(nd.path.mnt); +out: if (nd.root.mnt) path_put(&nd.root); + if (filp == ERR_PTR(-ESTALE) && !force_reval) { + force_reval = 1; + goto reval; + } return filp; -exit_mutex_unlock: - mutex_unlock(&dir->d_inode->i_mutex); exit_dput: path_put_conditional(&path, &nd); -exit: if (!IS_ERR(nd.intent.open.file)) release_open_intent(&nd); exit_parent: - if (nd.root.mnt) - path_put(&nd.root); path_put(&nd.path); - return ERR_PTR(error); - -do_link: - error = -ELOOP; - if (flag & O_NOFOLLOW) - goto exit_dput; - /* - * This is subtle. Instead of calling do_follow_link() we do the - * thing by hands. The reason is that this way we have zero link_count - * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT. - * After that we have the parent and last component, i.e. - * we are in the same situation as after the first path_walk(). - * Well, almost - if the last component is normal we get its copy - * stored in nd->last.name and we will have to putname() it when we - * are done. Procfs-like symlinks just set LAST_BIND. - */ - nd.flags |= LOOKUP_PARENT; - error = security_inode_follow_link(path.dentry, &nd); - if (error) - goto exit_dput; - error = __do_follow_link(&path, &nd); - path_put(&path); - if (error) { - /* Does someone understand code flow here? Or it is only - * me so stupid? Anathema to whoever designed this non-sense - * with "intent.open". - */ - release_open_intent(&nd); - if (nd.root.mnt) - path_put(&nd.root); - if (error == -ESTALE && !force_reval) { - force_reval = 1; - goto reval; - } - return ERR_PTR(error); - } - nd.flags &= ~LOOKUP_PARENT; - if (nd.last_type == LAST_BIND) - goto ok; - error = -EISDIR; - if (nd.last_type != LAST_NORM) - goto exit; - if (nd.last.name[nd.last.len]) { - __putname(nd.last.name); - goto exit; - } - error = -ELOOP; - if (count++==32) { - __putname(nd.last.name); - goto exit; - } - dir = nd.path.dentry; - mutex_lock(&dir->d_inode->i_mutex); - path.dentry = lookup_hash(&nd); - path.mnt = nd.path.mnt; - __putname(nd.last.name); - goto do_last; + filp = ERR_PTR(error); + goto out; } /** @@ -2264,8 +2254,11 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry) error = -EBUSY; else { error = security_inode_unlink(dir, dentry); - if (!error) + if (!error) { error = dir->i_op->unlink(dir, dentry); + if (!error) + dentry->d_inode->i_flags |= S_DEAD; + } } mutex_unlock(&dentry->d_inode->i_mutex); @@ -2616,6 +2609,8 @@ static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, else error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); if (!error) { + if (target) + target->i_flags |= S_DEAD; if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) d_move(old_dentry, new_dentry); } @@ -2655,11 +2650,9 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry); else error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry); - if (!error) { - const char *new_name = old_dentry->d_name.name; - fsnotify_move(old_dir, new_dir, old_name, new_name, is_dir, + if (!error) + fsnotify_move(old_dir, new_dir, old_name, is_dir, new_dentry->d_inode, old_dentry); - } fsnotify_oldname_free(old_name); return error; |