diff options
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 220 |
1 files changed, 132 insertions, 88 deletions
diff --git a/fs/namei.c b/fs/namei.c index ecb7b95c2ca3..84a0e0b0111c 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -125,6 +125,13 @@ #define EMBEDDED_NAME_MAX (PATH_MAX - offsetof(struct filename, iname)) +static inline void initname(struct filename *name, const char __user *uptr) +{ + name->uptr = uptr; + name->aname = NULL; + atomic_set(&name->refcnt, 1); +} + struct filename * getname_flags(const char __user *filename, int flags) { @@ -203,10 +210,7 @@ getname_flags(const char __user *filename, int flags) return ERR_PTR(-ENAMETOOLONG); } } - - atomic_set(&result->refcnt, 1); - result->uptr = filename; - result->aname = NULL; + initname(result, filename); audit_getname(result); return result; } @@ -218,11 +222,6 @@ struct filename *getname_uflags(const char __user *filename, int uflags) return getname_flags(filename, flags); } -struct filename *getname(const char __user * filename) -{ - return getname_flags(filename, 0); -} - struct filename *__getname_maybe_null(const char __user *pathname) { struct filename *name; @@ -269,25 +268,27 @@ struct filename *getname_kernel(const char * filename) return ERR_PTR(-ENAMETOOLONG); } memcpy((char *)result->name, filename, len); - result->uptr = NULL; - result->aname = NULL; - atomic_set(&result->refcnt, 1); + initname(result, NULL); audit_getname(result); - return result; } EXPORT_SYMBOL(getname_kernel); void putname(struct filename *name) { + int refcnt; + if (IS_ERR_OR_NULL(name)) return; - if (WARN_ON_ONCE(!atomic_read(&name->refcnt))) - return; + refcnt = atomic_read(&name->refcnt); + if (refcnt != 1) { + if (WARN_ON_ONCE(!refcnt)) + return; - if (!atomic_dec_and_test(&name->refcnt)) - return; + if (!atomic_dec_and_test(&name->refcnt)) + return; + } if (name->name != name->iname) { __putname(name->name); @@ -1664,25 +1665,20 @@ static struct dentry *lookup_dcache(const struct qstr *name, return dentry; } -/* - * Parent directory has inode locked exclusive. This is one - * and only case when ->lookup() gets called on non in-lookup - * dentries - as the matter of fact, this only gets called - * when directory is guaranteed to have no in-lookup children - * at all. - */ -struct dentry *lookup_one_qstr_excl(const struct qstr *name, - struct dentry *base, - unsigned int flags) +static struct dentry *lookup_one_qstr_excl_raw(const struct qstr *name, + struct dentry *base, + unsigned int flags) { - struct dentry *dentry = lookup_dcache(name, base, flags); + struct dentry *dentry; struct dentry *old; - struct inode *dir = base->d_inode; + struct inode *dir; + dentry = lookup_dcache(name, base, flags); if (dentry) return dentry; /* Don't create child dentry for a dead directory. */ + dir = base->d_inode; if (unlikely(IS_DEADDIR(dir))) return ERR_PTR(-ENOENT); @@ -1697,6 +1693,34 @@ struct dentry *lookup_one_qstr_excl(const struct qstr *name, } return dentry; } + +/* + * Parent directory has inode locked exclusive. This is one + * and only case when ->lookup() gets called on non in-lookup + * dentries - as the matter of fact, this only gets called + * when directory is guaranteed to have no in-lookup children + * at all. + * Will return -ENOENT if name isn't found and LOOKUP_CREATE wasn't passed. + * Will return -EEXIST if name is found and LOOKUP_EXCL was passed. + */ +struct dentry *lookup_one_qstr_excl(const struct qstr *name, + struct dentry *base, unsigned int flags) +{ + struct dentry *dentry; + + dentry = lookup_one_qstr_excl_raw(name, base, flags); + if (IS_ERR(dentry)) + return dentry; + if (d_is_negative(dentry) && !(flags & LOOKUP_CREATE)) { + dput(dentry); + return ERR_PTR(-ENOENT); + } + if (d_is_positive(dentry) && (flags & LOOKUP_EXCL)) { + dput(dentry); + return ERR_PTR(-EEXIST); + } + return dentry; +} EXPORT_SYMBOL(lookup_one_qstr_excl); /** @@ -2728,23 +2752,48 @@ static int filename_parentat(int dfd, struct filename *name, /* does lookup, returns the object with parent locked */ static struct dentry *__kern_path_locked(int dfd, struct filename *name, struct path *path) { + struct path parent_path __free(path_put) = {}; struct dentry *d; struct qstr last; int type, error; - error = filename_parentat(dfd, name, 0, path, &last, &type); + error = filename_parentat(dfd, name, 0, &parent_path, &last, &type); if (error) return ERR_PTR(error); - if (unlikely(type != LAST_NORM)) { - path_put(path); + if (unlikely(type != LAST_NORM)) return ERR_PTR(-EINVAL); + inode_lock_nested(parent_path.dentry->d_inode, I_MUTEX_PARENT); + d = lookup_one_qstr_excl(&last, parent_path.dentry, 0); + if (IS_ERR(d)) { + inode_unlock(parent_path.dentry->d_inode); + return d; } - inode_lock_nested(path->dentry->d_inode, I_MUTEX_PARENT); - d = lookup_one_qstr_excl(&last, path->dentry, 0); + path->dentry = no_free_ptr(parent_path.dentry); + path->mnt = no_free_ptr(parent_path.mnt); + return d; +} + +struct dentry *kern_path_locked_negative(const char *name, struct path *path) +{ + struct path parent_path __free(path_put) = {}; + struct filename *filename __free(putname) = getname_kernel(name); + struct dentry *d; + struct qstr last; + int type, error; + + error = filename_parentat(AT_FDCWD, filename, 0, &parent_path, &last, &type); + if (error) + return ERR_PTR(error); + if (unlikely(type != LAST_NORM)) + return ERR_PTR(-EINVAL); + inode_lock_nested(parent_path.dentry->d_inode, I_MUTEX_PARENT); + d = lookup_one_qstr_excl_raw(&last, parent_path.dentry, 0); if (IS_ERR(d)) { - inode_unlock(path->dentry->d_inode); - path_put(path); + inode_unlock(parent_path.dentry->d_inode); + return d; } + path->dentry = no_free_ptr(parent_path.dentry); + path->mnt = no_free_ptr(parent_path.mnt); return d; } @@ -2863,15 +2912,14 @@ static int lookup_one_common(struct mnt_idmap *idmap, * Note that this routine is purely a helper for filesystem usage and should * not be called by generic code. * - * The caller must hold base->i_mutex. + * No locks need be held - only a counted reference to @base is needed. + * */ struct dentry *try_lookup_one_len(const char *name, struct dentry *base, int len) { struct qstr this; int err; - WARN_ON_ONCE(!inode_is_locked(base->d_inode)); - err = lookup_one_common(&nop_mnt_idmap, name, base, len, &this); if (err) return ERR_PTR(err); @@ -3415,6 +3463,8 @@ static int may_open(struct mnt_idmap *idmap, const struct path *path, if ((acc_mode & MAY_EXEC) && path_noexec(path)) return -EACCES; break; + default: + VFS_BUG_ON_INODE(1, inode); } error = inode_permission(idmap, inode, MAY_OPEN | acc_mode); @@ -3995,7 +4045,7 @@ static struct file *path_openat(struct nameidata *nd, WARN_ON(1); error = -EINVAL; } - fput(file); + fput_close(file); if (error == -EOPENSTALE) { if (flags & LOOKUP_RCU) error = -ECHILD; @@ -4078,27 +4128,13 @@ static struct dentry *filename_create(int dfd, struct filename *name, * '/', and a directory wasn't requested. */ if (last.name[last.len] && !want_dir) - create_flags = 0; + create_flags &= ~LOOKUP_CREATE; inode_lock_nested(path->dentry->d_inode, I_MUTEX_PARENT); dentry = lookup_one_qstr_excl(&last, path->dentry, reval_flag | create_flags); if (IS_ERR(dentry)) goto unlock; - error = -EEXIST; - if (d_is_positive(dentry)) - goto fail; - - /* - * Special case - lookup gave negative, but... we had foo/bar/ - * From the vfs_mknod() POV we just have a negative dentry - - * all is fine. Let's be bastards - you had / on the end, you've - * been asking for (non-existent) directory. -ENOENT for you. - */ - if (unlikely(!create_flags)) { - error = -ENOENT; - goto fail; - } if (unlikely(err2)) { error = err2; goto fail; @@ -4129,7 +4165,8 @@ EXPORT_SYMBOL(kern_path_create); void done_path_create(struct path *path, struct dentry *dentry) { - dput(dentry); + if (!IS_ERR(dentry)) + dput(dentry); inode_unlock(path->dentry->d_inode); mnt_drop_write(path->mnt); path_put(path); @@ -4275,7 +4312,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d } /** - * vfs_mkdir - create directory + * vfs_mkdir - create directory returning correct dentry if possible * @idmap: idmap of the mount the inode was found from * @dir: inode of the parent directory * @dentry: dentry of the child directory @@ -4288,32 +4325,51 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d * care to map the inode according to @idmap before checking permissions. * On non-idmapped mounts or if permission checking is to be performed on the * raw inode simply pass @nop_mnt_idmap. + * + * In the event that the filesystem does not use the *@dentry but leaves it + * negative or unhashes it and possibly splices a different one returning it, + * the original dentry is dput() and the alternate is returned. + * + * In case of an error the dentry is dput() and an ERR_PTR() is returned. */ -int vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, - struct dentry *dentry, umode_t mode) +struct dentry *vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode) { int error; unsigned max_links = dir->i_sb->s_max_links; + struct dentry *de; error = may_create(idmap, dir, dentry); if (error) - return error; + goto err; + error = -EPERM; if (!dir->i_op->mkdir) - return -EPERM; + goto err; mode = vfs_prepare_mode(idmap, dir, mode, S_IRWXUGO | S_ISVTX, 0); error = security_inode_mkdir(dir, dentry, mode); if (error) - return error; + goto err; + error = -EMLINK; if (max_links && dir->i_nlink >= max_links) - return -EMLINK; + goto err; - error = dir->i_op->mkdir(idmap, dir, dentry, mode); - if (!error) - fsnotify_mkdir(dir, dentry); - return error; + de = dir->i_op->mkdir(idmap, dir, dentry, mode); + error = PTR_ERR(de); + if (IS_ERR(de)) + goto err; + if (de) { + dput(dentry); + dentry = de; + } + fsnotify_mkdir(dir, dentry); + return dentry; + +err: + dput(dentry); + return ERR_PTR(error); } EXPORT_SYMBOL(vfs_mkdir); @@ -4333,8 +4389,10 @@ retry: error = security_path_mkdir(&path, dentry, mode_strip_umask(path.dentry->d_inode, mode)); if (!error) { - error = vfs_mkdir(mnt_idmap(path.mnt), path.dentry->d_inode, + dentry = vfs_mkdir(mnt_idmap(path.mnt), path.dentry->d_inode, dentry, mode); + if (IS_ERR(dentry)) + error = PTR_ERR(dentry); } done_path_create(&path, dentry); if (retry_estale(error, lookup_flags)) { @@ -4445,10 +4503,6 @@ retry: error = PTR_ERR(dentry); if (IS_ERR(dentry)) goto exit3; - if (!dentry->d_inode) { - error = -ENOENT; - goto exit4; - } error = security_path_rmdir(&path, dentry); if (error) goto exit4; @@ -4579,7 +4633,7 @@ retry_deleg: if (!IS_ERR(dentry)) { /* Why not before? Because we want correct error value */ - if (last.name[last.len] || d_is_negative(dentry)) + if (last.name[last.len]) goto slashes; inode = dentry->d_inode; ihold(inode); @@ -4613,9 +4667,7 @@ exit1: return error; slashes: - if (d_is_negative(dentry)) - error = -ENOENT; - else if (d_is_dir(dentry)) + if (d_is_dir(dentry)) error = -EISDIR; else error = -ENOTDIR; @@ -5115,7 +5167,8 @@ int do_renameat2(int olddfd, struct filename *from, int newdfd, struct qstr old_last, new_last; int old_type, new_type; struct inode *delegated_inode = NULL; - unsigned int lookup_flags = 0, target_flags = LOOKUP_RENAME_TARGET; + unsigned int lookup_flags = 0, target_flags = + LOOKUP_RENAME_TARGET | LOOKUP_CREATE; bool should_retry = false; int error = -EINVAL; @@ -5128,6 +5181,8 @@ int do_renameat2(int olddfd, struct filename *from, int newdfd, if (flags & RENAME_EXCHANGE) target_flags = 0; + if (flags & RENAME_NOREPLACE) + target_flags |= LOOKUP_EXCL; retry: error = filename_parentat(olddfd, from, lookup_flags, &old_path, @@ -5169,23 +5224,12 @@ retry_deleg: error = PTR_ERR(old_dentry); if (IS_ERR(old_dentry)) goto exit3; - /* source must exist */ - error = -ENOENT; - if (d_is_negative(old_dentry)) - goto exit4; new_dentry = lookup_one_qstr_excl(&new_last, new_path.dentry, lookup_flags | target_flags); error = PTR_ERR(new_dentry); if (IS_ERR(new_dentry)) goto exit4; - error = -EEXIST; - if ((flags & RENAME_NOREPLACE) && d_is_positive(new_dentry)) - goto exit5; if (flags & RENAME_EXCHANGE) { - error = -ENOENT; - if (d_is_negative(new_dentry)) - goto exit5; - if (!d_is_dir(new_dentry)) { error = -ENOTDIR; if (new_last.name[new_last.len]) |