diff options
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 1579 |
1 files changed, 1079 insertions, 500 deletions
diff --git a/fs/namei.c b/fs/namei.c index 7d694194024a..8b61d103a8a7 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -117,18 +117,70 @@ * POSIX.1 2.4: an empty pathname is invalid (ENOENT). * PATH_MAX includes the nul terminator --RR. */ -static char *getname_flags(const char __user *filename, int flags, int *empty) +void final_putname(struct filename *name) { - char *result = __getname(), *err; + if (name->separate) { + __putname(name->name); + kfree(name); + } else { + __putname(name); + } +} + +#define EMBEDDED_NAME_MAX (PATH_MAX - sizeof(struct filename)) + +static struct filename * +getname_flags(const char __user *filename, int flags, int *empty) +{ + struct filename *result, *err; int len; + long max; + char *kname; + result = audit_reusename(filename); + if (result) + return result; + + result = __getname(); if (unlikely(!result)) return ERR_PTR(-ENOMEM); - len = strncpy_from_user(result, filename, PATH_MAX); - err = ERR_PTR(len); - if (unlikely(len < 0)) + /* + * First, try to embed the struct filename inside the names_cache + * allocation + */ + kname = (char *)result + sizeof(*result); + result->name = kname; + result->separate = false; + max = EMBEDDED_NAME_MAX; + +recopy: + len = strncpy_from_user(kname, filename, max); + if (unlikely(len < 0)) { + err = ERR_PTR(len); goto error; + } + + /* + * Uh-oh. We have a name that's approaching PATH_MAX. Allocate a + * separate struct filename so we can dedicate the entire + * names_cache allocation for the pathname, and re-do the copy from + * userland. + */ + if (len == EMBEDDED_NAME_MAX && max == EMBEDDED_NAME_MAX) { + kname = (char *)result; + + result = kzalloc(sizeof(*result), GFP_KERNEL); + if (!result) { + err = ERR_PTR(-ENOMEM); + result = (struct filename *)kname; + goto error; + } + result->name = kname; + result->separate = true; + max = PATH_MAX; + goto recopy; + } /* The empty path is special. */ if (unlikely(!len)) { @@ -140,30 +192,32 @@ static char *getname_flags(const char __user *filename, int flags, int *empty) } err = ERR_PTR(-ENAMETOOLONG); - if (likely(len < PATH_MAX)) { - audit_getname(result); - return result; - } + if (unlikely(len >= PATH_MAX)) + goto error; + + result->uptr = filename; + audit_getname(result); + return result; error: - __putname(result); + final_putname(result); return err; } -char *getname(const char __user * filename) +struct filename * +getname(const char __user * filename) { return getname_flags(filename, 0, NULL); } +EXPORT_SYMBOL(getname); #ifdef CONFIG_AUDITSYSCALL -void putname(const char *name) +void putname(struct filename *name) { if (unlikely(!audit_dummy_context())) - audit_putname(name); - else - __putname(name); + return audit_putname(name); + final_putname(name); } -EXPORT_SYMBOL(putname); #endif static int check_acl(struct inode *inode, int mask) @@ -315,31 +369,22 @@ 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, ...) + * __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) * - * 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. + * Check for read/write/execute permissions on an inode. * * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask. + * + * This does not check for a read-only file system. You probably want + * inode_permission(). */ -int inode_permission(struct inode *inode, int mask) +int __inode_permission(struct inode *inode, int mask) { int retval; if (unlikely(mask & MAY_WRITE)) { - umode_t mode = inode->i_mode; - - /* - * Nobody gets write access to a read-only fs. - */ - if (IS_RDONLY(inode) && - (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) - return -EROFS; - /* * Nobody gets write access to an immutable file. */ @@ -359,12 +404,54 @@ int inode_permission(struct inode *inode, int mask) } /** + * sb_permission - Check superblock-level permissions + * @sb: Superblock of inode to check permission on + * @inode: Inode to check permission on + * @mask: Right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) + * + * Separate out file-system wide checks from inode-specific permission checks. + */ +static int sb_permission(struct super_block *sb, struct inode *inode, int mask) +{ + if (unlikely(mask & MAY_WRITE)) { + umode_t mode = inode->i_mode; + + /* Nobody gets write access to a read-only fs. */ + if ((sb->s_flags & MS_RDONLY) && + (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) + return -EROFS; + } + return 0; +} + +/** + * 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) + * + * Check for read/write/execute permissions on an inode. We use fs[ug]id 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) +{ + int retval; + + retval = sb_permission(inode->i_sb, inode, mask); + if (retval) + return retval; + return __inode_permission(inode, mask); +} + +/** * path_get - get a reference to a path * @path: path to get the reference to * * Given a path increment the reference count to the dentry and the vfsmount. */ -void path_get(struct path *path) +void path_get(const struct path *path) { mntget(path->mnt); dget(path->dentry); @@ -377,7 +464,7 @@ EXPORT_SYMBOL(path_get); * * Given a path decrement the reference count to the dentry and the vfsmount. */ -void path_put(struct path *path) +void path_put(const struct path *path) { dput(path->dentry); mntput(path->mnt); @@ -395,6 +482,18 @@ EXPORT_SYMBOL(path_put); * to restart the path walk from the beginning in ref-walk mode. */ +static inline void lock_rcu_walk(void) +{ + br_read_lock(&vfsmount_lock); + rcu_read_lock(); +} + +static inline void unlock_rcu_walk(void) +{ + rcu_read_unlock(); + br_read_unlock(&vfsmount_lock); +} + /** * unlazy_walk - try to switch to ref-walk mode. * @nd: nameidata pathwalk data @@ -448,8 +547,7 @@ static int unlazy_walk(struct nameidata *nd, struct dentry *dentry) } mntget(nd->path.mnt); - rcu_read_unlock(); - br_read_unlock(&vfsmount_lock); + unlock_rcu_walk(); nd->flags &= ~LOOKUP_RCU; return 0; @@ -463,25 +561,9 @@ err_root: return -ECHILD; } -/** - * release_open_intent - free up open intent resources - * @nd: pointer to nameidata - */ -void release_open_intent(struct nameidata *nd) -{ - struct file *file = nd->intent.open.file; - - if (file && !IS_ERR(file)) { - if (file->f_path.dentry == NULL) - put_filp(file); - else - fput(file); - } -} - -static inline int d_revalidate(struct dentry *dentry, struct nameidata *nd) +static inline int d_revalidate(struct dentry *dentry, unsigned int flags) { - return dentry->d_op->d_revalidate(dentry, nd); + return dentry->d_op->d_revalidate(dentry, flags); } /** @@ -506,28 +588,22 @@ static int complete_walk(struct nameidata *nd) spin_lock(&dentry->d_lock); if (unlikely(!__d_rcu_to_refcount(dentry, nd->seq))) { spin_unlock(&dentry->d_lock); - rcu_read_unlock(); - br_read_unlock(&vfsmount_lock); + unlock_rcu_walk(); return -ECHILD; } BUG_ON(nd->inode != dentry->d_inode); spin_unlock(&dentry->d_lock); mntget(nd->path.mnt); - rcu_read_unlock(); - br_read_unlock(&vfsmount_lock); + unlock_rcu_walk(); } if (likely(!(nd->flags & LOOKUP_JUMPED))) return 0; - if (likely(!(dentry->d_flags & DCACHE_OP_REVALIDATE))) - return 0; - - if (likely(!(dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT))) + if (likely(!(dentry->d_flags & DCACHE_OP_WEAK_REVALIDATE))) return 0; - /* Note: we do not d_invalidate() */ - status = d_revalidate(dentry, nd); + status = dentry->d_op->d_weak_revalidate(dentry, nd->flags); if (status > 0) return 0; @@ -602,30 +678,159 @@ static inline void path_to_nameidata(const struct path *path, nd->path.dentry = path->dentry; } +/* + * Helper to directly jump to a known parsed path from ->follow_link, + * caller must have taken a reference to path beforehand. + */ +void nd_jump_link(struct nameidata *nd, struct path *path) +{ + path_put(&nd->path); + + nd->path = *path; + nd->inode = nd->path.dentry->d_inode; + nd->flags |= LOOKUP_JUMPED; +} + static inline void put_link(struct nameidata *nd, struct path *link, void *cookie) { struct inode *inode = link->dentry->d_inode; - if (!IS_ERR(cookie) && inode->i_op->put_link) + if (inode->i_op->put_link) inode->i_op->put_link(link->dentry, nd, cookie); path_put(link); } +int sysctl_protected_symlinks __read_mostly = 0; +int sysctl_protected_hardlinks __read_mostly = 0; + +/** + * may_follow_link - Check symlink following for unsafe situations + * @link: The path of the symlink + * @nd: nameidata pathwalk data + * + * In the case of the sysctl_protected_symlinks sysctl being enabled, + * CAP_DAC_OVERRIDE needs to be specifically ignored if the symlink is + * in a sticky world-writable directory. This is to protect privileged + * processes from failing races against path names that may change out + * from under them by way of other users creating malicious symlinks. + * It will permit symlinks to be followed only when outside a sticky + * world-writable directory, or when the uid of the symlink and follower + * match, or when the directory owner matches the symlink's owner. + * + * Returns 0 if following the symlink is allowed, -ve on error. + */ +static inline int may_follow_link(struct path *link, struct nameidata *nd) +{ + const struct inode *inode; + const struct inode *parent; + + if (!sysctl_protected_symlinks) + return 0; + + /* Allowed if owner and follower match. */ + inode = link->dentry->d_inode; + if (uid_eq(current_cred()->fsuid, inode->i_uid)) + return 0; + + /* Allowed if parent directory not sticky and world-writable. */ + parent = nd->path.dentry->d_inode; + if ((parent->i_mode & (S_ISVTX|S_IWOTH)) != (S_ISVTX|S_IWOTH)) + return 0; + + /* Allowed if parent directory and link owner match. */ + if (uid_eq(parent->i_uid, inode->i_uid)) + return 0; + + audit_log_link_denied("follow_link", link); + path_put_conditional(link, nd); + path_put(&nd->path); + return -EACCES; +} + +/** + * safe_hardlink_source - Check for safe hardlink conditions + * @inode: the source inode to hardlink from + * + * Return false if at least one of the following conditions: + * - inode is not a regular file + * - inode is setuid + * - inode is setgid and group-exec + * - access failure for read and write + * + * Otherwise returns true. + */ +static bool safe_hardlink_source(struct inode *inode) +{ + umode_t mode = inode->i_mode; + + /* Special files should not get pinned to the filesystem. */ + if (!S_ISREG(mode)) + return false; + + /* Setuid files should not get pinned to the filesystem. */ + if (mode & S_ISUID) + return false; + + /* Executable setgid files should not get pinned to the filesystem. */ + if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) + return false; + + /* Hardlinking to unreadable or unwritable sources is dangerous. */ + if (inode_permission(inode, MAY_READ | MAY_WRITE)) + return false; + + return true; +} + +/** + * may_linkat - Check permissions for creating a hardlink + * @link: the source to hardlink from + * + * Block hardlink when all of: + * - sysctl_protected_hardlinks enabled + * - fsuid does not match inode + * - hardlink source is unsafe (see safe_hardlink_source() above) + * - not CAP_FOWNER + * + * Returns 0 if successful, -ve on error. + */ +static int may_linkat(struct path *link) +{ + const struct cred *cred; + struct inode *inode; + + if (!sysctl_protected_hardlinks) + return 0; + + cred = current_cred(); + inode = link->dentry->d_inode; + + /* Source inode owner (or CAP_FOWNER) can hardlink all they like, + * otherwise, it must be a safe source. + */ + if (uid_eq(cred->fsuid, inode->i_uid) || safe_hardlink_source(inode) || + capable(CAP_FOWNER)) + return 0; + + audit_log_link_denied("linkat", link); + return -EPERM; +} + static __always_inline int follow_link(struct path *link, struct nameidata *nd, void **p) { - int error; struct dentry *dentry = link->dentry; + int error; + char *s; BUG_ON(nd->flags & LOOKUP_RCU); if (link->mnt == nd->path.mnt) mntget(link->mnt); - if (unlikely(current->total_link_count >= 40)) { - *p = ERR_PTR(-ELOOP); /* no ->put_link(), please */ - path_put(&nd->path); - return -ELOOP; - } + error = -ELOOP; + if (unlikely(current->total_link_count >= 40)) + goto out_put_nd_path; + cond_resched(); current->total_link_count++; @@ -633,30 +838,29 @@ follow_link(struct path *link, struct nameidata *nd, void **p) nd_set_link(nd, NULL); error = security_inode_follow_link(link->dentry, nd); - if (error) { - *p = ERR_PTR(error); /* no ->put_link(), please */ - path_put(&nd->path); - return error; - } + if (error) + goto out_put_nd_path; nd->last_type = LAST_BIND; *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) - error = __vfs_follow_link(nd, s); - else if (nd->last_type == LAST_BIND) { - nd->flags |= LOOKUP_JUMPED; - nd->inode = nd->path.dentry->d_inode; - if (nd->inode->i_op->follow_link) { - /* stepped on a _really_ weird one */ - path_put(&nd->path); - error = -ELOOP; - } - } + if (IS_ERR(*p)) + goto out_put_nd_path; + + error = 0; + s = nd_get_link(nd); + if (s) { + error = __vfs_follow_link(nd, s); + if (unlikely(error)) + put_link(nd, link, *p); } + + return error; + +out_put_nd_path: + *p = NULL; + path_put(&nd->path); + path_put(link); return error; } @@ -675,6 +879,16 @@ static int follow_up_rcu(struct path *path) return 1; } +/* + * follow_up - Find the mountpoint of path's vfsmount + * + * Given a path, find the mountpoint of its source file system. + * Replace @path with the path of the mountpoint in the parent mount. + * Up is towards /. + * + * Return 1 if we went up a level and 0 if we were already at the + * root. + */ int follow_up(struct path *path) { struct mount *mnt = real_mount(path->mnt); @@ -683,7 +897,7 @@ int follow_up(struct path *path) br_read_lock(&vfsmount_lock); parent = mnt->mnt_parent; - if (&parent->mnt == path->mnt) { + if (parent == mnt) { br_read_unlock(&vfsmount_lock); return 0; } @@ -946,8 +1160,7 @@ failed: nd->flags &= ~LOOKUP_RCU; if (!(nd->flags & LOOKUP_ROOT)) nd->root.mnt = NULL; - rcu_read_unlock(); - br_read_unlock(&vfsmount_lock); + unlock_rcu_walk(); return -ECHILD; } @@ -1048,7 +1261,7 @@ static void follow_dotdot(struct nameidata *nd) * dir->d_inode->i_mutex must be held */ static struct dentry *lookup_dcache(struct qstr *name, struct dentry *dir, - struct nameidata *nd, bool *need_lookup) + unsigned int flags, bool *need_lookup) { struct dentry *dentry; int error; @@ -1056,10 +1269,8 @@ static struct dentry *lookup_dcache(struct qstr *name, struct dentry *dir, *need_lookup = false; dentry = d_lookup(dir, name); if (dentry) { - if (d_need_lookup(dentry)) { - *need_lookup = true; - } else if (dentry->d_flags & DCACHE_OP_REVALIDATE) { - error = d_revalidate(dentry, nd); + if (dentry->d_flags & DCACHE_OP_REVALIDATE) { + error = d_revalidate(dentry, flags); if (unlikely(error <= 0)) { if (error < 0) { dput(dentry); @@ -1089,7 +1300,7 @@ static struct dentry *lookup_dcache(struct qstr *name, struct dentry *dir, * dir->d_inode->i_mutex must be held */ static struct dentry *lookup_real(struct inode *dir, struct dentry *dentry, - struct nameidata *nd) + unsigned int flags) { struct dentry *old; @@ -1099,7 +1310,7 @@ static struct dentry *lookup_real(struct inode *dir, struct dentry *dentry, return ERR_PTR(-ENOENT); } - old = dir->i_op->lookup(dir, dentry, nd); + old = dir->i_op->lookup(dir, dentry, flags); if (unlikely(old)) { dput(dentry); dentry = old; @@ -1108,16 +1319,16 @@ static struct dentry *lookup_real(struct inode *dir, struct dentry *dentry, } static struct dentry *__lookup_hash(struct qstr *name, - struct dentry *base, struct nameidata *nd) + struct dentry *base, unsigned int flags) { bool need_lookup; struct dentry *dentry; - dentry = lookup_dcache(name, base, nd, &need_lookup); + dentry = lookup_dcache(name, base, flags, &need_lookup); if (!need_lookup) return dentry; - return lookup_real(base->d_inode, dentry, nd); + return lookup_real(base->d_inode, dentry, flags); } /* @@ -1125,7 +1336,7 @@ static struct dentry *__lookup_hash(struct qstr *name, * small and for now I'd prefer to have fast path as straight as possible. * It _is_ time-critical. */ -static int lookup_fast(struct nameidata *nd, struct qstr *name, +static int lookup_fast(struct nameidata *nd, struct path *path, struct inode **inode) { struct vfsmount *mnt = nd->path.mnt; @@ -1141,7 +1352,7 @@ static int lookup_fast(struct nameidata *nd, struct qstr *name, */ if (nd->flags & LOOKUP_RCU) { unsigned seq; - dentry = __d_lookup_rcu(parent, name, &seq, nd->inode); + dentry = __d_lookup_rcu(parent, &nd->last, &seq); if (!dentry) goto unlazy; @@ -1164,10 +1375,8 @@ static int lookup_fast(struct nameidata *nd, struct qstr *name, return -ECHILD; nd->seq = seq; - if (unlikely(d_need_lookup(dentry))) - goto unlazy; if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) { - status = d_revalidate(dentry, nd); + status = d_revalidate(dentry, nd->flags); if (unlikely(status <= 0)) { if (status != -ECHILD) need_reval = 0; @@ -1185,19 +1394,14 @@ unlazy: if (unlazy_walk(nd, dentry)) return -ECHILD; } else { - dentry = __d_lookup(parent, name); + dentry = __d_lookup(parent, &nd->last); } if (unlikely(!dentry)) goto need_lookup; - if (unlikely(d_need_lookup(dentry))) { - dput(dentry); - goto need_lookup; - } - if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE) && need_reval) - status = d_revalidate(dentry, nd); + status = d_revalidate(dentry, nd->flags); if (unlikely(status <= 0)) { if (status < 0) { dput(dentry); @@ -1226,8 +1430,7 @@ need_lookup: } /* Fast lookup failed, do it the slow way */ -static int lookup_slow(struct nameidata *nd, struct qstr *name, - struct path *path) +static int lookup_slow(struct nameidata *nd, struct path *path) { struct dentry *dentry, *parent; int err; @@ -1236,7 +1439,7 @@ static int lookup_slow(struct nameidata *nd, struct qstr *name, BUG_ON(nd->inode != parent->d_inode); mutex_lock(&parent->d_inode->i_mutex); - dentry = __lookup_hash(name, parent, nd); + dentry = __lookup_hash(&nd->last, parent, nd->flags); mutex_unlock(&parent->d_inode->i_mutex); if (IS_ERR(dentry)) return PTR_ERR(dentry); @@ -1284,8 +1487,7 @@ static void terminate_walk(struct nameidata *nd) nd->flags &= ~LOOKUP_RCU; if (!(nd->flags & LOOKUP_ROOT)) nd->root.mnt = NULL; - rcu_read_unlock(); - br_read_unlock(&vfsmount_lock); + unlock_rcu_walk(); } } @@ -1310,7 +1512,7 @@ static inline int should_follow_link(struct inode *inode, int follow) } static inline int walk_component(struct nameidata *nd, struct path *path, - struct qstr *name, int type, int follow) + int follow) { struct inode *inode; int err; @@ -1319,14 +1521,14 @@ static inline int walk_component(struct nameidata *nd, struct path *path, * to be able to know about the current root directory and * parent relationships. */ - if (unlikely(type != LAST_NORM)) - return handle_dots(nd, type); - err = lookup_fast(nd, name, path, &inode); + if (unlikely(nd->last_type != LAST_NORM)) + return handle_dots(nd, nd->last_type); + err = lookup_fast(nd, path, &inode); if (unlikely(err)) { if (err < 0) goto out_err; - err = lookup_slow(nd, name, path); + err = lookup_slow(nd, path); if (err < 0) goto out_err; @@ -1383,9 +1585,9 @@ static inline int nested_symlink(struct path *path, struct nameidata *nd) void *cookie; res = follow_link(&link, nd, &cookie); - if (!res) - res = walk_component(nd, path, &nd->last, - nd->last_type, LOOKUP_FOLLOW); + if (res) + break; + res = walk_component(nd, path, LOOKUP_FOLLOW); put_link(nd, &link, cookie); } while (res > 0); @@ -1585,15 +1787,17 @@ static int link_path_walk(const char *name, struct nameidata *nd) struct dentry *parent = nd->path.dentry; nd->flags &= ~LOOKUP_JUMPED; if (unlikely(parent->d_flags & DCACHE_OP_HASH)) { - err = parent->d_op->d_hash(parent, nd->inode, - &this); + err = parent->d_op->d_hash(parent, &this); if (err < 0) break; } } + nd->last = this; + nd->last_type = type; + if (!name[len]) - goto last_component; + return 0; /* * If it wasn't NUL, we know it was '/'. Skip that * slash, and continue until no more slashes. @@ -1602,10 +1806,11 @@ static int link_path_walk(const char *name, struct nameidata *nd) len++; } while (unlikely(name[len] == '/')); if (!name[len]) - goto last_component; + return 0; + name += len; - err = walk_component(nd, &next, &this, type, LOOKUP_FOLLOW); + err = walk_component(nd, &next, LOOKUP_FOLLOW); if (err < 0) return err; @@ -1614,16 +1819,10 @@ static int link_path_walk(const char *name, struct nameidata *nd) if (err) return err; } - if (can_lookup(nd->inode)) - continue; - err = -ENOTDIR; - break; - /* here ends the main loop */ - -last_component: - nd->last = this; - nd->last_type = type; - return 0; + if (!can_lookup(nd->inode)) { + err = -ENOTDIR; + break; + } } terminate_walk(nd); return err; @@ -1633,8 +1832,6 @@ static int path_init(int dfd, const char *name, unsigned int flags, struct nameidata *nd, struct file **fp) { int retval = 0; - int fput_needed; - struct file *file; nd->last_type = LAST_ROOT; /* if there are only slashes... */ nd->flags = flags | LOOKUP_JUMPED; @@ -1642,7 +1839,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, if (flags & LOOKUP_ROOT) { struct inode *inode = nd->root.dentry->d_inode; if (*name) { - if (!inode->i_op->lookup) + if (!can_lookup(inode)) return -ENOTDIR; retval = inode_permission(inode, MAY_EXEC); if (retval) @@ -1651,8 +1848,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, nd->path = nd->root; nd->inode = inode; if (flags & LOOKUP_RCU) { - br_read_lock(&vfsmount_lock); - rcu_read_lock(); + lock_rcu_walk(); nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); } else { path_get(&nd->path); @@ -1664,8 +1860,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, if (*name=='/') { if (flags & LOOKUP_RCU) { - br_read_lock(&vfsmount_lock); - rcu_read_lock(); + lock_rcu_walk(); set_root_rcu(nd); } else { set_root(nd); @@ -1677,8 +1872,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, struct fs_struct *fs = current->fs; unsigned seq; - br_read_lock(&vfsmount_lock); - rcu_read_lock(); + lock_rcu_walk(); do { seq = read_seqcount_begin(&fs->seq); @@ -1689,45 +1883,36 @@ static int path_init(int dfd, const char *name, unsigned int flags, get_fs_pwd(current->fs, &nd->path); } } else { + /* Caller must check execute permissions on the starting path component */ + struct fd f = fdget_raw(dfd); struct dentry *dentry; - file = fget_raw_light(dfd, &fput_needed); - retval = -EBADF; - if (!file) - goto out_fail; + if (!f.file) + return -EBADF; - dentry = file->f_path.dentry; + dentry = f.file->f_path.dentry; if (*name) { - retval = -ENOTDIR; - if (!S_ISDIR(dentry->d_inode->i_mode)) - goto fput_fail; - - retval = inode_permission(dentry->d_inode, MAY_EXEC); - if (retval) - goto fput_fail; + if (!can_lookup(dentry->d_inode)) { + fdput(f); + return -ENOTDIR; + } } - nd->path = file->f_path; + nd->path = f.file->f_path; if (flags & LOOKUP_RCU) { - if (fput_needed) - *fp = file; + if (f.need_put) + *fp = f.file; nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); - br_read_lock(&vfsmount_lock); - rcu_read_lock(); + lock_rcu_walk(); } else { - path_get(&file->f_path); - fput_light(file, fput_needed); + path_get(&nd->path); + fdput(f); } } nd->inode = nd->path.dentry->d_inode; return 0; - -fput_fail: - fput_light(file, fput_needed); -out_fail: - return retval; } static inline int lookup_last(struct nameidata *nd, struct path *path) @@ -1736,8 +1921,7 @@ static inline int lookup_last(struct nameidata *nd, struct path *path) nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; nd->flags &= ~LOOKUP_PARENT; - return walk_component(nd, path, &nd->last, nd->last_type, - nd->flags & LOOKUP_FOLLOW); + return walk_component(nd, path, nd->flags & LOOKUP_FOLLOW); } /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ @@ -1775,10 +1959,14 @@ static int path_lookupat(int dfd, const char *name, while (err > 0) { void *cookie; struct path link = path; + err = may_follow_link(&link, nd); + if (unlikely(err)) + break; nd->flags |= LOOKUP_PARENT; err = follow_link(&link, nd, &cookie); - if (!err) - err = lookup_last(nd, &path); + if (err) + break; + err = lookup_last(nd, &path); put_link(nd, &link, cookie); } } @@ -1787,7 +1975,7 @@ static int path_lookupat(int dfd, const char *name, err = complete_walk(nd); if (!err && nd->flags & LOOKUP_DIRECTORY) { - if (!nd->inode->i_op->lookup) { + if (!can_lookup(nd->inode)) { path_put(&nd->path); err = -ENOTDIR; } @@ -1803,27 +1991,50 @@ static int path_lookupat(int dfd, const char *name, return err; } -static int do_path_lookup(int dfd, const char *name, +static int filename_lookup(int dfd, struct filename *name, unsigned int flags, struct nameidata *nd) { - int retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd); + int retval = path_lookupat(dfd, name->name, flags | LOOKUP_RCU, nd); if (unlikely(retval == -ECHILD)) - retval = path_lookupat(dfd, name, flags, nd); + retval = path_lookupat(dfd, name->name, flags, nd); if (unlikely(retval == -ESTALE)) - retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL, nd); + retval = path_lookupat(dfd, name->name, + flags | LOOKUP_REVAL, nd); - if (likely(!retval)) { - if (unlikely(!audit_dummy_context())) { - if (nd->path.dentry && nd->inode) - audit_inode(name, nd->path.dentry); - } - } + if (likely(!retval)) + audit_inode(name, nd->path.dentry, flags & LOOKUP_PARENT); return retval; } -int kern_path_parent(const char *name, struct nameidata *nd) +static int do_path_lookup(int dfd, const char *name, + unsigned int flags, struct nameidata *nd) +{ + struct filename filename = { .name = name }; + + return filename_lookup(dfd, &filename, flags, nd); +} + +/* does lookup, returns the object with parent locked */ +struct dentry *kern_path_locked(const char *name, struct path *path) { - return do_path_lookup(AT_FDCWD, name, LOOKUP_PARENT, nd); + struct nameidata nd; + struct dentry *d; + int err = do_path_lookup(AT_FDCWD, name, LOOKUP_PARENT, &nd); + if (err) + return ERR_PTR(err); + if (nd.last_type != LAST_NORM) { + path_put(&nd.path); + return ERR_PTR(-EINVAL); + } + mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); + d = __lookup_hash(&nd.last, nd.path.dentry, 0); + if (IS_ERR(d)) { + mutex_unlock(&nd.path.dentry->d_inode->i_mutex); + path_put(&nd.path); + return d; + } + *path = nd.path; + return d; } int kern_path(const char *name, unsigned int flags, struct path *path) @@ -1866,7 +2077,7 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, */ static struct dentry *lookup_hash(struct nameidata *nd) { - return __lookup_hash(&nd->last, nd->path.dentry, nd); + return __lookup_hash(&nd->last, nd->path.dentry, nd->flags); } /** @@ -1894,6 +2105,11 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) if (!len) return ERR_PTR(-EACCES); + if (unlikely(name[0] == '.')) { + if (len < 2 || (len == 2 && name[1] == '.')) + return ERR_PTR(-EACCES); + } + while (len--) { c = *(const unsigned char *)name++; if (c == '/' || c == '\0') @@ -1904,7 +2120,7 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) * to use its own hash.. */ if (base->d_flags & DCACHE_OP_HASH) { - int err = base->d_op->d_hash(base, base->d_inode, &this); + int err = base->d_op->d_hash(base, &this); if (err < 0) return ERR_PTR(err); } @@ -1913,20 +2129,20 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) if (err) return ERR_PTR(err); - return __lookup_hash(&this, base, NULL); + return __lookup_hash(&this, base, 0); } 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, empty); + struct filename *tmp = getname_flags(name, flags, empty); int err = PTR_ERR(tmp); if (!IS_ERR(tmp)) { BUG_ON(flags & LOOKUP_PARENT); - err = do_path_lookup(dfd, tmp, flags, &nd); + err = filename_lookup(dfd, tmp, flags, &nd); putname(tmp); if (!err) *path = nd.path; @@ -1940,22 +2156,32 @@ int user_path_at(int dfd, const char __user *name, unsigned flags, return user_path_at_empty(dfd, name, flags, path, NULL); } -static int user_path_parent(int dfd, const char __user *path, - struct nameidata *nd, char **name) +/* + * NB: most callers don't do anything directly with the reference to the + * to struct filename, but the nd->last pointer points into the name string + * allocated by getname. So we must hold the reference to it until all + * path-walking is complete. + */ +static struct filename * +user_path_parent(int dfd, const char __user *path, struct nameidata *nd, + unsigned int flags) { - char *s = getname(path); + struct filename *s = getname(path); int error; + /* only LOOKUP_REVAL is allowed in extra flags */ + flags &= LOOKUP_REVAL; + if (IS_ERR(s)) - return PTR_ERR(s); + return s; - error = do_path_lookup(dfd, s, LOOKUP_PARENT, nd); - if (error) + error = filename_lookup(dfd, s, flags | LOOKUP_PARENT, nd); + if (error) { putname(s); - else - *name = s; + return ERR_PTR(error); + } - return error; + return s; } /* @@ -2002,7 +2228,7 @@ 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, dir); + audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE); error = inode_permission(dir, MAY_WRITE | MAY_EXEC); if (error) @@ -2086,10 +2312,9 @@ void unlock_rename(struct dentry *p1, struct dentry *p2) } int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, - struct nameidata *nd) + bool want_excl) { int error = may_create(dir, dentry); - if (error) return error; @@ -2100,7 +2325,7 @@ int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, error = security_inode_create(dir, dentry, mode); if (error) return error; - error = dir->i_op->create(dir, dentry, mode, nd); + error = dir->i_op->create(dir, dentry, mode, want_excl); if (!error) fsnotify_create(dir, dentry); return error; @@ -2187,103 +2412,229 @@ static inline int open_to_namei_flags(int flag) return flag; } +static int may_o_create(struct path *dir, struct dentry *dentry, umode_t mode) +{ + int error = security_path_mknod(dir, dentry, mode, 0); + if (error) + return error; + + error = inode_permission(dir->dentry->d_inode, MAY_WRITE | MAY_EXEC); + if (error) + return error; + + return security_inode_create(dir->dentry->d_inode, dentry, mode); +} + /* - * Handle the last step of open() + * Attempt to atomically look up, create and open a file from a negative + * dentry. + * + * Returns 0 if successful. The file will have been created and attached to + * @file by the filesystem calling finish_open(). + * + * Returns 1 if the file was looked up only or didn't need creating. The + * caller will need to perform the open themselves. @path will have been + * updated to point to the new dentry. This may be negative. + * + * Returns an error code otherwise. */ -static struct file *do_last(struct nameidata *nd, struct path *path, - const struct open_flags *op, const char *pathname) +static int atomic_open(struct nameidata *nd, struct dentry *dentry, + struct path *path, struct file *file, + const struct open_flags *op, + bool got_write, bool need_lookup, + int *opened) { - struct dentry *dir = nd->path.dentry; - struct dentry *dentry; - int open_flag = op->open_flag; - int will_truncate = open_flag & O_TRUNC; - int want_write = 0; - int acc_mode = op->acc_mode; - struct file *filp; - struct inode *inode; - int symlink_ok = 0; - struct path save_parent = { .dentry = NULL, .mnt = NULL }; - bool retried = false; + struct inode *dir = nd->path.dentry->d_inode; + unsigned open_flag = open_to_namei_flags(op->open_flag); + umode_t mode; int error; + int acc_mode; + int create_error = 0; + struct dentry *const DENTRY_NOT_SET = (void *) -1UL; - nd->flags &= ~LOOKUP_PARENT; - nd->flags |= op->intent; + BUG_ON(dentry->d_inode); - switch (nd->last_type) { - case LAST_DOTDOT: - case LAST_DOT: - error = handle_dots(nd, nd->last_type); - if (error) - return ERR_PTR(error); - /* fallthrough */ - case LAST_ROOT: - error = complete_walk(nd); - if (error) - return ERR_PTR(error); - audit_inode(pathname, nd->path.dentry); - if (open_flag & O_CREAT) { - error = -EISDIR; - goto exit; + /* Don't create child dentry for a dead directory. */ + if (unlikely(IS_DEADDIR(dir))) { + error = -ENOENT; + goto out; + } + + mode = op->mode; + if ((open_flag & O_CREAT) && !IS_POSIXACL(dir)) + mode &= ~current_umask(); + + if ((open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT)) { + open_flag &= ~O_TRUNC; + *opened |= FILE_CREATED; + } + + /* + * Checking write permission is tricky, bacuse we don't know if we are + * going to actually need it: O_CREAT opens should work as long as the + * file exists. But checking existence breaks atomicity. The trick is + * to check access and if not granted clear O_CREAT from the flags. + * + * Another problem is returing the "right" error value (e.g. for an + * O_EXCL open we want to return EEXIST not EROFS). + */ + if (((open_flag & (O_CREAT | O_TRUNC)) || + (open_flag & O_ACCMODE) != O_RDONLY) && unlikely(!got_write)) { + if (!(open_flag & O_CREAT)) { + /* + * No O_CREATE -> atomicity not a requirement -> fall + * back to lookup + open + */ + goto no_open; + } else if (open_flag & (O_EXCL | O_TRUNC)) { + /* Fall back and fail with the right error */ + create_error = -EROFS; + goto no_open; + } else { + /* No side effects, safe to clear O_CREAT */ + create_error = -EROFS; + open_flag &= ~O_CREAT; } - goto ok; - case LAST_BIND: - error = complete_walk(nd); - if (error) - return ERR_PTR(error); - audit_inode(pathname, dir); - goto ok; } - if (!(open_flag & O_CREAT)) { - if (nd->last.name[nd->last.len]) - nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; - if (open_flag & O_PATH && !(nd->flags & LOOKUP_FOLLOW)) - symlink_ok = 1; - /* we _can_ be in RCU mode here */ - error = lookup_fast(nd, &nd->last, path, &inode); - if (unlikely(error)) { - if (error < 0) - goto exit; + if (open_flag & O_CREAT) { + error = may_o_create(&nd->path, dentry, mode); + if (error) { + create_error = error; + if (open_flag & O_EXCL) + goto no_open; + open_flag &= ~O_CREAT; + } + } - error = lookup_slow(nd, &nd->last, path); - if (error < 0) - goto exit; + if (nd->flags & LOOKUP_DIRECTORY) + open_flag |= O_DIRECTORY; - inode = path->dentry->d_inode; + file->f_path.dentry = DENTRY_NOT_SET; + file->f_path.mnt = nd->path.mnt; + error = dir->i_op->atomic_open(dir, dentry, file, open_flag, mode, + opened); + if (error < 0) { + if (create_error && error == -ENOENT) + error = create_error; + goto out; + } + + acc_mode = op->acc_mode; + if (*opened & FILE_CREATED) { + fsnotify_create(dir, dentry); + acc_mode = MAY_OPEN; + } + + if (error) { /* returned 1, that is */ + if (WARN_ON(file->f_path.dentry == DENTRY_NOT_SET)) { + error = -EIO; + goto out; + } + if (file->f_path.dentry) { + dput(dentry); + dentry = file->f_path.dentry; } - goto finish_lookup; + if (create_error && dentry->d_inode == NULL) { + error = create_error; + goto out; + } + goto looked_up; } - /* 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 + * We didn't have the inode before the open, so check open permission + * here. */ - error = complete_walk(nd); + error = may_open(&file->f_path, acc_mode, open_flag); if (error) - return ERR_PTR(error); + fput(file); - audit_inode(pathname, dir); - error = -EISDIR; - /* trailing slashes? */ - if (nd->last.name[nd->last.len]) - goto exit; - -retry_lookup: - mutex_lock(&dir->d_inode->i_mutex); +out: + dput(dentry); + return error; - dentry = lookup_hash(nd); - error = PTR_ERR(dentry); - if (IS_ERR(dentry)) { - mutex_unlock(&dir->d_inode->i_mutex); - goto exit; +no_open: + if (need_lookup) { + dentry = lookup_real(dir, dentry, nd->flags); + if (IS_ERR(dentry)) + return PTR_ERR(dentry); + + if (create_error) { + int open_flag = op->open_flag; + + error = create_error; + if ((open_flag & O_EXCL)) { + if (!dentry->d_inode) + goto out; + } else if (!dentry->d_inode) { + goto out; + } else if ((open_flag & O_TRUNC) && + S_ISREG(dentry->d_inode->i_mode)) { + goto out; + } + /* will fail later, go on to get the right error */ + } } - +looked_up: path->dentry = dentry; path->mnt = nd->path.mnt; + return 1; +} + +/* + * Look up and maybe create and open the last component. + * + * Must be called with i_mutex held on parent. + * + * Returns 0 if the file was successfully atomically created (if necessary) and + * opened. In this case the file will be returned attached to @file. + * + * Returns 1 if the file was not completely opened at this time, though lookups + * and creations will have been performed and the dentry returned in @path will + * be positive upon return if O_CREAT was specified. If O_CREAT wasn't + * specified then a negative dentry may be returned. + * + * An error code is returned otherwise. + * + * FILE_CREATE will be set in @*opened if the dentry was created and will be + * cleared otherwise prior to returning. + */ +static int lookup_open(struct nameidata *nd, struct path *path, + struct file *file, + const struct open_flags *op, + bool got_write, int *opened) +{ + struct dentry *dir = nd->path.dentry; + struct inode *dir_inode = dir->d_inode; + struct dentry *dentry; + int error; + bool need_lookup; + + *opened &= ~FILE_CREATED; + dentry = lookup_dcache(&nd->last, dir, nd->flags, &need_lookup); + if (IS_ERR(dentry)) + return PTR_ERR(dentry); + + /* Cached positive dentry: will open in f_op->open */ + if (!need_lookup && dentry->d_inode) + goto out_no_open; + + if ((nd->flags & LOOKUP_OPEN) && dir_inode->i_op->atomic_open) { + return atomic_open(nd, dentry, path, file, op, got_write, + need_lookup, opened); + } + + if (need_lookup) { + BUG_ON(dentry->d_inode); + + dentry = lookup_real(dir_inode, dentry, nd->flags); + if (IS_ERR(dentry)) + return PTR_ERR(dentry); + } /* Negative dentry, just create the file */ - if (!dentry->d_inode) { + if (!dentry->d_inode && (op->open_flag & O_CREAT)) { umode_t mode = op->mode; if (!IS_POSIXACL(dir->d_inode)) mode &= ~current_umask(); @@ -2292,36 +2643,145 @@ retry_lookup: * rw->ro transition does not occur between * the time when the file is created and when * a permanent write count is taken through - * the 'struct file' in nameidata_to_filp(). + * the 'struct file' in finish_open(). + */ + if (!got_write) { + error = -EROFS; + goto out_dput; + } + *opened |= FILE_CREATED; + error = security_path_mknod(&nd->path, dentry, mode, 0); + if (error) + goto out_dput; + error = vfs_create(dir->d_inode, dentry, mode, + nd->flags & LOOKUP_EXCL); + if (error) + goto out_dput; + } +out_no_open: + path->dentry = dentry; + path->mnt = nd->path.mnt; + return 1; + +out_dput: + dput(dentry); + return error; +} + +/* + * Handle the last step of open() + */ +static int do_last(struct nameidata *nd, struct path *path, + struct file *file, const struct open_flags *op, + int *opened, struct filename *name) +{ + struct dentry *dir = nd->path.dentry; + int open_flag = op->open_flag; + bool will_truncate = (open_flag & O_TRUNC) != 0; + bool got_write = false; + int acc_mode = op->acc_mode; + struct inode *inode; + bool symlink_ok = false; + struct path save_parent = { .dentry = NULL, .mnt = NULL }; + bool retried = false; + int error; + + nd->flags &= ~LOOKUP_PARENT; + nd->flags |= op->intent; + + if (nd->last_type != LAST_NORM) { + error = handle_dots(nd, nd->last_type); + if (error) + return error; + goto finish_open; + } + + if (!(open_flag & O_CREAT)) { + if (nd->last.name[nd->last.len]) + nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; + if (open_flag & O_PATH && !(nd->flags & LOOKUP_FOLLOW)) + symlink_ok = true; + /* we _can_ be in RCU mode here */ + error = lookup_fast(nd, path, &inode); + if (likely(!error)) + goto finish_lookup; + + if (error < 0) + goto out; + + BUG_ON(nd->inode != dir->d_inode); + } else { + /* 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 error; + + audit_inode(name, dir, LOOKUP_PARENT); + error = -EISDIR; + /* trailing slashes? */ + if (nd->last.name[nd->last.len]) + goto out; + } + +retry_lookup: + if (op->open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) { error = mnt_want_write(nd->path.mnt); + if (!error) + got_write = true; + /* + * do _not_ fail yet - we might not need that or fail with + * a different error; let lookup_open() decide; we'll be + * dropping this one anyway. + */ + } + mutex_lock(&dir->d_inode->i_mutex); + error = lookup_open(nd, path, file, op, got_write, opened); + mutex_unlock(&dir->d_inode->i_mutex); + + if (error <= 0) { if (error) - goto exit_mutex_unlock; - want_write = 1; + goto out; + + if ((*opened & FILE_CREATED) || + !S_ISREG(file_inode(file)->i_mode)) + will_truncate = false; + + audit_inode(name, file->f_path.dentry, 0); + goto opened; + } + + if (*opened & FILE_CREATED) { /* Don't check for write permission, don't truncate */ open_flag &= ~O_TRUNC; - will_truncate = 0; + will_truncate = false; acc_mode = MAY_OPEN; - error = security_path_mknod(&nd->path, dentry, mode, 0); - if (error) - goto exit_mutex_unlock; - error = vfs_create(dir->d_inode, dentry, mode, nd); - if (error) - goto exit_mutex_unlock; - mutex_unlock(&dir->d_inode->i_mutex); - dput(nd->path.dentry); - nd->path.dentry = dentry; - goto common; + path_to_nameidata(path, nd); + goto finish_open_created; } /* - * It already exists. + * create/update audit record if it already exists. */ - mutex_unlock(&dir->d_inode->i_mutex); - audit_inode(pathname, path->dentry); + if (path->dentry->d_inode) + audit_inode(name, path->dentry, 0); + + /* + * If atomic_open() acquired write access it is dropped now due to + * possible mount and symlink following (this might be optimized away if + * necessary...) + */ + if (got_write) { + mnt_drop_write(nd->path.mnt); + got_write = false; + } error = -EEXIST; - if (open_flag & O_EXCL) + if ((open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT)) goto exit_dput; error = follow_managed(path, nd->flags); @@ -2338,18 +2798,18 @@ finish_lookup: error = -ENOENT; if (!inode) { path_to_nameidata(path, nd); - goto exit; + goto out; } if (should_follow_link(inode, !symlink_ok)) { if (nd->flags & LOOKUP_RCU) { if (unlikely(unlazy_walk(nd, path->dentry))) { error = -ECHILD; - goto exit; + goto out; } } BUG_ON(inode != path->dentry->d_inode); - return NULL; + return 1; } if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path->mnt) { @@ -2362,122 +2822,194 @@ finish_lookup: } nd->inode = inode; /* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */ +finish_open: error = complete_walk(nd); if (error) { path_put(&save_parent); - return ERR_PTR(error); + return error; } + audit_inode(name, nd->path.dentry, 0); error = -EISDIR; if ((open_flag & O_CREAT) && S_ISDIR(nd->inode->i_mode)) - goto exit; + goto out; error = -ENOTDIR; - if ((nd->flags & LOOKUP_DIRECTORY) && !nd->inode->i_op->lookup) - goto exit; - audit_inode(pathname, nd->path.dentry); -ok: + if ((nd->flags & LOOKUP_DIRECTORY) && !can_lookup(nd->inode)) + goto out; if (!S_ISREG(nd->inode->i_mode)) - will_truncate = 0; + will_truncate = false; if (will_truncate) { error = mnt_want_write(nd->path.mnt); if (error) - goto exit; - want_write = 1; + goto out; + got_write = true; } -common: +finish_open_created: error = may_open(&nd->path, acc_mode, open_flag); if (error) - goto exit; - filp = nameidata_to_filp(nd); - if (filp == ERR_PTR(-EOPENSTALE) && save_parent.dentry && !retried) { - BUG_ON(save_parent.dentry != dir); - path_put(&nd->path); - nd->path = save_parent; - nd->inode = dir->d_inode; - save_parent.mnt = NULL; - save_parent.dentry = NULL; - if (want_write) { - mnt_drop_write(nd->path.mnt); - want_write = 0; - } - retried = true; - goto retry_lookup; - } - if (!IS_ERR(filp)) { - error = ima_file_check(filp, op->acc_mode); - if (error) { - fput(filp); - filp = ERR_PTR(error); - } + goto out; + file->f_path.mnt = nd->path.mnt; + error = finish_open(file, nd->path.dentry, NULL, opened); + if (error) { + if (error == -EOPENSTALE) + goto stale_open; + goto out; } - if (!IS_ERR(filp)) { - if (will_truncate) { - error = handle_truncate(filp); - if (error) { - fput(filp); - filp = ERR_PTR(error); - } - } +opened: + error = open_check_o_direct(file); + if (error) + goto exit_fput; + error = ima_file_check(file, op->acc_mode); + if (error) + goto exit_fput; + + if (will_truncate) { + error = handle_truncate(file); + if (error) + goto exit_fput; } out: - if (want_write) + if (got_write) mnt_drop_write(nd->path.mnt); path_put(&save_parent); terminate_walk(nd); - return filp; + return error; -exit_mutex_unlock: - mutex_unlock(&dir->d_inode->i_mutex); exit_dput: path_put_conditional(path, nd); -exit: - filp = ERR_PTR(error); goto out; +exit_fput: + fput(file); + goto out; + +stale_open: + /* If no saved parent or already retried then can't retry */ + if (!save_parent.dentry || retried) + goto out; + + BUG_ON(save_parent.dentry != dir); + path_put(&nd->path); + nd->path = save_parent; + nd->inode = dir->d_inode; + save_parent.mnt = NULL; + save_parent.dentry = NULL; + if (got_write) { + mnt_drop_write(nd->path.mnt); + got_write = false; + } + retried = true; + goto retry_lookup; } -static struct file *path_openat(int dfd, const char *pathname, +static int do_tmpfile(int dfd, struct filename *pathname, + struct nameidata *nd, int flags, + const struct open_flags *op, + struct file *file, int *opened) +{ + static const struct qstr name = QSTR_INIT("/", 1); + struct dentry *dentry, *child; + struct inode *dir; + int error = path_lookupat(dfd, pathname->name, + flags | LOOKUP_DIRECTORY, nd); + if (unlikely(error)) + return error; + error = mnt_want_write(nd->path.mnt); + if (unlikely(error)) + goto out; + /* we want directory to be writable */ + error = inode_permission(nd->inode, MAY_WRITE | MAY_EXEC); + if (error) + goto out2; + dentry = nd->path.dentry; + dir = dentry->d_inode; + if (!dir->i_op->tmpfile) { + error = -EOPNOTSUPP; + goto out2; + } + child = d_alloc(dentry, &name); + if (unlikely(!child)) { + error = -ENOMEM; + goto out2; + } + nd->flags &= ~LOOKUP_DIRECTORY; + nd->flags |= op->intent; + dput(nd->path.dentry); + nd->path.dentry = child; + error = dir->i_op->tmpfile(dir, nd->path.dentry, op->mode); + if (error) + goto out2; + audit_inode(pathname, nd->path.dentry, 0); + error = may_open(&nd->path, op->acc_mode, op->open_flag); + if (error) + goto out2; + file->f_path.mnt = nd->path.mnt; + error = finish_open(file, nd->path.dentry, NULL, opened); + if (error) + goto out2; + error = open_check_o_direct(file); + if (error) { + fput(file); + } else if (!(op->open_flag & O_EXCL)) { + struct inode *inode = file_inode(file); + spin_lock(&inode->i_lock); + inode->i_state |= I_LINKABLE; + spin_unlock(&inode->i_lock); + } +out2: + mnt_drop_write(nd->path.mnt); +out: + path_put(&nd->path); + return error; +} + +static struct file *path_openat(int dfd, struct filename *pathname, struct nameidata *nd, const struct open_flags *op, int flags) { struct file *base = NULL; - struct file *filp; + struct file *file; struct path path; + int opened = 0; int error; - filp = get_empty_filp(); - if (!filp) - return ERR_PTR(-ENFILE); + file = get_empty_filp(); + if (IS_ERR(file)) + return file; - filp->f_flags = op->open_flag; - nd->intent.open.file = filp; - nd->intent.open.flags = open_to_namei_flags(op->open_flag); - nd->intent.open.create_mode = op->mode; + file->f_flags = op->open_flag; - error = path_init(dfd, pathname, flags | LOOKUP_PARENT, nd, &base); + if (unlikely(file->f_flags & __O_TMPFILE)) { + error = do_tmpfile(dfd, pathname, nd, flags, op, file, &opened); + goto out; + } + + error = path_init(dfd, pathname->name, flags | LOOKUP_PARENT, nd, &base); if (unlikely(error)) - goto out_filp; + goto out; current->total_link_count = 0; - error = link_path_walk(pathname, nd); + error = link_path_walk(pathname->name, nd); if (unlikely(error)) - goto out_filp; + goto out; - filp = do_last(nd, &path, op, pathname); - while (unlikely(!filp)) { /* trailing symlink */ + error = do_last(nd, &path, file, op, &opened, pathname); + while (unlikely(error > 0)) { /* trailing symlink */ struct path link = path; void *cookie; if (!(nd->flags & LOOKUP_FOLLOW)) { path_put_conditional(&path, nd); path_put(&nd->path); - filp = ERR_PTR(-ELOOP); + error = -ELOOP; break; } + error = may_follow_link(&link, nd); + if (unlikely(error)) + break; nd->flags |= LOOKUP_PARENT; nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL); error = follow_link(&link, nd, &cookie); if (unlikely(error)) - filp = ERR_PTR(error); - else - filp = do_last(nd, &path, op, pathname); + break; + error = do_last(nd, &path, file, op, &opened, pathname); put_link(nd, &link, cookie); } out: @@ -2485,24 +3017,27 @@ out: path_put(&nd->root); if (base) fput(base); - release_open_intent(nd); - if (filp == ERR_PTR(-EOPENSTALE)) { - if (flags & LOOKUP_RCU) - filp = ERR_PTR(-ECHILD); - else - filp = ERR_PTR(-ESTALE); + if (!(opened & FILE_OPENED)) { + BUG_ON(!error); + put_filp(file); } - return filp; - -out_filp: - filp = ERR_PTR(error); - goto out; + if (unlikely(error)) { + if (error == -EOPENSTALE) { + if (flags & LOOKUP_RCU) + error = -ECHILD; + else + error = -ESTALE; + } + file = ERR_PTR(error); + } + return file; } -struct file *do_filp_open(int dfd, const char *pathname, - const struct open_flags *op, int flags) +struct file *do_filp_open(int dfd, struct filename *pathname, + const struct open_flags *op) { struct nameidata nd; + int flags = op->lookup_flags; struct file *filp; filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_RCU); @@ -2514,32 +3049,43 @@ struct file *do_filp_open(int dfd, const char *pathname, } struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt, - const char *name, const struct open_flags *op, int flags) + const char *name, const struct open_flags *op) { struct nameidata nd; struct file *file; + struct filename filename = { .name = name }; + int flags = op->lookup_flags | LOOKUP_ROOT; nd.root.mnt = mnt; nd.root.dentry = dentry; - flags |= LOOKUP_ROOT; - if (dentry->d_inode->i_op->follow_link && op->intent & LOOKUP_OPEN) return ERR_PTR(-ELOOP); - file = path_openat(-1, name, &nd, op, flags | LOOKUP_RCU); + file = path_openat(-1, &filename, &nd, op, flags | LOOKUP_RCU); if (unlikely(file == ERR_PTR(-ECHILD))) - file = path_openat(-1, name, &nd, op, flags); + file = path_openat(-1, &filename, &nd, op, flags); if (unlikely(file == ERR_PTR(-ESTALE))) - file = path_openat(-1, name, &nd, op, flags | LOOKUP_REVAL); + file = path_openat(-1, &filename, &nd, op, flags | LOOKUP_REVAL); return file; } -struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path, int is_dir) +struct dentry *kern_path_create(int dfd, const char *pathname, + struct path *path, unsigned int lookup_flags) { struct dentry *dentry = ERR_PTR(-EEXIST); struct nameidata nd; - int error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd); + int err2; + int error; + bool is_dir = (lookup_flags & LOOKUP_DIRECTORY); + + /* + * Note that only LOOKUP_REVAL and LOOKUP_DIRECTORY matter here. Any + * other flags passed in are ignored! + */ + lookup_flags &= LOOKUP_REVAL; + + error = do_path_lookup(dfd, pathname, LOOKUP_PARENT|lookup_flags, &nd); if (error) return ERR_PTR(error); @@ -2551,18 +3097,20 @@ struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path goto out; nd.flags &= ~LOOKUP_PARENT; nd.flags |= LOOKUP_CREATE | LOOKUP_EXCL; - nd.intent.open.flags = O_EXCL; + /* don't fail immediately if it's r/o, at least try to report other errors */ + err2 = mnt_want_write(nd.path.mnt); /* * Do the final lookup. */ mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); dentry = lookup_hash(&nd); if (IS_ERR(dentry)) - goto fail; + goto unlock; + error = -EEXIST; if (dentry->d_inode) - goto eexist; + goto fail; /* * Special case - lookup gave negative, but... we had foo/bar/ * From the vfs_mknod() POV we just have a negative dentry - @@ -2570,30 +3118,45 @@ struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path * been asking for (non-existent) directory. -ENOENT for you. */ if (unlikely(!is_dir && nd.last.name[nd.last.len])) { - dput(dentry); - dentry = ERR_PTR(-ENOENT); + error = -ENOENT; + goto fail; + } + if (unlikely(err2)) { + error = err2; goto fail; } *path = nd.path; return dentry; -eexist: - dput(dentry); - dentry = ERR_PTR(-EEXIST); fail: + dput(dentry); + dentry = ERR_PTR(error); +unlock: mutex_unlock(&nd.path.dentry->d_inode->i_mutex); + if (!err2) + mnt_drop_write(nd.path.mnt); out: path_put(&nd.path); return dentry; } EXPORT_SYMBOL(kern_path_create); -struct dentry *user_path_create(int dfd, const char __user *pathname, struct path *path, int is_dir) +void done_path_create(struct path *path, struct dentry *dentry) { - char *tmp = getname(pathname); + dput(dentry); + mutex_unlock(&path->dentry->d_inode->i_mutex); + mnt_drop_write(path->mnt); + path_put(path); +} +EXPORT_SYMBOL(done_path_create); + +struct dentry *user_path_create(int dfd, const char __user *pathname, + struct path *path, unsigned int lookup_flags) +{ + struct filename *tmp = getname(pathname); struct dentry *res; if (IS_ERR(tmp)) return ERR_CAST(tmp); - res = kern_path_create(dfd, tmp, path, is_dir); + res = kern_path_create(dfd, tmp->name, path, lookup_flags); putname(tmp); return res; } @@ -2649,28 +3212,24 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode, struct dentry *dentry; struct path path; int error; + unsigned int lookup_flags = 0; - if (S_ISDIR(mode)) - return -EPERM; - - dentry = user_path_create(dfd, filename, &path, 0); + error = may_mknod(mode); + if (error) + return error; +retry: + dentry = user_path_create(dfd, filename, &path, lookup_flags); if (IS_ERR(dentry)) return PTR_ERR(dentry); if (!IS_POSIXACL(path.dentry->d_inode)) mode &= ~current_umask(); - error = may_mknod(mode); - if (error) - goto out_dput; - error = mnt_want_write(path.mnt); - if (error) - goto out_dput; error = security_path_mknod(&path, dentry, mode, dev); if (error) - goto out_drop_write; + goto out; switch (mode & S_IFMT) { case 0: case S_IFREG: - error = vfs_create(path.dentry->d_inode,dentry,mode,NULL); + error = vfs_create(path.dentry->d_inode,dentry,mode,true); break; case S_IFCHR: case S_IFBLK: error = vfs_mknod(path.dentry->d_inode,dentry,mode, @@ -2680,13 +3239,12 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode, error = vfs_mknod(path.dentry->d_inode,dentry,mode,0); break; } -out_drop_write: - mnt_drop_write(path.mnt); -out_dput: - dput(dentry); - mutex_unlock(&path.dentry->d_inode->i_mutex); - path_put(&path); - +out: + done_path_create(&path, dentry); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } @@ -2725,26 +3283,23 @@ SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode) struct dentry *dentry; struct path path; int error; + unsigned int lookup_flags = LOOKUP_DIRECTORY; - dentry = user_path_create(dfd, pathname, &path, 1); +retry: + dentry = user_path_create(dfd, pathname, &path, lookup_flags); if (IS_ERR(dentry)) return PTR_ERR(dentry); if (!IS_POSIXACL(path.dentry->d_inode)) mode &= ~current_umask(); - error = mnt_want_write(path.mnt); - if (error) - goto out_dput; error = security_path_mkdir(&path, dentry, mode); - if (error) - goto out_drop_write; - error = vfs_mkdir(path.dentry->d_inode, dentry, mode); -out_drop_write: - mnt_drop_write(path.mnt); -out_dput: - dput(dentry); - mutex_unlock(&path.dentry->d_inode->i_mutex); - path_put(&path); + if (!error) + error = vfs_mkdir(path.dentry->d_inode, dentry, mode); + done_path_create(&path, dentry); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } @@ -2817,13 +3372,14 @@ out: static long do_rmdir(int dfd, const char __user *pathname) { int error = 0; - char * name; + struct filename *name; struct dentry *dentry; struct nameidata nd; - - error = user_path_parent(dfd, pathname, &nd, &name); - if (error) - return error; + unsigned int lookup_flags = 0; +retry: + name = user_path_parent(dfd, pathname, &nd, lookup_flags); + if (IS_ERR(name)) + return PTR_ERR(name); switch(nd.last_type) { case LAST_DOTDOT: @@ -2838,6 +3394,9 @@ static long do_rmdir(int dfd, const char __user *pathname) } nd.flags &= ~LOOKUP_PARENT; + error = mnt_want_write(nd.path.mnt); + if (error) + goto exit1; mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); dentry = lookup_hash(&nd); @@ -2848,22 +3407,22 @@ static long do_rmdir(int dfd, const char __user *pathname) error = -ENOENT; goto exit3; } - error = mnt_want_write(nd.path.mnt); - if (error) - goto exit3; error = security_path_rmdir(&nd.path, dentry); if (error) - goto exit4; + goto exit3; error = vfs_rmdir(nd.path.dentry->d_inode, dentry); -exit4: - mnt_drop_write(nd.path.mnt); exit3: dput(dentry); exit2: mutex_unlock(&nd.path.dentry->d_inode->i_mutex); + mnt_drop_write(nd.path.mnt); exit1: path_put(&nd.path); putname(name); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } return error; } @@ -2913,20 +3472,24 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry) static long do_unlinkat(int dfd, const char __user *pathname) { int error; - char *name; + struct filename *name; struct dentry *dentry; struct nameidata nd; struct inode *inode = NULL; - - error = user_path_parent(dfd, pathname, &nd, &name); - if (error) - return error; + unsigned int lookup_flags = 0; +retry: + name = user_path_parent(dfd, pathname, &nd, lookup_flags); + if (IS_ERR(name)) + return PTR_ERR(name); error = -EISDIR; if (nd.last_type != LAST_NORM) goto exit1; nd.flags &= ~LOOKUP_PARENT; + error = mnt_want_write(nd.path.mnt); + if (error) + goto exit1; mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); dentry = lookup_hash(&nd); @@ -2939,24 +3502,25 @@ static long do_unlinkat(int dfd, const char __user *pathname) if (!inode) goto slashes; ihold(inode); - error = mnt_want_write(nd.path.mnt); - if (error) - goto exit2; error = security_path_unlink(&nd.path, dentry); if (error) - goto exit3; + goto exit2; error = vfs_unlink(nd.path.dentry->d_inode, dentry); -exit3: - mnt_drop_write(nd.path.mnt); - exit2: +exit2: dput(dentry); } mutex_unlock(&nd.path.dentry->d_inode->i_mutex); if (inode) iput(inode); /* truncate the inode here */ + mnt_drop_write(nd.path.mnt); exit1: path_put(&nd.path); putname(name); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + inode = NULL; + goto retry; + } return error; slashes: @@ -3005,32 +3569,28 @@ SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, int, newdfd, const char __user *, newname) { int error; - char *from; + struct filename *from; struct dentry *dentry; struct path path; + unsigned int lookup_flags = 0; from = getname(oldname); if (IS_ERR(from)) return PTR_ERR(from); - - dentry = user_path_create(newdfd, newname, &path, 0); +retry: + dentry = user_path_create(newdfd, newname, &path, lookup_flags); error = PTR_ERR(dentry); if (IS_ERR(dentry)) goto out_putname; - error = mnt_want_write(path.mnt); - if (error) - goto out_dput; - error = security_path_symlink(&path, dentry, from); - if (error) - goto out_drop_write; - error = vfs_symlink(path.dentry->d_inode, dentry, from); -out_drop_write: - mnt_drop_write(path.mnt); -out_dput: - dput(dentry); - mutex_unlock(&path.dentry->d_inode->i_mutex); - path_put(&path); + error = security_path_symlink(&path, dentry, from->name); + if (!error) + error = vfs_symlink(path.dentry->d_inode, dentry, from->name); + done_path_create(&path, dentry); + if (retry_estale(error, lookup_flags)) { + lookup_flags |= LOOKUP_REVAL; + goto retry; + } out_putname: putname(from); return error; @@ -3073,12 +3633,18 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de mutex_lock(&inode->i_mutex); /* Make sure we don't allow creating hardlink to an unlinked file */ - if (inode->i_nlink == 0) + if (inode->i_nlink == 0 && !(inode->i_state & I_LINKABLE)) error = -ENOENT; else if (max_links && inode->i_nlink >= max_links) error = -EMLINK; else error = dir->i_op->link(old_dentry, dir, new_dentry); + + if (!error && (inode->i_state & I_LINKABLE)) { + spin_lock(&inode->i_lock); + inode->i_state &= ~I_LINKABLE; + spin_unlock(&inode->i_lock); + } mutex_unlock(&inode->i_mutex); if (!error) fsnotify_link(dir, inode, new_dentry); @@ -3117,12 +3683,13 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, if (flags & AT_SYMLINK_FOLLOW) how |= LOOKUP_FOLLOW; - +retry: error = user_path_at(olddfd, oldname, how, &old_path); if (error) return error; - new_dentry = user_path_create(newdfd, newname, &new_path, 0); + new_dentry = user_path_create(newdfd, newname, &new_path, + (how & LOOKUP_REVAL)); error = PTR_ERR(new_dentry); if (IS_ERR(new_dentry)) goto out; @@ -3130,19 +3697,19 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, error = -EXDEV; if (old_path.mnt != new_path.mnt) goto out_dput; - error = mnt_want_write(new_path.mnt); - if (error) + error = may_linkat(&old_path); + if (unlikely(error)) goto out_dput; error = security_path_link(old_path.dentry, &new_path, new_dentry); if (error) - goto out_drop_write; + goto out_dput; error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry); -out_drop_write: - mnt_drop_write(new_path.mnt); out_dput: - dput(new_dentry); - mutex_unlock(&new_path.dentry->d_inode->i_mutex); - path_put(&new_path); + done_path_create(&new_path, new_dentry); + if (retry_estale(error, how)) { + how |= LOOKUP_REVAL; + goto retry; + } out: path_put(&old_path); @@ -3313,17 +3880,23 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, struct dentry *old_dentry, *new_dentry; struct dentry *trap; struct nameidata oldnd, newnd; - char *from; - char *to; + struct filename *from; + struct filename *to; + unsigned int lookup_flags = 0; + bool should_retry = false; int error; - - error = user_path_parent(olddfd, oldname, &oldnd, &from); - if (error) +retry: + from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags); + if (IS_ERR(from)) { + error = PTR_ERR(from); goto exit; + } - error = user_path_parent(newdfd, newname, &newnd, &to); - if (error) + to = user_path_parent(newdfd, newname, &newnd, lookup_flags); + if (IS_ERR(to)) { + error = PTR_ERR(to); goto exit1; + } error = -EXDEV; if (oldnd.path.mnt != newnd.path.mnt) @@ -3338,6 +3911,10 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, if (newnd.last_type != LAST_NORM) goto exit2; + error = mnt_want_write(oldnd.path.mnt); + if (error) + goto exit2; + oldnd.flags &= ~LOOKUP_PARENT; newnd.flags &= ~LOOKUP_PARENT; newnd.flags |= LOOKUP_RENAME_TARGET; @@ -3373,29 +3950,32 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, if (new_dentry == trap) goto exit5; - error = mnt_want_write(oldnd.path.mnt); - if (error) - goto exit5; error = security_path_rename(&oldnd.path, old_dentry, &newnd.path, new_dentry); if (error) - goto exit6; + goto exit5; error = vfs_rename(old_dir->d_inode, old_dentry, new_dir->d_inode, new_dentry); -exit6: - mnt_drop_write(oldnd.path.mnt); exit5: dput(new_dentry); exit4: dput(old_dentry); exit3: unlock_rename(new_dir, old_dir); + mnt_drop_write(oldnd.path.mnt); exit2: + if (retry_estale(error, lookup_flags)) + should_retry = true; path_put(&newnd.path); putname(to); exit1: path_put(&oldnd.path); putname(from); + if (should_retry) { + should_retry = false; + lookup_flags |= LOOKUP_REVAL; + goto retry; + } exit: return error; } @@ -3546,8 +4126,7 @@ EXPORT_SYMBOL(user_path_at); EXPORT_SYMBOL(follow_down_one); EXPORT_SYMBOL(follow_down); EXPORT_SYMBOL(follow_up); -EXPORT_SYMBOL(get_write_access); /* binfmt_aout */ -EXPORT_SYMBOL(getname); +EXPORT_SYMBOL(get_write_access); /* nfsd */ EXPORT_SYMBOL(lock_rename); EXPORT_SYMBOL(lookup_one_len); EXPORT_SYMBOL(page_follow_link_light); |