diff options
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 970 |
1 files changed, 471 insertions, 499 deletions
diff --git a/fs/namei.c b/fs/namei.c index d11f404667e..1c0fca6e899 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -19,7 +19,6 @@ #include <linux/slab.h> #include <linux/fs.h> #include <linux/namei.h> -#include <linux/quotaops.h> #include <linux/pagemap.h> #include <linux/fsnotify.h> #include <linux/personality.h> @@ -35,7 +34,7 @@ #include <linux/fs_struct.h> #include <asm/uaccess.h> -#define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE]) +#include "internal.h" /* [Feb-1997 T. Schoebel-Theuer] * Fundamental changes in the pathname lookup mechanisms (namei) @@ -108,8 +107,6 @@ * any extra contention... */ -static int __link_path_walk(const char *name, struct nameidata *nd); - /* In order to reduce some races, while at the same time doing additional * checking and hopefully speeding things up, we copy filenames to the * kernel data space before using them.. @@ -234,6 +231,7 @@ int generic_permission(struct inode *inode, int mask, /* * Searching includes executable on directories, else just read. */ + mask &= MAY_READ | MAY_WRITE | MAY_EXEC; if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE))) if (capable(CAP_DAC_READ_SEARCH)) return 0; @@ -414,36 +412,55 @@ do_revalidate(struct dentry *dentry, struct nameidata *nd) } /* - * Internal lookup() using the new generic dcache. - * SMP-safe + * force_reval_path - force revalidation of a dentry + * + * In some situations the path walking code will trust dentries without + * revalidating them. This causes problems for filesystems that depend on + * d_revalidate to handle file opens (e.g. NFSv4). When FS_REVAL_DOT is set + * (which indicates that it's possible for the dentry to go stale), force + * a d_revalidate call before proceeding. + * + * Returns 0 if the revalidation was successful. If the revalidation fails, + * either return the error returned by d_revalidate or -ESTALE if the + * revalidation it just returned 0. If d_revalidate returns 0, we attempt to + * invalidate the dentry. It's up to the caller to handle putting references + * to the path if necessary. */ -static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) +static int +force_reval_path(struct path *path, struct nameidata *nd) { - struct dentry * dentry = __d_lookup(parent, name); + int status; + struct dentry *dentry = path->dentry; - /* lockess __d_lookup may fail due to concurrent d_move() - * in some unrelated directory, so try with d_lookup + /* + * only check on filesystems where it's possible for the dentry to + * become stale. It's assumed that if this flag is set then the + * d_revalidate op will also be defined. */ - if (!dentry) - dentry = d_lookup(parent, name); + if (!(dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)) + return 0; - if (dentry && dentry->d_op && dentry->d_op->d_revalidate) - dentry = do_revalidate(dentry, nd); + status = dentry->d_op->d_revalidate(dentry, nd); + if (status > 0) + return 0; - return dentry; + if (!status) { + d_invalidate(dentry); + status = -ESTALE; + } + return status; } /* - * Short-cut version of permission(), for calling by - * path_walk(), when dcache lock is held. Combines parts - * of permission() and generic_permission(), and tests ONLY for - * MAY_EXEC permission. + * Short-cut version of permission(), for calling on directories + * during pathname resolution. Combines parts of permission() + * and generic_permission(), and tests ONLY for MAY_EXEC permission. * * If appropriate, check DAC only. If not appropriate, or - * short-cut DAC fails, then call permission() to do more + * short-cut DAC fails, then call ->permission() to do more * complete permission check. */ -static int exec_permission_lite(struct inode *inode) +static int exec_permission(struct inode *inode) { int ret; @@ -465,99 +482,6 @@ ok: return security_inode_permission(inode, MAY_EXEC); } -/* - * This is called when everything else fails, and we actually have - * to go to the low-level filesystem to find out what we should do.. - * - * We get the directory semaphore, and after getting that we also - * make sure that nobody added the entry to the dcache in the meantime.. - * SMP-safe - */ -static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) -{ - struct dentry * result; - struct inode *dir = parent->d_inode; - - mutex_lock(&dir->i_mutex); - /* - * First re-do the cached lookup just in case it was created - * while we waited for the directory semaphore.. - * - * FIXME! This could use version numbering or similar to - * avoid unnecessary cache lookups. - * - * The "dcache_lock" is purely to protect the RCU list walker - * from concurrent renames at this point (we mustn't get false - * negatives from the RCU list walk here, unlike the optimistic - * fast walk). - * - * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup - */ - result = d_lookup(parent, name); - if (!result) { - struct dentry *dentry; - - /* Don't create child dentry for a dead directory. */ - result = ERR_PTR(-ENOENT); - if (IS_DEADDIR(dir)) - goto out_unlock; - - dentry = d_alloc(parent, name); - result = ERR_PTR(-ENOMEM); - if (dentry) { - result = dir->i_op->lookup(dir, dentry, nd); - if (result) - dput(dentry); - else - result = dentry; - } -out_unlock: - mutex_unlock(&dir->i_mutex); - return result; - } - - /* - * Uhhuh! Nasty case: the cache was re-populated while - * we waited on the semaphore. Need to revalidate. - */ - mutex_unlock(&dir->i_mutex); - if (result->d_op && result->d_op->d_revalidate) { - result = do_revalidate(result, nd); - if (!result) - result = ERR_PTR(-ENOENT); - } - return result; -} - -/* - * Wrapper to retry pathname resolution whenever the underlying - * file system returns an ESTALE. - * - * Retry the whole path once, forcing real lookup requests - * instead of relying on the dcache. - */ -static __always_inline int link_path_walk(const char *name, struct nameidata *nd) -{ - struct path save = nd->path; - int result; - - /* make sure the stuff we saved doesn't go away */ - path_get(&save); - - result = __link_path_walk(name, nd); - if (result == -ESTALE) { - /* nd->path had been dropped */ - nd->path = save; - path_get(&nd->path); - nd->flags |= LOOKUP_REVAL; - result = __link_path_walk(name, nd); - } - - path_put(&save); - - return result; -} - static __always_inline void set_root(struct nameidata *nd) { if (!nd->root.mnt) { @@ -569,10 +493,10 @@ static __always_inline void set_root(struct nameidata *nd) } } +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; @@ -583,22 +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); @@ -620,10 +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); @@ -634,18 +543,20 @@ static __always_inline int __do_follow_link(struct path *path, struct nameidata dget(dentry); } mntget(path->mnt); - cookie = dentry->d_inode->i_op->follow_link(dentry, nd); - error = PTR_ERR(cookie); - if (!IS_ERR(cookie)) { + 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); - if (dentry->d_inode->i_op->put_link) - dentry->d_inode->i_op->put_link(dentry, nd, cookie); + else if (nd->last_type == LAST_BIND) { + error = force_reval_path(&nd->path, nd); + if (error) + path_put(&nd->path); + } } - path_put(path); - return error; } @@ -658,6 +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; @@ -671,7 +583,10 @@ 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--; return err; @@ -757,33 +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); } @@ -797,8 +699,19 @@ static int do_lookup(struct nameidata *nd, struct qstr *name, struct path *path) { struct vfsmount *mnt = nd->path.mnt; - struct dentry *dentry = __d_lookup(nd->path.dentry, name); + struct dentry *dentry, *parent; + struct inode *dir; + /* + * See if the low-level filesystem might want + * to use its own hash.. + */ + if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) { + int err = nd->path.dentry->d_op->d_hash(nd->path.dentry, name); + if (err < 0) + return err; + } + dentry = __d_lookup(nd->path.dentry, name); if (!dentry) goto need_lookup; if (dentry->d_op && dentry->d_op->d_revalidate) @@ -810,7 +723,59 @@ done: return 0; need_lookup: - dentry = real_lookup(nd->path.dentry, name, nd); + parent = nd->path.dentry; + dir = parent->d_inode; + + mutex_lock(&dir->i_mutex); + /* + * First re-do the cached lookup just in case it was created + * while we waited for the directory semaphore.. + * + * FIXME! This could use version numbering or similar to + * avoid unnecessary cache lookups. + * + * The "dcache_lock" is purely to protect the RCU list walker + * from concurrent renames at this point (we mustn't get false + * negatives from the RCU list walk here, unlike the optimistic + * fast walk). + * + * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup + */ + dentry = d_lookup(parent, name); + if (!dentry) { + struct dentry *new; + + /* Don't create child dentry for a dead directory. */ + dentry = ERR_PTR(-ENOENT); + if (IS_DEADDIR(dir)) + goto out_unlock; + + new = d_alloc(parent, name); + dentry = ERR_PTR(-ENOMEM); + if (new) { + dentry = dir->i_op->lookup(dir, new, nd); + if (dentry) + dput(new); + else + dentry = new; + } +out_unlock: + mutex_unlock(&dir->i_mutex); + if (IS_ERR(dentry)) + goto fail; + goto done; + } + + /* + * Uhhuh! Nasty case: the cache was re-populated while + * we waited on the semaphore. Need to revalidate. + */ + mutex_unlock(&dir->i_mutex); + if (dentry->d_op && dentry->d_op->d_revalidate) { + dentry = do_revalidate(dentry, nd); + if (!dentry) + dentry = ERR_PTR(-ENOENT); + } if (IS_ERR(dentry)) goto fail; goto done; @@ -828,6 +793,17 @@ fail: } /* + * This is a temporary kludge to deal with "automount" symlinks; proper + * solution is to trigger them on follow_mount(), so that do_lookup() + * would DTRT. To be killed before 2.6.34-final. + */ +static inline int follow_on_final(struct inode *inode, unsigned lookup_flags) +{ + return inode && unlikely(inode->i_op->follow_link) && + ((lookup_flags & LOOKUP_FOLLOW) || S_ISDIR(inode->i_mode)); +} + +/* * Name resolution. * This is the basic name resolution function, turning a pathname into * the final dentry. We expect 'base' to be positive and a directory. @@ -835,7 +811,7 @@ fail: * Returns 0 and nd will have valid dentry and mnt on success. * Returns error and drops reference to input namei data on failure. */ -static int __link_path_walk(const char *name, struct nameidata *nd) +static int link_path_walk(const char *name, struct nameidata *nd) { struct path next; struct inode *inode; @@ -858,7 +834,7 @@ static int __link_path_walk(const char *name, struct nameidata *nd) unsigned int c; nd->flags |= LOOKUP_CONTINUE; - err = exec_permission_lite(inode); + err = exec_permission(inode); if (err) break; @@ -898,16 +874,6 @@ static int __link_path_walk(const char *name, struct nameidata *nd) case 1: continue; } - /* - * See if the low-level filesystem might want - * to use its own hash.. - */ - if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) { - err = nd->path.dentry->d_op->d_hash(nd->path.dentry, - &this); - if (err < 0) - break; - } /* This does the actual lookups.. */ err = do_lookup(nd, &this, &next); if (err) @@ -953,18 +919,11 @@ last_component: case 1: goto return_reval; } - if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) { - err = nd->path.dentry->d_op->d_hash(nd->path.dentry, - &this); - if (err < 0) - break; - } err = do_lookup(nd, &this, &next); if (err) break; inode = next.dentry->d_inode; - if ((lookup_flags & LOOKUP_FOLLOW) - && inode && inode->i_op->follow_link) { + if (follow_on_final(inode, lookup_flags)) { err = do_follow_link(&next, nd); if (err) goto return_err; @@ -1017,8 +976,27 @@ return_err: static int path_walk(const char *name, struct nameidata *nd) { + struct path save = nd->path; + int result; + current->total_link_count = 0; - return link_path_walk(name, nd); + + /* make sure the stuff we saved doesn't go away */ + path_get(&save); + + result = link_path_walk(name, nd); + if (result == -ESTALE) { + /* nd->path had been dropped */ + current->total_link_count = 0; + nd->path = save; + path_get(&nd->path); + nd->flags |= LOOKUP_REVAL; + result = link_path_walk(name, nd); + } + + path_put(&save); + + return result; } static int path_init(int dfd, const char *name, unsigned int flags, struct nameidata *nd) @@ -1141,36 +1119,6 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, return retval; } -/** - * path_lookup_open - lookup a file path with open intent - * @dfd: the directory to use as base, or AT_FDCWD - * @name: pointer to file name - * @lookup_flags: lookup intent flags - * @nd: pointer to nameidata - * @open_flags: open intent flags - */ -static int path_lookup_open(int dfd, const char *name, - unsigned int lookup_flags, struct nameidata *nd, int open_flags) -{ - struct file *filp = get_empty_filp(); - int err; - - if (filp == NULL) - return -ENFILE; - nd->intent.open.file = filp; - nd->intent.open.flags = open_flags; - nd->intent.open.create_mode = 0; - err = do_path_lookup(dfd, name, lookup_flags|LOOKUP_OPEN, nd); - if (IS_ERR(nd->intent.open.file)) { - if (err == 0) { - err = PTR_ERR(nd->intent.open.file); - path_put(&nd->path); - } - } else if (err != 0) - release_open_intent(nd); - return err; -} - static struct dentry *__lookup_hash(struct qstr *name, struct dentry *base, struct nameidata *nd) { @@ -1191,7 +1139,17 @@ static struct dentry *__lookup_hash(struct qstr *name, goto out; } - dentry = cached_lookup(base, name, nd); + dentry = __d_lookup(base, name); + + /* lockess __d_lookup may fail due to concurrent d_move() + * in some unrelated directory, so try with d_lookup + */ + if (!dentry) + dentry = d_lookup(base, name); + + if (dentry && dentry->d_op && dentry->d_op->d_revalidate) + dentry = do_revalidate(dentry, nd); + if (!dentry) { struct dentry *new; @@ -1223,7 +1181,7 @@ static struct dentry *lookup_hash(struct nameidata *nd) { int err; - err = inode_permission(nd->path.dentry->d_inode, MAY_EXEC); + err = exec_permission(nd->path.dentry->d_inode); if (err) return ERR_PTR(err); return __lookup_hash(&nd->last, nd->path.dentry, nd); @@ -1273,29 +1231,7 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) if (err) return ERR_PTR(err); - err = inode_permission(base->d_inode, MAY_EXEC); - if (err) - return ERR_PTR(err); - return __lookup_hash(&this, base, NULL); -} - -/** - * lookup_one_noperm - bad hack for sysfs - * @name: pathname component to lookup - * @base: base directory to lookup from - * - * This is a variant of lookup_one_len that doesn't perform any permission - * checks. It's a horrible hack to work around the braindead sysfs - * architecture and should not be used anywhere else. - * - * DON'T USE THIS FUNCTION EVER, thanks. - */ -struct dentry *lookup_one_noperm(const char *name, struct dentry *base) -{ - int err; - struct qstr this; - - err = __lookup_one_len(name, &this, base, strlen(name)); + err = exec_permission(base->d_inode); if (err) return ERR_PTR(err); return __lookup_hash(&this, base, NULL); @@ -1381,7 +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) @@ -1422,22 +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. */ @@ -1495,7 +1415,6 @@ int vfs_create(struct inode *dir, struct dentry *dentry, int mode, error = security_inode_create(dir, dentry, mode); if (error) return error; - vfs_dq_init(dir); error = dir->i_op->create(dir, dentry, mode, nd); if (!error) fsnotify_create(dir, dentry); @@ -1533,69 +1452,45 @@ int may_open(struct path *path, int acc_mode, int flag) if (error) return error; - error = ima_path_check(path, acc_mode ? - acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC) : - ACC_MODE(flag) & (MAY_READ | MAY_WRITE), - IMA_COUNT_UPDATE); - - if (error) - return error; /* * An append-only file must be opened in append mode for writing. */ if (IS_APPEND(inode)) { - error = -EPERM; - if ((flag & FMODE_WRITE) && !(flag & O_APPEND)) - goto err_out; + if ((flag & O_ACCMODE) != O_RDONLY && !(flag & O_APPEND)) + return -EPERM; if (flag & O_TRUNC) - goto err_out; + return -EPERM; } /* O_NOATIME can only be set by the owner or superuser */ - if (flag & O_NOATIME) - if (!is_owner_or_cap(inode)) { - error = -EPERM; - goto err_out; - } + if (flag & O_NOATIME && !is_owner_or_cap(inode)) + return -EPERM; /* * Ensure there are no outstanding leases on the file. */ - error = break_lease(inode, flag); - if (error) - goto err_out; - - if (flag & O_TRUNC) { - error = get_write_access(inode); - if (error) - goto err_out; - - /* - * Refuse to truncate files with mandatory locks held on them. - */ - error = locks_verify_locked(inode); - if (!error) - error = security_path_truncate(path, 0, - ATTR_MTIME|ATTR_CTIME|ATTR_OPEN); - if (!error) { - vfs_dq_init(inode); - - error = do_truncate(dentry, 0, - ATTR_MTIME|ATTR_CTIME|ATTR_OPEN, - NULL); - } - put_write_access(inode); - if (error) - goto err_out; - } else - if (flag & FMODE_WRITE) - vfs_dq_init(inode); + return break_lease(inode, flag); +} - return 0; -err_out: - ima_counts_put(path, acc_mode ? - acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC) : - ACC_MODE(flag) & (MAY_READ | MAY_WRITE)); +static int handle_truncate(struct path *path) +{ + struct inode *inode = path->dentry->d_inode; + int error = get_write_access(inode); + if (error) + return error; + /* + * Refuse to truncate files with mandatory locks held on them. + */ + error = locks_verify_locked(inode); + if (!error) + error = security_path_truncate(path, 0, + ATTR_MTIME|ATTR_CTIME|ATTR_OPEN); + if (!error) { + error = do_truncate(path->dentry, 0, + ATTR_MTIME|ATTR_CTIME|ATTR_OPEN, + NULL); + } + put_write_access(inode); return error; } @@ -1605,7 +1500,7 @@ err_out: * 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; @@ -1623,7 +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); } /* @@ -1650,7 +1545,7 @@ static inline int open_to_namei_flags(int flag) return flag; } -static int open_will_write_to_fs(int flag, struct inode *inode) +static int open_will_truncate(int flag, struct inode *inode) { /* * We'll never write to the fs underlying @@ -1661,100 +1556,132 @@ static int open_will_write_to_fs(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 will_truncate; int error; - struct path path; - struct dentry *dir; - int count = 0; - int will_write; - int flag = open_to_namei_flags(open_flag); - if (!acc_mode) - acc_mode = MAY_OPEN | ACC_MODE(flag); + 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); + } + } + } + /* + * 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); + 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)) { - error = path_lookup_open(dfd, pathname, lookup_flags(flag), - &nd, flag); - if (error) - return ERR_PTR(error); + 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; + } + } + /* 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. - */ - error = path_init(dfd, pathname, LOOKUP_PARENT, &nd); - if (error) - return ERR_PTR(error); - 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; - 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 @@ -1762,22 +1689,23 @@ 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, open_flag); - if (IS_ERR(filp)) - ima_counts_put(&nd.path, - acc_mode & (MAY_READ | MAY_WRITE | - MAY_EXEC)); - 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) { + fput(filp); + filp = ERR_PTR(error); + } + } return filp; } @@ -1785,129 +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 (path.dentry->d_inode && S_ISDIR(path.dentry->d_inode->i_mode)) + if (S_ISDIR(path->dentry->d_inode->i_mode)) goto exit; ok: - /* - * 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. - */ - will_write = open_will_write_to_fs(flag, nd.path.dentry->d_inode); - if (will_write) { - error = mnt_want_write(nd.path.mnt); - if (error) - goto exit; - } - error = may_open(&nd.path, acc_mode, flag); - if (error) { - if (will_write) - mnt_drop_write(nd.path.mnt); - goto exit; - } - filp = nameidata_to_filp(&nd, open_flag); - if (IS_ERR(filp)) - ima_counts_put(&nd.path, - acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC)); - /* - * It is now safe to drop the mnt write - * because the filp has had a write taken - * on its behalf. - */ - if (will_write) - mnt_drop_write(nd.path.mnt); - if (nd.root.mnt) - path_put(&nd.root); + 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); + 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); + 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; -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. + * 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. */ - nd.flags |= LOOKUP_PARENT; - error = security_inode_follow_link(path.dentry, &nd); + 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) - goto exit_dput; - error = __do_follow_link(&path, &nd); - 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); return ERR_PTR(error); + if (force_reval) + nd.flags |= LOOKUP_REVAL; + + current->total_link_count = 0; + error = link_path_walk(pathname, &nd); + if (error) { + filp = ERR_PTR(error); + goto out; } + 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; - 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; + nd.flags |= LOOKUP_OPEN; + if (open_flag & O_CREAT) { + nd.flags |= LOOKUP_CREATE; + if (open_flag & O_EXCL) + nd.flags |= LOOKUP_EXCL; } - error = -ELOOP; - if (count++==32) { - __putname(nd.last.name); - goto exit; + 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); } - 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; +out: + if (nd.root.mnt) + path_put(&nd.root); + if (filp == ERR_PTR(-ESTALE) && !force_reval) { + force_reval = 1; + goto reval; + } + return filp; + +exit_dput: + path_put_conditional(&path, &nd); + if (!IS_ERR(nd.intent.open.file)) + release_open_intent(&nd); +exit_parent: + path_put(&nd.path); + filp = ERR_PTR(error); + goto out; } /** @@ -2001,7 +1981,6 @@ int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) if (error) return error; - vfs_dq_init(dir); error = dir->i_op->mknod(dir, dentry, mode, dev); if (!error) fsnotify_create(dir, dentry); @@ -2100,7 +2079,6 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) if (error) return error; - vfs_dq_init(dir); error = dir->i_op->mkdir(dir, dentry, mode); if (!error) fsnotify_mkdir(dir, dentry); @@ -2186,8 +2164,6 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry) if (!dir->i_op->rmdir) return -EPERM; - vfs_dq_init(dir); - mutex_lock(&dentry->d_inode->i_mutex); dentry_unhash(dentry); if (d_mountpoint(dentry)) @@ -2273,15 +2249,16 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry) if (!dir->i_op->unlink) return -EPERM; - vfs_dq_init(dir); - mutex_lock(&dentry->d_inode->i_mutex); if (d_mountpoint(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); @@ -2384,7 +2361,6 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) if (error) return error; - vfs_dq_init(dir); error = dir->i_op->symlink(dir, dentry, oldname); if (!error) fsnotify_create(dir, dentry); @@ -2468,7 +2444,6 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de return error; mutex_lock(&inode->i_mutex); - vfs_dq_init(dir); error = dir->i_op->link(old_dentry, dir, new_dentry); mutex_unlock(&inode->i_mutex); if (!error) @@ -2569,7 +2544,7 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname * e) conversion from fhandle to dentry may come in the wrong moment - when * we are removing the target. Solution: we will have to grab ->i_mutex * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on - * ->i_mutex on parents, which works but leads to some truely excessive + * ->i_mutex on parents, which works but leads to some truly excessive * locking]. */ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, @@ -2634,6 +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); } @@ -2667,20 +2644,15 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, if (!old_dir->i_op->rename) return -EPERM; - vfs_dq_init(old_dir); - vfs_dq_init(new_dir); - old_name = fsnotify_oldname_init(old_dentry->d_name.name); if (is_dir) 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; |