X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fnamei.c;h=68921d9b53020d16e12021ede6188e5e642830a7;hb=f793067eb91afa37904d33075bd44fd8b2774b8a;hp=5cc0dc95a7a5b730782d1b538f8e558577b6fae1;hpb=3fb64190aa3c23c10e6e9fd0124ac030115c99bf;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/namei.c b/fs/namei.c index 5cc0dc9..68921d9 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -31,9 +32,10 @@ #include #include #include +#include #include -#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) @@ -106,8 +108,6 @@ * 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.. @@ -167,19 +167,10 @@ void putname(const char *name) EXPORT_SYMBOL(putname); #endif - -/** - * generic_permission - check for access rights on a Posix-like filesystem - * @inode: inode to check access rights for - * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) - * @check_acl: optional callback to check for Posix ACLs - * - * Used to check for read/write/execute permissions on a file. - * We use "fsuid" for this, letting us set arbitrary permissions - * for filesystem access without changing the "normal" uids which - * are used for other things.. +/* + * This does basic POSIX ACL permission checking */ -int generic_permission(struct inode *inode, int mask, +static int acl_permission_check(struct inode *inode, int mask, int (*check_acl)(struct inode *inode, int mask)) { umode_t mode = inode->i_mode; @@ -191,9 +182,7 @@ int generic_permission(struct inode *inode, int mask, else { if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) { int error = check_acl(inode, mask); - if (error == -EACCES) - goto check_capabilities; - else if (error != -EAGAIN) + if (error != -EAGAIN) return error; } @@ -206,8 +195,32 @@ int generic_permission(struct inode *inode, int mask, */ if ((mask & ~mode) == 0) return 0; + return -EACCES; +} + +/** + * generic_permission - check for access rights on a Posix-like filesystem + * @inode: inode to check access rights for + * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) + * @check_acl: optional callback to check for Posix ACLs + * + * Used to check for read/write/execute permissions on a file. + * We use "fsuid" for this, letting us set arbitrary permissions + * for filesystem access without changing the "normal" uids which + * are used for other things.. + */ +int generic_permission(struct inode *inode, int mask, + int (*check_acl)(struct inode *inode, int mask)) +{ + int ret; + + /* + * Do the basic POSIX ACL permission checks. + */ + ret = acl_permission_check(inode, mask, check_acl); + if (ret != -EACCES) + return ret; - check_capabilities: /* * Read/write DACs are always overridable. * Executable DACs are overridable if at least one exec bit is set. @@ -226,6 +239,16 @@ int generic_permission(struct inode *inode, int mask, return -EACCES; } +/** + * 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. + */ int inode_permission(struct inode *inode, int mask) { int retval; @@ -247,10 +270,10 @@ int inode_permission(struct inode *inode, int mask) return -EACCES; } - if (inode->i_op && inode->i_op->permission) + if (inode->i_op->permission) retval = inode->i_op->permission(inode, mask); else - retval = generic_permission(inode, mask, NULL); + retval = generic_permission(inode, mask, inode->i_op->check_acl); if (retval) return retval; @@ -264,21 +287,6 @@ int inode_permission(struct inode *inode, int mask) } /** - * vfs_permission - check for access rights to a given path - * @nd: lookup result that describes the path - * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) - * - * Used to check for read/write/execute permissions on a path. - * We use "fsuid" for this, letting us set arbitrary permissions - * for filesystem access without changing the "normal" uids which - * are used for other things. - */ -int vfs_permission(struct nameidata *nd, int mask) -{ - return inode_permission(nd->path.dentry->d_inode, mask); -} - -/** * file_permission - check for additional access rights to a given file * @file: file to check access rights for * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) @@ -288,7 +296,7 @@ int vfs_permission(struct nameidata *nd, int mask) * * Note: * Do not use this function in new code. All access checks should - * be done using vfs_permission(). + * be done using inode_permission(). */ int file_permission(struct file *file, int mask) { @@ -404,156 +412,88 @@ 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) { - umode_t mode = inode->i_mode; - - if (inode->i_op && inode->i_op->permission) - return -EAGAIN; - - if (current_fsuid() == inode->i_uid) - mode >>= 6; - else if (in_group_p(inode->i_gid)) - mode >>= 3; - - if (mode & MAY_EXEC) - goto ok; + int ret; - if ((inode->i_mode & S_IXUGO) && capable(CAP_DAC_OVERRIDE)) - goto ok; - - if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_OVERRIDE)) + if (inode->i_op->permission) { + ret = inode->i_op->permission(inode, MAY_EXEC); + if (!ret) + goto ok; + return ret; + } + ret = acl_permission_check(inode, MAY_EXEC, inode->i_op->check_acl); + if (!ret) goto ok; - if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_READ_SEARCH)) + if (capable(CAP_DAC_OVERRIDE) || capable(CAP_DAC_READ_SEARCH)) goto ok; - return -EACCES; + return ret; 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) +static __always_inline void set_root(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); + if (!nd->root.mnt) { + struct fs_struct *fs = current->fs; + read_lock(&fs->lock); + nd->root = fs->root; + path_get(&nd->root); + read_unlock(&fs->lock); } - 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 int link_path_walk(const char *, struct nameidata *); static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link) { @@ -563,14 +503,10 @@ static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *l goto fail; if (*link == '/') { - struct fs_struct *fs = current->fs; - + set_root(nd); path_put(&nd->path); - - read_lock(&fs->lock); - nd->path = fs->root; - path_get(&fs->root); - read_unlock(&fs->lock); + nd->path = nd->root; + path_get(&nd->root); } res = link_path_walk(link, nd); @@ -631,11 +567,14 @@ static __always_inline int __do_follow_link(struct path *path, struct nameidata error = 0; if (s) error = __vfs_follow_link(nd, s); + else if (nd->last_type == LAST_BIND) { + error = force_reval_path(&nd->path, nd); + if (error) + path_put(&nd->path); + } if (dentry->d_inode->i_op->put_link) dentry->d_inode->i_op->put_link(dentry, nd, cookie); } - path_put(path); - return error; } @@ -662,6 +601,7 @@ static inline int do_follow_link(struct path *path, struct nameidata *nd) current->total_link_count++; nd->depth++; err = __do_follow_link(path, nd); + path_put(path); current->link_count--; nd->depth--; return err; @@ -671,23 +611,23 @@ loop: return err; } -int follow_up(struct vfsmount **mnt, struct dentry **dentry) +int follow_up(struct path *path) { struct vfsmount *parent; struct dentry *mountpoint; spin_lock(&vfsmount_lock); - parent=(*mnt)->mnt_parent; - if (parent == *mnt) { + parent = path->mnt->mnt_parent; + if (parent == path->mnt) { spin_unlock(&vfsmount_lock); return 0; } mntget(parent); - mountpoint=dget((*mnt)->mnt_mountpoint); + mountpoint = dget(path->mnt->mnt_mountpoint); spin_unlock(&vfsmount_lock); - dput(*dentry); - *dentry = mountpoint; - mntput(*mnt); - *mnt = parent; + dput(path->dentry); + path->dentry = mountpoint; + mntput(path->mnt); + path->mnt = parent; return 1; } @@ -698,7 +638,7 @@ static int __follow_mount(struct path *path) { int res = 0; while (d_mountpoint(path->dentry)) { - struct vfsmount *mounted = lookup_mnt(path->mnt, path->dentry); + struct vfsmount *mounted = lookup_mnt(path); if (!mounted) break; dput(path->dentry); @@ -711,32 +651,32 @@ static int __follow_mount(struct path *path) return res; } -static void follow_mount(struct vfsmount **mnt, struct dentry **dentry) +static void follow_mount(struct path *path) { - while (d_mountpoint(*dentry)) { - struct vfsmount *mounted = lookup_mnt(*mnt, *dentry); + while (d_mountpoint(path->dentry)) { + struct vfsmount *mounted = lookup_mnt(path); if (!mounted) break; - dput(*dentry); - mntput(*mnt); - *mnt = mounted; - *dentry = dget(mounted->mnt_root); + dput(path->dentry); + mntput(path->mnt); + path->mnt = mounted; + path->dentry = dget(mounted->mnt_root); } } /* no need for dcache_lock, as serialization is taken care in * namespace.c */ -int follow_down(struct vfsmount **mnt, struct dentry **dentry) +int follow_down(struct path *path) { struct vfsmount *mounted; - mounted = lookup_mnt(*mnt, *dentry); + mounted = lookup_mnt(path); if (mounted) { - dput(*dentry); - mntput(*mnt); - *mnt = mounted; - *dentry = dget(mounted->mnt_root); + dput(path->dentry); + mntput(path->mnt); + path->mnt = mounted; + path->dentry = dget(mounted->mnt_root); return 1; } return 0; @@ -744,19 +684,16 @@ int follow_down(struct vfsmount **mnt, struct dentry **dentry) static __always_inline void follow_dotdot(struct nameidata *nd) { - struct fs_struct *fs = current->fs; + set_root(nd); while(1) { struct vfsmount *parent; struct dentry *old = nd->path.dentry; - read_lock(&fs->lock); - if (nd->path.dentry == fs->root.dentry && - nd->path.mnt == fs->root.mnt) { - read_unlock(&fs->lock); + if (nd->path.dentry == nd->root.dentry && + nd->path.mnt == nd->root.mnt) { break; } - read_unlock(&fs->lock); spin_lock(&dcache_lock); if (nd->path.dentry != nd->path.mnt->mnt_root) { nd->path.dentry = dget(nd->path.dentry->d_parent); @@ -778,7 +715,7 @@ static __always_inline void follow_dotdot(struct nameidata *nd) mntput(nd->path.mnt); nd->path.mnt = parent; } - follow_mount(&nd->path.mnt, &nd->path.dentry); + follow_mount(&nd->path); } /* @@ -790,8 +727,19 @@ 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) @@ -803,7 +751,59 @@ 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; @@ -828,7 +828,7 @@ 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; @@ -851,9 +851,7 @@ static int __link_path_walk(const char *name, struct nameidata *nd) unsigned int c; nd->flags |= LOOKUP_CONTINUE; - err = exec_permission_lite(inode); - if (err == -EAGAIN) - err = vfs_permission(nd, MAY_EXEC); + err = exec_permission(inode); if (err) break; @@ -893,16 +891,6 @@ 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) @@ -912,9 +900,6 @@ static int __link_path_walk(const char *name, struct nameidata *nd) inode = next.dentry->d_inode; if (!inode) goto out_dput; - err = -ENOTDIR; - if (!inode->i_op) - goto out_dput; if (inode->i_op->follow_link) { err = do_follow_link(&next, nd); @@ -924,9 +909,6 @@ static int __link_path_walk(const char *name, struct nameidata *nd) inode = nd->path.dentry->d_inode; if (!inode) break; - err = -ENOTDIR; - if (!inode->i_op) - break; } else path_to_nameidata(&next, nd); err = -ENOTDIR; @@ -954,18 +936,12 @@ 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 && inode->i_op->follow_link) { + && inode && inode->i_op->follow_link) { err = do_follow_link(&next, nd); if (err) goto return_err; @@ -977,7 +953,7 @@ last_component: break; if (lookup_flags & LOOKUP_DIRECTORY) { err = -ENOTDIR; - if (!inode->i_op || !inode->i_op->lookup) + if (!inode->i_op->lookup) break; } goto return_base; @@ -1018,29 +994,46 @@ 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; } -/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ -static int do_path_lookup(int dfd, const char *name, - unsigned int flags, struct nameidata *nd) +static int path_init(int dfd, const char *name, unsigned int flags, struct nameidata *nd) { int retval = 0; int fput_needed; struct file *file; - struct fs_struct *fs = current->fs; nd->last_type = LAST_ROOT; /* if there are only slashes... */ nd->flags = flags; nd->depth = 0; + nd->root.mnt = NULL; if (*name=='/') { - read_lock(&fs->lock); - nd->path = fs->root; - path_get(&fs->root); - read_unlock(&fs->lock); + set_root(nd); + nd->path = nd->root; + path_get(&nd->root); } else if (dfd == AT_FDCWD) { + struct fs_struct *fs = current->fs; read_lock(&fs->lock); nd->path = fs->pwd; path_get(&fs->pwd); @@ -1068,17 +1061,29 @@ static int do_path_lookup(int dfd, const char *name, fput_light(file, fput_needed); } + return 0; - retval = path_walk(name, nd); +fput_fail: + fput_light(file, fput_needed); +out_fail: + return retval; +} + +/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ +static int do_path_lookup(int dfd, const char *name, + unsigned int flags, struct nameidata *nd) +{ + int retval = path_init(dfd, name, flags, nd); + if (!retval) + retval = path_walk(name, nd); if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry && nd->path.dentry->d_inode)) audit_inode(name, nd->path.dentry); -out_fail: + if (nd->root.mnt) { + path_put(&nd->root); + nd->root.mnt = NULL; + } return retval; - -fput_fail: - fput_light(file, fput_needed); - goto out_fail; } int path_lookup(const char *name, unsigned int flags, @@ -1118,44 +1123,18 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, nd->path.dentry = dentry; nd->path.mnt = mnt; path_get(&nd->path); + nd->root = nd->path; + path_get(&nd->root); retval = path_walk(name, nd); if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry && nd->path.dentry->d_inode)) audit_inode(name, nd->path.dentry); - return retval; + path_put(&nd->root); + nd->root.mnt = NULL; -} - -/** - * 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 - */ -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; + return retval; } static struct dentry *__lookup_hash(struct qstr *name, @@ -1178,7 +1157,17 @@ 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; @@ -1210,7 +1199,7 @@ 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); @@ -1254,33 +1243,13 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) int err; struct qstr this; - err = __lookup_one_len(name, &this, base, len); - if (err) - return ERR_PTR(err); + WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex)); - err = inode_permission(base->d_inode, MAY_EXEC); + err = __lookup_one_len(name, &this, base, len); 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); @@ -1473,14 +1442,14 @@ int vfs_create(struct inode *dir, struct dentry *dentry, int mode, if (error) return error; - if (!dir->i_op || !dir->i_op->create) + if (!dir->i_op->create) return -EACCES; /* shouldn't it be ENOSYS? */ mode &= S_IALLUGO; mode |= S_IFREG; error = security_inode_create(dir, dentry, mode); if (error) return error; - DQUOT_INIT(dir); + vfs_dq_init(dir); error = dir->i_op->create(dir, dentry, mode, nd); if (!error) fsnotify_create(dir, dentry); @@ -1496,29 +1465,28 @@ int may_open(struct path *path, int acc_mode, int flag) if (!inode) return -ENOENT; - if (S_ISLNK(inode->i_mode)) + switch (inode->i_mode & S_IFMT) { + case S_IFLNK: return -ELOOP; - - if (S_ISDIR(inode->i_mode) && (acc_mode & MAY_WRITE)) - return -EISDIR; - - /* - * FIFO's, sockets and device files are special: they don't - * actually live on the filesystem itself, and as such you - * can write to them even if the filesystem is read-only. - */ - if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { - flag &= ~O_TRUNC; - } else if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode)) { + case S_IFDIR: + if (acc_mode & MAY_WRITE) + return -EISDIR; + break; + case S_IFBLK: + case S_IFCHR: if (path->mnt->mnt_flags & MNT_NODEV) return -EACCES; - + /*FALLTHRU*/ + case S_IFIFO: + case S_IFSOCK: flag &= ~O_TRUNC; + break; } error = inode_permission(inode, acc_mode); if (error) return error; + /* * An append-only file must be opened in append mode for writing. */ @@ -1530,44 +1498,35 @@ int may_open(struct path *path, int acc_mode, int flag) } /* O_NOATIME can only be set by the owner or superuser */ - if (flag & O_NOATIME) - if (!is_owner_or_cap(inode)) - return -EPERM; + 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); + return break_lease(inode, flag); +} + +static int handle_truncate(struct path *path) +{ + struct inode *inode = path->dentry->d_inode; + int error = get_write_access(inode); if (error) return error; - - if (flag & O_TRUNC) { - 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) { - DQUOT_INIT(inode); - - error = do_truncate(dentry, 0, - ATTR_MTIME|ATTR_CTIME|ATTR_OPEN, - NULL); - } - put_write_access(inode); - if (error) - return error; - } else - if (flag & FMODE_WRITE) - DQUOT_INIT(inode); - - return 0; + /* + * 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; } /* @@ -1582,7 +1541,7 @@ static int __open_namei_create(struct nameidata *nd, struct path *path, struct dentry *dir = nd->path.dentry; if (!IS_POSIXACL(dir->d_inode)) - mode &= ~current->fs->umask; + mode &= ~current_umask(); error = security_path_mknod(&nd->path, path->dentry, mode, 0); if (error) goto out_unlock; @@ -1621,7 +1580,7 @@ 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 @@ -1638,18 +1597,28 @@ static int open_will_write_to_fs(int flag, struct inode *inode) * open_to_namei_flags() for more details. */ struct file *do_filp_open(int dfd, const char *pathname, - int open_flag, int mode) + int open_flag, int mode, int acc_mode) { struct file *filp; struct nameidata nd; - int acc_mode, error; - struct path path; + int error; + struct path path, save; struct dentry *dir; int count = 0; - int will_write; + int will_truncate; int flag = open_to_namei_flags(open_flag); - acc_mode = MAY_OPEN | ACC_MODE(flag); + /* + * 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. + */ + if (open_flag & __O_SYNC) + open_flag |= O_DSYNC; + + if (!acc_mode) + acc_mode = MAY_OPEN | ACC_MODE(flag); /* O_TRUNC implies we need access checks for write permissions */ if (flag & O_TRUNC) @@ -1664,8 +1633,23 @@ struct file *do_filp_open(int dfd, const char *pathname, * The simplest case - just a plain lookup. */ if (!(flag & O_CREAT)) { - error = path_lookup_open(dfd, pathname, lookup_flags(flag), - &nd, flag); + filp = get_empty_filp(); + + if (filp == NULL) + return ERR_PTR(-ENFILE); + nd.intent.open.file = filp; + filp->f_flags = open_flag; + nd.intent.open.flags = flag; + nd.intent.open.create_mode = 0; + error = do_path_lookup(dfd, pathname, + lookup_flags(flag)|LOOKUP_OPEN, &nd); + if (IS_ERR(nd.intent.open.file)) { + if (error == 0) { + error = PTR_ERR(nd.intent.open.file); + path_put(&nd.path); + } + } else if (error) + release_open_intent(&nd); if (error) return ERR_PTR(error); goto ok; @@ -1674,9 +1658,17 @@ struct file *do_filp_open(int dfd, const char *pathname, /* * Create - we need to know the parent. */ - error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd); + 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); + } + if (unlikely(!audit_dummy_context())) + audit_inode(pathname, nd.path.dentry); /* * We have the parent and last component. First of all, check @@ -1692,6 +1684,7 @@ struct file *do_filp_open(int dfd, const char *pathname, if (filp == NULL) goto exit_parent; nd.intent.open.file = filp; + filp->f_flags = open_flag; nd.intent.open.flags = flag; nd.intent.open.create_mode = mode; dir = nd.path.dentry; @@ -1732,8 +1725,18 @@ do_last: mnt_drop_write(nd.path.mnt); goto exit; } - filp = nameidata_to_filp(&nd, open_flag); + filp = nameidata_to_filp(&nd); mnt_drop_write(nd.path.mnt); + if (nd.root.mnt) + path_put(&nd.root); + if (!IS_ERR(filp)) { + error = ima_path_check(&filp->f_path, filp->f_mode & + (MAY_READ | MAY_WRITE | MAY_EXEC)); + if (error) { + fput(filp); + filp = ERR_PTR(error); + } + } return filp; } @@ -1756,12 +1759,12 @@ do_last: error = -ENOENT; if (!path.dentry->d_inode) goto exit_dput; - if (path.dentry->d_inode->i_op && path.dentry->d_inode->i_op->follow_link) + if (path.dentry->d_inode->i_op->follow_link) goto do_link; 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: /* @@ -1774,26 +1777,48 @@ ok: * 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) { + will_truncate = open_will_truncate(flag, nd.path.dentry->d_inode); + if (will_truncate) { error = mnt_want_write(nd.path.mnt); if (error) goto exit; } error = may_open(&nd.path, acc_mode, flag); if (error) { - if (will_write) + if (will_truncate) mnt_drop_write(nd.path.mnt); goto exit; } - filp = nameidata_to_filp(&nd, open_flag); + filp = nameidata_to_filp(&nd); + if (!IS_ERR(filp)) { + error = ima_path_check(&filp->f_path, filp->f_mode & + (MAY_READ | MAY_WRITE | MAY_EXEC)); + if (error) { + fput(filp); + filp = ERR_PTR(error); + } + } + if (!IS_ERR(filp)) { + if (acc_mode & MAY_WRITE) + vfs_dq_init(nd.path.dentry->d_inode); + + 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_write) + if (will_truncate) mnt_drop_write(nd.path.mnt); + if (nd.root.mnt) + path_put(&nd.root); return filp; exit_mutex_unlock: @@ -1804,6 +1829,8 @@ exit: if (!IS_ERR(nd.intent.open.file)) release_open_intent(&nd); exit_parent: + if (nd.root.mnt) + path_put(&nd.root); path_put(&nd.path); return ERR_PTR(error); @@ -1825,13 +1852,26 @@ do_link: error = security_inode_follow_link(path.dentry, &nd); if (error) goto exit_dput; + save = nd.path; + path_get(&save); error = __do_follow_link(&path, &nd); + if (error == -ESTALE) { + /* nd.path had been dropped */ + nd.path = save; + path_get(&nd.path); + nd.flags |= LOOKUP_REVAL; + error = __do_follow_link(&path, &nd); + } + path_put(&save); + path_put(&path); if (error) { /* Does someone understand code flow here? Or it is only * me so stupid? Anathema to whoever designed this non-sense * with "intent.open". */ release_open_intent(&nd); + if (nd.root.mnt) + path_put(&nd.root); return ERR_PTR(error); } nd.flags &= ~LOOKUP_PARENT; @@ -1870,7 +1910,7 @@ do_link: */ struct file *filp_open(const char *filename, int flags, int mode) { - return do_filp_open(AT_FDCWD, filename, flags, mode); + return do_filp_open(AT_FDCWD, filename, flags, mode, 0); } EXPORT_SYMBOL(filp_open); @@ -1937,7 +1977,7 @@ int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD)) return -EPERM; - if (!dir->i_op || !dir->i_op->mknod) + if (!dir->i_op->mknod) return -EPERM; error = devcgroup_inode_mknod(mode, dev); @@ -1948,7 +1988,7 @@ int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) if (error) return error; - DQUOT_INIT(dir); + vfs_dq_init(dir); error = dir->i_op->mknod(dir, dentry, mode, dev); if (!error) fsnotify_create(dir, dentry); @@ -1972,8 +2012,8 @@ static int may_mknod(mode_t mode) } } -asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode, - unsigned dev) +SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, int, mode, + unsigned, dev) { int error; char *tmp; @@ -1993,7 +2033,7 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode, goto out_unlock; } if (!IS_POSIXACL(nd.path.dentry->d_inode)) - mode &= ~current->fs->umask; + mode &= ~current_umask(); error = may_mknod(mode); if (error) goto out_dput; @@ -2027,7 +2067,7 @@ out_unlock: return error; } -asmlinkage long sys_mknod(const char __user *filename, int mode, unsigned dev) +SYSCALL_DEFINE3(mknod, const char __user *, filename, int, mode, unsigned, dev) { return sys_mknodat(AT_FDCWD, filename, mode, dev); } @@ -2039,7 +2079,7 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) if (error) return error; - if (!dir->i_op || !dir->i_op->mkdir) + if (!dir->i_op->mkdir) return -EPERM; mode &= (S_IRWXUGO|S_ISVTX); @@ -2047,14 +2087,14 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) if (error) return error; - DQUOT_INIT(dir); + vfs_dq_init(dir); error = dir->i_op->mkdir(dir, dentry, mode); if (!error) fsnotify_mkdir(dir, dentry); return error; } -asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode) +SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, int, mode) { int error = 0; char * tmp; @@ -2071,7 +2111,7 @@ asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode) goto out_unlock; if (!IS_POSIXACL(nd.path.dentry->d_inode)) - mode &= ~current->fs->umask; + mode &= ~current_umask(); error = mnt_want_write(nd.path.mnt); if (error) goto out_dput; @@ -2091,7 +2131,7 @@ out_err: return error; } -asmlinkage long sys_mkdir(const char __user *pathname, int mode) +SYSCALL_DEFINE2(mkdir, const char __user *, pathname, int, mode) { return sys_mkdirat(AT_FDCWD, pathname, mode); } @@ -2130,10 +2170,10 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry) if (error) return error; - if (!dir->i_op || !dir->i_op->rmdir) + if (!dir->i_op->rmdir) return -EPERM; - DQUOT_INIT(dir); + vfs_dq_init(dir); mutex_lock(&dentry->d_inode->i_mutex); dentry_unhash(dentry); @@ -2205,7 +2245,7 @@ exit1: return error; } -asmlinkage long sys_rmdir(const char __user *pathname) +SYSCALL_DEFINE1(rmdir, const char __user *, pathname) { return do_rmdir(AT_FDCWD, pathname); } @@ -2217,10 +2257,10 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry) if (error) return error; - if (!dir->i_op || !dir->i_op->unlink) + if (!dir->i_op->unlink) return -EPERM; - DQUOT_INIT(dir); + vfs_dq_init(dir); mutex_lock(&dentry->d_inode->i_mutex); if (d_mountpoint(dentry)) @@ -2301,7 +2341,7 @@ slashes: goto exit2; } -asmlinkage long sys_unlinkat(int dfd, const char __user *pathname, int flag) +SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag) { if ((flag & ~AT_REMOVEDIR) != 0) return -EINVAL; @@ -2312,7 +2352,7 @@ asmlinkage long sys_unlinkat(int dfd, const char __user *pathname, int flag) return do_unlinkat(dfd, pathname); } -asmlinkage long sys_unlink(const char __user *pathname) +SYSCALL_DEFINE1(unlink, const char __user *, pathname) { return do_unlinkat(AT_FDCWD, pathname); } @@ -2324,22 +2364,22 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) if (error) return error; - if (!dir->i_op || !dir->i_op->symlink) + if (!dir->i_op->symlink) return -EPERM; error = security_inode_symlink(dir, dentry, oldname); if (error) return error; - DQUOT_INIT(dir); + vfs_dq_init(dir); error = dir->i_op->symlink(dir, dentry, oldname); if (!error) fsnotify_create(dir, dentry); return error; } -asmlinkage long sys_symlinkat(const char __user *oldname, - int newdfd, const char __user *newname) +SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, + int, newdfd, const char __user *, newname) { int error; char *from; @@ -2380,7 +2420,7 @@ out_putname: return error; } -asmlinkage long sys_symlink(const char __user *oldname, const char __user *newname) +SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname) { return sys_symlinkat(oldname, AT_FDCWD, newname); } @@ -2405,7 +2445,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de */ if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) return -EPERM; - if (!dir->i_op || !dir->i_op->link) + if (!dir->i_op->link) return -EPERM; if (S_ISDIR(inode->i_mode)) return -EPERM; @@ -2415,7 +2455,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de return error; mutex_lock(&inode->i_mutex); - DQUOT_INIT(dir); + vfs_dq_init(dir); error = dir->i_op->link(old_dentry, dir, new_dentry); mutex_unlock(&inode->i_mutex); if (!error) @@ -2432,9 +2472,8 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de * with linux 2.0, and to avoid hard-linking to directories * and other special files. --ADM */ -asmlinkage long sys_linkat(int olddfd, const char __user *oldname, - int newdfd, const char __user *newname, - int flags) +SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, + int, newdfd, const char __user *, newname, int, flags) { struct dentry *new_dentry; struct nameidata nd; @@ -2483,7 +2522,7 @@ out: return error; } -asmlinkage long sys_link(const char __user *oldname, const char __user *newname) +SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname) { return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); } @@ -2612,11 +2651,11 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, if (error) return error; - if (!old_dir->i_op || !old_dir->i_op->rename) + if (!old_dir->i_op->rename) return -EPERM; - DQUOT_INIT(old_dir); - DQUOT_INIT(new_dir); + vfs_dq_init(old_dir); + vfs_dq_init(new_dir); old_name = fsnotify_oldname_init(old_dentry->d_name.name); @@ -2634,8 +2673,8 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, return error; } -asmlinkage long sys_renameat(int olddfd, const char __user *oldname, - int newdfd, const char __user *newname) +SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, + int, newdfd, const char __user *, newname) { struct dentry *old_dir, *new_dir; struct dentry *old_dentry, *new_dentry; @@ -2728,7 +2767,7 @@ exit: return error; } -asmlinkage long sys_rename(const char __user *oldname, const char __user *newname) +SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname) { return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname); } @@ -2821,18 +2860,23 @@ void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) } } -int __page_symlink(struct inode *inode, const char *symname, int len, - gfp_t gfp_mask) +/* + * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS + */ +int __page_symlink(struct inode *inode, const char *symname, int len, int nofs) { struct address_space *mapping = inode->i_mapping; struct page *page; void *fsdata; int err; char *kaddr; + unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE; + if (nofs) + flags |= AOP_FLAG_NOFS; retry: err = pagecache_write_begin(NULL, mapping, 0, len-1, - AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); + flags, &page, &fsdata); if (err) goto fail; @@ -2856,7 +2900,7 @@ fail: int page_symlink(struct inode *inode, const char *symname, int len) { return __page_symlink(inode, symname, len, - mapping_gfp_mask(inode->i_mapping)); + !(mapping_gfp_mask(inode->i_mapping) & __GFP_FS)); } const struct inode_operations page_symlink_inode_operations = { @@ -2882,7 +2926,6 @@ EXPORT_SYMBOL(path_lookup); EXPORT_SYMBOL(kern_path); EXPORT_SYMBOL(vfs_path_lookup); EXPORT_SYMBOL(inode_permission); -EXPORT_SYMBOL(vfs_permission); EXPORT_SYMBOL(file_permission); EXPORT_SYMBOL(unlock_rename); EXPORT_SYMBOL(vfs_create);