diff options
| -rw-r--r-- | fs/namei.c | 48 | ||||
| -rw-r--r-- | fs/namespace.c | 18 | ||||
| -rw-r--r-- | fs/open.c | 9 | ||||
| -rw-r--r-- | include/linux/namei.h | 1 |
4 files changed, 55 insertions, 21 deletions
diff --git a/fs/namei.c b/fs/namei.c index 7286f87ce863..6571a5f5112e 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2142,7 +2142,6 @@ OK: static const char *path_init(struct nameidata *nd, unsigned flags) { - int retval = 0; const char *s = nd->name->name; if (!*s) @@ -2154,13 +2153,8 @@ static const char *path_init(struct nameidata *nd, unsigned flags) if (flags & LOOKUP_ROOT) { struct dentry *root = nd->root.dentry; struct inode *inode = root->d_inode; - if (*s) { - if (!d_can_lookup(root)) - return ERR_PTR(-ENOTDIR); - retval = inode_permission(inode, MAY_EXEC); - if (retval) - return ERR_PTR(retval); - } + if (*s && unlikely(!d_can_lookup(root))) + return ERR_PTR(-ENOTDIR); nd->path = nd->root; nd->inode = inode; if (flags & LOOKUP_RCU) { @@ -2258,6 +2252,35 @@ static inline int lookup_last(struct nameidata *nd) return walk_component(nd, 0); } +static int handle_lookup_down(struct nameidata *nd) +{ + struct path path = nd->path; + struct inode *inode = nd->inode; + unsigned seq = nd->seq; + int err; + + if (nd->flags & LOOKUP_RCU) { + /* + * don't bother with unlazy_walk on failure - we are + * at the very beginning of walk, so we lose nothing + * if we simply redo everything in non-RCU mode + */ + if (unlikely(!__follow_mount_rcu(nd, &path, &inode, &seq))) + return -ECHILD; + } else { + dget(path.dentry); + err = follow_managed(&path, nd); + if (unlikely(err < 0)) + return err; + inode = d_backing_inode(path.dentry); + seq = 0; + } + path_to_nameidata(&path, nd); + nd->inode = inode; + nd->seq = seq; + return 0; +} + /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path) { @@ -2266,6 +2289,15 @@ static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path if (IS_ERR(s)) return PTR_ERR(s); + + if (unlikely(flags & LOOKUP_DOWN)) { + err = handle_lookup_down(nd); + if (unlikely(err < 0)) { + terminate_walk(nd); + return err; + } + } + while (!(err = link_path_walk(s, nd)) && ((err = lookup_last(nd)) > 0)) { s = trailing_symlink(nd); diff --git a/fs/namespace.c b/fs/namespace.c index b3b115bd4e1e..8bd3e4d448b9 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3462,8 +3462,9 @@ static void mntns_put(struct ns_common *ns) static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns) { struct fs_struct *fs = current->fs; - struct mnt_namespace *mnt_ns = to_mnt_ns(ns); + struct mnt_namespace *mnt_ns = to_mnt_ns(ns), *old_mnt_ns; struct path root; + int err; if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) || !ns_capable(current_user_ns(), CAP_SYS_CHROOT) || @@ -3474,15 +3475,18 @@ static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns) return -EINVAL; get_mnt_ns(mnt_ns); - put_mnt_ns(nsproxy->mnt_ns); + old_mnt_ns = nsproxy->mnt_ns; nsproxy->mnt_ns = mnt_ns; /* Find the root */ - root.mnt = &mnt_ns->root->mnt; - root.dentry = mnt_ns->root->mnt.mnt_root; - path_get(&root); - while(d_mountpoint(root.dentry) && follow_down_one(&root)) - ; + err = vfs_path_lookup(mnt_ns->root->mnt.mnt_root, &mnt_ns->root->mnt, + "/", LOOKUP_DOWN, &root); + if (err) { + /* revert to old namespace */ + nsproxy->mnt_ns = old_mnt_ns; + put_mnt_ns(mnt_ns); + return err; + } /* Update the pwd and root */ set_fs_pwd(fs, &root); diff --git a/fs/open.c b/fs/open.c index 6d2d2b33ac54..cd0c5be8d012 100644 --- a/fs/open.c +++ b/fs/open.c @@ -460,20 +460,17 @@ out: SYSCALL_DEFINE1(fchdir, unsigned int, fd) { struct fd f = fdget_raw(fd); - struct inode *inode; - int error = -EBADF; + int error; error = -EBADF; if (!f.file) goto out; - inode = file_inode(f.file); - error = -ENOTDIR; - if (!S_ISDIR(inode->i_mode)) + if (!d_can_lookup(f.file->f_path.dentry)) goto out_putf; - error = inode_permission(inode, MAY_EXEC | MAY_CHDIR); + error = inode_permission(file_inode(f.file), MAY_EXEC | MAY_CHDIR); if (!error) set_fs_pwd(current->fs, &f.file->f_path); out_putf: diff --git a/include/linux/namei.h b/include/linux/namei.h index f29abda31e6d..8b4794e83196 100644 --- a/include/linux/namei.h +++ b/include/linux/namei.h @@ -44,6 +44,7 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND}; #define LOOKUP_JUMPED 0x1000 #define LOOKUP_ROOT 0x2000 #define LOOKUP_EMPTY 0x4000 +#define LOOKUP_DOWN 0x8000 extern int path_pts(struct path *path); |