diff options
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 160 |
1 files changed, 97 insertions, 63 deletions
diff --git a/fs/namei.c b/fs/namei.c index af3783fff1de..f05bed242422 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -226,6 +226,16 @@ 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; @@ -247,8 +257,7 @@ int inode_permission(struct inode *inode, int mask) return -EACCES; } - /* Ordinary permission routines do not understand MAY_APPEND. */ - 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); @@ -265,21 +274,6 @@ 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) @@ -289,7 +283,7 @@ 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) { @@ -438,7 +432,7 @@ static int exec_permission_lite(struct inode *inode) { umode_t mode = inode->i_mode; - if (inode->i_op && inode->i_op->permission) + if (inode->i_op->permission) return -EAGAIN; if (current_fsuid() == inode->i_uid) @@ -527,18 +521,6 @@ out_unlock: return result; } -/* SMP-safe */ -static __always_inline void -walk_init_root(const char *name, struct nameidata *nd) -{ - struct fs_struct *fs = current->fs; - - read_lock(&fs->lock); - nd->path = fs->root; - path_get(&fs->root); - read_unlock(&fs->lock); -} - /* * Wrapper to retry pathname resolution whenever the underlying * file system returns an ESTALE. @@ -576,9 +558,16 @@ static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *l goto fail; if (*link == '/') { + struct fs_struct *fs = current->fs; + path_put(&nd->path); - walk_init_root(link, nd); + + read_lock(&fs->lock); + nd->path = fs->root; + path_get(&fs->root); + read_unlock(&fs->lock); } + res = link_path_walk(link, nd); if (nd->depth || res || nd->last_type!=LAST_NORM) return res; @@ -859,7 +848,8 @@ static int __link_path_walk(const char *name, struct nameidata *nd) nd->flags |= LOOKUP_CONTINUE; err = exec_permission_lite(inode); if (err == -EAGAIN) - err = vfs_permission(nd, MAY_EXEC); + err = inode_permission(nd->path.dentry->d_inode, + MAY_EXEC); if (err) break; @@ -918,9 +908,6 @@ 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); @@ -930,9 +917,6 @@ 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; @@ -971,7 +955,7 @@ last_component: 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; @@ -983,7 +967,7 @@ 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; @@ -1479,7 +1463,7 @@ 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; @@ -1493,9 +1477,9 @@ int vfs_create(struct inode *dir, struct dentry *dentry, int mode, return error; } -int may_open(struct nameidata *nd, int acc_mode, int flag) +int may_open(struct path *path, int acc_mode, int flag) { - struct dentry *dentry = nd->path.dentry; + struct dentry *dentry = path->dentry; struct inode *inode = dentry->d_inode; int error; @@ -1516,13 +1500,13 @@ int may_open(struct nameidata *nd, int acc_mode, int flag) 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)) { - if (nd->path.mnt->mnt_flags & MNT_NODEV) + if (path->mnt->mnt_flags & MNT_NODEV) return -EACCES; flag &= ~O_TRUNC; } - error = vfs_permission(nd, acc_mode); + error = inode_permission(inode, acc_mode); if (error) return error; /* @@ -1556,6 +1540,9 @@ int may_open(struct nameidata *nd, int acc_mode, int flag) * 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); @@ -1586,14 +1573,18 @@ static int __open_namei_create(struct nameidata *nd, struct path *path, if (!IS_POSIXACL(dir->d_inode)) mode &= ~current->fs->umask; + error = security_path_mknod(&nd->path, path->dentry, mode, 0); + if (error) + goto out_unlock; error = vfs_create(dir->d_inode, path->dentry, mode, nd); +out_unlock: mutex_unlock(&dir->d_inode->i_mutex); dput(nd->path.dentry); nd->path.dentry = path->dentry; if (error) return error; /* Don't check for write permission, don't truncate */ - return may_open(nd, 0, flag & ~O_TRUNC); + return may_open(&nd->path, 0, flag & ~O_TRUNC); } /* @@ -1755,7 +1746,7 @@ 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); @@ -1779,7 +1770,7 @@ ok: if (error) goto exit; } - error = may_open(&nd, acc_mode, flag); + error = may_open(&nd.path, acc_mode, flag); if (error) { if (will_write) mnt_drop_write(nd.path.mnt); @@ -1936,7 +1927,7 @@ 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); @@ -1999,6 +1990,9 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode, error = mnt_want_write(nd.path.mnt); if (error) goto out_dput; + error = security_path_mknod(&nd.path, dentry, mode, dev); + if (error) + goto out_drop_write; switch (mode & S_IFMT) { case 0: case S_IFREG: error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd); @@ -2011,6 +2005,7 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode, error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0); break; } +out_drop_write: mnt_drop_write(nd.path.mnt); out_dput: dput(dentry); @@ -2034,7 +2029,7 @@ 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); @@ -2070,7 +2065,11 @@ asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode) error = mnt_want_write(nd.path.mnt); if (error) goto out_dput; + error = security_path_mkdir(&nd.path, dentry, mode); + if (error) + goto out_drop_write; error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode); +out_drop_write: mnt_drop_write(nd.path.mnt); out_dput: dput(dentry); @@ -2121,7 +2120,7 @@ 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); @@ -2180,7 +2179,11 @@ static long do_rmdir(int dfd, const char __user *pathname) error = mnt_want_write(nd.path.mnt); if (error) goto exit3; + error = security_path_rmdir(&nd.path, dentry); + if (error) + goto exit4; error = vfs_rmdir(nd.path.dentry->d_inode, dentry); +exit4: mnt_drop_write(nd.path.mnt); exit3: dput(dentry); @@ -2204,7 +2207,7 @@ 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); @@ -2265,7 +2268,11 @@ static long do_unlinkat(int dfd, const char __user *pathname) error = mnt_want_write(nd.path.mnt); if (error) goto exit2; + error = security_path_unlink(&nd.path, dentry); + if (error) + goto exit3; error = vfs_unlink(nd.path.dentry->d_inode, dentry); +exit3: mnt_drop_write(nd.path.mnt); exit2: dput(dentry); @@ -2307,7 +2314,7 @@ 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); @@ -2346,7 +2353,11 @@ asmlinkage long sys_symlinkat(const char __user *oldname, error = mnt_want_write(nd.path.mnt); if (error) goto out_dput; + error = security_path_symlink(&nd.path, dentry, from); + if (error) + goto out_drop_write; error = vfs_symlink(nd.path.dentry->d_inode, dentry, from); +out_drop_write: mnt_drop_write(nd.path.mnt); out_dput: dput(dentry); @@ -2384,7 +2395,7 @@ 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; @@ -2443,7 +2454,11 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname, error = mnt_want_write(nd.path.mnt); if (error) goto out_dput; + error = security_path_link(old_path.dentry, &nd.path, new_dentry); + if (error) + goto out_drop_write; error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry); +out_drop_write: mnt_drop_write(nd.path.mnt); out_dput: dput(new_dentry); @@ -2587,7 +2602,7 @@ 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); @@ -2679,8 +2694,13 @@ asmlinkage long sys_renameat(int olddfd, const char __user *oldname, 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; 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); @@ -2750,13 +2770,16 @@ int vfs_follow_link(struct nameidata *nd, const char *link) /* get the link contents into pagecache */ static char *page_getlink(struct dentry * dentry, struct page **ppage) { - struct page * page; + char *kaddr; + struct page *page; struct address_space *mapping = dentry->d_inode->i_mapping; page = read_mapping_page(mapping, 0, NULL); if (IS_ERR(page)) return (char*)page; *ppage = page; - return kmap(page); + kaddr = kmap(page); + nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1); + return kaddr; } int page_readlink(struct dentry *dentry, char __user *buffer, int buflen) @@ -2788,18 +2811,23 @@ 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; @@ -2823,7 +2851,7 @@ 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 = { @@ -2849,7 +2877,6 @@ 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); @@ -2865,3 +2892,10 @@ EXPORT_SYMBOL(vfs_symlink); EXPORT_SYMBOL(vfs_unlink); EXPORT_SYMBOL(dentry_unhash); EXPORT_SYMBOL(generic_readlink); + +/* to be mentioned only in INIT_TASK */ +struct fs_struct init_fs = { + .count = ATOMIC_INIT(1), + .lock = __RW_LOCK_UNLOCKED(init_fs.lock), + .umask = 0022, +}; 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