[PATCH] sanitize __user_walk_fd() et.al.

* do not pass nameidata; struct path is all the callers want.
* switch to new helpers:
	user_path_at(dfd, pathname, flags, &path)
	user_path(pathname, &path)
	user_lpath(pathname, &path)
	user_path_dir(pathname, &path)  (fail if not a directory)
  The last 3 are trivial macro wrappers for the first one.
* remove nameidata in callers.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 62 insertions, 62 deletions

diff --git a/fs/open.c b/fs/open.c
index e94266700eda..3fe1a6857c75 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -122,37 +122,37 @@ static int vfs_statfs64(struct dentry *dentry, struct statfs64 *buf)
         return 0;
 }
 
-asmlinkage long sys_statfs(const char __user * path, struct statfs __user * buf)
+asmlinkage long sys_statfs(const char __user *pathname, struct statfs __user * buf)
 {
-        struct nameidata nd;
+        struct path path;
         int error;
 
-        error = user_path_walk(path, &nd);
+        error = user_path(pathname, &path);
         if (!error) {
                 struct statfs tmp;
-                error = vfs_statfs_native(nd.path.dentry, &tmp);
+                error = vfs_statfs_native(path.dentry, &tmp);
                 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
                         error = -EFAULT;
-                path_put(&nd.path);
+                path_put(&path);
         }
         return error;
 }
 
 
-asmlinkage long sys_statfs64(const char __user *path, size_t sz, struct statfs64 __user *buf)
+asmlinkage long sys_statfs64(const char __user *pathname, size_t sz, struct statfs64 __user *buf)
 {
-        struct nameidata nd;
+        struct path path;
         long error;
 
         if (sz != sizeof(*buf))
                 return -EINVAL;
-        error = user_path_walk(path, &nd);
+        error = user_path(pathname, &path);
         if (!error) {
                 struct statfs64 tmp;
-                error = vfs_statfs64(nd.path.dentry, &tmp);
+                error = vfs_statfs64(path.dentry, &tmp);
                 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
                         error = -EFAULT;
-                path_put(&nd.path);
+                path_put(&path);
         }
         return error;
 }
@@ -223,20 +223,20 @@ int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
         return err;
 }
 
-static long do_sys_truncate(const char __user * path, loff_t length)
+static long do_sys_truncate(const char __user *pathname, loff_t length)
 {
-        struct nameidata nd;
-        struct inode * inode;
+        struct path path;
+        struct inode *inode;
         int error;
 
         error = -EINVAL;
         if (length < 0) /* sorry, but loff_t says... */
                 goto out;
 
-        error = user_path_walk(path, &nd);
+        error = user_path(pathname, &path);
         if (error)
                 goto out;
-        inode = nd.path.dentry->d_inode;
+        inode = path.dentry->d_inode;
 
         /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
         error = -EISDIR;
@@ -247,7 +247,7 @@ static long do_sys_truncate(const char __user * path, loff_t length)
         if (!S_ISREG(inode->i_mode))
                 goto dput_and_out;
 
-        error = mnt_want_write(nd.path.mnt);
+        error = mnt_want_write(path.mnt);
         if (error)
                 goto dput_and_out;
 
@@ -274,15 +274,15 @@ static long do_sys_truncate(const char __user * path, loff_t length)
         error = locks_verify_truncate(inode, NULL, length);
         if (!error) {
                 DQUOT_INIT(inode);
-                error = do_truncate(nd.path.dentry, length, 0, NULL);
+                error = do_truncate(path.dentry, length, 0, NULL);
         }
 
 put_write_and_out:
         put_write_access(inode);
 mnt_drop_write_and_out:
-        mnt_drop_write(nd.path.mnt);
+        mnt_drop_write(path.mnt);
 dput_and_out:
-        path_put(&nd.path);
+        path_put(&path);
 out:
         return error;
 }
@@ -425,7 +425,7 @@ out:
  */
 asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
 {
-        struct nameidata nd;
+        struct path path;
         struct inode *inode;
         int old_fsuid, old_fsgid;
         kernel_cap_t uninitialized_var(old_cap);  /* !SECURE_NO_SETUID_FIXUP */
@@ -449,7 +449,7 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
                  * FIXME: There is a race here against sys_capset.  The
                  * capabilities can change yet we will restore the old
                  * value below.  We should hold task_capabilities_lock,
-                 * but we cannot because user_path_walk can sleep.
+                 * but we cannot because user_path_at can sleep.
                  */
 #endif /* ndef CONFIG_SECURITY_FILE_CAPABILITIES */
                 if (current->uid)
@@ -458,11 +458,11 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
                         old_cap = cap_set_effective(current->cap_permitted);
         }
 
-        res = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW, &nd);
+        res = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
         if (res)
                 goto out;
 
-        inode = nd.path.dentry->d_inode;
+        inode = path.dentry->d_inode;
 
         if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
                 /*
@@ -470,7 +470,7 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
                  * with the "noexec" flag.
                  */
                 res = -EACCES;
-                if (nd.path.mnt->mnt_flags & MNT_NOEXEC)
+                if (path.mnt->mnt_flags & MNT_NOEXEC)
                         goto out_path_release;
         }
 
@@ -488,11 +488,11 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
          * inherently racy and know that the fs may change
          * state before we even see this result.
          */
-        if (__mnt_is_readonly(nd.path.mnt))
+        if (__mnt_is_readonly(path.mnt))
                 res = -EROFS;
 
 out_path_release:
-        path_put(&nd.path);
+        path_put(&path);
 out:
         current->fsuid = old_fsuid;
         current->fsgid = old_fsgid;
@@ -510,21 +510,21 @@ asmlinkage long sys_access(const char __user *filename, int mode)
 
 asmlinkage long sys_chdir(const char __user * filename)
 {
-        struct nameidata nd;
+        struct path path;
         int error;
 
-        error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd);
+        error = user_path_dir(filename, &path);
         if (error)
                 goto out;
 
-        error = inode_permission(nd.path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
+        error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
         if (error)
                 goto dput_and_out;
 
-        set_fs_pwd(current->fs, &nd.path);
+        set_fs_pwd(current->fs, &path);
 
 dput_and_out:
-        path_put(&nd.path);
+        path_put(&path);
 out:
         return error;
 }
@@ -557,14 +557,14 @@ out:
 
 asmlinkage long sys_chroot(const char __user * filename)
 {
-        struct nameidata nd;
+        struct path path;
         int error;
 
-        error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &nd);
+        error = user_path_dir(filename, &path);
         if (error)
                 goto out;
 
-        error = inode_permission(nd.path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
+        error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
         if (error)
                 goto dput_and_out;
 
@@ -572,10 +572,10 @@ asmlinkage long sys_chroot(const char __user * filename)
         if (!capable(CAP_SYS_CHROOT))
                 goto dput_and_out;
 
-        set_fs_root(current->fs, &nd.path);
+        set_fs_root(current->fs, &path);
         error = 0;
 dput_and_out:
-        path_put(&nd.path);
+        path_put(&path);
 out:
         return error;
 }
@@ -617,17 +617,17 @@ out:
 asmlinkage long sys_fchmodat(int dfd, const char __user *filename,
                              mode_t mode)
 {
-        struct nameidata nd;
-        struct inode * inode;
+        struct path path;
+        struct inode *inode;
         int error;
         struct iattr newattrs;
 
-        error = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW, &nd);
+        error = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
         if (error)
                 goto out;
-        inode = nd.path.dentry->d_inode;
+        inode = path.dentry->d_inode;
 
-        error = mnt_want_write(nd.path.mnt);
+        error = mnt_want_write(path.mnt);
         if (error)
                 goto dput_and_out;
         mutex_lock(&inode->i_mutex);
@@ -635,11 +635,11 @@ asmlinkage long sys_fchmodat(int dfd, const char __user *filename,
                 mode = inode->i_mode;
         newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
         newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
-        error = notify_change(nd.path.dentry, &newattrs);
+        error = notify_change(path.dentry, &newattrs);
         mutex_unlock(&inode->i_mutex);
-        mnt_drop_write(nd.path.mnt);
+        mnt_drop_write(path.mnt);
 dput_and_out:
-        path_put(&nd.path);
+        path_put(&path);
 out:
         return error;
 }
@@ -676,19 +676,19 @@ static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
 
 asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group)
 {
-        struct nameidata nd;
+        struct path path;
         int error;
 
-        error = user_path_walk(filename, &nd);
+        error = user_path(filename, &path);
         if (error)
                 goto out;
-        error = mnt_want_write(nd.path.mnt);
+        error = mnt_want_write(path.mnt);
         if (error)
                 goto out_release;
-        error = chown_common(nd.path.dentry, user, group);
-        mnt_drop_write(nd.path.mnt);
+        error = chown_common(path.dentry, user, group);
+        mnt_drop_write(path.mnt);
 out_release:
-        path_put(&nd.path);
+        path_put(&path);
 out:
         return error;
 }
@@ -696,7 +696,7 @@ out:
 asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user,
                              gid_t group, int flag)
 {
-        struct nameidata nd;
+        struct path path;
         int error = -EINVAL;
         int follow;
 
@@ -704,35 +704,35 @@ asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user,
                 goto out;
 
         follow = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
-        error = __user_walk_fd(dfd, filename, follow, &nd);
+        error = user_path_at(dfd, filename, follow, &path);
         if (error)
                 goto out;
-        error = mnt_want_write(nd.path.mnt);
+        error = mnt_want_write(path.mnt);
         if (error)
                 goto out_release;
-        error = chown_common(nd.path.dentry, user, group);
-        mnt_drop_write(nd.path.mnt);
+        error = chown_common(path.dentry, user, group);
+        mnt_drop_write(path.mnt);
 out_release:
-        path_put(&nd.path);
+        path_put(&path);
 out:
         return error;
 }
 
 asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group)
 {
-        struct nameidata nd;
+        struct path path;
         int error;
 
-        error = user_path_walk_link(filename, &nd);
+        error = user_lpath(filename, &path);
         if (error)
                 goto out;
-        error = mnt_want_write(nd.path.mnt);
+        error = mnt_want_write(path.mnt);
         if (error)
                 goto out_release;
-        error = chown_common(nd.path.dentry, user, group);
-        mnt_drop_write(nd.path.mnt);
+        error = chown_common(path.dentry, user, group);
+        mnt_drop_write(path.mnt);
 out_release:
-        path_put(&nd.path);
+        path_put(&path);
 out:
         return error;
 }