Merge tag 'pull-xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull xattr updates from Al Viro:
 "Sanitize xattr and io_uring interactions with it, add *xattrat()
  syscalls, sanitize struct filename handling in there"

* tag 'pull-xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  xattr: remove redundant check on variable err
  fs/xattr: add *at family syscalls
  new helpers: file_removexattr(), filename_removexattr()
  new helpers: file_listxattr(), filename_listxattr()
  replace do_getxattr() with saner helpers.
  replace do_setxattr() with saner helpers.
  new helper: import_xattr_name()
  fs: rename struct xattr_ctx to kernel_xattr_ctx
  xattr: switch to CLASS(fd)
  io_[gs]etxattr_prep(): just use getname()
  io_uring: IORING_OP_F[GS]ETXATTR is fine with REQ_F_FIXED_FILE
  getname_maybe_null() - the third variant of pathname copy-in
  teach filename_lookup() to treat NULL filename as ""

1 files changed, 25 insertions, 72 deletions

diff --git a/io_uring/xattr.c b/io_uring/xattr.c
index 6cf41c3bc369..de5064fcae8a 100644
--- a/io_uring/xattr.c
+++ b/io_uring/xattr.c
@@ -18,7 +18,7 @@
 
 struct io_xattr {
 	struct file			*file;
-	struct xattr_ctx		ctx;
+	struct kernel_xattr_ctx		ctx;
 	struct filename			*filename;
 };
 
@@ -48,13 +48,10 @@ static int __io_getxattr_prep(struct io_kiocb *req,
 	const char __user *name;
 	int ret;
 
-	if (unlikely(req->flags & REQ_F_FIXED_FILE))
-		return -EBADF;
-
 	ix->filename = NULL;
 	ix->ctx.kvalue = NULL;
 	name = u64_to_user_ptr(READ_ONCE(sqe->addr));
-	ix->ctx.cvalue = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	ix->ctx.value = u64_to_user_ptr(READ_ONCE(sqe->addr2));
 	ix->ctx.size = READ_ONCE(sqe->len);
 	ix->ctx.flags = READ_ONCE(sqe->xattr_flags);
 
@@ -65,11 +62,8 @@ static int __io_getxattr_prep(struct io_kiocb *req,
 	if (!ix->ctx.kname)
 		return -ENOMEM;
 
-	ret = strncpy_from_user(ix->ctx.kname->name, name,
-				sizeof(ix->ctx.kname->name));
-	if (!ret || ret == sizeof(ix->ctx.kname->name))
-		ret = -ERANGE;
-	if (ret < 0) {
+	ret = import_xattr_name(ix->ctx.kname, name);
+	if (ret) {
 		kfree(ix->ctx.kname);
 		return ret;
 	}
@@ -90,19 +84,20 @@ int io_getxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	const char __user *path;
 	int ret;
 
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
 	ret = __io_getxattr_prep(req, sqe);
 	if (ret)
 		return ret;
 
 	path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
 
-	ix->filename = getname_flags(path, LOOKUP_FOLLOW);
-	if (IS_ERR(ix->filename)) {
-		ret = PTR_ERR(ix->filename);
-		ix->filename = NULL;
-	}
+	ix->filename = getname(path);
+	if (IS_ERR(ix->filename))
+		return PTR_ERR(ix->filename);
 
-	return ret;
+	return 0;
 }
 
 int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
@@ -112,10 +107,7 @@ int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
 
 	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
 
-	ret = do_getxattr(file_mnt_idmap(req->file),
-			req->file->f_path.dentry,
-			&ix->ctx);
-
+	ret = file_getxattr(req->file, &ix->ctx);
 	io_xattr_finish(req, ret);
 	return IOU_OK;
 }
@@ -123,24 +115,12 @@ int io_fgetxattr(struct io_kiocb *req, unsigned int issue_flags)
 int io_getxattr(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
-	unsigned int lookup_flags = LOOKUP_FOLLOW;
-	struct path path;
 	int ret;
 
 	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
 
-retry:
-	ret = filename_lookup(AT_FDCWD, ix->filename, lookup_flags, &path, NULL);
-	if (!ret) {
-		ret = do_getxattr(mnt_idmap(path.mnt), path.dentry, &ix->ctx);
-
-		path_put(&path);
-		if (retry_estale(ret, lookup_flags)) {
-			lookup_flags |= LOOKUP_REVAL;
-			goto retry;
-		}
-	}
-
+	ret = filename_getxattr(AT_FDCWD, ix->filename, LOOKUP_FOLLOW, &ix->ctx);
+	ix->filename = NULL;
 	io_xattr_finish(req, ret);
 	return IOU_OK;
 }
@@ -152,9 +132,6 @@ static int __io_setxattr_prep(struct io_kiocb *req,
 	const char __user *name;
 	int ret;
 
-	if (unlikely(req->flags & REQ_F_FIXED_FILE))
-		return -EBADF;
-
 	ix->filename = NULL;
 	name = u64_to_user_ptr(READ_ONCE(sqe->addr));
 	ix->ctx.cvalue = u64_to_user_ptr(READ_ONCE(sqe->addr2));
@@ -183,19 +160,20 @@ int io_setxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	const char __user *path;
 	int ret;
 
+	if (unlikely(req->flags & REQ_F_FIXED_FILE))
+		return -EBADF;
+
 	ret = __io_setxattr_prep(req, sqe);
 	if (ret)
 		return ret;
 
 	path = u64_to_user_ptr(READ_ONCE(sqe->addr3));
 
-	ix->filename = getname_flags(path, LOOKUP_FOLLOW);
-	if (IS_ERR(ix->filename)) {
-		ret = PTR_ERR(ix->filename);
-		ix->filename = NULL;
-	}
+	ix->filename = getname(path);
+	if (IS_ERR(ix->filename))
+		return PTR_ERR(ix->filename);
 
-	return ret;
+	return 0;
 }
 
 int io_fsetxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
@@ -203,28 +181,14 @@ int io_fsetxattr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	return __io_setxattr_prep(req, sqe);
 }
 
-static int __io_setxattr(struct io_kiocb *req, unsigned int issue_flags,
-			const struct path *path)
-{
-	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
-	int ret;
-
-	ret = mnt_want_write(path->mnt);
-	if (!ret) {
-		ret = do_setxattr(mnt_idmap(path->mnt), path->dentry, &ix->ctx);
-		mnt_drop_write(path->mnt);
-	}
-
-	return ret;
-}
-
 int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
 {
+	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
 	int ret;
 
 	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
 
-	ret = __io_setxattr(req, issue_flags, &req->file->f_path);
+	ret = file_setxattr(req->file, &ix->ctx);
 	io_xattr_finish(req, ret);
 	return IOU_OK;
 }
@@ -232,23 +196,12 @@ int io_fsetxattr(struct io_kiocb *req, unsigned int issue_flags)
 int io_setxattr(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_xattr *ix = io_kiocb_to_cmd(req, struct io_xattr);
-	unsigned int lookup_flags = LOOKUP_FOLLOW;
-	struct path path;
 	int ret;
 
 	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
 
-retry:
-	ret = filename_lookup(AT_FDCWD, ix->filename, lookup_flags, &path, NULL);
-	if (!ret) {
-		ret = __io_setxattr(req, issue_flags, &path);
-		path_put(&path);
-		if (retry_estale(ret, lookup_flags)) {
-			lookup_flags |= LOOKUP_REVAL;
-			goto retry;
-		}
-	}
-
+	ret = filename_setxattr(AT_FDCWD, ix->filename, LOOKUP_FOLLOW, &ix->ctx);
+	ix->filename = NULL;
 	io_xattr_finish(req, ret);
 	return IOU_OK;
 }