linux-kernel - [PATCH 5.15 041/779] fs: Add missing umask strip in vfs

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Date:   Mon, 15 Aug 2022 19:54:45 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        "Christian Brauner (Microsoft)" <brauner@...nel.org>,
        "Darrick J. Wong" <djwong@...nel.org>,
        Yang Xu <xuyang2018.jy@...itsu.com>,
        Jeff Layton <jlayton@...nel.org>
Subject: [PATCH 5.15 041/779] fs: Add missing umask strip in vfs_tmpfile

From: Yang Xu <xuyang2018.jy@...itsu.com>

commit ac6800e279a22b28f4fc21439843025a0d5bf03e upstream.

All creation paths except for O_TMPFILE handle umask in the vfs directly
if the filesystem doesn't support or enable POSIX ACLs. If the filesystem
does then umask handling is deferred until posix_acl_create().
Because, O_TMPFILE misses umask handling in the vfs it will not honor
umask settings. Fix this by adding the missing umask handling.

Link: https://lore.kernel.org/r/1657779088-2242-2-git-send-email-xuyang2018.jy@fujitsu.com
Fixes: 60545d0d4610 ("[O_TMPFILE] it's still short a few helpers, but infrastructure should be OK now...")
Cc: <stable@...r.kernel.org> # 4.19+
Reported-by: Christian Brauner (Microsoft) <brauner@...nel.org>
Reviewed-by: Darrick J. Wong <djwong@...nel.org>
Reviewed-and-Tested-by: Jeff Layton <jlayton@...nel.org>
Acked-by: Christian Brauner (Microsoft) <brauner@...nel.org>
Signed-off-by: Yang Xu <xuyang2018.jy@...itsu.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/namei.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3523,6 +3523,8 @@ struct dentry *vfs_tmpfile(struct user_n
 	child = d_alloc(dentry, &slash_name);
 	if (unlikely(!child))
 		goto out_err;
+	if (!IS_POSIXACL(dir))
+		mode &= ~current_umask();
 	error = dir->i_op->tmpfile(mnt_userns, dir, child, mode);
 	if (error)
 		goto out_err;