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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>,
        David Howells <dhowells@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.12 348/677] afs: Fix updating of i_mode due to 3rd party change
Date:   Wed, 12 May 2021 16:46:34 +0200
Message-Id: <20210512144848.873474197@linuxfoundation.org>
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From: David Howells <dhowells@redhat.com>

[ Upstream commit 6e1eb04a87f954eb06a89ee6034c166351dfff6e ]

Fix afs_apply_status() to mask off the irrelevant bits from status->mode
when OR'ing them into i_mode.  This can happen when a 3rd party chmod
occurs.

Also fix afs_inode_init_from_status() to mask off the mode bits when
initialising i_mode.

Fixes: 260a980317da ("[AFS]: Add "directory write" support.")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/afs/inode.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 12be88716e4c..5a70c09f5325 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -102,13 +102,13 @@ static int afs_inode_init_from_status(struct afs_operation *op,
 
 	switch (status->type) {
 	case AFS_FTYPE_FILE:
-		inode->i_mode	= S_IFREG | status->mode;
+		inode->i_mode	= S_IFREG | (status->mode & S_IALLUGO);
 		inode->i_op	= &afs_file_inode_operations;
 		inode->i_fop	= &afs_file_operations;
 		inode->i_mapping->a_ops	= &afs_fs_aops;
 		break;
 	case AFS_FTYPE_DIR:
-		inode->i_mode	= S_IFDIR | status->mode;
+		inode->i_mode	= S_IFDIR |  (status->mode & S_IALLUGO);
 		inode->i_op	= &afs_dir_inode_operations;
 		inode->i_fop	= &afs_dir_file_operations;
 		inode->i_mapping->a_ops	= &afs_dir_aops;
@@ -198,7 +198,7 @@ static void afs_apply_status(struct afs_operation *op,
 	if (status->mode != vnode->status.mode) {
 		mode = inode->i_mode;
 		mode &= ~S_IALLUGO;
-		mode |= status->mode;
+		mode |= status->mode & S_IALLUGO;
 		WRITE_ONCE(inode->i_mode, mode);
 	}
 
-- 
2.30.2