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From: Christian Brauner <brauner@kernel.org>
To: Amir Goldstein <amir73il@gmail.com>,
	Miklos Szeredi <miklos@szeredi.hu>,
	"Darrick J . Wong" <djwong@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>, Christoph Hellwig <hch@lst.de>,
	Seth Forshee <sforshee@kernel.org>,
	Yang Xu <xuyang2018.jy@fujitsu.com>,
	Filipe Manana <fdmanana@kernel.org>,
	Christian Brauner <brauner@kernel.org>,
	linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Miklos Szeredi <mszeredi@redhat.com>
Subject: [PATCH v4 5/6] ovl: remove privs in ovl_copyfile()
Date: Mon, 17 Oct 2022 17:06:38 +0200	[thread overview]
Message-ID: <20221017150640.112577-6-brauner@kernel.org> (raw)
In-Reply-To: <20221017150640.112577-1-brauner@kernel.org>

From: Amir Goldstein <amir73il@gmail.com>

Underlying fs doesn't remove privs because copy_range/remap_range are
called with privileged mounter credentials.

This fixes some failures in fstest generic/673.

Fixes: 8ede205541ff ("ovl: add reflink/copyfile/dedup support")
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---

Notes:
    /* v2 */
    Acked-by: Miklos Szeredi <miklos@szeredi.hu>
    
    /* v3 */
    unchanged
    
    /* v4 */
    unchanged

 fs/overlayfs/file.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index a1a22f58ba18..755a11c63596 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -567,14 +567,23 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
 	const struct cred *old_cred;
 	loff_t ret;
 
+	inode_lock(inode_out);
+	if (op != OVL_DEDUPE) {
+		/* Update mode */
+		ovl_copyattr(inode_out);
+		ret = file_remove_privs(file_out);
+		if (ret)
+			goto out_unlock;
+	}
+
 	ret = ovl_real_fdget(file_out, &real_out);
 	if (ret)
-		return ret;
+		goto out_unlock;
 
 	ret = ovl_real_fdget(file_in, &real_in);
 	if (ret) {
 		fdput(real_out);
-		return ret;
+		goto out_unlock;
 	}
 
 	old_cred = ovl_override_creds(file_inode(file_out)->i_sb);
@@ -603,6 +612,9 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
 	fdput(real_in);
 	fdput(real_out);
 
+out_unlock:
+	inode_unlock(inode_out);
+
 	return ret;
 }
 
-- 
2.34.1


  parent reply	other threads:[~2022-10-17 15:09 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-17 15:06 [PATCH v4 0/6] fs: improve setgid stripping consistency even more Christian Brauner
2022-10-17 15:06 ` [PATCH v4 1/6] attr: add in_group_or_capable() Christian Brauner
2022-10-17 15:06 ` [PATCH v4 2/6] fs: move should_remove_suid() Christian Brauner
2022-10-17 15:06 ` [PATCH v4 3/6] attr: add setattr_should_drop_sgid() Christian Brauner
2022-10-17 15:06 ` [PATCH v4 4/6] attr: use consistent sgid stripping checks Christian Brauner
2022-10-17 15:06 ` Christian Brauner [this message]
2022-10-17 15:06 ` [PATCH v4 6/6] ovl: remove privs in ovl_fallocate() Christian Brauner
2022-10-18  8:23 ` [PATCH v4 0/6] fs: improve setgid stripping consistency even more Christian Brauner

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