[PATCH 5.10 0/1] Fix CVE-2020-16120

[PATCH 5.10 0/1] Fix CVE-2020-16120

[hsimeliere.opensource]

https://nvd.nist.gov/vuln/detail/CVE-2020-16120

[PATCH 5.10 1/1] ovl: do not fail because of O_NOATIME

[hsimeliere.opensource]

From: Miklos Szeredi <mszeredi@redhat.com>

commit b6650dab404c701d7fe08a108b746542a934da84 upstream.

In case the file cannot be opened with O_NOATIME because of lack of
capabilities, then clear O_NOATIME instead of failing.

Remove WARN_ON(), since it would now trigger if O_NOATIME was cleared.
Noticed by Amir Goldstein.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Hugo SIMELIERE <hsimeliere.opensource@witekio.com>
---
 fs/overlayfs/file.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 244e4258ce16..4440ff43cb66 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -53,9 +53,10 @@ static struct file *ovl_open_realfile(const struct file *file,
 	err = inode_permission(realinode, MAY_OPEN | acc_mode);
 	if (err) {
 		realfile = ERR_PTR(err);
-	} else if (!inode_owner_or_capable(realinode)) {
-		realfile = ERR_PTR(-EPERM);
 	} else {
+		if (!inode_owner_or_capable(realinode))
+			flags &= ~O_NOATIME;
+
 		realfile = open_with_fake_path(&file->f_path, flags, realinode,
 					       current_cred());
 	}
@@ -75,12 +76,6 @@ static int ovl_change_flags(struct file *file, unsigned int flags)
 	struct inode *inode = file_inode(file);
 	int err;
 
-	flags |= OVL_OPEN_FLAGS;
-
-	/* If some flag changed that cannot be changed then something's amiss */
-	if (WARN_ON((file->f_flags ^ flags) & ~OVL_SETFL_MASK))
-		return -EIO;
-
 	flags &= OVL_SETFL_MASK;
 
 	if (((flags ^ file->f_flags) & O_APPEND) && IS_APPEND(inode))
-- 
2.43.0

Re: [PATCH 5.10 1/1] ovl: do not fail because of O_NOATIME

[Greg KH]

On Fri, Aug 30, 2024 at 11:27:45AM +0200, hsimeliere.opensource@witekio.com wrote:
> From: Miklos Szeredi <mszeredi@redhat.com>
> 
> commit b6650dab404c701d7fe08a108b746542a934da84 upstream.
> 
> In case the file cannot be opened with O_NOATIME because of lack of
> capabilities, then clear O_NOATIME instead of failing.
> 
> Remove WARN_ON(), since it would now trigger if O_NOATIME was cleared.
> Noticed by Amir Goldstein.
> 
> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
> Signed-off-by: Hugo SIMELIERE <hsimeliere.opensource@witekio.com>
> ---
>  fs/overlayfs/file.c | 11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
> 

Now queued up, thanks.

greg k-h