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From: Amir Goldstein <amir73il@gmail.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: overlayfs <linux-unionfs@vger.kernel.org>
Subject: Re: [bug report] ovl: copy up of disconnected dentries
Date: Mon, 22 Mar 2021 14:25:44 +0200	[thread overview]
Message-ID: <CAOQ4uxjNVHGReF5_TXBXHdVb0asJ4RQH_CT6Gy7r1J8MWEe1yg@mail.gmail.com> (raw)
In-Reply-To: <YFiK/GhGReGqh52w@mwanda>

On Mon, Mar 22, 2021 at 2:18 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> Hello Amir Goldstein,
>
> The patch aa3ff3c152ff: "ovl: copy up of disconnected dentries" from
> Oct 15, 2017, leads to the following static checker warning:

Heh! that's fashionably late :)

>
>         fs/overlayfs/copy_up.c:972 ovl_copy_up_flags()
>         warn: 'old_cred' not released on lines: 944.
>
> fs/overlayfs/copy_up.c
>    932  static int ovl_copy_up_flags(struct dentry *dentry, int flags)
>    933  {
>    934          int err = 0;
>    935          const struct cred *old_cred = ovl_override_creds(dentry->d_sb);
>    936          bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED);
>    937
>    938          /*
>    939           * With NFS export, copy up can get called for a disconnected non-dir.
>    940           * In this case, we will copy up lower inode to index dir without
>    941           * linking it to upper dir.
>    942           */
>    943          if (WARN_ON(disconnected && d_is_dir(dentry)))
>    944                  return -EIO;
>
> Should this call revert_creds(old_cred); before returning?

Yes. Here's a simple fix, care to post it?

Thanks,
Amir.

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 0b2891c6c71e..2846b943e80c 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -932,7 +932,7 @@ static int ovl_copy_up_one(struct dentry *parent,
struct dentry *dentry,
 static int ovl_copy_up_flags(struct dentry *dentry, int flags)
 {
        int err = 0;
-       const struct cred *old_cred = ovl_override_creds(dentry->d_sb);
+       const struct cred *old_cred;
        bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED);

        /*
@@ -943,6 +943,7 @@ static int ovl_copy_up_flags(struct dentry
*dentry, int flags)
        if (WARN_ON(disconnected && d_is_dir(dentry)))
                return -EIO;

+       old_cred = ovl_override_creds(dentry->d_sb);
        while (!err) {
                struct dentry *next;
                struct dentry *parent = NULL;

  reply	other threads:[~2021-03-22 12:26 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-22 12:18 [bug report] ovl: copy up of disconnected dentries Dan Carpenter
2021-03-22 12:25 ` Amir Goldstein [this message]
2021-03-22 12:35   ` Dan Carpenter

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