Linux-NFS Archive on lore.kernel.org
 help / color / Atom feed
From: Olga Kornievskaia <aglo@umich.edu>
To: Trond Myklebust <trondmy@hammerspace.com>
Cc: "pakki001@umn.edu" <pakki001@umn.edu>,
	"davem@davemloft.net" <davem@davemloft.net>,
	"chuck.lever@oracle.com" <chuck.lever@oracle.com>,
	"dwysocha@redhat.com" <dwysocha@redhat.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"kuba@kernel.org" <kuba@kernel.org>,
	"bfields@fieldses.org" <bfields@fieldses.org>,
	"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
	"anna.schumaker@netapp.com" <anna.schumaker@netapp.com>
Subject: Re: [PATCH] SUNRPC: Add a check for gss_release_msg
Date: Thu, 8 Apr 2021 11:24:45 -0400
Message-ID: <CAN-5tyETkDBVfYQrBOm1veAzMdo-9K37bfgL+QZTPW=d2OAP9A@mail.gmail.com> (raw)
In-Reply-To: <c0de0985c0bf09a96efc538da2146f86e6fa7037.camel@hammerspace.com>

On Thu, Apr 8, 2021 at 11:01 AM Trond Myklebust <trondmy@hammerspace.com> wrote:
>
> On Tue, 2021-04-06 at 19:16 -0500, Aditya Pakki wrote:
> > In gss_pipe_destroy_msg(), in case of error in msg, gss_release_msg
> > deletes gss_msg. The patch adds a check to avoid a potential double
> > free.
> >
> > Signed-off-by: Aditya Pakki <pakki001@umn.edu>
> > ---
> >  net/sunrpc/auth_gss/auth_gss.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/net/sunrpc/auth_gss/auth_gss.c
> > b/net/sunrpc/auth_gss/auth_gss.c
> > index 5f42aa5fc612..eb52eebb3923 100644
> > --- a/net/sunrpc/auth_gss/auth_gss.c
> > +++ b/net/sunrpc/auth_gss/auth_gss.c
> > @@ -848,7 +848,8 @@ gss_pipe_destroy_msg(struct rpc_pipe_msg *msg)
> >                         warn_gssd();
> >                 gss_release_msg(gss_msg);
> >         }
> > -       gss_release_msg(gss_msg);
> > +       if (gss_msg)
> > +               gss_release_msg(gss_msg);
> >  }
> >
> >  static void gss_pipe_dentry_destroy(struct dentry *dir,
>
>
> NACK. There's no double free there.

I disagree that there is no double free, the wording of the commit
describes the problem in the error case is that we call
gss_release_msg() and then we call it again but the 1st one released
the gss_msg. However, I think the fix should probably be instead:
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 5f42aa5fc612..e8aae617e981 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -846,7 +846,7 @@ gss_pipe_destroy_msg(struct rpc_pipe_msg *msg)
                gss_unhash_msg(gss_msg);
                if (msg->errno == -ETIMEDOUT)
                        warn_gssd();
-               gss_release_msg(gss_msg);
+               return gss_release_msg(gss_msg);
        }
        gss_release_msg(gss_msg);
 }

>
> --
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> trond.myklebust@hammerspace.com
>
>

  reply index

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-07  0:16 Aditya Pakki
2021-04-07 15:34 ` J. Bruce Fields
2021-04-08 15:01 ` Trond Myklebust
2021-04-08 15:24   ` Olga Kornievskaia [this message]
2021-04-08 16:02     ` Trond Myklebust
2021-04-20  7:15 ` Greg KH
2021-04-20 17:10   ` J. Bruce Fields
2021-04-21  5:10     ` Leon Romanovsky
2021-04-21  5:43       ` Greg KH
2021-04-21  6:08         ` Leon Romanovsky
     [not found]         ` <CA+EnHHSw4X+ubOUNYP2zXNpu70G74NN1Sct2Zin6pRgq--TqhA@mail.gmail.com>
2021-04-21  8:15           ` Greg KH
2021-04-21 10:07         ` Sudip Mukherjee
2021-04-21 10:21           ` Greg KH
2021-04-21 11:58             ` Shelat, Abhi
2021-04-21 12:08               ` Greg KH
2021-04-21 12:19               ` Leon Romanovsky
2021-04-21 13:11                 ` Trond Myklebust
2021-04-21 13:20                   ` Leon Romanovsky
2021-04-21 13:42                     ` Steven Rostedt
2021-04-21 13:21                   ` gregkh
2021-04-21 13:34                     ` Leon Romanovsky
2021-04-21 13:50                       ` gregkh
2021-04-21 14:12                         ` Leon Romanovsky
2021-04-21 18:50                         ` Alexander Grund
2021-04-21 13:37               ` J. Bruce Fields
2021-04-21 13:49                 ` Leon Romanovsky
2021-04-21 13:56                   ` J. Bruce Fields
2021-04-22 19:39                     ` J. Bruce Fields
2021-04-23 17:25                       ` Leon Romanovsky
2021-04-23 18:07                         ` J. Bruce Fields
2021-04-23 19:29                           ` Leon Romanovsky
2021-04-23 21:48                             ` J. Bruce Fields
2021-04-24  7:21                               ` Leon Romanovsky
2021-04-24 18:34                               ` Al Viro
2021-04-24 21:34                                 ` J. Bruce Fields
2021-04-25  0:41                                   ` Theodore Ts'o
2021-04-25  6:29                                     ` Greg KH
     [not found]                                       ` <20210426133605.GD21222@fieldses.org>
2021-04-26 13:47                                         ` J. Bruce Fields
2021-04-22  8:10             ` Sudip Mukherjee
2021-04-22  8:27               ` Greg KH
2021-04-21 12:51       ` Anna Schumaker
2021-04-21 14:15         ` Leon Romanovsky
2021-04-21 15:48           ` Theodore Ts'o
2021-04-21 17:34             ` Mike Rapoport
2021-04-22  3:57               ` Leon Romanovsky
2021-04-21 22:52 ` Guenter Roeck
     [not found] <CAHr+ZK-ayy2vku9ovuSB4egtOxrPEKxCdVQN3nFqMK07+K5_8g@mail.gmail.com>
2021-04-21 19:49 ` Theodore Ts'o
2021-04-22  7:50   ` Eric Biggers
2021-04-21 20:27 Weikeng Chen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAN-5tyETkDBVfYQrBOm1veAzMdo-9K37bfgL+QZTPW=d2OAP9A@mail.gmail.com' \
    --to=aglo@umich.edu \
    --cc=anna.schumaker@netapp.com \
    --cc=bfields@fieldses.org \
    --cc=chuck.lever@oracle.com \
    --cc=davem@davemloft.net \
    --cc=dwysocha@redhat.com \
    --cc=kuba@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-nfs@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=pakki001@umn.edu \
    --cc=trondmy@hammerspace.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-NFS Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-nfs/0 linux-nfs/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-nfs linux-nfs/ https://lore.kernel.org/linux-nfs \
		linux-nfs@vger.kernel.org
	public-inbox-index linux-nfs

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-nfs


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git