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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Mon, 31 Aug 2020 18:27:38 +0300
Message-ID: <CAMj1kXFUhqz8HPcssWXKCZ92c-pZvgYKk4aX6xmq2qocmiTKsA@mail.gmail.com>
Subject: Re: [PATCH] gss_krb5: Fix memleak in krb5_make_rc4_seq_num
To:     "J. Bruce Fields" <bfields@fieldses.org>
Cc:     Dinghao Liu <dinghao.liu@zju.edu.cn>, Kangjie Lu <kjlu@umn.edu>,
        Trond Myklebust <trond.myklebust@hammerspace.com>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        Chuck Lever <chuck.lever@oracle.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Scott Mayhew <smayhew@redhat.com>, linux-nfs@vger.kernel.org,
        "open list:BPF JIT for MIPS (32-BIT AND 64-BIT)" 
        <netdev@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Sat, 29 Aug 2020 at 18:43, J. Bruce Fields <bfields@fieldses.org> wrote:
>
> This code is rarely if ever used, and there are pending patches to
> remove it completely, so I don't think it's worth trying to fix a rare
> memory leak at this point.
>
> --b.
>

FYI I just submitted v3 of my series removing this code to the
linux-crypto list, and so hopefully it will disappear in v5.10


> On Thu, Aug 27, 2020 at 04:02:50PM +0800, Dinghao Liu wrote:
> > When kmalloc() fails, cipher should be freed
> > just like when krb5_rc4_setup_seq_key() fails.
> >
> > Fixes: e7afe6c1d486b ("sunrpc: fix 4 more call sites that were using stack memory with a scatterlist")
> > Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> > ---
> >  net/sunrpc/auth_gss/gss_krb5_seqnum.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/sunrpc/auth_gss/gss_krb5_seqnum.c b/net/sunrpc/auth_gss/gss_krb5_seqnum.c
> > index 507105127095..88ca58d11082 100644
> > --- a/net/sunrpc/auth_gss/gss_krb5_seqnum.c
> > +++ b/net/sunrpc/auth_gss/gss_krb5_seqnum.c
> > @@ -53,8 +53,10 @@ krb5_make_rc4_seq_num(struct krb5_ctx *kctx, int direction, s32 seqnum,
> >               return PTR_ERR(cipher);
> >
> >       plain = kmalloc(8, GFP_NOFS);
> > -     if (!plain)
> > -             return -ENOMEM;
> > +     if (!plain) {
> > +             code = -ENOMEM;
> > +             goto out;
> > +     }
> >
> >       plain[0] = (unsigned char) ((seqnum >> 24) & 0xff);
> >       plain[1] = (unsigned char) ((seqnum >> 16) & 0xff);
> > --
> > 2.17.1