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From:   Luis Henriques <lhenriques@suse.com>
To:     Aditya Pakki <pakki001@umn.edu>
Cc:     kjlu@umn.edu, Ilya Dryomov <idryomov@gmail.com>,
        "Yan\, Zheng" <zyan@redhat.com>, Sage Weil <sage@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        ceph-devel@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] libceph: Avoid a NULL pointer dereference
References: <20190314211724.21306-1-pakki001@umn.edu>
Date:   Fri, 15 Mar 2019 11:24:26 +0000
In-Reply-To: <20190314211724.21306-1-pakki001@umn.edu> (Aditya Pakki's message
        of "Thu, 14 Mar 2019 16:17:24 -0500")
Message-ID: <87ef78bct1.fsf@suse.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
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Aditya Pakki <pakki001@umn.edu> writes:

> kmalloc allocates memory for dest->name and attempts to call
> memcpy without a check for failure. This patch avoids such a scenario.

Since kmalloc is being invoked with the __GFP_NOFAIL flag, it will never
fail.  Thus, there's no point in checking for NULL in this case.

Cheers,
-- 
Luis


>
> Signed-off-by: Aditya Pakki <pakki001@umn.edu>
> ---
>  net/ceph/osdmap.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
> index 48a31dc9161c..c76a7c7e6a77 100644
> --- a/net/ceph/osdmap.c
> +++ b/net/ceph/osdmap.c
> @@ -1901,6 +1901,8 @@ void ceph_oid_copy(struct ceph_object_id *dest,
>  	} else {
>  		dest->name = dest->inline_name;
>  	}
> +	if (!dest->name)
> +		return;
>  	memcpy(dest->name, src->name, src->name_len + 1);
>  	dest->name_len = src->name_len;
>  }