From: Mike Snitzer <snitzer@redhat.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Alasdair Kergon <agk@redhat.com>,
dm-devel@redhat.com, Neil Brown <neilb@suse.de>,
linux-raid@vger.kernel.org, kernel-janitors@vger.kernel.org,
Heinz Mauelshagen <heinzm@redhat.com>
Subject: Re: dm raid: pointer math issue in super_sync()
Date: Tue, 21 Oct 2014 08:48:26 -0400 [thread overview]
Message-ID: <20141021124826.GC20625@redhat.com> (raw)
In-Reply-To: <20141021124336.GA20791@mwanda>
On Tue, Oct 21 2014 at 8:43am -0400,
Dan Carpenter <dan.carpenter@oracle.com> wrote:
> "sb" is a dm_raid_superblock struct pointer so the pointer math doesn't
> work and we will end up corrupting memory.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
> index b802644..a7cb9dd 100644
> --- a/drivers/md/dm-raid.c
> +++ b/drivers/md/dm-raid.c
> @@ -826,7 +826,7 @@ static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
> test_bit(Faulty, &(rs->dev[i].rdev.flags)))
> failed_devices |= (1ULL << i);
>
> - memset(sb + sizeof(*sb), 0, rdev->sb_size - sizeof(*sb));
> + memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
>
> sb->magic = cpu_to_le32(DM_RAID_MAGIC);
> sb->features = cpu_to_le32(0); /* No features yet */
Not following... sizeof(*sb) != sizeof(sb). So I'm not seeing a
problem.
Nor am I seeing how you think sb + 1 is equivalent to what Heinz
intended (zero the memory following the sizeof(struct dm_raid_superblock)).
WARNING: multiple messages have this Message-ID (diff)
From: Mike Snitzer <snitzer@redhat.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Alasdair Kergon <agk@redhat.com>,
dm-devel@redhat.com, Neil Brown <neilb@suse.de>,
linux-raid@vger.kernel.org, kernel-janitors@vger.kernel.org,
Heinz Mauelshagen <heinzm@redhat.com>
Subject: Re: dm raid: pointer math issue in super_sync()
Date: Tue, 21 Oct 2014 12:48:26 +0000 [thread overview]
Message-ID: <20141021124826.GC20625@redhat.com> (raw)
In-Reply-To: <20141021124336.GA20791@mwanda>
On Tue, Oct 21 2014 at 8:43am -0400,
Dan Carpenter <dan.carpenter@oracle.com> wrote:
> "sb" is a dm_raid_superblock struct pointer so the pointer math doesn't
> work and we will end up corrupting memory.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
> index b802644..a7cb9dd 100644
> --- a/drivers/md/dm-raid.c
> +++ b/drivers/md/dm-raid.c
> @@ -826,7 +826,7 @@ static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
> test_bit(Faulty, &(rs->dev[i].rdev.flags)))
> failed_devices |= (1ULL << i);
>
> - memset(sb + sizeof(*sb), 0, rdev->sb_size - sizeof(*sb));
> + memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));
>
> sb->magic = cpu_to_le32(DM_RAID_MAGIC);
> sb->features = cpu_to_le32(0); /* No features yet */
Not following... sizeof(*sb) != sizeof(sb). So I'm not seeing a
problem.
Nor am I seeing how you think sb + 1 is equivalent to what Heinz
intended (zero the memory following the sizeof(struct dm_raid_superblock)).
next prev parent reply other threads:[~2014-10-21 12:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-21 12:43 [patch] dm raid: pointer math issue in super_sync() Dan Carpenter
2014-10-21 12:43 ` Dan Carpenter
2014-10-21 12:48 ` Mike Snitzer [this message]
2014-10-21 12:48 ` Mike Snitzer
2014-10-21 12:57 ` Dan Carpenter
2014-10-21 12:57 ` Dan Carpenter
2014-10-21 13:25 ` Mike Snitzer
2014-10-21 13:25 ` Mike Snitzer
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