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Re: [PATCH] virtiofsd: Fix potential NULL pointer dereference in virtio_
From: |
Alex Chen |
Subject: |
Re: [PATCH] virtiofsd: Fix potential NULL pointer dereference in virtio_send_msg() |
Date: |
Fri, 11 Dec 2020 18:16:32 +0800 |
User-agent: |
Mozilla/5.0 (Windows NT 6.2; WOW64; rv:17.0) Gecko/20130509 Thunderbird/17.0.6 |
Hi Dave,
On 2020/12/11 2:00, Dr. David Alan Gilbert wrote:
> * Alex Chen (alex.chen@huawei.com) wrote:
>> The 'ch' will be NULL in the following stack:
>> send_notify_iov()->fuse_send_msg()->virtio_send_msg(),
>> so we should check 'ch' is valid before dereferencing it
>>
>> Reported-by: Euler Robot <euler.robot@huawei.com>
>> Signed-off-by: Alex Chen <alex.chen@huawei.com>
>
> Please check, but I don't think we can currently hit this because
> we never call send_notify_iov - it's currently called by
> fuse_lowlevel_notify_inval_entry, inval_inode, and
> fuse_lowlevel_notify_poll -
> but I don't think those are called anywhere.
>
Thanks for your review.
The send_notify_iov() is really not being called.
> In that case, probably the best fix is to remove those until we
> put notify back in.
>
OK, I will remove those temporarily useless code and send patch v2 to fix this
problem.
Thanks,
Alex
> Dave
>
>> ---
>> tools/virtiofsd/fuse_virtio.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
>> index 623812c432..31b2187a15 100644
>> --- a/tools/virtiofsd/fuse_virtio.c
>> +++ b/tools/virtiofsd/fuse_virtio.c
>> @@ -205,6 +205,8 @@ static void copy_iov(struct iovec *src_iov, int
>> src_count,
>> int virtio_send_msg(struct fuse_session *se, struct fuse_chan *ch,
>> struct iovec *iov, int count)
>> {
>> + assert(ch);
>> +
>> FVRequest *req = container_of(ch, FVRequest, ch);
>> struct fv_QueueInfo *qi = ch->qi;
>> VuDev *dev = &se->virtio_dev->dev;
>> --
>> 2.19.1
>>