Re: [PATCH] dma-buf: Fix possible UAF in dma_buf_export

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Thanks T.J and Christian, thanks everyone for taking time to review this patch.

Charan, actually I don't have a good patch to to fix it, if you can submit
a new patch to solve it, please feel free to do it.

By the way, I'd appreciate it if you could send to me the new patch when you submit it.

Thanks again!

Gaosheng.

On 2022/11/24 13:56, Charan Teja Kalla wrote:
Thanks T.J and Christian for the inputs.

On 11/19/2022 7:00 PM, Christian König wrote:
     Yes, exactly that's the idea.

     The only alternatives I can see would be to either move allocating
     the
     file and so completing the dma_buf initialization last again or just
     ignore errors from sysfs.

     > If we still want to avoid calling dmabuf->ops->release(dmabuf) in
     > dma_buf_release like the comment says I guess we could use
     sysfs_entry
     > and ERR_PTR to flag that, otherwise it looks like we'd need a bit
     > somewhere.

     No, this should be dropped as far as I can see. The sysfs cleanup
     code
     looks like it can handle not initialized kobj pointers.


Yeah there is also the null check in dma_buf_stats_teardown() that
would prevent it from running, but I understood the comment to be
referring to the release() dma_buf_ops call into the exporter which
comes right after the teardown call. That looks like it's preventing
the fput task work calling back into the exporter after the exporter
already got an error from dma_buf_export(). Otherwise the exporter
sees a release() for a buffer that it doesn't know about / thinks
shouldn't exist. So I could imagine an exporter trying to double free:
once for the failed dma_buf_export() call, and again when the
release() op is called later.

Oh, very good point as well. Yeah, then creating the file should
probably come last.

@Gaosheng: Could you please make these changes or you let me to do?

Regards,
Christian.
.



[Index of Archives]     [Linux Input]     [Video for Linux]     [Gstreamer Embedded]     [Mplayer Users]     [Linux USB Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [Yosemite Backpacking]

  Powered by Linux