Messages in this thread | | | Date | Sun, 18 Jul 2021 14:31:23 +0530 | From | Anirudh Rayabharam <> | Subject | Re: [PATCH] firmware_loader: Fix use-after-free Read in firmware_loading_store |
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On Thu, Jul 15, 2021 at 04:21:05PM -0700, Luis Chamberlain wrote: > On Thu, Jul 15, 2021 at 04:46:24PM -0600, Shuah Khan wrote: > > On 7/15/21 4:28 PM, Luis Chamberlain wrote: > > > On Fri, Jul 09, 2021 at 10:38:12AM -0600, Shuah Khan wrote: > > > > However I am seeing the following over and over again in the > > > > log - hence I think it is safer to check the aborted status > > > > in __fw_load_abort(). > > > > > > > > ? __list_del_entry_valid+0xe0/0xf0 > > > > [ 348.604808][T12994] __list_del_entry_valid+0xe0/0xf0 > > > > [ 348.610020][T12994] firmware_loading_store+0x141/0x650 > > > > [ 348.615761][T12994] ? firmware_data_write+0x4e0/0x4e0 > > > > [ 348.621064][T12994] ? sysfs_file_ops+0x1c0/0x1c0 > > > > [ 348.625921][T12994] dev_attr_store+0x50/0x80 > > > > > > > > Also the fallback logic takes actions based on errors as in > > > > fw_load_sysfs_fallback() that returns -EAGAIN which would > > > > trigger request_firmware() again. > > > > > > > > Based on all of this I think this fix is needed, if only I can > > > > test for sure. > > > > > > Shuah, curious if you had read this patch from Anirudh Rayabharam > > > and my response to that v4 patch iteration? > > > > > > https://lkml.kernel.org/r/20210518155921.4181-1-mail@anirudhrb.com > > > > > > > Yes. I realized I am trying to fix the same problem we have been > > discussing. :) Sorry for the noise. > > No worries, and thanks again for you help! > > > Ignore my patch. I will follow the thread. > > OK ! I think all we need is just Anirudh to split his patch to > remove the -EAGAIN return value in a separate patch as a first step, > documenting in the commmit log that: > > The only motivation on her part with using -EAGAIN on commit > 0542ad88fbdd81bb ("firmware loader: Fix _request_firmware_load() > return val for fw load abort") was to distinguish the error from > -ENOMEM, and so there is no real reason in keeping it. Keeping
Are you sure about this? As per Shuah's explanation [1], it sounds to me like certain media drivers explicitly check for -EAGAIN to retry the firmware load. Shuah, is my understanding correct?
[1]: https://lore.kernel.org/lkml/04b5bb2f-edf7-5b43-585a-3267d83bd8c3@linuxfoundation.org/
> -ETIMEDOUT is much telling of what the reason for a failure is, > so just use that. > > Then his second patch would be simplified without the -EAGAIN > condition. > > All I asked was to confirm that the -ETIMEDOUT was indeed propagated.
Yes, -ETIMEDOUT is indeed propagated by fw_sysfs_wait_timeout.
> > Anirudh, sorry for the trouble, but can I ask you for a v5 with two > patches as described above?
Sure, I will do that.
- Anirudh.
> > Luis
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