Messages in this thread | | | Subject | Re: [PATCH v8 2/2] firmware_loader: fix use-after-free in firmware_fallback_sysfs | From | Shuah Khan <> | Date | Wed, 28 Jul 2021 10:37:38 -0600 |
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On 7/28/21 2:51 AM, Anirudh Rayabharam wrote: > This use-after-free happens when a fw_priv object has been freed but > hasn't been removed from the pending list (pending_fw_head). The next > time fw_load_sysfs_fallback tries to insert into the list, it ends up > accessing the pending_list member of the previously freed fw_priv. > > The root cause here is that all code paths that abort the fw load > don't delete it from the pending list. For example: > > _request_firmware() > -> fw_abort_batch_reqs() > -> fw_state_aborted() > > To fix this, delete the fw_priv from the list in __fw_set_state() if > the new state is DONE or ABORTED. This way, all aborts will remove > the fw_priv from the list. Accordingly, remove calls to list_del_init > that were being made before calling fw_state_(aborted|done). > > Also, in fw_load_sysfs_fallback, don't add the fw_priv to the pending > list if it is already aborted. Instead, just jump out and return early. > > Fixes: bcfbd3523f3c ("firmware: fix a double abort case with fw_load_sysfs_fallback") > Reported-by: syzbot+de271708674e2093097b@syzkaller.appspotmail.com > Tested-by: syzbot+de271708674e2093097b@syzkaller.appspotmail.com > Acked-by: Luis Chamberlain <mcgrof@kernel.org> > Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com> > --- > drivers/base/firmware_loader/fallback.c | 12 ++++++++---- > drivers/base/firmware_loader/firmware.h | 10 +++++++++- > drivers/base/firmware_loader/main.c | 2 ++ > 3 files changed, 19 insertions(+), 5 deletions(-) >
Thank you. Looks good.
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
thanks, -- Shuah
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