IF YOU WOULD LIKE TO GET AN ACCOUNT, please write an
email to Administrator. User accounts are meant only to access repo
and report issues and/or generate pull requests.
This is a purpose-specific Git hosting for
BaseALT
projects. Thank you for your understanding!
Только зарегистрированные пользователи имеют доступ к сервису!
Для получения аккаунта, обратитесь к администратору.
The virtio rng device kicks off a new entropy request whenever the
data available reaches zero. When a new request occurs at the end
of a read operation, that is, when the result of that request is
only needed by the next reader, then there is a race between the
writing of the new data and the next reader.
This is because there is no synchronisation whatsoever between the
writer and the reader.
Fix this by writing data_avail with smp_store_release and reading
it with smp_load_acquire when we first enter read. The subsequent
reads are safe because they're either protected by the first load
acquire, or by the completion mechanism.
Also remove the redundant zeroing of data_idx in random_recv_done
(data_idx must already be zero at this point) and data_avail in
request_entropy (ditto).
Reported-by: syzbot+726dc8c62c3536431ceb@syzkaller.appspotmail.com
Fixes: f7f510ec1957 ("virtio: An entropy device, as suggested by hpa.")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
ac52578d6e