From b5c3d49b3d5889f334d519d7a4535a3bd8632d47 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Mon, 12 Feb 2018 15:20:51 +0100 Subject: [PATCH] ALSA: seq: Fix racy pool initializations MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit d15d662e89fc667b90cd294b0eb45694e33144da upstream. ALSA sequencer core initializes the event pool on demand by invoking snd_seq_pool_init() when the first write happens and the pool is empty. Meanwhile user can reset the pool size manually via ioctl concurrently, and this may lead to UAF or out-of-bound accesses since the function tries to vmalloc / vfree the buffer. A simple fix is to just wrap the snd_seq_pool_init() call with the recently introduced client->ioctl_mutex; as the calls for snd_seq_pool_init() from other side are always protected with this mutex, we can avoid the race. Reported-by: 范龙飞 Signed-off-by: Takashi Iwai Signed-off-by: Ben Hutchings --- Reading git-format-patch failed