From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from extorris.mess.org (extorris.mess.org [92.243.27.206]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2A55E4D991D; Wed, 22 Jul 2026 10:23:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=92.243.27.206 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784715827; cv=none; b=XKCFAeIU5YkqT4qsk2+91OSQTedzHS3bTZQqM3LdnyrNS18mnc6XEJ3RN9RPwUx9shXkulafyBAyagwQSgIPpehc6yqdBdfz/69O72BT/fkXrkWbVzahQ9ZdjJ7u0Os9ldjbEqqh8kRwO2nP3M8GlgQ9A6RTzHILnT6s7a0plOU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784715827; c=relaxed/simple; bh=KmBEI0QqBfLJsbIjc2Gk7pu9WEqMvEOx9sfqp1Aled0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Q2N6NIPTkBrAk2M99y2z2UFn9x+VHJPpRr1VEVgrfHbMxw2Kg3zbufyvb2OBUTZbBjjXHXtJ+H6z7hIf0nwGcpIfK9G2o+7GuxeIyL+Be8Aa4yFLjxdutn5SFHX8/wcqzpqlAIv8NO4QMmyhKwES4yhisy31lp98XJ7oVMiks/I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mess.org; spf=pass smtp.mailfrom=mess.org; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b=GnXEPpI7; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b=jKsXW2Rh; arc=none smtp.client-ip=92.243.27.206 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mess.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mess.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b="GnXEPpI7"; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b="jKsXW2Rh" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mess.org; s=2020; t=1784715823; bh=KmBEI0QqBfLJsbIjc2Gk7pu9WEqMvEOx9sfqp1Aled0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GnXEPpI7WojQs5xx0JMVTnSJoueJH5f7svQ5DaongSIAKXt6WfWhEi5Wp+58DJF02 SpLy1VObE+MZWpytPloqrej/JbVVdmz9C5VPoJfcZAqiQ4EuuVnMpejBMl/ZBhX9Je N9tBo4Kj7mm8kyPsAvA7+WoWrncR75ge6L1bJAx40EOZXSk3eOFUP1ud3vXL78r15f iwBPHys/H3hxiXVxYASTUMGe49utpliFrwe8uBqmoGo51O+/w4rkud8CH0FhzJ2/vm XkS5IinKVYchw7pLovRWOxQLdculzA5wqxMdDKjfMsKrepYz1kA+IJP4cmPl4RCYR3 hKGtX2Yyeac2A== Received: by extorris.mess.org (Postfix, from userid 1004) id A56F54017A; Wed, 22 Jul 2026 11:23:43 +0100 (BST) X-Spam-Level: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mess.org; s=2020; t=1784715822; bh=KmBEI0QqBfLJsbIjc2Gk7pu9WEqMvEOx9sfqp1Aled0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jKsXW2Rh+L5FPEDcWhvyyWoe1MaTpBdyeIRX8/LisFuybM6EH4afPPC8JyT5P/aHE ynqYd7HS94M1SVEbMRfEXo0UYcaGOb8Q/vv5UJtCIdOFqQY+W1wYnf/AfuFeEL8qPi I3Z73fEgQq4iMOpnhYrG3vpjYqKE79Mbd5pLgM052OMnnrdYWOesCjX0J6C3MasY1G VftVAc9Z5Bq3jwByC6eY1bKwzRsaF+Eqqv5AmHv87Qfs/7ry8tX6Yhh9clLHXeWT2s /5XkiIBiexSLMziwjeVTTo3NpErfQYps5SiZq/xqcQoxc2F8zxrGRfHIhsUKTX+vm/ uNYTzXxo0nY+g== Received: from maru.local (unknown [62.232.99.130]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by extorris.mess.org (Postfix) with ESMTPSA id 40B8F42540; Wed, 22 Jul 2026 11:23:42 +0100 (BST) From: Sean Young To: linux-media@vger.kernel.org, Sean Young , Mauro Carvalho Chehab , Patrice Chotard , Hans Verkuil Cc: linux-kernel@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH v3 12/13] media: rc: Fix use after free in bpf progs Date: Wed, 22 Jul 2026 11:23:24 +0100 Message-ID: X-Mailer: git-send-email 2.55.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Since commit dccc0c3ddf8f ("media: rc: fix race between unregister and urb/irq callbacks"), rcdev->raw is no longer set to NULL after device unregister. raw->progs could point to stale data. Fixes: dccc0c3ddf8f ("media: rc: fix race between unregister and urb/irq callbacks") Signed-off-by: Sean Young --- drivers/media/rc/bpf-lirc.c | 18 +++++++++++++----- drivers/media/rc/rc-ir-raw.c | 11 +++-------- 2 files changed, 16 insertions(+), 13 deletions(-) diff --git a/drivers/media/rc/bpf-lirc.c b/drivers/media/rc/bpf-lirc.c index 2f7564f26445..14ab611e7445 100644 --- a/drivers/media/rc/bpf-lirc.c +++ b/drivers/media/rc/bpf-lirc.c @@ -148,12 +148,13 @@ static int lirc_bpf_attach(struct rc_dev *rcdev, struct bpf_prog *prog) if (ret) return ret; - raw = rcdev->raw; - if (!raw) { + if (!rcdev->registered) { ret = -ENODEV; goto unlock; } + raw = rcdev->raw; + old_array = lirc_rcu_dereference(raw->progs); if (old_array && bpf_prog_array_length(old_array) >= BPF_MAX_PROGS) { ret = -E2BIG; @@ -186,12 +187,13 @@ static int lirc_bpf_detach(struct rc_dev *rcdev, struct bpf_prog *prog) if (ret) return ret; - raw = rcdev->raw; - if (!raw) { + if (!rcdev->registered) { ret = -ENODEV; goto unlock; } + raw = rcdev->raw; + old_array = lirc_rcu_dereference(raw->progs); ret = bpf_prog_array_copy(old_array, prog, NULL, 0, &new_array); /* @@ -235,7 +237,8 @@ void lirc_bpf_free(struct rc_dev *rcdev) struct bpf_prog_array_item *item; struct bpf_prog_array *array; - array = lirc_rcu_dereference(rcdev->raw->progs); + array = rcu_replace_pointer(rcdev->raw->progs, NULL, + lockdep_is_held(&ir_raw_handler_lock)); if (!array) return; @@ -316,6 +319,11 @@ int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) if (ret) goto put; + if (!rcdev->registered) { + ret = -ENODEV; + goto unlock; + } + progs = lirc_rcu_dereference(rcdev->raw->progs); cnt = progs ? bpf_prog_array_length(progs) : 0; diff --git a/drivers/media/rc/rc-ir-raw.c b/drivers/media/rc/rc-ir-raw.c index f066176c9f37..26962b500b0c 100644 --- a/drivers/media/rc/rc-ir-raw.c +++ b/drivers/media/rc/rc-ir-raw.c @@ -650,8 +650,11 @@ int ir_raw_event_register(struct rc_dev *dev) void ir_raw_event_free(struct rc_dev *dev) { if (dev->raw) { + mutex_lock(&ir_raw_handler_lock); if (dev->raw->thread) put_task_struct(dev->raw->thread); + lirc_bpf_free(dev); + mutex_unlock(&ir_raw_handler_lock); kfree(dev->raw); dev->raw = NULL; } @@ -661,9 +664,6 @@ void ir_raw_event_unregister(struct rc_dev *dev) { struct ir_raw_handler *handler; - if (!dev || !dev->raw) - return; - kthread_stop(dev->raw->thread); timer_delete_sync(&dev->raw->edge_handle); @@ -676,11 +676,6 @@ void ir_raw_event_unregister(struct rc_dev *dev) lirc_bpf_free(dev); - /* - * A user can be calling bpf(BPF_PROG_{QUERY|ATTACH|DETACH}), so - * ensure that the raw member is null on unlock; this is how - * "device gone" is checked. - */ mutex_unlock(&ir_raw_handler_lock); } -- 2.55.0