From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 96B192C11D6 for ; Sun, 12 Apr 2026 16:57:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776013069; cv=none; b=FJkxmtNNpggNtH5ez2iXuqHmWCvYIpp6euqqaWR6+A904bYdb+xgniSiwavqNs2z/fogOEPMOnU12MhNXeb0Ujl2D3LJx2eyqd9Bbr21CrSBs6FKsY9iv4sbgQTkxR3qTl4DBAaTZTjVTI+Jr64RNIPBM4uWH4y6j+BSO+0JnA8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776013069; c=relaxed/simple; bh=Qhknvl29n/MlucxgPim0Q+U/iID37WHLextIcOSIVVQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oj62N4zQwi68+9aQKiQF3AWFBqx+JyRKtbOjqJBuMXQLSCD7ni+Nj222OPYI+SDo+yLWUh+bd1yGqx1gjaXL/lv03PDIcnSMittkrBMkh9CdUd7bZyd5c4wKVFP6CsDFBMEQThxYv20SfYZIA+F2WGExLe3X/PWvzUTJ2anLtQg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YVugMQqt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YVugMQqt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46577C19424; Sun, 12 Apr 2026 16:57:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776013069; bh=Qhknvl29n/MlucxgPim0Q+U/iID37WHLextIcOSIVVQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YVugMQqtDJ1HAeq34txYKw9314I23a7GEiSO6jtiTnHvGYMhLHMZNfgH1aZf5og3a JRPJ/BiknEkbvOoJAB/plS4rFozeENOvZKYiSj8jdPqd+KAODka2y9QBhBqhRh4rhX iGOuMbMN4x/IAb4AueTHeJQlsSEFb7gp1K1ab36shfQIrkJ+KOYXlnTZ3YtM0BqWt/ dK06B9Cf36t/C6dqZOrcDntu//8XKLLuUDWw6Ikjw7FCRlVVrw9/7jbrvPpXEy/Vbz 4KA/083kqGUVBpfjmNPOhXLCTcQm6HJsLFatWHGN1RExp2vuqHCV6I0Wp6XqgRqtzV ilaSIfjH/KkAQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , Johannes Berg , Yuan Tan , Yifan Wu , Juefei Pu , Xin Liu , stable , Johannes Berg , Sasha Levin Subject: [PATCH 5.15.y] net: rfkill: prevent unlimited numbers of rfkill events from being created Date: Sun, 12 Apr 2026 12:57:46 -0400 Message-ID: <20260412165746.2348467-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026041216-voltage-rewrap-e053@gregkh> References: <2026041216-voltage-rewrap-e053@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman [ Upstream commit ea245d78dec594372e27d8c79616baf49e98a4a1 ] Userspace can create an unlimited number of rfkill events if the system is so configured, while not consuming them from the rfkill file descriptor, causing a potential out of memory situation. Prevent this from bounding the number of pending rfkill events at a "large" number (i.e. 1000) to prevent abuses like this. Cc: Johannes Berg Reported-by: Yuan Tan Reported-by: Yifan Wu Reported-by: Juefei Pu Reported-by: Xin Liu Cc: stable Signed-off-by: Greg Kroah-Hartman Link: https://patch.msgid.link/2026033013-disfigure-scroll-e25e@gregkh Signed-off-by: Johannes Berg [ replaced `scoped_guard()` with explicit `mutex_lock()`/`mutex_unlock()` calls ] Signed-off-by: Sasha Levin --- net/rfkill/core.c | 37 +++++++++++++++++++++++++------------ 1 file changed, 25 insertions(+), 12 deletions(-) diff --git a/net/rfkill/core.c b/net/rfkill/core.c index 068c7bcd30c94..7bcb7a9c1fcfd 100644 --- a/net/rfkill/core.c +++ b/net/rfkill/core.c @@ -72,11 +72,14 @@ struct rfkill_int_event { struct rfkill_event_ext ev; }; +/* Max rfkill events that can be "in-flight" for one data source */ +#define MAX_RFKILL_EVENT 1000 struct rfkill_data { struct list_head list; struct list_head events; struct mutex mtx; wait_queue_head_t read_wait; + u32 event_count; bool input_handler; u8 max_size; }; @@ -254,10 +257,12 @@ static void rfkill_global_led_trigger_unregister(void) } #endif /* CONFIG_RFKILL_LEDS */ -static void rfkill_fill_event(struct rfkill_event_ext *ev, - struct rfkill *rfkill, - enum rfkill_operation op) +static int rfkill_fill_event(struct rfkill_int_event *int_ev, + struct rfkill *rfkill, + struct rfkill_data *data, + enum rfkill_operation op) { + struct rfkill_event_ext *ev = &int_ev->ev; unsigned long flags; ev->idx = rfkill->idx; @@ -270,6 +275,16 @@ static void rfkill_fill_event(struct rfkill_event_ext *ev, RFKILL_BLOCK_SW_PREV)); ev->hard_block_reasons = rfkill->hard_block_reasons; spin_unlock_irqrestore(&rfkill->lock, flags); + + mutex_lock(&data->mtx); + if (data->event_count++ > MAX_RFKILL_EVENT) { + data->event_count--; + mutex_unlock(&data->mtx); + return -ENOSPC; + } + list_add_tail(&int_ev->list, &data->events); + mutex_unlock(&data->mtx); + return 0; } static void rfkill_send_events(struct rfkill *rfkill, enum rfkill_operation op) @@ -281,10 +296,10 @@ static void rfkill_send_events(struct rfkill *rfkill, enum rfkill_operation op) ev = kzalloc(sizeof(*ev), GFP_KERNEL); if (!ev) continue; - rfkill_fill_event(&ev->ev, rfkill, op); - mutex_lock(&data->mtx); - list_add_tail(&ev->list, &data->events); - mutex_unlock(&data->mtx); + if (rfkill_fill_event(ev, rfkill, data, op)) { + kfree(ev); + continue; + } wake_up_interruptible(&data->read_wait); } } @@ -1149,7 +1164,6 @@ static int rfkill_fop_open(struct inode *inode, struct file *file) init_waitqueue_head(&data->read_wait); mutex_lock(&rfkill_global_mutex); - mutex_lock(&data->mtx); /* * start getting events from elsewhere but hold mtx to get * startup events added first @@ -1159,11 +1173,10 @@ static int rfkill_fop_open(struct inode *inode, struct file *file) ev = kzalloc(sizeof(*ev), GFP_KERNEL); if (!ev) goto free; - rfkill_fill_event(&ev->ev, rfkill, RFKILL_OP_ADD); - list_add_tail(&ev->list, &data->events); + if (rfkill_fill_event(ev, rfkill, data, RFKILL_OP_ADD)) + kfree(ev); } list_add(&data->list, &rfkill_fds); - mutex_unlock(&data->mtx); mutex_unlock(&rfkill_global_mutex); file->private_data = data; @@ -1171,7 +1184,6 @@ static int rfkill_fop_open(struct inode *inode, struct file *file) return stream_open(inode, file); free: - mutex_unlock(&data->mtx); mutex_unlock(&rfkill_global_mutex); mutex_destroy(&data->mtx); list_for_each_entry_safe(ev, tmp, &data->events, list) @@ -1232,6 +1244,7 @@ static ssize_t rfkill_fop_read(struct file *file, char __user *buf, ret = -EFAULT; list_del(&ev->list); + data->event_count--; kfree(ev); out: mutex_unlock(&data->mtx); -- 2.53.0