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 321BA18EB0 for ; Sun, 12 Apr 2026 12:55:22 +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=1775998522; cv=none; b=etwKkVLVj033o7MhC1/bSfENzkwdhVv8xiRggoghHGB8iIk2SWNpNyP2iKh3dgGQWgHq/B65e2atkPcONeuyq2dh2LuE0dXaMImGNUnLTYymdEDlrAb3bG2Jr4K023zld36bi5MOltDrFKr9oNZ5Qqb2P7Cw/lnM3mTAJwATwj8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775998522; c=relaxed/simple; bh=21XVKAFEMZEuNtPCNZWqqwqdKFGnrESixTYj9ydv5o8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TIQb8zBLlKMdZY0ca5Kjeg9Nq3x6hSp88dlKG5NaqGU4Ll28EHXnDT6ZBUuZP/T8125CB5hOIojQFpUbgjazrHXhvbU4DWtyou6s4mD7zSjQhviCK87oOtkCstbSwWt7/koP+p4SrJhnrSGpMXKrzxAS0XO8hsZkcSXzyqGE26M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BfqghYgW; 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="BfqghYgW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C4EAC19424; Sun, 12 Apr 2026 12:55:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775998522; bh=21XVKAFEMZEuNtPCNZWqqwqdKFGnrESixTYj9ydv5o8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BfqghYgWay/iZNaKyooZyygr3eg/dlK2hz8KdbTw/4i2Xb5JQtmkxLW2BQWam2uU6 Gg6rBofs4JgpA+07kDIgAvBWv/akHxM/dPXVZ5rGvYxKlSAIHhjB7XAvKzODNQmdTq HkzNXGAf1HcKEyptlU2ZSUpGD1FznCrUOxj4rjhfhL6MjVvVd99i4NFCCSkhfLzcsV VnHhDrxgrVGIixA1Xvp+kIfdTzDbRHUVgW5JMmepzz2gdkZ8fV3Kj3owUYD90hnJgP r3CJwkKGVvwD53dcgFnfydt1li53o3QRONMzCGRnY1TCrqYC6lx9QKM9cLtLWNeo+b RhnHXZPNZ62GQ== 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 6.1.y 4/4] net: rfkill: prevent unlimited numbers of rfkill events from being created Date: Sun, 12 Apr 2026 08:55:17 -0400 Message-ID: <20260412125517.2219007-4-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260412125517.2219007-1-sashal@kernel.org> References: <2026041215-clamp-serpent-1558@gregkh> <20260412125517.2219007-1-sashal@kernel.org> 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 Signed-off-by: Sasha Levin --- net/rfkill/core.c | 35 ++++++++++++++++++++++++----------- 1 file changed, 24 insertions(+), 11 deletions(-) diff --git a/net/rfkill/core.c b/net/rfkill/core.c index 7ec100adf5945..7a995e7a491b5 100644 --- a/net/rfkill/core.c +++ b/net/rfkill/core.c @@ -73,11 +73,14 @@ 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; }; @@ -255,10 +258,12 @@ 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; @@ -271,6 +276,15 @@ 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); + + scoped_guard(mutex, &data->mtx) { + if (data->event_count++ > MAX_RFKILL_EVENT) { + data->event_count--; + return -ENOSPC; + } + list_add_tail(&int_ev->list, &data->events); + } + return 0; } static void rfkill_send_events(struct rfkill *rfkill, enum rfkill_operation op) @@ -282,10 +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); } } @@ -1190,10 +1204,8 @@ static int rfkill_fop_open(struct inode *inode, struct file *file) if (!ev) goto free; rfkill_sync(rfkill); - rfkill_fill_event(&ev->ev, rfkill, RFKILL_OP_ADD); - mutex_lock(&data->mtx); - list_add_tail(&ev->list, &data->events); - mutex_unlock(&data->mtx); + if (rfkill_fill_event(ev, rfkill, data, RFKILL_OP_ADD)) + kfree(ev); } list_add(&data->list, &rfkill_fds); mutex_unlock(&rfkill_global_mutex); @@ -1263,6 +1275,7 @@ 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