From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 0768A31F984 for ; Tue, 25 Aug 2026 10:58:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787655487; cv=none; b=reXtosnmFfEGp1QLANXGQOfzC8xkhiMlqDVEUKnUP0WycufqDjumQQNCMlbNOCMvTTk6rV+3ZO51fzSN+GvqyQwdUu9y1Ig93oKC8jBXP2w+bmuCrNbD+Ui433PZVPmA+nbZbMF1Xm/GUFx4y2qeZpMySaDmxtcGxFM9WxBj9VM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787655487; c=relaxed/simple; bh=odk03354eswshxHE79aAwxrCrkKI+gdcTH4WnDpwevw=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=OwmtVIU8zrnzrxurx6GYpRl+XbrTGqfItCVvT3z/Hq7unP5SOm/aFefXUUwLoSvkno9rAGIxpcZRT+v+gmMcfSS4DTaAWmD3y9WzbdnsDPefXstoqsjId3yCfupn0w29mc95S2yI1PTZ1LcxPeFTJgZZRSxkwwwiIjany1EHxpY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=AjKYZAgv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="AjKYZAgv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C96E1F000E9; Tue, 25 Aug 2026 10:58:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787655485; bh=fqZufQLwwFZ6ZbNMjCsxuBFWF5iTSMYROW8SSRNwxD8=; h=Subject:To:Cc:From:Date; b=AjKYZAgvlSlb6W+s1dNzdZGvM5i5RVaFMr+KdjsMuUjAG9hhzlkYyOviWmiKCLw0N /3C4gvF5daU1I2Dz8VD5keknP9hMWTAcfic0K+ZdOYNfz8+5wd4W/CaZgn1uRHBvxa QLU+BqMTAXEOB/8+wjKCwAZU99o7OeIjAMP4tX88= Subject: FAILED: patch "[PATCH] HID: magicmouse: prevent unbounded recursion in" failed to apply to 5.15-stable tree To: pepemontfort@gmail.com,jkosina@suse.com,signshop.alec@gmail.com Cc: From: Date: Tue, 25 Aug 2026 12:57:26 +0200 Message-ID: <2026082526-status-turbine-ec0a@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x db8d634128d2ba88d79c0b601e983ebe14bb0519 # git commit -s git send-email --to '' --in-reply-to '2026082526-status-turbine-ec0a@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From db8d634128d2ba88d79c0b601e983ebe14bb0519 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jose=20Villase=C3=B1or=20Montfort?= Date: Tue, 14 Jul 2026 23:35:26 -0600 Subject: [PATCH] HID: magicmouse: prevent unbounded recursion in magicmouse_raw_event() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit magicmouse_raw_event() handles DOUBLE_REPORT_ID (0xf7) packets, which pack two touch reports into one, by splitting the packet and calling itself on each half. The only guard against runaway recursion is a "size < 1" check, which stops zero-sized calls but does not bound the recursion depth. A malicious HID device that matches this driver can send a report starting with DOUBLE_REPORT_ID and filled with the sequence [0xf7, 0x00]. Each level consumes two bytes and recurses on the remainder, so an incoming report of up to HID_MAX_BUFFER_SIZE (16 KiB) drives roughly 8000 nested calls. That easily exhausts the 16 KiB kernel stack, leading to a stack overflow: a panic with CONFIG_VMAP_STACK, or memory corruption without it. A double report only ever wraps two normal reports; it is never legitimately nested. Refuse to re-enter the DOUBLE_REPORT_ID case from a recursive call so the recursion depth is bounded to two, while all valid packets keep being parsed exactly as before. Fixes: a462230e16ac ("HID: magicmouse: enable Magic Trackpad support") Link: https://lore.kernel.org/linux-input/20260706181347.700DB1F00A3F@smtp.kernel.org/ Cc: stable@vger.kernel.org Signed-off-by: Jose Villaseñor Montfort Reviewed-by: Alec Hall Tested-by: Alec Hall Signed-off-by: Jiri Kosina diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c index 802a3479e24b..97562765a01d 100644 --- a/drivers/hid/hid-magicmouse.c +++ b/drivers/hid/hid-magicmouse.c @@ -383,8 +383,8 @@ static void magicmouse_emit_touch(struct magicmouse_sc *msc, int raw_id, u8 *tda } } -static int magicmouse_raw_event(struct hid_device *hdev, - struct hid_report *report, u8 *data, int size) +static int __magicmouse_raw_event(struct hid_device *hdev, + struct hid_report *report, u8 *data, int size, bool nested) { struct magicmouse_sc *msc = hid_get_drvdata(hdev); struct input_dev *input = msc->input; @@ -495,6 +495,15 @@ static int magicmouse_raw_event(struct hid_device *hdev, * packet. */ + /* + * A double report only ever wraps two normal reports, so it is + * never nested. Refuse to recurse a second time; otherwise a + * malicious device could chain DOUBLE_REPORT_ID packets to drive + * unbounded recursion and overflow the kernel stack. + */ + if (nested) + return 0; + /* Ensure that we have at least 2 elements (report type and size) */ if (size < 2) return 0; @@ -506,9 +515,9 @@ static int magicmouse_raw_event(struct hid_device *hdev, return 0; } - magicmouse_raw_event(hdev, report, data + 2, data[1]); - magicmouse_raw_event(hdev, report, data + 2 + data[1], - size - 2 - data[1]); + __magicmouse_raw_event(hdev, report, data + 2, data[1], true); + __magicmouse_raw_event(hdev, report, data + 2 + data[1], + size - 2 - data[1], true); return 0; default: return 0; @@ -534,6 +543,12 @@ static int magicmouse_raw_event(struct hid_device *hdev, return 1; } +static int magicmouse_raw_event(struct hid_device *hdev, + struct hid_report *report, u8 *data, int size) +{ + return __magicmouse_raw_event(hdev, report, data, size, false); +} + static int magicmouse_event(struct hid_device *hdev, struct hid_field *field, struct hid_usage *usage, __s32 value) {