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 D2DCA40F726 for ; Wed, 22 Jul 2026 10:51:17 +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=1784717479; cv=none; b=Ds1tpmfTxO9uPnQGZMqex0KaYVpBSrzgjLzcynauR2C/IaWgifRJQ7Y2pPgFOYskKXFjWHG8NC9Xir97nD8wXEXcoMSKPOybuOe4VaXEsia5GwwG4j3sadj0LUkL+fcNEeVbjBpMEwlbFLzKByVTQDxkm4WHqoIvUkBq92KDhfs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784717479; c=relaxed/simple; bh=TN28kpJU6F1WDjFpK9FMy0WK26IGdSxgM6RzEAr8bYg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=THES8OergcJai5XsGC8FEDfyF0piTXaKN4+P5J9HY6NdfGnAupwyEGjVxmqKMwPjr5FPxjKCkeO2wArjZ6bfyaW6G9jg+cqcwyxa94PUYKgoPJqB49P+iDn+S5HR+0oqGX7eWcenF0u9oV67qgZvlLPgaq8CJC5P/PMyqEWUQSY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WoW2ut11; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WoW2ut11" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0DE7C1F000E9; Wed, 22 Jul 2026 10:51:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784717477; bh=/jP63cDhnnMLklOUMO0duw07b+xaCOgSu3ZIIdnt/9o=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=WoW2ut11NRcjGJ2HVDPhVrEEqQS8KY2Fjiuty95Uf1/XgsC6hRnxsVEYDM9+LK/zg fCX0zQEfDonSvSbkJiCeS451r6NOoJ699lLJ17ekxYmRrUenroMsliJr4MGxdoJRCs FnemjKgHjINnUcnPKArLt+AVz0I9PkaxqBNm6KGXR9cUhrosNKyu2ICmfnS26gl/Em y8pjmvBvYf7IhHo/o2/g4Ic0fiNdpNMnoAoPMZ05bkuflOJU2RxE1fzHKXXqCSexEG 7Lws2ko89AWbgMWCG+R5jcR54T/lSn7BRbEvCJNKFG83bc1KohGR70CYCe92FqJov7 iCkQBpOD7tjJg== From: Sasha Levin To: stable@vger.kernel.org Cc: Bryam Vargas , Dmitry Torokhov Subject: [PATCH 5.10.y] Input: mms114 - reject an oversized device packet size Date: Wed, 22 Jul 2026 06:51:14 -0400 Message-ID: <20260722105114.989610-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026071638-seltzer-gambling-3268@gregkh> References: <2026071638-seltzer-gambling-3268@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: Bryam Vargas mms114_interrupt() reads a packet of touch data from the device into a fixed-size on-stack buffer struct mms114_touch touch[MMS114_MAX_TOUCH]; which holds MMS114_MAX_TOUCH (10) events of MMS114_EVENT_SIZE (8) bytes, i.e. 80 bytes. The length of the I2C read into it is taken verbatim from the device: packet_size = mms114_read_reg(data, MMS114_PACKET_SIZE); if (packet_size <= 0) goto out; ... error = __mms114_read_reg(data, MMS114_INFORMATION, packet_size, (u8 *)touch); packet_size is a single device register byte (0x0F) and the only check is the lower bound packet_size <= 0; it is never bounded against the size of touch[]. A malfunctioning, malicious or counterfeit controller (or an attacker tampering with the I2C bus) can report a packet_size of up to 255, so __mms114_read_reg() writes up to 175 bytes past the end of touch[] on the IRQ-thread stack: a stack out-of-bounds write that can overwrite the stack canary, saved registers and the return address. A well-formed device never reports more than the buffer holds, so reject an oversized packet and drop the report, consistent with the handler's other error paths, rather than reading past the buffer. Fixes: 07b8481d4aff ("Input: add MELFAS mms114 touchscreen driver") Signed-off-by: Bryam Vargas Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260612-b4-disp-dc4b8dc4-v1-1-d7cb0a828d92@proton.me Signed-off-by: Dmitry Torokhov (cherry picked from commit 66725039f7090afe14c31bd259e2059a68f04023) [ sashal: adjusted for 5.10, which lacks 53fefdd1d3a3 ("Input: mms114 - support MMS136") and bf93349b11ab ("Input: mms114 - add support for touch keys"): kept the flat touch_size = packet_size / MMS114_PACKET_NUM computation instead of the MMS136/MMS134S event-size selection, and used &data->client->dev in the new dev_err() since mms114_interrupt() has no client local here. ] --- drivers/input/touchscreen/mms114.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/input/touchscreen/mms114.c b/drivers/input/touchscreen/mms114.c index 1f96657310b751..f89676655dd3f3 100644 --- a/drivers/input/touchscreen/mms114.c +++ b/drivers/input/touchscreen/mms114.c @@ -209,6 +209,12 @@ static irqreturn_t mms114_interrupt(int irq, void *dev_id) if (packet_size <= 0) goto out; + if (packet_size > sizeof(touch)) { + dev_err(&data->client->dev, "Invalid packet size %d (max %zu)\n", + packet_size, sizeof(touch)); + goto out; + } + touch_size = packet_size / MMS114_PACKET_NUM; error = __mms114_read_reg(data, MMS114_INFORMATION, packet_size, -- 2.53.0