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 2F0B1339375 for ; Wed, 22 Jul 2026 10:30:42 +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=1784716244; cv=none; b=blPbIRBzP0eFlVhvziAmUt+UsGlCS0vfrS5kMDqlkNq4Mw9sn9NnsYRD6PQnWcij+Z9GJ+52cBrW9sJ2Msh/LKwkC/ro1Db4c+sfmiQ33ACZS56hCgMi0Aeoq8ixzbkQfoVD290IhrkDr5ooDZ12GJ1jPDIyf6VzVdAv3NLggTU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784716244; c=relaxed/simple; bh=RhehwHHBb8H4OBjE7eqWKzTTFv6N/2VV1vQcwbnVPZg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=U55a/qgrPVlLEaZLnfOqyoQHlufC/erGH2PosGMc79N8uzuBtPjbtve9E3FKTUkxf7oNMcJt7PFb9uQphzr155GIyD71vCzwO86o9q3RhI/yB8URkgSVVgGjvLMDC4b16MC7mvQCrL82KKlUloYLdUKD5Q+hnC8ltorFVUci0eo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mDuhMV1M; 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="mDuhMV1M" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52BB41F00A3F; Wed, 22 Jul 2026 10:30:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784716242; bh=64Q4fCb7iHZWkyyvPNGmWvoD0jglG3qdOb4ULx/Yvo8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mDuhMV1MrT7eae7ryFCvrHyMDZ+ZCjTrPo3Gn7gMHbAAzo6umU2zTom5ofv3nVv0U aHhdfz1KqGiIc8Cu2Oa6zRWyVokAq6jXnUaWh/OOjO26Q36GpXItlQtvUwIvE2F80z nIYpLT0litq15OOoq3AZfH0B8Bbuj0uqh3aRUvQDGT81w6frldxq1ZkVE9LUeETQF8 EaYyr7KivLJRilw7/5LfnoKzzMapGSLbb4trsIqDxhqGw3GlyH3cjdIshnHnAqQriS fHfZZ5Vk5dD8jF3fz/NsSbRGtkZ6XImMc5cnSsJ/MWUPm0GzDp8z1G1c4WIgLp/k4w j3YySALqh7W6w== From: Sasha Levin To: stable@vger.kernel.org Cc: Bryam Vargas , Dmitry Torokhov , Sasha Levin Subject: [PATCH 5.15.y] Input: mms114 - reject an oversized device packet size Date: Wed, 22 Jul 2026 06:30:40 -0400 Message-ID: <20260722103040.891331-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026071645-latch-matchless-9242@gregkh> References: <2026071645-latch-matchless-9242@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 [ Upstream commit 66725039f7090afe14c31bd259e2059a68f04023 ] 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 [ changed `&client->dev` to `&data->client->dev` since 6.1's interrupt handler lacks the `client` local variable ] Signed-off-by: Sasha Levin --- 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 9fa3b0e421be2a..566a95ab0cc347 100644 --- a/drivers/input/touchscreen/mms114.c +++ b/drivers/input/touchscreen/mms114.c @@ -212,6 +212,12 @@ 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; + } + /* MMS136 has slightly different event size */ if (data->type == TYPE_MMS134S || data->type == TYPE_MMS136) touch_size = packet_size / MMS136_EVENT_SIZE; -- 2.53.0