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 737F237F739 for ; Thu, 3 Sep 2026 13:54:17 +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=1788443668; cv=none; b=L65WdxVYDZuarjEEzZWI9EJXv4vUqqBd8EAHkJcveugGwpK3IoLnCyrtlRbhseFe8IHscrdrUB2XYF4g7PcWa8xCOdfpmT/N+S+RvapTUBobbikfDWPMAoxdk0Pl42Vfu28NTWUBsZeclyLI3Oo8etQU5mWz4KmHCsnvvHklkgI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788443668; c=relaxed/simple; bh=83+kC3DR1A9lYe1uT2vCEU1MfHy4704BF+0hidrVyEo=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=S0dfyou1e6M5+y9Ycjl4KGrWRfLwMNw3sn/FNWVPzP/gLDT23evB6KxM7YPfLetC3smRUllGfJeh5fzv4Xi1PemHEuT5DnSxjaDKwIVbta9NslI8GPE9yf9T9po37yxnRVs1IGaPR17N+9p6yXEj+OGfQ2cXvrRrBHbr6KVTC34= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yEehj0hE; 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="yEehj0hE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A9021F00A3A; Thu, 3 Sep 2026 13:54:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788443656; bh=jmSpAinGx1c3ppzz+q+yBjB8T6LpEbTPhCh9o5WovMk=; h=Subject:To:Cc:From:Date; b=yEehj0hE/+Mr2CH07fjQjbZGxeBF5dRwUU7RDze8FaePnMwEcscS+a/9CvjtptoFn 5yI3zeOWVImykwz8yJpcnxEr78Co7+6l7y6l0fIMOlaKWaO48dNUkoF3WEvqy2NjYf xCNqo7hn174FisAJQPpMANkM6cAh8KkxUc97d2k4= Subject: FAILED: patch "[PATCH] HID: mcp2221: clear rxbuf after I2C/SMBus transfer completes" failed to apply to 6.6-stable tree To: yijiangshan@kylinos.cn,jkosina@suse.com Cc: From: Date: Thu, 03 Sep 2026 15:36:57 +0200 Message-ID: <2026090356-ramble-footing-c350@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=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-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-6.6.y git checkout FETCH_HEAD git cherry-pick -x db2333f88729c8aae062cb171ed058725ff5c901 # git commit -s git send-email --to '' --in-reply-to '2026090356-ramble-footing-c350@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From db2333f88729c8aae062cb171ed058725ff5c901 Mon Sep 17 00:00:00 2001 From: Jiangshan Yi Date: Tue, 28 Jul 2026 21:14:41 +0800 Subject: [PATCH] HID: mcp2221: clear rxbuf after I2C/SMBus transfer completes mcp_i2c_smbus_read() stores the caller-supplied buffer pointer in mcp->rxbuf for the duration of a transfer but never clears it when the transfer finishes or times out. Once the caller frees or reuses the buffer, mcp->rxbuf becomes a dangling pointer. A delayed or spurious MCP2221_I2C_GET_DATA report can then drive mcp2221_raw_event() to memcpy device data into the freed memory, causing a write use-after-free. Route all return paths through a single exit point that clears mcp->rxbuf and mcp->rxbuf_size, so that the existing !mcp->rxbuf guard in the raw_event handler can reject any report arriving after the transfer has ended. Fixes: 67a95c21463d ("HID: mcp2221: add usb to i2c-smbus host bridge") Cc: stable@vger.kernel.org Signed-off-by: Jiangshan Yi Signed-off-by: Jiri Kosina diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c index 5c7fc56c7c67..9e03d1f733ff 100644 --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -343,7 +343,7 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp, ret = mcp_send_data_req_status(mcp, mcp->txbuf, 4); if (ret) - return ret; + goto out; mcp->rxbuf_idx = 0; @@ -365,7 +365,7 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp, } else { usleep_range(980, 1000); mcp_cancel_last_cmd(mcp); - return ret; + goto out; } } else { retries = 0; @@ -375,6 +375,10 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp, usleep_range(980, 1000); ret = mcp_chk_last_cmd_status_free_bus(mcp); +out: + mcp->rxbuf = NULL; + mcp->rxbuf_size = 0; + return ret; }