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 3E22753FD37; Wed, 9 Sep 2026 14:36:46 +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=1788964607; cv=none; b=Co0ThunNyP8gg4qxXupTB5jys1Tv6AR5ZH/qKQ4UDcE+ztrYipRjJyj06oFaFNJarrp5vO5qnQdfzf/5Q2o/xcQBSCMrxj8z79q9cUeAGtNfIAKjm8c8ZfxED7sTUCBrz0vzQWTQnFJseojiflbAc6OIglE2HRnjomekt2NwF+0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788964607; c=relaxed/simple; bh=8hndO4oHZdg1cLhQQ0Psvg1Kx08ALDOuuxP3oaD/7jE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=vBbWeJrKAEcHhiGENBLWm9Jeks70NlrrTBGE19SNJA1aJiwkRdAYvxafgPdOL49ywXT09CKoa3+XKCUpES4IP8dvF1lo0b/MgVf5wAnDHZ4pVL1daxEyXfROjQJpGRjz6W9ysOddxkRAIeK/6/GkQvY0KmDV+5HgctmdTp/x/3E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=bUvFurmE; 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="bUvFurmE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96A1D1F00A3A; Wed, 9 Sep 2026 14:36:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788964606; bh=vLY8iozEPt/u+Qm4bef3U7oNMYvlSN5fFWE1qGpJUSA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=bUvFurmEWniyUPC1k3VREATLxiYdTj9MMWh4FdOkjh8ripeEJ+iOFMrKHyvLLphCC LMzaGMZs/tHXQcd6qKjmIrBtOOJuBf+j24tgCKFrtKh67TyTngC4dr9N/Zcyaffv9K V8bkQL0hOe4hWdspq16onRWo12mRZ6m55nXbvMtY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiangshan Yi , Jiri Kosina , Sasha Levin Subject: [PATCH 6.18 474/583] HID: mcp2221: clear rxbuf after I2C/SMBus transfer completes Date: Wed, 9 Sep 2026 15:42:39 +0200 Message-ID: <20260909134254.286035704@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260909134237.773280130@linuxfoundation.org> References: <20260909134237.773280130@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiangshan Yi [ Upstream commit db2333f88729c8aae062cb171ed058725ff5c901 ] 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 Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/hid/hid-mcp2221.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -336,7 +336,7 @@ static int mcp_i2c_smbus_read(struct mcp ret = mcp_send_data_req_status(mcp, mcp->txbuf, 4); if (ret) - return ret; + goto out; mcp->rxbuf_idx = 0; @@ -358,7 +358,7 @@ static int mcp_i2c_smbus_read(struct mcp } else { usleep_range(980, 1000); mcp_cancel_last_cmd(mcp); - return ret; + goto out; } } else { retries = 0; @@ -368,6 +368,10 @@ static int mcp_i2c_smbus_read(struct mcp usleep_range(980, 1000); ret = mcp_chk_last_cmd_status_free_bus(mcp); +out: + mcp->rxbuf = NULL; + mcp->rxbuf_size = 0; + return ret; }