From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.247 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794190995; b=PreCe95Zd+UcEiPldqOKGNvvFXVbmKL6aXcoNaWqkTM6kUIJDQ4bxDEq1xly7Xq9eUcr kxPv25WOzEArIlpw2pVwbWa5S37wTEpyS7Zhofg9ddcCXf3HKTjtnWzbqr0fyaKtc2aof nKvZv5Cu9qLXprazGU5y/NX3NKLubpN8mT/21gLaOvnHUNWDyWn2olREpCVhB1ARjkPcy BBGlXLqwy6qpyQQgR+xV9Uor8fVYu72QUb/jqM0rGQ4K0vFJ5zM8newSJH5JKpYPnzzDm Kv3HJi1E9nNV6ghWZak4VpSMeo+LiBOXFTiTksjwDOzL1cfEhkbhRcHBVmUADAhigzA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794190995; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:Message-ID:Date:MIME-Version:User-Agent: Cc:Subject:To:References:From:In-Reply-To:Content-Type: Content-Transfer-Encoding; bh=616SavEERcf0wLBB3MtaB5Vjvy14ra3RY8LHIRO6Zwc=; b=bi180/wIcJlJWBL3CBKaEieO+uxO2FAyH5jrZESbfMAN2Y2XlT/Cu00HGyOd/jOG8JNo 4lrR0m4tSuhIuoTrjuSlLc72LudQ/PvFH+k7NY2LiNCk+dHHsU3L3Hw10CpSgoKg4WKGr G/vRTLzNXbvnPMb/1iRJU0IT9Fy226gCeZR/BWfGmVfgc1OIp44qPW/+JPUTmKPsXQmVg ULAh1jyaKp0AYNBL3tWZJ/A0IaaiCTP+L3wGzWhJ7jpznw5oDBOQKaPKpYrHAmCjGcgct AH0pyt6vr+M3FAkSsNdYoRSmWw8ntXUNCRbcF+A9uiDo5TbgSr2OgItfgZHDlEqY9VQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=xM+kWndo; arc=none smtp.remote-ip=91.218.175.247 Received: from mta0.migadu.com (out-247.mta0.migadu.com [91.218.175.247]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ADF13606A321 for ; Mon, 9 Nov 2026 02:23:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org ADF13606A321 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=xM+kWndo X-Envelope-To: linux-trace-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=5wreqCYW4ZBo70/LRl2EgOAhGbY7eNZsCbsiZu1vgfk=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794190992; v=1; x=1794795792; b=xM+kWndod1z2Bk3XjnVdMLp7WfWv/br1i8Ab2oUCjf2uJ10UFHT0jXjkFUcieB/z36P9nh8f EY0OQT+rLkczRKQh8G8tHQLu8biBduodhBkSLvu5uScRcaV1uSp+dY0nrtc1OhsTs5w7F2FZ5Et rvlnCT1TQzueZEZrI3pi5k7s= X-Envelope-To: linux-trace-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 68f29b38e50f4bf4; Mon, 09 Nov 2026 02:23:12 +0000 X-Mizu-Trace-ID: 68f29b38e50f4bf4 X-Migadu-Flow: FLOW_OUT Message-ID: <91c8d6b5-9496-4c0f-b81d-ac31fbe2748d@linux.dev> Date: Mon, 9 Nov 2026 10:22:59 +0800 X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: cui.tao@linux.dev, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH] blktrace: require CAP_SYS_ADMIN for the BLKTRACE ioctls To: sashiko-reviews@lists.linux.dev References: <20261106142852.3233950-1-cui.tao@linux.dev> From: Tao Cui In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi， 在 2026/11/6 22:39, sashiko-bot@kernel.org 写道: > Thank you for your contribution! Sashiko AI review found 1 potential > issue to consider: > - [Medium] blktrace: missing CAP_SYS_ADMIN check in sg_ioctl_common() > -- > > commit 8392196724a6f06dfb860d63cf54fba3357cc04e > Author: Tao Cui > > blktrace: require CAP_SYS_ADMIN for the BLKTRACE ioctls > > This commit adds a CAP_SYS_ADMIN capability check to blk_trace_ioctl() to > restrict block tracing ioctls to privileged users. > >> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c >> index 8cd2520b4c99e..c1bf8ca350fee 100644 >> --- a/kernel/trace/blktrace.c >> +++ b/kernel/trace/blktrace.c >> @@ -927,6 +927,9 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) >> int ret, start = 0; >> char b[BDEVNAME_SIZE]; >> >> + if (!capable(CAP_SYS_ADMIN)) >> + return -EPERM; >> + >> switch (cmd) { >> case BLKTRACESETUP2: >> snprintf(b, sizeof(b), "%pg", bdev); > > [Severity: Medium] > Does checking CAP_SYS_ADMIN only in blk_trace_ioctl() leave the sg > passthrough path in sg_ioctl_common() ungated? > > drivers/scsi/sg.c:sg_ioctl_common() { > ... > case BLKTRACESETUP: > return blk_trace_setup(sdp->device->request_queue, sdp->name, > MKDEV(SCSI_GENERIC_MAJOR, sdp->index), > NULL, p); > case BLKTRACESTART: > return blk_trace_startstop(sdp->device->request_queue, 1); > case BLKTRACESTOP: > return blk_trace_startstop(sdp->device->request_queue, 0); > case BLKTRACETEARDOWN: > return blk_trace_remove(sdp->device->request_queue); > ... > } > > Because sg_ioctl_common() calls blk_trace_setup(), blk_trace_startstop() > and blk_trace_remove() directly rather than going through > blk_trace_ioctl(), an unprivileged process with access to an /dev/sg* node > can still allocate persistent relay buffers and control tracing state on > the underlying request_queue. Thanks for catching this. The sg path is covered by patch 1/7 of the memcg accounting series: https://lore.kernel.org/all/20261106131829.3228926-2-cui.tao@linux.dev/ Originally these changes were part of a single series. Since the blktrace capability check isn't itself a memcg accounting fix, I split it out into a separate series, but the corresponding sg_ioctl_common() change remained with the memcg patches. You're right that the standalone blktrace patch is incomplete by itself. I'll fold the sg-side check into the blktrace patch in the next revision so it is self-contained. Thanks>