From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 898341EF094; Wed, 4 Jun 2025 12:31:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749040313; cv=none; b=I9dM4dDySR5f79JHrzodrlijPgNLq7M/AsZgWtC8v9m8rvUAmkYLxV2lrY+cEG2d8RKW77B9NE7sNvSoqXbO39zLMbVl+srjh8mvUJI3iZ4EVvKVEgVHXqdRbv57UGe1lanvKVq4s98CKEVnpBj1ynaZrOXi0UlJfEWtGA3xl+0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749040313; c=relaxed/simple; bh=TrXtM1E9qeh0reHLNw5PD86uabM3Wq90I2FvMMDenCA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=FiC4buhrmVHOZKnZaHHxyUl4drGPi3dH2NMW8Yz0kClQztXFOyZRireYybOfc5GIdSXUe7CZoKgZCoD1OYfP9sfUgXohQ+VSRSBqnI9B+1H55s1JyxmghxusId/0Duaufyvk+ZgfemSQwiGIhg+SAPFkgcV4n2Hs2KbzCKbR/Ms= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=bGRNAc2O; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="bGRNAc2O" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A293AC4CEE7; Wed, 4 Jun 2025 12:31:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1749040312; bh=TrXtM1E9qeh0reHLNw5PD86uabM3Wq90I2FvMMDenCA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bGRNAc2OfiEw/PboRedKKVMeVYBfNNVTAZd8eJxqigSWHLjZTCYqldkdx6LNG+wuL o5NTVELpQYmXW4Vl13RpQiBGJ0byBIjIVKgG8JqxP9gNDBdrVSvISKgRVCefrBR5Pd jNcD4OFCYFh+h5gbRK5uDcYRtXqsL5vqBfD7XBvk= Date: Wed, 4 Jun 2025 14:31:49 +0200 From: Greg Kroah-Hartman To: Steven Rostedt Cc: stable@vger.kernel.org, patches@lists.linux.dev, syzbot+c8cd2d2c412b868263fb@syzkaller.appspotmail.com, Jeongjun Park Subject: Re: [PATCH 5.4 009/204] tracing: Fix oob write in trace_seq_to_buffer() Message-ID: <2025060414-dreamily-reentry-ab52@gregkh> References: <20250602134255.449974357@linuxfoundation.org> <20250602134255.842400124@linuxfoundation.org> <20250602103639.6d9776d5@gandalf.local.home> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250602103639.6d9776d5@gandalf.local.home> On Mon, Jun 02, 2025 at 10:36:39AM -0400, Steven Rostedt wrote: > On Mon, 2 Jun 2025 15:45:42 +0200 > Greg Kroah-Hartman wrote: > > > 5.4-stable review patch. If anyone has any objections, please let me know. > > > > ------------------ > > > > From: Jeongjun Park > > > > commit f5178c41bb43444a6008150fe6094497135d07cb upstream. > > > > syzbot reported this bug: > > ================================================================== > > BUG: KASAN: slab-out-of-bounds in trace_seq_to_buffer kernel/trace/trace.c:1830 [inline] > > BUG: KASAN: slab-out-of-bounds in tracing_splice_read_pipe+0x6be/0xdd0 kernel/trace/trace.c:6822 > > Write of size 4507 at addr ffff888032b6b000 by task syz.2.320/7260 > > > > CPU: 1 UID: 0 PID: 7260 Comm: syz.2.320 Not tainted 6.15.0-rc1-syzkaller-00301-g3bde70a2c827 #0 PREEMPT(full) > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 > > Call Trace: > > > > __dump_stack lib/dump_stack.c:94 [inline] > > dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 > > print_address_description mm/kasan/report.c:408 [inline] > > print_report+0xc3/0x670 mm/kasan/report.c:521 > > kasan_report+0xe0/0x110 mm/kasan/report.c:634 > > check_region_inline mm/kasan/generic.c:183 [inline] > > kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189 > > __asan_memcpy+0x3c/0x60 mm/kasan/shadow.c:106 > > trace_seq_to_buffer kernel/trace/trace.c:1830 [inline] > > tracing_splice_read_pipe+0x6be/0xdd0 kernel/trace/trace.c:6822 > > .... > > ================================================================== > > > > It has been reported that trace_seq_to_buffer() tries to copy more data > > than PAGE_SIZE to buf. Therefore, to prevent this, we should use the > > smaller of trace_seq_used(&iter->seq) and PAGE_SIZE as an argument. > > > > Link: https://lore.kernel.org/20250422113026.13308-1-aha310510@gmail.com > > Reported-by: syzbot+c8cd2d2c412b868263fb@syzkaller.appspotmail.com > > Fixes: 3c56819b14b0 ("tracing: splice support for tracing_pipe") > > Suggested-by: Steven Rostedt > > Signed-off-by: Jeongjun Park > > Signed-off-by: Steven Rostedt (Google) > > Signed-off-by: Greg Kroah-Hartman > > --- > > kernel/trace/trace.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > --- a/kernel/trace/trace.c > > +++ b/kernel/trace/trace.c > > @@ -6331,13 +6331,14 @@ static ssize_t tracing_splice_read_pipe( > > /* Copy the data into the page, so we can start over. */ > > ret = trace_seq_to_buffer(&iter->seq, > > page_address(spd.pages[i]), > > - trace_seq_used(&iter->seq)); > > + min((size_t)trace_seq_used(&iter->seq), > > + PAGE_SIZE)); > > Note this will require this patch too: > > Link: https://lore.kernel.org/20250526013731.1198030-1-pantaixi@huaweicloud.com > > commit 2fbdb6d8e03b ("tracing: Fix compilation warning on arm32") Thanks for the link, I'll queue this up once it hits a released kernel. greg k-h