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 1B3231EEA48 for ; Fri, 24 Jan 2025 23:12:40 +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=1737760360; cv=none; b=XJtuYqR0cG4u575sZyBa3ZlTApdWcdbnnlbK9NoA1DH4c4lX7tdsDJCRzJ0PAnyAU9RMtKFnKp/wTyXBblTEhz8xKh6Zk2pIvH+N4kkOe5umxfqE0MTTdAfDdmOGUQu6/EE4MA+Tay66ePd3AUvUXV2xsV9of6YWde1ZH7yaFgM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737760360; c=relaxed/simple; bh=bhyzA5kmdeHBmDApfvYeoTJoA3zFyL7aqH0wr604cgw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=UghZOSrAy1aiI+s9WL5uTVtbQYITA8Zo3CCAEZvpSOYsEhAJavWfkKFGQWMBKoYmBtM2je1z0qGMYkf3Wv251SpZ2QTUhaDppo2kNW05iajexkHd5IkMll90zD4ZDHuDwrL15XazWS+FLmz+zNoJ7kNXg5/dg8H7KfInseyUAJo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WxglAF9s; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WxglAF9s" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2C3C9C4CED2; Fri, 24 Jan 2025 23:12:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737760360; bh=bhyzA5kmdeHBmDApfvYeoTJoA3zFyL7aqH0wr604cgw=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=WxglAF9saVagywwzvH9t/ASxPbgCEIiWgNpbfW/hY/KcMOM6OHtdkK81Udpr3JKq0 SZ+avbho602Paa81v59UiCQRSpQvD9K/DY/aaaRgKrQbfLUTeG0e285T4QhfJEMZwO Jp6Rf+A/haZRzKqmxXbBv6DvYaEA+caKdUr/h+kB8LApv6koTZcY3Z6tGuJ+aVqYHl sDzEcP1oZYGuyeulmOjDccDYaDSDAR8PJSYp/cKF6SC2906GEEJMaiW2AxK0+GvOdd 5votRCtYhLQbE4vbKw/xwbbJ/SpdgxrEBYuQWAwHUGYiCNPgruGc6BIrdYT6kOcok8 BVcy6l9A6kzLA== Message-ID: <4dee6487-4b9a-408c-aa7c-834802781887@kernel.org> Date: Sat, 25 Jan 2025 08:12:38 +0900 Precedence: bulk X-Mailing-List: linux-ide@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] ata: libata-sff: Ensure that we cannot write outside the allocated buffer To: Niklas Cassel Cc: Jens Axboe , Christoph Hellwig , "Martin K . Petersen" , reveliofuzzing , linux-ide@vger.kernel.org References: <20250124141118.3722754-2-cassel@kernel.org> From: Damien Le Moal Content-Language: en-US Organization: Western Digital Research In-Reply-To: <20250124141118.3722754-2-cassel@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 1/24/25 23:11, Niklas Cassel wrote: > reveliofuzzing reported that a SCSI_IOCTL_SEND_COMMAND ioctl with out_len > set to 0xd42, SCSI command set to ATA_16 PASS-THROUGH, ATA command set to > ATA_NOP, and protocol set to ATA_PROT_PIO, can cause ata_pio_sector() to > write outside the allocated buffer, overwriting random memory. > > While a ATA device is supposed to abort a ATA_NOP command, there does seem > to be a bug either in libata-sff or QEMU, where either this status is not > set, or the status is cleared before read by ata_sff_hsm_move(). > Anyway, that is most likely a separate bug. > > Looking at __atapi_pio_bytes(), it already has a safety check to ensure > that __atapi_pio_bytes() cannot write outside the allocated buffer. > > Add a similar check to ata_pio_sector(), such that also ata_pio_sector() > cannot write outside the allocated buffer. > > Reported-by: reveliofuzzing > Closes: https://lore.kernel.org/linux-ide/CA+-ZZ_jTgxh3bS7m+KX07_EWckSnW3N2adX3KV63y4g7M4CZ2A@mail.gmail.com/ > Signed-off-by: Niklas Cassel Looks good to me. But doesn't this need Fixes + Cc-stable tags ? > --- > drivers/ata/libata-sff.c | 18 ++++++++++-------- > 1 file changed, 10 insertions(+), 8 deletions(-) > > diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c > index 67f277e1c3bf..5a46c066abc3 100644 > --- a/drivers/ata/libata-sff.c > +++ b/drivers/ata/libata-sff.c > @@ -601,7 +601,7 @@ static void ata_pio_sector(struct ata_queued_cmd *qc) > { > struct ata_port *ap = qc->ap; > struct page *page; > - unsigned int offset; > + unsigned int offset, count; > > if (!qc->cursg) { > qc->curbytes = qc->nbytes; > @@ -617,25 +617,27 @@ static void ata_pio_sector(struct ata_queued_cmd *qc) > page = nth_page(page, (offset >> PAGE_SHIFT)); > offset %= PAGE_SIZE; > > - trace_ata_sff_pio_transfer_data(qc, offset, qc->sect_size); > + /* don't overrun current sg */ > + count = min(qc->cursg->length - qc->cursg_ofs, qc->sect_size); > + > + trace_ata_sff_pio_transfer_data(qc, offset, count); > > /* > * Split the transfer when it splits a page boundary. Note that the > * split still has to be dword aligned like all ATA data transfers. > */ > WARN_ON_ONCE(offset % 4); > - if (offset + qc->sect_size > PAGE_SIZE) { > + if (offset + count > PAGE_SIZE) { > unsigned int split_len = PAGE_SIZE - offset; > > ata_pio_xfer(qc, page, offset, split_len); > - ata_pio_xfer(qc, nth_page(page, 1), 0, > - qc->sect_size - split_len); > + ata_pio_xfer(qc, nth_page(page, 1), 0, count - split_len); > } else { > - ata_pio_xfer(qc, page, offset, qc->sect_size); > + ata_pio_xfer(qc, page, offset, count); > } > > - qc->curbytes += qc->sect_size; > - qc->cursg_ofs += qc->sect_size; > + qc->curbytes += count; > + qc->cursg_ofs += count; > > if (qc->cursg_ofs == qc->cursg->length) { > qc->cursg = sg_next(qc->cursg); -- Damien Le Moal Western Digital Research