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Re: [Qemu-devel] [PATCH 2/3] adlib: mark as insecure and deprecated.
From: |
Thomas Huth |
Subject: |
Re: [Qemu-devel] [PATCH 2/3] adlib: mark as insecure and deprecated. |
Date: |
Thu, 25 Oct 2018 21:27:37 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 |
On 2018-10-25 09:52, Gerd Hoffmann wrote:
> We have a lovely, guest-triggerable buffer overflow in opl2 emulation.
>
> Reproducer:
> outw(0xff60, 0x220);
> outw(0x1020, 0x220);
> outw(0xffb0, 0x220);
> Result:
> Will overflow FM_OPL->AR_TABLE[] (see hw/audio/fmopl.[ch])
>
> The specs google finds (http://www.symphoniae.com/Yamaha/YSC/YM3812.pdf)
> are rather sparse, possibly incomplete (looks like scanned fax with a
> scrambled page at the end) and not really helpful in identifying which
> of the register writes sets some illegal value.
>
> So, go tag the device as deprecated with a warning messge, to notify
> users and schedule it for removal according to our deprecation policy.
>
> Signed-off-by: Gerd Hoffmann <address@hidden>
> ---
> hw/audio/adlib.c | 1 +
> qemu-deprecated.texi | 4 ++++
> 2 files changed, 5 insertions(+)
>
> diff --git a/hw/audio/adlib.c b/hw/audio/adlib.c
> index 97b876c..fb4a29c 100644
> --- a/hw/audio/adlib.c
> +++ b/hw/audio/adlib.c
> @@ -311,6 +311,7 @@ static void adlib_class_initfn (ObjectClass *klass, void
> *data)
> set_bit(DEVICE_CATEGORY_SOUND, dc->categories);
> dc->desc = ADLIB_DESC;
> dc->props = adlib_properties;
> + dc->deprecation_reason = "insecure, buffer overflow in opl2 emulation";
> }
>
> static const TypeInfo adlib_info = {
> diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi
> index 11b870c..7951a4f 100644
> --- a/qemu-deprecated.texi
> +++ b/qemu-deprecated.texi
> @@ -116,6 +116,10 @@ The @option{[hub_id name]} parameter tuple of the
> 'hostfwd_add' and
> The ``ivshmem'' device type is replaced by either the ``ivshmem-plain''
> or ``ivshmem-doorbell`` device types.
>
> address@hidden adlib (since 3.1)
> +
> +Has known buffer overflow.
> +
> @section System emulator machines
>
> @subsection pc-0.10 and pc-0.11 (since 3.0)
>
Any chance you could maybe at least add an assert() to the affected code
so that it crashes instead of silently overflowing the buffer?
Anyway, with the "messge" typo fixed:
Reviewed-by: Thomas Huth <address@hidden>
[Qemu-devel] [PATCH 2/3] adlib: mark as insecure and deprecated., Gerd Hoffmann, 2018/10/25
Re: [Qemu-devel] [PATCH 2/3] adlib: mark as insecure and deprecated., Philippe Mathieu-Daudé, 2018/10/25
Re: [Qemu-devel] [PATCH 2/3] adlib: mark as insecure and deprecated.,
Thomas Huth <=
Re: [Qemu-devel] [PATCH 2/3] adlib: mark as insecure and deprecated., Paolo Bonzini, 2018/10/26
[Qemu-devel] [PATCH 1/3] qdev: add deprecation_reason to DeviceClass, Gerd Hoffmann, 2018/10/25