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From: "Philippe Mathieu-Daudé" <f4bug@amsat.org>
To: Qiang Liu <cyruscyliu@gmail.com>
Cc: Laurent Vivier <lvivier@redhat.com>,
	Thomas Huth <thuth@redhat.com>,
	qemu-devel@nongnu.org, Alexander Bulekov <alxndr@bu.edu>,
	Bandan Das <bsd@redhat.com>, Gerd Hoffmann <kraxel@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH v2] hw/audio/sb16: Avoid assertion by restricting I/O sampling rate range
Date: Wed, 16 Jun 2021 14:47:35 +0200	[thread overview]
Message-ID: <a7b8eb63-dae8-1086-49db-efae43660dd2@amsat.org> (raw)
In-Reply-To: <CAAKa2j=au0tnqPg8iPB7e3SHNZVL+RO9xb7=u6aszUWRiSC0Ew@mail.gmail.com>

On 6/16/21 1:58 PM, Qiang Liu wrote:
> Thx. I learned a lot about contributing to QEMU from this discussion!

I think this was a misunderstanding with Gerd, the maintainer.

Maintainers use some tools to ease their patch-by-email workflow.
As a tester/reviewer you simply reply to a patch with a "Reviewed-by"
or "Tested-by" tag (with your name and email) and the tools will
collect your tags. Then the maintainer take the patches with the
tags amended. So a v2 shouldn't be necessary normally. And this is
certainly not a task of the reviewer to resend the patch as v2 adding
its own R-b/T-b tags.
It might help you to look at the list mail archives:
https://lists.gnu.org/archive/html/qemu-devel/
or even better subscribe to the list (high traffic! you need to filter
for your interests).

> Best,
> Qiang
> 
> On Wed, Jun 16, 2021 at 6:43 PM Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>>
>> While the SB16 seems to work up to 48000 Hz, the "Sound Blaster Series
>> Hardware Programming Guide" limit the sampling range from 4000 Hz to
>> 44100 Hz (Section 3-9, 3-10: Digitized Sound I/O Programming, tables
>> 3-2 and 3-3).
>>
>> Later, section 6-15 (DSP Commands) is more specific regarding the 41h /
>> 42h registers (Set digitized sound output sampling rate):
>>
>>   Valid sampling rates range from 5000 to 45000 Hz inclusive.
>>
>> There is no comment regarding error handling if the register is filled
>> with an out-of-range value.  (See also section 3-28 "8-bit or 16-bit
>> Auto-initialize Transfer"). Assume limits are enforced in hardware.
>>
>> This fixes triggering an assertion in audio_calloc():
>>
>>   #1 abort
>>   #2 audio_bug audio/audio.c:119:9
>>   #3 audio_calloc audio/audio.c:154:9
>>   #4 audio_pcm_sw_alloc_resources_out audio/audio_template.h:116:15
>>   #5 audio_pcm_sw_init_out audio/audio_template.h:175:11
>>   #6 audio_pcm_create_voice_pair_out audio/audio_template.h:410:9
>>   #7 AUD_open_out audio/audio_template.h:503:14
>>   #8 continue_dma8 hw/audio/sb16.c:216:20
>>   #9 dma_cmd8 hw/audio/sb16.c:276:5
>>   #10 command hw/audio/sb16.c:0
>>   #11 dsp_write hw/audio/sb16.c:949:13
>>   #12 portio_write softmmu/ioport.c:205:13
>>   #13 memory_region_write_accessor softmmu/memory.c:491:5
>>   #14 access_with_adjusted_size softmmu/memory.c:552:18
>>   #15 memory_region_dispatch_write softmmu/memory.c:0:13
>>   #16 flatview_write_continue softmmu/physmem.c:2759:23
>>   #17 flatview_write softmmu/physmem.c:2799:14
>>   #18 address_space_write softmmu/physmem.c:2891:18
>>   #19 cpu_outw softmmu/ioport.c:70:5
>>
>> [*] http://www.baudline.com/solutions/full_duplex/sb16_pci/index.html
>>
>> Fixes: 85571bc7415 ("audio merge (malc)")
>> Buglink: https://bugs.launchpad.net/bugs/1910603
>> OSS-Fuzz Report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=29174
>> Tested-by: Qiang Liu <cyruscyliu@gmail.com>
>> Reviewed-by: Qiang Liu <cyruscyliu@gmail.com>
>> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>> ---
>> v2: Added Qiang Liu's T-b/R-b tags ¯\_(ツ)_/¯
>> ---
>>  hw/audio/sb16.c              | 14 ++++++++++
>>  tests/qtest/fuzz-sb16-test.c | 52 ++++++++++++++++++++++++++++++++++++
>>  MAINTAINERS                  |  1 +
>>  tests/qtest/meson.build      |  1 +
>>  4 files changed, 68 insertions(+)
>>  create mode 100644 tests/qtest/fuzz-sb16-test.c
>>
>> diff --git a/hw/audio/sb16.c b/hw/audio/sb16.c
>> index 8b207004102..5cf121fe363 100644
>> --- a/hw/audio/sb16.c
>> +++ b/hw/audio/sb16.c
>> @@ -115,6 +115,9 @@ struct SB16State {
>>      PortioList portio_list;
>>  };
>>
>> +#define SAMPLE_RATE_MIN 5000
>> +#define SAMPLE_RATE_MAX 45000
>> +
>>  static void SB_audio_callback (void *opaque, int free);
>>
>>  static int magic_of_irq (int irq)
>> @@ -241,6 +244,17 @@ static void dma_cmd8 (SB16State *s, int mask, int dma_len)
>>          int tmp = (256 - s->time_const);
>>          s->freq = (1000000 + (tmp / 2)) / tmp;
>>      }
>> +    if (s->freq < SAMPLE_RATE_MIN) {
>> +        qemu_log_mask(LOG_GUEST_ERROR,
>> +                      "sampling range too low: %d, increasing to %u\n",
>> +                      s->freq, SAMPLE_RATE_MIN);
>> +        s->freq = SAMPLE_RATE_MIN;
>> +    } else if (s->freq > SAMPLE_RATE_MAX) {
>> +        qemu_log_mask(LOG_GUEST_ERROR,
>> +                      "sampling range too high: %d, decreasing to %u\n",
>> +                      s->freq, SAMPLE_RATE_MAX);
>> +        s->freq = SAMPLE_RATE_MAX;
>> +    }
>>
>>      if (dma_len != -1) {
>>          s->block_size = dma_len << s->fmt_stereo;
>> diff --git a/tests/qtest/fuzz-sb16-test.c b/tests/qtest/fuzz-sb16-test.c
>> new file mode 100644
>> index 00000000000..51030cd7dc4
>> --- /dev/null
>> +++ b/tests/qtest/fuzz-sb16-test.c
>> @@ -0,0 +1,52 @@
>> +/*
>> + * QTest fuzzer-generated testcase for sb16 audio device
>> + *
>> + * Copyright (c) 2021 Philippe Mathieu-Daudé <f4bug@amsat.org>
>> + *
>> + * SPDX-License-Identifier: GPL-2.0-or-later
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +#include "libqos/libqtest.h"
>> +
>> +/*
>> + * This used to trigger the assert in audio_calloc
>> + * https://bugs.launchpad.net/qemu/+bug/1910603
>> + */
>> +static void test_fuzz_sb16_0x1c(void)
>> +{
>> +    QTestState *s = qtest_init("-M q35 -display none "
>> +                               "-device sb16,audiodev=snd0 "
>> +                               "-audiodev none,id=snd0");
>> +    qtest_outw(s, 0x22c, 0x41);
>> +    qtest_outb(s, 0x22c, 0x00);
>> +    qtest_outw(s, 0x22c, 0x1004);
>> +    qtest_outw(s, 0x22c, 0x001c);
>> +    qtest_quit(s);
>> +}
>> +
>> +static void test_fuzz_sb16_0x91(void)
>> +{
>> +    QTestState *s = qtest_init("-M pc -display none "
>> +                               "-device sb16,audiodev=none "
>> +                               "-audiodev id=none,driver=none");
>> +    qtest_outw(s, 0x22c, 0xf141);
>> +    qtest_outb(s, 0x22c, 0x00);
>> +    qtest_outb(s, 0x22c, 0x24);
>> +    qtest_outb(s, 0x22c, 0x91);
>> +    qtest_quit(s);
>> +}
>> +
>> +int main(int argc, char **argv)
>> +{
>> +    const char *arch = qtest_get_arch();
>> +
>> +    g_test_init(&argc, &argv, NULL);
>> +
>> +   if (strcmp(arch, "i386") == 0) {
>> +        qtest_add_func("fuzz/test_fuzz_sb16/1c", test_fuzz_sb16_0x1c);
>> +        qtest_add_func("fuzz/test_fuzz_sb16/91", test_fuzz_sb16_0x91);
>> +   }
>> +
>> +   return g_test_run();
>> +}
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 7d9cd290426..d619ea8fcd1 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -2221,6 +2221,7 @@ F: qapi/audio.json
>>  F: tests/qtest/ac97-test.c
>>  F: tests/qtest/es1370-test.c
>>  F: tests/qtest/intel-hda-test.c
>> +F: tests/qtest/fuzz-sb16-test.c
>>
>>  Block layer core
>>  M: Kevin Wolf <kwolf@redhat.com>
>> diff --git a/tests/qtest/meson.build b/tests/qtest/meson.build
>> index c3a223a83d6..b03e8541700 100644
>> --- a/tests/qtest/meson.build
>> +++ b/tests/qtest/meson.build
>> @@ -20,6 +20,7 @@
>>  qtests_generic = \
>>    (config_all_devices.has_key('CONFIG_MEGASAS_SCSI_PCI') ? ['fuzz-megasas-test'] : []) + \
>>    (config_all_devices.has_key('CONFIG_VIRTIO_SCSI') ? ['fuzz-virtio-scsi-test'] : []) + \
>> +  (config_all_devices.has_key('CONFIG_SB16') ? ['fuzz-sb16-test'] : []) + \
>>    [
>>    'cdrom-test',
>>    'device-introspect-test',
>> --
>> 2.31.1
>>
> 


  reply	other threads:[~2021-06-16 12:48 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-16 10:43 [PATCH v2] hw/audio/sb16: Avoid assertion by restricting I/O sampling rate range Philippe Mathieu-Daudé
2021-06-16 11:58 ` Qiang Liu
2021-06-16 12:47   ` Philippe Mathieu-Daudé [this message]
2021-06-17  9:55     ` Gerd Hoffmann
2021-06-17  9:56 ` Gerd Hoffmann
2021-06-22  8:54   ` Qiang Liu
2021-06-22  9:15     ` Philippe Mathieu-Daudé
2021-06-22 10:13       ` Qiang Liu

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