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Re: [PATCH] hw/audio/sb16: Avoid assertion by restricting I/O sampling r
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From: |
Qiang Liu |
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Subject: |
Re: [PATCH] hw/audio/sb16: Avoid assertion by restricting I/O sampling rate range |
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Date: |
Tue, 15 Jun 2021 21:43:31 +0800 |
On Mon, Jun 14, 2021 at 11:06 PM Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>
> On 6/14/21 2:11 PM, Qiang Liu wrote:
> > Hi Phil,
> >
> > Thanks for inviting me. I've applied your patch. It seems fine
> > because my sb16 fuzzer is running for another 24 hours and
> > it has no crash yet.
>
> Thanks for testing!
>
> Can we use your "Tested-by: Qiang Liu <cyruscyliu@gmail.com>" tag?
Yes. My sb16 fuzzer has no crash yet after 24h, so I think the patch is good.
> > I can also double-check the specification.
>
> If you do, please send a "Reviewed-by: Qiang Liu <cyruscyliu@gmail.com>"
> tag :)
Yes, I did. I agree to follow the specific frequency limit regarding
the 41h/42h registers.
> >>> Valid sampling rates range from 5000 to 45000 Hz inclusive.
Should I send this patch with tag V2?
> > Best,
> > Qiang
> >
> > On Mon, Jun 14, 2021 at 7:13 PM Philippe Mathieu-Daudé <f4bug@amsat.org>
> > wrote:
> >>
> >> ping?
> >>
> >> On 6/1/21 5:18 PM, Philippe Mathieu-Daudé 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
> >>> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> >>> ---
> >>> 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 5f55404f2fa..7edb26d2293 100644
> >>> --- a/MAINTAINERS
> >>> +++ b/MAINTAINERS
> >>> @@ -2213,6 +2213,7 @@ 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',
> >>>
> >