* [PATCH] hw/audio/sb16: Restrict I/O sampling rate range for command 41h/42h
[not found] <CAAKa2jkj=rJVhOuE9XXC9ccsAt=2vg3_MO_NDL3OL98ALHMeFw@mail.gmail.com>
@ 2021-06-23 0:24 ` Qiang Liu
2021-06-23 12:20 ` Gerd Hoffmann
0 siblings, 1 reply; 4+ messages in thread
From: Qiang Liu @ 2021-06-23 0:24 UTC (permalink / raw)
To: qemu-devel, Gerd Hoffmann, Philippe Mathieu-Daudé
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The I/O sampling rate range is enforced to 5000 to 45000HZ according to
commit a2cd86a9. Setting I/O sampling rate with command 41h/42h, a guest
user can break this assumption and trigger an assertion in audio_calloc
via command 0xd4. This patch restricts the I/O sampling rate range for
command 41h/42h.
Fixes: 85571bc7415 ("audio merge (malc)")
Signed-off-by: Qiang Liu <cyruscyliu@gmail.com>
---
hw/audio/sb16.c | 31 +++++++++++++++++++------------
tests/qtest/fuzz-sb16-test.c | 17 +++++++++++++++++
2 files changed, 36 insertions(+), 12 deletions(-)
diff --git a/hw/audio/sb16.c b/hw/audio/sb16.c
index 5cf121f..60f1f75 100644
--- a/hw/audio/sb16.c
+++ b/hw/audio/sb16.c
@@ -229,6 +229,23 @@ static void continue_dma8 (SB16State *s)
control (s, 1);
}
+static inline int restrict_sampling_rate(int freq)
+{
+ if (freq < SAMPLE_RATE_MIN) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "sampling range too low: %d, increasing to %u\n",
+ freq, SAMPLE_RATE_MIN);
+ return SAMPLE_RATE_MIN;
+ } else if (freq > SAMPLE_RATE_MAX) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "sampling range too high: %d, decreasing to %u\n",
+ freq, SAMPLE_RATE_MAX);
+ return SAMPLE_RATE_MAX;
+ } else {
+ return freq;
+ }
+}
+
static void dma_cmd8 (SB16State *s, int mask, int dma_len)
{
s->fmt = AUDIO_FORMAT_U8;
@@ -244,17 +261,7 @@ 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;
- }
+ s->freq = restrict_sampling_rate(s->freq);
if (dma_len != -1) {
s->block_size = dma_len << s->fmt_stereo;
@@ -768,7 +775,7 @@ static void complete (SB16State *s)
* and FT2 sets output freq with this (go figure). Compare:
*
http://homepages.cae.wisc.edu/~brodskye/sb16doc/sb16doc.html#SamplingRate
*/
- s->freq = dsp_get_hilo (s);
+ s->freq = restrict_sampling_rate(dsp_get_hilo(s));
ldebug ("set freq %d\n", s->freq);
break;
diff --git a/tests/qtest/fuzz-sb16-test.c b/tests/qtest/fuzz-sb16-test.c
index 51030cd..f47a8bc 100644
--- a/tests/qtest/fuzz-sb16-test.c
+++ b/tests/qtest/fuzz-sb16-test.c
@@ -37,6 +37,22 @@ static void test_fuzz_sb16_0x91(void)
qtest_quit(s);
}
+/*
+ * This used to trigger the assert in audio_calloc
+ * through command 0xd4
+ */
+static void test_fuzz_sb16_0xd4(void)
+{
+ QTestState *s = qtest_init("-M pc -display none "
+ "-device sb16,audiodev=none "
+ "-audiodev id=none,driver=none");
+ qtest_outb(s, 0x22c, 0x41);
+ qtest_outb(s, 0x22c, 0x00);
+ qtest_outb(s, 0x22c, 0x14);
+ qtest_outb(s, 0x22c, 0xd4);
+ qtest_quit(s);
+}
+
int main(int argc, char **argv)
{
const char *arch = qtest_get_arch();
@@ -46,6 +62,7 @@ int main(int argc, char **argv)
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);
+ qtest_add_func("fuzz/test_fuzz_sb16/d4", test_fuzz_sb16_0xd4);
}
return g_test_run();
--
2.7.4
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