[PATCH] hw/audio/sb16: validate VMState fields in post_load

[Jenny Guanni Qu <qguanni@gmail.com>]

The SB16 VMState loads in_index and out_data_len as raw INT32
values with no bounds validation. A crafted migration stream or
VM snapshot can set these to values exceeding their respective
buffer sizes (in2_data[10] and out_data[50]), causing heap OOB
write in dsp_write() and heap OOB read in dsp_read().

Add bounds checks in sb16_post_load() to reject invalid values
before they can be used as array indices.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3326
Reported-by: Jenny Guanni Qu <qguanni@gmail.com>
Signed-off-by: Jenny Guanni Qu <qguanni@gmail.com>
---
 hw/audio/sb16.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/audio/sb16.c b/hw/audio/sb16.c
index 1b5e452a29..1838d3ef7b 100644
--- a/hw/audio/sb16.c
+++ b/hw/audio/sb16.c
@@ -1286,6 +1286,13 @@ static int sb16_post_load (void *opaque, int version_id)
 {
     SB16State *s = opaque;
 
+
+    if (s->in_index < 0 || s->in_index > (int)sizeof(s->in2_data)) {
+        return -1;
+    }
+    if (s->out_data_len < 0 || s->out_data_len > (int)sizeof(s->out_data)) {
+        return -1;
+    }
     if (s->voice) {
         audio_be_close_out(s->audio_be, s->voice);
         s->voice = NULL;
-- 
2.34.1