audio/wavcapture: prevent freq overflow and corrupted WAV header

Reject freq <= 0 in wav_start_capture() early, before it is used to
compute the WAV header fields.

Reported-by: Hui Peng <benquike@gmail.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-ID: <20261004-issue-4560-v1-12-ccbef537cbeb@redhat.com>

audio/wavcapture.c

@@ -131,6 +131,12 @@ int wav_start_capture(AudioBackend *state, CaptureState *s, const char *path,
         return -1;
     }
 
+    if (freq <= 0 || freq > 384000) {
+        error_report("invalid frequency %d, must be between 1 and 384000",
+                     freq);
+        return -1;
+    }
+
     stereo = nchannels == 2;
     bits16 = bits == 16;