ipc3: handler: Add check for pipeline->source_comp being NULL

The fuzzer engine has produced crash caused by NULL pointer read that
originated from ipc_stream_pcm_free(). The crash happens when the
pipeline of the found comp_dev does not have a source_comp and
pipeline_reset() is called for it. This commit simply adds a test
for such a situation and bails out if it is found.

Here is the call stack from the situation:

    #0 0x81e9317 in dev_comp_pipe_id sof/sof/src/include/sof/audio/component.h:646:25
    thesofproject#1 0x81e8015 in pipeline_comp_reset sof/sof/src/audio/pipeline/pipeline-graph.c:326:22
    thesofproject#2 0x81e7d1d in pipeline_reset sof/sof/src/audio/pipeline/pipeline-graph.c:393:8
    thesofproject#3 0x820d7ea in ipc_stream_pcm_free sof/sof/src/ipc/ipc3/handler.c:398:8
    thesofproject#4 0x8208969 in ipc_cmd sof/sof/src/ipc/ipc3/handler.c:1689:9
    thesofproject#5 0x81cbed8 in ipc_platform_do_cmd sof/sof/src/platform/posix/ipc.c:162:2
    thesofproject#6 0x81d10db in ipc_do_cmd sof/sof/src/ipc/ipc-common.c:330:9
    thesofproject#7 0x81f87e9 in task_run sof/sof/zephyr/include/rtos/task.h:94:9
    thesofproject#8 0x81f8308 in edf_work_handler sof/sof/zephyr/edf_schedule.c:31:16
    thesofproject#9 0x82b4b32 in work_queue_main sof/zephyr/kernel/work.c:668:3
    thesofproject#10 0x8193ec2 in z_thread_entry sof/zephyr/lib/os/thread_entry.c:36:2
    thesofproject#11 0x815f639 in __asan::AsanThread::ThreadStart(unsigned long long) /src/llvm-project/compiler-rt/lib/asan/asan_thread.cpp:277:25

Signed-off-by: Jyri Sarha <jyri.sarha@linux.intel.com>

src/ipc/ipc3/handler.c

@@ -386,6 +386,13 @@ static int ipc_stream_pcm_free(uint32_t header)
 		return -EINVAL;
 	}
 
+	/* pipeline_reset() crashes if source_comp is NULL */
+	if (!pcm_dev->cd->pipeline->source_comp) {
+		ipc_cmd_err(&ipc_tr, "ipc: comp %d source comp not found",
+			    free_req.comp_id);
+		return -EINVAL;
+	}
+
 	/* reset the pipeline */
 	ret = pipeline_reset(pcm_dev->cd->pipeline, pcm_dev->cd);