From 544b1db62b7b1458d09e03885ef722dd7dfd28b0 Mon Sep 17 00:00:00 2001
From: Lars Immisch <lars@ibp.de>
Date: Thu, 23 Nov 2023 17:38:34 +0100
Subject: [PATCH] rem/aufile: test and fix aufile_set_position nread (#1010)

Also fix a bug: wav files can contain data after the data chunk. If we don't update nread in aufile_set_position, we can read invalid data.
---
 rem/aufile/aufile.c |   4 +++
 test/CMakeLists.txt |   1 +
 test/aupos.c        |  61 ++++++++++++++++++++++++++++++++++++++++++++
 test/data/beep.wav  | Bin 6156 -> 6158 bytes
 test/test.c         |   1 +
 test/test.h         |   1 +
 6 files changed, 68 insertions(+)
 create mode 100644 test/aupos.c

diff --git a/rem/aufile/aufile.c b/rem/aufile/aufile.c
index 42185e92c..f5ceb7eaa 100644
--- a/rem/aufile/aufile.c
+++ b/rem/aufile/aufile.c
@@ -294,8 +294,12 @@ int aufile_set_position(struct aufile *af, const struct aufile_prm *prm,
 	off_t pos = (off_t)(prm->srate * aufmt_sample_size(prm->fmt)
 		* prm->channels * pos_ms / 1000);
 
+	pos = min((off_t)datasize, pos);
+
 	if (fseek(af->f, pos, SEEK_CUR) < 0)
 		return errno;
 
+	af->nread = pos;
+
 	return 0;
 }
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 9412ac2f5..7e2610395 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -72,6 +72,7 @@ set(SRCS
   aubuf.c
   aulength.c
   aulevel.c
+  aupos.c
   auresamp.c
   av1.c
   base64.c
diff --git a/test/aupos.c b/test/aupos.c
new file mode 100644
index 000000000..4ff40868d
--- /dev/null
+++ b/test/aupos.c
@@ -0,0 +1,61 @@
+/**
+ * @file src/aupos.c audio file setposition test
+ *
+ * Copyright (C) 2023 Lars Immisch
+ */
+
+#include <re.h>
+#include <rem.h>
+#include "test.h"
+
+
+#define DEBUG_MODULE "auposition"
+#define DEBUG_LEVEL 5
+#include <re_dbg.h>
+
+
+int test_auposition(void)
+{
+	struct aufile *af = NULL;
+	struct aufile_prm prm;
+	char path[256];
+	uint8_t buffer[512];
+
+	re_snprintf(path, sizeof(path), "%s/beep.wav", test_datapath());
+
+	int err = aufile_open(&af, &prm, path, AUFILE_READ);
+	TEST_ERR(err);
+
+	err = aufile_set_position(af, &prm, 67);
+	TEST_ERR(err);
+
+	/* That file is exactly 67 ms long, so we shouldn't read anything */
+	size_t size = sizeof(buffer);
+	err = aufile_read(af, buffer, &size);
+	TEST_ERR(err);
+
+	/* It's possible we read data up to a ms */
+	TEST_ASSERT(size < 16);
+
+	af = mem_deref(af);
+
+	err = aufile_open(&af, &prm, path, AUFILE_READ);
+	TEST_ERR(err);
+
+	err = aufile_set_position(af, &prm, 37);
+	TEST_ERR(err);
+
+	size = sizeof(buffer);
+	err = aufile_read(af, buffer, &size);
+	TEST_ERR(err);
+
+	/* 30 ms should be left, at 8000Hz/s, one channels and 16 bit samples
+	   that's 480 bytes */
+	TEST_ASSERT(size - 480 < 16);
+
+
+out:
+	mem_deref(af);
+
+	return err;
+}
diff --git a/test/data/beep.wav b/test/data/beep.wav
index a148a48aef8380792d9e36af36f0e50bace99212..2ff0b0d65c42e8c5c9d75267f91527831a442b89 100644
GIT binary patch
delta 294
zcmeA%=rdpq@^o`!o5-rnXs}V!n1wYyz&B#m=4_Umtel1+h6Ywf##Y9Yy|`?Vc)eUU
zDrpu5rb#Kr#=1#nsY$vfsTQWXiN+RYx`xS?X{IJA7G~xtDU;uFnJb%_C0UpnBwOev
zC!1L4niv`y=vtbkB<WhDTACT9rKTmOrA~I|b|6aKD(-tksawrsgK+NVw>%My#JP73
Sk2ONy<hMLiHrw%^;{X5!)=}92

delta 288
zcmeA(=rLdo@^o`!naHZlXthz(n1!DK2>$;Ek?{e(5%V@DvfN~4GYBy>vNE0Q%w-E>
zc5>OMSePdpnOPbd=q9Hbn(CUEr={s8r6wiorX(7enj57WTO=i!O@7H`u56TSW@%z+
zVWw-4oSLd@l9-aFYiVp`tZS5Nnq*><oNAtGIN6!ofhcv$xbG3AZaI$))UBJ}@I){Y
P=hziI)-X+L_>wpQh51gj

diff --git a/test/test.c b/test/test.c
index ca71e99a7..cb23ed030 100644
--- a/test/test.c
+++ b/test/test.c
@@ -55,6 +55,7 @@ static const struct test tests[] = {
 	TEST(test_aubuf),
 	TEST(test_aulength),
 	TEST(test_aulevel),
+	TEST(test_auposition),
 	TEST(test_auresamp),
 	TEST(test_async),
 	TEST(test_av1),
diff --git a/test/test.h b/test/test.h
index 306d9bf47..8b8c06e58 100644
--- a/test/test.h
+++ b/test/test.h
@@ -160,6 +160,7 @@ int test_aes_gcm(void);
 int test_aubuf(void);
 int test_aulevel(void);
 int test_aulength(void);
+int test_auposition(void);
 int test_auresamp(void);
 int test_async(void);
 int test_av1(void);