From 6e270e2530fc095c7fe96296aa0d0fd6c0c64796 Mon Sep 17 00:00:00 2001
From: Vadim Yanitskiy <axilirator@gmail.com>
Date: Wed, 19 Feb 2020 05:55:49 +0700
Subject: [PATCH] tests/bitvec: add a unit test for bitvec_read_field()

The aim of this unit test is to demonstrate the problem described
in OS#4388: bitvec_read_field() can never return negative value
on error (e.g. out of bounds access).

Change-Id: I340ab5799fa53d5345edb02f3e2a3655527705c0
Related: OS#4388
---
 tests/bitvec/bitvec_test.c  | 42 +++++++++++++++++++++++++++++++++++++
 tests/bitvec/bitvec_test.ok | 18 ++++++++++++++++
 2 files changed, 60 insertions(+)

diff --git a/tests/bitvec/bitvec_test.c b/tests/bitvec/bitvec_test.c
index fbf5c5dde..b4764e685 100644
--- a/tests/bitvec/bitvec_test.c
+++ b/tests/bitvec/bitvec_test.c
@@ -222,6 +222,45 @@ static void test_tailroom()
 	}
 }
 
+static void test_bitvec_read_field(void)
+{
+	uint8_t data[8] = { 0xde, 0xad, 0xbe, 0xef, 0xfe, 0xeb, 0xda, 0xed };
+	struct bitvec bv = {
+		.data_len = sizeof(data),
+		.data = data,
+		.cur_bit = 0,
+	};
+
+	unsigned int readIndex;
+	uint64_t field;
+
+#define _bitvec_read_field(idx, len) \
+	readIndex = idx; \
+	field = bitvec_read_field(&bv, &readIndex, len); \
+	printf("bitvec_read_field(idx=%u, len=%u) => %" PRIx64 "\n", idx, len, field);
+
+	_bitvec_read_field(0, 64);
+	_bitvec_read_field(0, 32);
+	_bitvec_read_field(0, 16);
+	_bitvec_read_field(0, 8);
+	_bitvec_read_field(0, 0);
+
+	_bitvec_read_field(8, 8);
+	_bitvec_read_field(8, 4);
+	_bitvec_read_field(8, 0);
+
+	_bitvec_read_field(10, 9);
+	_bitvec_read_field(10, 7);
+	_bitvec_read_field(10, 5);
+	_bitvec_read_field(10, 3);
+	_bitvec_read_field(10, 1);
+
+	/* Out of bounds (see OS#4388) */
+	_bitvec_read_field(8 * 8 * 8, 16); /* index too far */
+	_bitvec_read_field(0, 8 * 8 + 1); /* too many bits */
+	_bitvec_read_field(8 * 8, 16); /* 16 bits past */
+}
+
 int main(int argc, char **argv)
 {
 	struct bitvec bv;
@@ -331,6 +370,9 @@ int main(int argc, char **argv)
 	test_used_bytes();
 	test_tailroom();
 
+	printf("\ntest bitvec_read_field():\n");
+	test_bitvec_read_field();
+
 	printf("\nbitvec ok.\n");
 	return 0;
 }
diff --git a/tests/bitvec/bitvec_test.ok b/tests/bitvec/bitvec_test.ok
index a48912d57..297455453 100644
--- a/tests/bitvec/bitvec_test.ok
+++ b/tests/bitvec/bitvec_test.ok
@@ -170,4 +170,22 @@ bitvec_runlength....
 
 bitvec bytes used.
 
+test bitvec_read_field():
+bitvec_read_field(idx=0, len=64) => deadbeeffeebdaed
+bitvec_read_field(idx=0, len=32) => deadbeef
+bitvec_read_field(idx=0, len=16) => dead
+bitvec_read_field(idx=0, len=8) => de
+bitvec_read_field(idx=0, len=0) => 0
+bitvec_read_field(idx=8, len=8) => ad
+bitvec_read_field(idx=8, len=4) => a
+bitvec_read_field(idx=8, len=0) => 0
+bitvec_read_field(idx=10, len=9) => 16d
+bitvec_read_field(idx=10, len=7) => 5b
+bitvec_read_field(idx=10, len=5) => 16
+bitvec_read_field(idx=10, len=3) => 5
+bitvec_read_field(idx=10, len=1) => 1
+bitvec_read_field(idx=512, len=16) => ffffffffffffffea
+bitvec_read_field(idx=0, len=65) => ffffffffffffffea
+bitvec_read_field(idx=64, len=16) => ffffffffffffffea
+
 bitvec ok.