Commit 8b365c4f authored by Guan-Chun Wu's avatar Guan-Chun Wu Committed by Andrew Morton
Browse files

lib: add KUnit tests for base64 encoding/decoding 

Add a KUnit test suite to validate the base64 helpers.  The tests cover
both encoding and decoding, including padded and unpadded forms as defined
by RFC 4648 (standard base64), and add negative cases for malformed inputs
and padding errors.

The test suite also validates other variants (URLSAFE, IMAP) to ensure
their correctness.

In addition to functional checks, the suite includes simple
microbenchmarks which report average encode/decode latency for small (64B)
and larger (1KB) inputs.  These numbers are informational only and do not
gate the tests.

Kconfig (BASE64_KUNIT) and lib/tests/Makefile are updated accordingly.

Sample KUnit output:

    KTAP version 1
    # Subtest: base64
    # module: base64_kunit
    1..4
    # base64_performance_tests: [64B] encode run : 32ns
    # base64_performance_tests: [64B] decode run : 35ns
    # base64_performance_tests: [1KB] encode run : 510ns
    # base64_performance_tests: [1KB] decode run : 530ns
    ok 1 base64_performance_tests
    ok 2 base64_std_encode_tests
    ok 3 base64_std_decode_tests
    ok 4 base64_variant_tests
    # base64: pass:4 fail:0 skip:0 total:4
    # Totals: pass:4 fail:0 skip:0 total:4

Link: https://lkml.kernel.org/r/20251114060157.89507-1-409411716@gms.tku.edu.tw


Signed-off-by: default avatarGuan-Chun Wu <409411716@gms.tku.edu.tw>
Reviewed-by: default avatarKuan-Wei Chiu <visitorckw@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Laight <david.laight.linux@gmail.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yu-Sheng Huang <home7438072@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 9c7d3cf9

lib/Kconfig.debug

+18 −1
Original line number Diff line number Diff line
@@ -2815,8 +2815,25 @@ config CMDLINE_KUNIT_TEST 


	  If unsure, say N.



config BASE64_KUNIT

	tristate "KUnit test for base64 decoding and encoding" if !KUNIT_ALL_TESTS

	depends on KUNIT

	default KUNIT_ALL_TESTS

	help

	  This builds the base64 unit tests.



	  The tests cover the encoding and decoding logic of Base64 functions

	  in the kernel.

	  In addition to correctness checks, simple performance benchmarks

	  for both encoding and decoding are also included.



	  For more information on KUnit and unit tests in general please refer

	  to the KUnit documentation in Documentation/dev-tools/kunit/.



	  If unsure, say N.



config BITS_TEST

	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS

	tristate "KUnit test for bit functions and macros" if !KUNIT_ALL_TESTS

	depends on KUNIT

	default KUNIT_ALL_TESTS

	help

lib/tests/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 


# KUnit tests

CFLAGS_bitfield_kunit.o := $(DISABLE_STRUCTLEAK_PLUGIN)

obj-$(CONFIG_BASE64_KUNIT) += base64_kunit.o

obj-$(CONFIG_BITFIELD_KUNIT) += bitfield_kunit.o

obj-$(CONFIG_BITS_TEST) += test_bits.o

obj-$(CONFIG_BLACKHOLE_DEV_KUNIT_TEST) += blackhole_dev_kunit.o

lib/tests/base64_kunit.c

0 → 100644
+294 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * base64_kunit_test.c - KUnit tests for base64 encoding and decoding functions

 *

 * Copyright (c) 2025, Guan-Chun Wu <409411716@gms.tku.edu.tw>

 */



#include <kunit/test.h>

#include <linux/base64.h>



/* ---------- Benchmark helpers ---------- */

static u64 bench_encode_ns(const u8 *data, int len, char *dst, int reps,

			   enum base64_variant variant)

{

	u64 t0, t1;



	t0 = ktime_get_ns();

	for (int i = 0; i < reps; i++)

		base64_encode(data, len, dst, true, variant);

	t1 = ktime_get_ns();



	return div64_u64(t1 - t0, (u64)reps);

}



static u64 bench_decode_ns(const char *data, int len, u8 *dst, int reps,

			   enum base64_variant variant)

{

	u64 t0, t1;



	t0 = ktime_get_ns();

	for (int i = 0; i < reps; i++)

		base64_decode(data, len, dst, true, variant);

	t1 = ktime_get_ns();



	return div64_u64(t1 - t0, (u64)reps);

}



static void run_perf_and_check(struct kunit *test, const char *label, int size,

			       enum base64_variant variant)

{

	const int reps = 1000;

	size_t outlen = DIV_ROUND_UP(size, 3) * 4;

	u8 *in = kmalloc(size, GFP_KERNEL);

	char *enc = kmalloc(outlen, GFP_KERNEL);

	u8 *decoded = kmalloc(size, GFP_KERNEL);



	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, in);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, enc);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, decoded);



	get_random_bytes(in, size);

	int enc_len = base64_encode(in, size, enc, true, variant);

	int dec_len = base64_decode(enc, enc_len, decoded, true, variant);



	/* correctness sanity check */

	KUNIT_EXPECT_EQ(test, dec_len, size);

	KUNIT_EXPECT_MEMEQ(test, decoded, in, size);



	/* benchmark encode */



	u64 t1 = bench_encode_ns(in, size, enc, reps, variant);



	kunit_info(test, "[%s] encode run : %lluns", label, t1);



	u64 t2 = bench_decode_ns(enc, enc_len, decoded, reps, variant);



	kunit_info(test, "[%s] decode run : %lluns", label, t2);



	kfree(in);

	kfree(enc);

	kfree(decoded);

}



static void base64_performance_tests(struct kunit *test)

{

	/* run on STD variant only */

	run_perf_and_check(test, "64B", 64, BASE64_STD);

	run_perf_and_check(test, "1KB", 1024, BASE64_STD);

}



/* ---------- Helpers for encode ---------- */

static void expect_encode_ok(struct kunit *test, const u8 *src, int srclen,

			     const char *expected, bool padding,

			     enum base64_variant variant)

{

	char buf[128];

	int encoded_len = base64_encode(src, srclen, buf, padding, variant);



	buf[encoded_len] = '\0';



	KUNIT_EXPECT_EQ(test, encoded_len, strlen(expected));

	KUNIT_EXPECT_STREQ(test, buf, expected);

}



/* ---------- Helpers for decode ---------- */

static void expect_decode_ok(struct kunit *test, const char *src,

			     const u8 *expected, int expected_len, bool padding,

			     enum base64_variant variant)

{

	u8 buf[128];

	int decoded_len = base64_decode(src, strlen(src), buf, padding, variant);



	KUNIT_EXPECT_EQ(test, decoded_len, expected_len);

	KUNIT_EXPECT_MEMEQ(test, buf, expected, expected_len);

}



static void expect_decode_err(struct kunit *test, const char *src,

			      int srclen, bool padding,

			      enum base64_variant variant)

{

	u8 buf[64];

	int decoded_len = base64_decode(src, srclen, buf, padding, variant);



	KUNIT_EXPECT_EQ(test, decoded_len, -1);

}



/* ---------- Encode Tests ---------- */

static void base64_std_encode_tests(struct kunit *test)

{

	/* With padding */

	expect_encode_ok(test, (const u8 *)"", 0, "", true, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"f", 1, "Zg==", true, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"fo", 2, "Zm8=", true, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"foo", 3, "Zm9v", true, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"foob", 4, "Zm9vYg==", true, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"fooba", 5, "Zm9vYmE=", true, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"foobar", 6, "Zm9vYmFy", true, BASE64_STD);



	/* Extra cases with padding */

	expect_encode_ok(test, (const u8 *)"Hello, world!", 13, "SGVsbG8sIHdvcmxkIQ==",

			 true, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26,

			 "QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVo=", true, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"abcdefghijklmnopqrstuvwxyz", 26,

			 "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXo=", true, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"0123456789+/", 12, "MDEyMzQ1Njc4OSsv",

			 true, BASE64_STD);



	/* Without padding */

	expect_encode_ok(test, (const u8 *)"", 0, "", false, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"f", 1, "Zg", false, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"fo", 2, "Zm8", false, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"foo", 3, "Zm9v", false, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"foob", 4, "Zm9vYg", false, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"fooba", 5, "Zm9vYmE", false, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"foobar", 6, "Zm9vYmFy", false, BASE64_STD);



	/* Extra cases without padding */

	expect_encode_ok(test, (const u8 *)"Hello, world!", 13, "SGVsbG8sIHdvcmxkIQ",

			 false, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26,

			 "QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVo", false, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"abcdefghijklmnopqrstuvwxyz", 26,

			 "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXo", false, BASE64_STD);

	expect_encode_ok(test, (const u8 *)"0123456789+/", 12, "MDEyMzQ1Njc4OSsv",

			 false, BASE64_STD);

}



/* ---------- Decode Tests ---------- */

static void base64_std_decode_tests(struct kunit *test)

{

	/* -------- With padding --------*/

	expect_decode_ok(test, "", (const u8 *)"", 0, true, BASE64_STD);

	expect_decode_ok(test, "Zg==", (const u8 *)"f", 1, true, BASE64_STD);

	expect_decode_ok(test, "Zm8=", (const u8 *)"fo", 2, true, BASE64_STD);

	expect_decode_ok(test, "Zm9v", (const u8 *)"foo", 3, true, BASE64_STD);

	expect_decode_ok(test, "Zm9vYg==", (const u8 *)"foob", 4, true, BASE64_STD);

	expect_decode_ok(test, "Zm9vYmE=", (const u8 *)"fooba", 5, true, BASE64_STD);

	expect_decode_ok(test, "Zm9vYmFy", (const u8 *)"foobar", 6, true, BASE64_STD);

	expect_decode_ok(test, "SGVsbG8sIHdvcmxkIQ==", (const u8 *)"Hello, world!", 13,

			 true, BASE64_STD);

	expect_decode_ok(test, "QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVo=",

			 (const u8 *)"ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26, true, BASE64_STD);

	expect_decode_ok(test, "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXo=",

			 (const u8 *)"abcdefghijklmnopqrstuvwxyz", 26, true, BASE64_STD);



	/* Error cases */

	expect_decode_err(test, "Zg=!", 4, true, BASE64_STD);

	expect_decode_err(test, "Zm$=", 4, true, BASE64_STD);

	expect_decode_err(test, "Z===", 4, true, BASE64_STD);

	expect_decode_err(test, "Zg", 2, true, BASE64_STD);

	expect_decode_err(test, "Zm9v====", 8, true, BASE64_STD);

	expect_decode_err(test, "Zm==A", 5, true, BASE64_STD);



	{

		char with_nul[4] = { 'Z', 'g', '\0', '=' };



		expect_decode_err(test, with_nul, 4, true, BASE64_STD);

	}



	/* -------- Without padding --------*/

	expect_decode_ok(test, "", (const u8 *)"", 0, false, BASE64_STD);

	expect_decode_ok(test, "Zg", (const u8 *)"f", 1, false, BASE64_STD);

	expect_decode_ok(test, "Zm8", (const u8 *)"fo", 2, false, BASE64_STD);

	expect_decode_ok(test, "Zm9v", (const u8 *)"foo", 3, false, BASE64_STD);

	expect_decode_ok(test, "Zm9vYg", (const u8 *)"foob", 4, false, BASE64_STD);

	expect_decode_ok(test, "Zm9vYmE", (const u8 *)"fooba", 5, false, BASE64_STD);

	expect_decode_ok(test, "Zm9vYmFy", (const u8 *)"foobar", 6, false, BASE64_STD);

	expect_decode_ok(test, "TWFu", (const u8 *)"Man", 3, false, BASE64_STD);

	expect_decode_ok(test, "SGVsbG8sIHdvcmxkIQ", (const u8 *)"Hello, world!", 13,

			 false, BASE64_STD);

	expect_decode_ok(test, "QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVo",

			 (const u8 *)"ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26, false, BASE64_STD);

	expect_decode_ok(test, "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXo",

			 (const u8 *)"abcdefghijklmnopqrstuvwxyz", 26, false, BASE64_STD);

	expect_decode_ok(test, "MDEyMzQ1Njc4OSsv", (const u8 *)"0123456789+/", 12,

			 false, BASE64_STD);



	/* Error cases */

	expect_decode_err(test, "Zg=!", 4, false, BASE64_STD);

	expect_decode_err(test, "Zm$=", 4, false, BASE64_STD);

	expect_decode_err(test, "Z===", 4, false, BASE64_STD);

	expect_decode_err(test, "Zg=", 3, false, BASE64_STD);

	expect_decode_err(test, "Zm9v====", 8, false, BASE64_STD);

	expect_decode_err(test, "Zm==v", 4, false, BASE64_STD);



	{

		char with_nul[4] = { 'Z', 'g', '\0', '=' };



		expect_decode_err(test, with_nul, 4, false, BASE64_STD);

	}

}



/* ---------- Variant tests (URLSAFE / IMAP) ---------- */

static void base64_variant_tests(struct kunit *test)

{

	const u8 sample1[] = { 0x00, 0xfb, 0xff, 0x7f, 0x80 };

	char std_buf[128], url_buf[128], imap_buf[128];

	u8 back[128];

	int n_std, n_url, n_imap, m;

	int i;



	n_std = base64_encode(sample1, sizeof(sample1), std_buf, false, BASE64_STD);

	n_url = base64_encode(sample1, sizeof(sample1), url_buf, false, BASE64_URLSAFE);

	std_buf[n_std] = '\0';

	url_buf[n_url] = '\0';



	for (i = 0; i < n_std; i++) {

		if (std_buf[i] == '+')

			std_buf[i] = '-';

		else if (std_buf[i] == '/')

			std_buf[i] = '_';

	}

	KUNIT_EXPECT_STREQ(test, std_buf, url_buf);



	m = base64_decode(url_buf, n_url, back, false, BASE64_URLSAFE);

	KUNIT_EXPECT_EQ(test, m, (int)sizeof(sample1));

	KUNIT_EXPECT_MEMEQ(test, back, sample1, sizeof(sample1));



	n_std  = base64_encode(sample1, sizeof(sample1), std_buf, false, BASE64_STD);

	n_imap = base64_encode(sample1, sizeof(sample1), imap_buf, false, BASE64_IMAP);

	std_buf[n_std]   = '\0';

	imap_buf[n_imap] = '\0';



	for (i = 0; i < n_std; i++)

		if (std_buf[i] == '/')

			std_buf[i] = ',';

	KUNIT_EXPECT_STREQ(test, std_buf, imap_buf);



	m = base64_decode(imap_buf, n_imap, back, false, BASE64_IMAP);

	KUNIT_EXPECT_EQ(test, m, (int)sizeof(sample1));

	KUNIT_EXPECT_MEMEQ(test, back, sample1, sizeof(sample1));



	{

		const char *bad = "Zg==";

		u8 tmp[8];



		m = base64_decode(bad, strlen(bad), tmp, false, BASE64_URLSAFE);

		KUNIT_EXPECT_EQ(test, m, -1);



		m = base64_decode(bad, strlen(bad), tmp, false, BASE64_IMAP);

		KUNIT_EXPECT_EQ(test, m, -1);

	}

}



/* ---------- Test registration ---------- */

static struct kunit_case base64_test_cases[] = {

	KUNIT_CASE(base64_performance_tests),

	KUNIT_CASE(base64_std_encode_tests),

	KUNIT_CASE(base64_std_decode_tests),

	KUNIT_CASE(base64_variant_tests),

	{}

};



static struct kunit_suite base64_test_suite = {

	.name = "base64",

	.test_cases = base64_test_cases,

};



kunit_test_suite(base64_test_suite);



MODULE_AUTHOR("Guan-Chun Wu <409411716@gms.tku.edu.tw>");

MODULE_DESCRIPTION("KUnit tests for Base64 encoding/decoding, including performance checks");

MODULE_LICENSE("GPL");