mbedtls/tests/suites/test_suite_entropy.function
Gilles Peskine c548468b69 MBEDTLS_PSA_INJECT_ENTROPY: Skip incompatible tests
When MBEDTLS_PSA_INJECT_ENTROPY is enabled, we disable standard entropy
sources, so mbedtls_entropy_func() doesn't work out of the box. Disable
tests that rely on it. MBEDTLS_PSA_INJECT_ENTROPY is intended for PSA-only
environments anyway, so it doesn't matter if some legacy features don't work
normally.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
2023-04-28 23:45:36 +02:00

560 lines
17 KiB
C

/* BEGIN_HEADER */
#include "mbedtls/entropy.h"
#include "entropy_poll.h"
#include "mbedtls/md.h"
#include "string.h"
typedef enum {
DUMMY_CONSTANT_LENGTH, /* Output context->length bytes */
DUMMY_REQUESTED_LENGTH, /* Output whatever length was requested */
DUMMY_FAIL, /* Return an error code */
} entropy_dummy_instruction;
typedef struct {
entropy_dummy_instruction instruction;
size_t length; /* Length to return for DUMMY_CONSTANT_LENGTH */
size_t calls; /* Incremented at each call */
} entropy_dummy_context;
/*
* Dummy entropy source
*
* If data is NULL, write exactly the requested length.
* Otherwise, write the length indicated by data or error if negative
*/
static int entropy_dummy_source(void *arg, unsigned char *output,
size_t len, size_t *olen)
{
entropy_dummy_context *context = arg;
++context->calls;
switch (context->instruction) {
case DUMMY_CONSTANT_LENGTH:
*olen = context->length;
break;
case DUMMY_REQUESTED_LENGTH:
*olen = len;
break;
case DUMMY_FAIL:
return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
}
memset(output, 0x2a, *olen);
return 0;
}
/*
* Ability to clear entropy sources to allow testing with just predefined
* entropy sources. This function or tests depending on it might break if there
* are internal changes to how entropy sources are registered.
*
* To be called immediately after mbedtls_entropy_init().
*
* Just resetting the counter. New sources will overwrite existing ones.
* This might break memory checks in the future if sources need 'free-ing' then
* as well.
*/
static void entropy_clear_sources(mbedtls_entropy_context *ctx)
{
ctx->source_count = 0;
}
#if defined(MBEDTLS_ENTROPY_NV_SEED)
/*
* NV seed read/write functions that use a buffer instead of a file
*/
static unsigned char buffer_seed[MBEDTLS_ENTROPY_BLOCK_SIZE];
int buffer_nv_seed_read(unsigned char *buf, size_t buf_len)
{
if (buf_len != MBEDTLS_ENTROPY_BLOCK_SIZE) {
return -1;
}
memcpy(buf, buffer_seed, MBEDTLS_ENTROPY_BLOCK_SIZE);
return 0;
}
int buffer_nv_seed_write(unsigned char *buf, size_t buf_len)
{
if (buf_len != MBEDTLS_ENTROPY_BLOCK_SIZE) {
return -1;
}
memcpy(buffer_seed, buf, MBEDTLS_ENTROPY_BLOCK_SIZE);
return 0;
}
/*
* NV seed read/write helpers that fill the base seedfile
*/
static int write_nv_seed(unsigned char *buf, size_t buf_len)
{
FILE *f;
if (buf_len != MBEDTLS_ENTROPY_BLOCK_SIZE) {
return -1;
}
if ((f = fopen(MBEDTLS_PLATFORM_STD_NV_SEED_FILE, "w")) == NULL) {
return -1;
}
if (fwrite(buf, 1, MBEDTLS_ENTROPY_BLOCK_SIZE, f) !=
MBEDTLS_ENTROPY_BLOCK_SIZE) {
return -1;
}
fclose(f);
return 0;
}
int read_nv_seed(unsigned char *buf, size_t buf_len)
{
FILE *f;
if (buf_len != MBEDTLS_ENTROPY_BLOCK_SIZE) {
return -1;
}
if ((f = fopen(MBEDTLS_PLATFORM_STD_NV_SEED_FILE, "rb")) == NULL) {
return -1;
}
if (fread(buf, 1, MBEDTLS_ENTROPY_BLOCK_SIZE, f) !=
MBEDTLS_ENTROPY_BLOCK_SIZE) {
return -1;
}
fclose(f);
return 0;
}
#endif /* MBEDTLS_ENTROPY_NV_SEED */
/* END_HEADER */
/* BEGIN_DEPENDENCIES
* depends_on:MBEDTLS_ENTROPY_C:!MBEDTLS_PSA_INJECT_ENTROPY
* END_DEPENDENCIES
*/
/* BEGIN_CASE */
void entropy_init_free(int reinit)
{
mbedtls_entropy_context ctx;
/* Double free is not explicitly documented to work, but it is convenient
* to call mbedtls_entropy_free() unconditionally on an error path without
* checking whether it has already been called in the success path. */
mbedtls_entropy_init(&ctx);
mbedtls_entropy_free(&ctx);
if (reinit) {
mbedtls_entropy_init(&ctx);
}
mbedtls_entropy_free(&ctx);
/* This test case always succeeds, functionally speaking. A plausible
* bug might trigger an invalid pointer dereference or a memory leak. */
goto exit;
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_ENTROPY_NV_SEED:MBEDTLS_FS_IO */
void entropy_seed_file(char *path, int ret)
{
mbedtls_entropy_context ctx;
MD_PSA_INIT();
mbedtls_entropy_init(&ctx);
TEST_ASSERT(mbedtls_entropy_write_seed_file(&ctx, path) == ret);
TEST_ASSERT(mbedtls_entropy_update_seed_file(&ctx, path) == ret);
exit:
mbedtls_entropy_free(&ctx);
MD_PSA_DONE();
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_ENTROPY_NV_SEED:MBEDTLS_FS_IO */
void entropy_write_base_seed_file(int ret)
{
mbedtls_entropy_context ctx;
MD_PSA_INIT();
mbedtls_entropy_init(&ctx);
TEST_ASSERT(mbedtls_entropy_write_seed_file(&ctx, MBEDTLS_PLATFORM_STD_NV_SEED_FILE) == ret);
TEST_ASSERT(mbedtls_entropy_update_seed_file(&ctx, MBEDTLS_PLATFORM_STD_NV_SEED_FILE) == ret);
exit:
mbedtls_entropy_free(&ctx);
MD_PSA_DONE();
}
/* END_CASE */
/* BEGIN_CASE */
void entropy_no_sources()
{
mbedtls_entropy_context ctx;
unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
mbedtls_entropy_init(&ctx);
entropy_clear_sources(&ctx);
TEST_EQUAL(mbedtls_entropy_func(&ctx, buf, sizeof(buf)),
MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED);
exit:
mbedtls_entropy_free(&ctx);
}
/* END_CASE */
/* BEGIN_CASE */
void entropy_too_many_sources()
{
mbedtls_entropy_context ctx;
size_t i;
entropy_dummy_context dummy = { DUMMY_REQUESTED_LENGTH, 0, 0 };
mbedtls_entropy_init(&ctx);
/*
* It's hard to tell precisely when the error will occur,
* since we don't know how many sources were automatically added.
*/
for (i = 0; i < MBEDTLS_ENTROPY_MAX_SOURCES; i++) {
(void) mbedtls_entropy_add_source(&ctx, entropy_dummy_source, &dummy,
16, MBEDTLS_ENTROPY_SOURCE_WEAK);
}
TEST_ASSERT(mbedtls_entropy_add_source(&ctx, entropy_dummy_source, &dummy,
16, MBEDTLS_ENTROPY_SOURCE_WEAK)
== MBEDTLS_ERR_ENTROPY_MAX_SOURCES);
exit:
mbedtls_entropy_free(&ctx);
}
/* END_CASE */
/* BEGIN_CASE depends_on:ENTROPY_HAVE_STRONG */
void entropy_func_len(int len, int ret)
{
mbedtls_entropy_context ctx;
unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE + 10] = { 0 };
unsigned char acc[MBEDTLS_ENTROPY_BLOCK_SIZE + 10] = { 0 };
size_t i, j;
MD_PSA_INIT();
mbedtls_entropy_init(&ctx);
/*
* See comments in mbedtls_entropy_self_test()
*/
for (i = 0; i < 8; i++) {
TEST_ASSERT(mbedtls_entropy_func(&ctx, buf, len) == ret);
for (j = 0; j < sizeof(buf); j++) {
acc[j] |= buf[j];
}
}
if (ret == 0) {
for (j = 0; j < (size_t) len; j++) {
TEST_ASSERT(acc[j] != 0);
}
}
for (j = len; j < sizeof(buf); j++) {
TEST_ASSERT(acc[j] == 0);
}
exit:
mbedtls_entropy_free(&ctx);
MD_PSA_DONE();
}
/* END_CASE */
/* BEGIN_CASE */
void entropy_source_fail(char *path)
{
mbedtls_entropy_context ctx;
unsigned char buf[16];
entropy_dummy_context dummy = { DUMMY_FAIL, 0, 0 };
MD_PSA_INIT();
mbedtls_entropy_init(&ctx);
TEST_ASSERT(mbedtls_entropy_add_source(&ctx, entropy_dummy_source,
&dummy, 16,
MBEDTLS_ENTROPY_SOURCE_WEAK)
== 0);
TEST_ASSERT(mbedtls_entropy_func(&ctx, buf, sizeof(buf))
== MBEDTLS_ERR_ENTROPY_SOURCE_FAILED);
TEST_ASSERT(mbedtls_entropy_gather(&ctx)
== MBEDTLS_ERR_ENTROPY_SOURCE_FAILED);
#if defined(MBEDTLS_FS_IO) && defined(MBEDTLS_ENTROPY_NV_SEED)
TEST_ASSERT(mbedtls_entropy_write_seed_file(&ctx, path)
== MBEDTLS_ERR_ENTROPY_SOURCE_FAILED);
TEST_ASSERT(mbedtls_entropy_update_seed_file(&ctx, path)
== MBEDTLS_ERR_ENTROPY_SOURCE_FAILED);
#else
((void) path);
#endif
exit:
mbedtls_entropy_free(&ctx);
MD_PSA_DONE();
}
/* END_CASE */
/* BEGIN_CASE */
void entropy_threshold(int threshold, int chunk_size, int result)
{
mbedtls_entropy_context ctx;
entropy_dummy_context strong =
{ DUMMY_CONSTANT_LENGTH, MBEDTLS_ENTROPY_BLOCK_SIZE, 0 };
entropy_dummy_context weak = { DUMMY_CONSTANT_LENGTH, chunk_size, 0 };
unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE] = { 0 };
int ret;
MD_PSA_INIT();
mbedtls_entropy_init(&ctx);
entropy_clear_sources(&ctx);
/* Set strong source that reaches its threshold immediately and
* a weak source whose threshold is a test parameter. */
TEST_ASSERT(mbedtls_entropy_add_source(&ctx, entropy_dummy_source,
&strong, 1,
MBEDTLS_ENTROPY_SOURCE_STRONG) == 0);
TEST_ASSERT(mbedtls_entropy_add_source(&ctx, entropy_dummy_source,
&weak, threshold,
MBEDTLS_ENTROPY_SOURCE_WEAK) == 0);
ret = mbedtls_entropy_func(&ctx, buf, sizeof(buf));
if (result >= 0) {
TEST_ASSERT(ret == 0);
#if defined(MBEDTLS_ENTROPY_NV_SEED)
/* If the NV seed functionality is enabled, there are two entropy
* updates: before and after updating the NV seed. */
result *= 2;
#endif
TEST_ASSERT(weak.calls == (size_t) result);
} else {
TEST_ASSERT(ret == result);
}
exit:
mbedtls_entropy_free(&ctx);
MD_PSA_DONE();
}
/* END_CASE */
/* BEGIN_CASE */
void entropy_calls(int strength1, int strength2,
int threshold, int chunk_size,
int result)
{
/*
* if result >= 0: result = expected number of calls to source 1
* if result < 0: result = expected return code from mbedtls_entropy_func()
*/
mbedtls_entropy_context ctx;
entropy_dummy_context dummy1 = { DUMMY_CONSTANT_LENGTH, chunk_size, 0 };
entropy_dummy_context dummy2 = { DUMMY_CONSTANT_LENGTH, chunk_size, 0 };
unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE] = { 0 };
int ret;
MD_PSA_INIT();
mbedtls_entropy_init(&ctx);
entropy_clear_sources(&ctx);
TEST_ASSERT(mbedtls_entropy_add_source(&ctx, entropy_dummy_source,
&dummy1, threshold,
strength1) == 0);
TEST_ASSERT(mbedtls_entropy_add_source(&ctx, entropy_dummy_source,
&dummy2, threshold,
strength2) == 0);
ret = mbedtls_entropy_func(&ctx, buf, sizeof(buf));
if (result >= 0) {
TEST_ASSERT(ret == 0);
#if defined(MBEDTLS_ENTROPY_NV_SEED)
/* If the NV seed functionality is enabled, there are two entropy
* updates: before and after updating the NV seed. */
result *= 2;
#endif
TEST_ASSERT(dummy1.calls == (size_t) result);
} else {
TEST_ASSERT(ret == result);
}
exit:
mbedtls_entropy_free(&ctx);
MD_PSA_DONE();
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_ENTROPY_NV_SEED:MBEDTLS_FS_IO */
void nv_seed_file_create()
{
unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
memset(buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE);
TEST_ASSERT(write_nv_seed(buf, MBEDTLS_ENTROPY_BLOCK_SIZE) == 0);
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_ENTROPY_NV_SEED:MBEDTLS_FS_IO:MBEDTLS_PLATFORM_NV_SEED_ALT */
void entropy_nv_seed_std_io()
{
unsigned char io_seed[MBEDTLS_ENTROPY_BLOCK_SIZE];
unsigned char check_seed[MBEDTLS_ENTROPY_BLOCK_SIZE];
memset(io_seed, 1, MBEDTLS_ENTROPY_BLOCK_SIZE);
memset(check_seed, 0, MBEDTLS_ENTROPY_BLOCK_SIZE);
mbedtls_platform_set_nv_seed(mbedtls_platform_std_nv_seed_read,
mbedtls_platform_std_nv_seed_write);
/* Check if platform NV read and write manipulate the same data */
TEST_ASSERT(write_nv_seed(io_seed, MBEDTLS_ENTROPY_BLOCK_SIZE) == 0);
TEST_ASSERT(mbedtls_nv_seed_read(check_seed, MBEDTLS_ENTROPY_BLOCK_SIZE) ==
MBEDTLS_ENTROPY_BLOCK_SIZE);
TEST_ASSERT(memcmp(io_seed, check_seed, MBEDTLS_ENTROPY_BLOCK_SIZE) == 0);
memset(check_seed, 0, MBEDTLS_ENTROPY_BLOCK_SIZE);
/* Check if platform NV write and raw read manipulate the same data */
TEST_ASSERT(mbedtls_nv_seed_write(io_seed, MBEDTLS_ENTROPY_BLOCK_SIZE) ==
MBEDTLS_ENTROPY_BLOCK_SIZE);
TEST_ASSERT(read_nv_seed(check_seed, MBEDTLS_ENTROPY_BLOCK_SIZE) == 0);
TEST_ASSERT(memcmp(io_seed, check_seed, MBEDTLS_ENTROPY_BLOCK_SIZE) == 0);
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_MD_C:MBEDTLS_ENTROPY_NV_SEED:MBEDTLS_PLATFORM_NV_SEED_ALT */
void entropy_nv_seed(data_t *read_seed)
{
#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
const mbedtls_md_info_t *md_info =
mbedtls_md_info_from_type(MBEDTLS_MD_SHA512);
#elif defined(MBEDTLS_ENTROPY_SHA256_ACCUMULATOR)
const mbedtls_md_info_t *md_info =
mbedtls_md_info_from_type(MBEDTLS_MD_SHA256);
#else
#error "Unsupported entropy accumulator"
#endif
mbedtls_md_context_t accumulator;
mbedtls_entropy_context ctx;
int (*original_mbedtls_nv_seed_read)(unsigned char *buf, size_t buf_len) =
mbedtls_nv_seed_read;
int (*original_mbedtls_nv_seed_write)(unsigned char *buf, size_t buf_len) =
mbedtls_nv_seed_write;
unsigned char header[2];
unsigned char entropy[MBEDTLS_ENTROPY_BLOCK_SIZE];
unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
unsigned char empty[MBEDTLS_ENTROPY_BLOCK_SIZE];
unsigned char check_seed[MBEDTLS_ENTROPY_BLOCK_SIZE];
unsigned char check_entropy[MBEDTLS_ENTROPY_BLOCK_SIZE];
MD_PSA_INIT();
memset(entropy, 0, MBEDTLS_ENTROPY_BLOCK_SIZE);
memset(buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE);
memset(empty, 0, MBEDTLS_ENTROPY_BLOCK_SIZE);
memset(check_seed, 2, MBEDTLS_ENTROPY_BLOCK_SIZE);
memset(check_entropy, 3, MBEDTLS_ENTROPY_BLOCK_SIZE);
// Make sure we read/write NV seed from our buffers
mbedtls_platform_set_nv_seed(buffer_nv_seed_read, buffer_nv_seed_write);
mbedtls_md_init(&accumulator);
mbedtls_entropy_init(&ctx);
entropy_clear_sources(&ctx);
TEST_ASSERT(mbedtls_entropy_add_source(&ctx, mbedtls_nv_seed_poll, NULL,
MBEDTLS_ENTROPY_BLOCK_SIZE,
MBEDTLS_ENTROPY_SOURCE_STRONG) == 0);
// Set the initial NV seed to read
TEST_ASSERT(read_seed->len >= MBEDTLS_ENTROPY_BLOCK_SIZE);
memcpy(buffer_seed, read_seed->x, MBEDTLS_ENTROPY_BLOCK_SIZE);
// Do an entropy run
TEST_ASSERT(mbedtls_entropy_func(&ctx, entropy, sizeof(entropy)) == 0);
// Determine what should have happened with manual entropy internal logic
// Init accumulator
header[1] = MBEDTLS_ENTROPY_BLOCK_SIZE;
TEST_ASSERT(mbedtls_md_setup(&accumulator, md_info, 0) == 0);
// First run for updating write_seed
header[0] = 0;
TEST_ASSERT(mbedtls_md_starts(&accumulator) == 0);
TEST_ASSERT(mbedtls_md_update(&accumulator, header, 2) == 0);
TEST_ASSERT(mbedtls_md_update(&accumulator,
read_seed->x, MBEDTLS_ENTROPY_BLOCK_SIZE) == 0);
TEST_ASSERT(mbedtls_md_finish(&accumulator, buf) == 0);
TEST_ASSERT(mbedtls_md_starts(&accumulator) == 0);
TEST_ASSERT(mbedtls_md_update(&accumulator,
buf, MBEDTLS_ENTROPY_BLOCK_SIZE) == 0);
TEST_ASSERT(mbedtls_md(md_info, buf, MBEDTLS_ENTROPY_BLOCK_SIZE,
check_seed) == 0);
// Second run for actual entropy (triggers mbedtls_entropy_update_nv_seed)
header[0] = MBEDTLS_ENTROPY_SOURCE_MANUAL;
TEST_ASSERT(mbedtls_md_update(&accumulator, header, 2) == 0);
TEST_ASSERT(mbedtls_md_update(&accumulator,
empty, MBEDTLS_ENTROPY_BLOCK_SIZE) == 0);
header[0] = 0;
TEST_ASSERT(mbedtls_md_update(&accumulator, header, 2) == 0);
TEST_ASSERT(mbedtls_md_update(&accumulator,
check_seed, MBEDTLS_ENTROPY_BLOCK_SIZE) == 0);
TEST_ASSERT(mbedtls_md_finish(&accumulator, buf) == 0);
TEST_ASSERT(mbedtls_md(md_info, buf, MBEDTLS_ENTROPY_BLOCK_SIZE,
check_entropy) == 0);
// Check result of both NV file and entropy received with the manual calculations
TEST_ASSERT(memcmp(check_seed, buffer_seed, MBEDTLS_ENTROPY_BLOCK_SIZE) == 0);
TEST_ASSERT(memcmp(check_entropy, entropy, MBEDTLS_ENTROPY_BLOCK_SIZE) == 0);
exit:
mbedtls_md_free(&accumulator);
mbedtls_entropy_free(&ctx);
mbedtls_nv_seed_read = original_mbedtls_nv_seed_read;
mbedtls_nv_seed_write = original_mbedtls_nv_seed_write;
MD_PSA_DONE();
}
/* END_CASE */
/* BEGIN_CASE depends_on:ENTROPY_HAVE_STRONG:MBEDTLS_SELF_TEST */
void entropy_selftest(int result)
{
MD_PSA_INIT();
TEST_ASSERT(mbedtls_entropy_self_test(1) == result);
exit:
MD_PSA_DONE();
}
/* END_CASE */