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Simplify zero-length buffers to always be NULL

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Since it is implementation-dependent whether
malloc(0) returns NULL or a pointer, explicitly
represent zero-length buffers as NULL in the
buffer-copy struct, so as to have a uniform
behaviour.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
This commit is contained in:
David Horstmann 2023-11-01 14:46:02 +00:00
parent 03b0472413
commit 0fee689e57
2 changed files with 20 additions and 2 deletions
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10
library/psa_crypto.c
View File

@ -8473,6 +8473,16 @@ psa_status_t psa_crypto_alloc_and_copy(const uint8_t *input, size_t input_len,
* on any pointers safely. */ * on any pointers safely. */
memset(buffers, 0, sizeof(*buffers)); memset(buffers, 0, sizeof(*buffers));
/* Since calloc() may return NULL if we try to allocate zero-length
* buffers anyway, deal with this corner case explicitly to ensure
* predictable behaviour. Represent zero-length buffers as NULL. */
if (input_len == 0) {
input = NULL;
}
if (output_len == 0) {
output = NULL;
}
if (output != NULL) { if (output != NULL) {
buffers->output = mbedtls_calloc(output_len, 1); buffers->output = mbedtls_calloc(output_len, 1);
if (buffers->output == NULL) { if (buffers->output == NULL) {

12
tests/suites/test_suite_psa_crypto.function
View File

@ -10430,8 +10430,16 @@ void psa_crypto_alloc_and_copy_zero_length(int input_zero_length,
&buffer_copies); &buffer_copies);
TEST_EQUAL(ret, PSA_SUCCESS); TEST_EQUAL(ret, PSA_SUCCESS);
TEST_MEMORY_COMPARE(input_buffer, input_len, buffer_copies.input, buffer_copies.input_len); if (input_zero_length) {
TEST_EQUAL(output_len, buffer_copies.output_len); TEST_ASSERT(buffer_copies.input == NULL);
} else {
TEST_MEMORY_COMPARE(input_buffer, input_len, buffer_copies.input, buffer_copies.input_len);
}
if (output_zero_length) {
TEST_ASSERT(buffer_copies.output == NULL);
} else {
TEST_EQUAL(output_len, buffer_copies.output_len);
}
exit: exit:
mbedtls_free(buffer_copies.input); mbedtls_free(buffer_copies.input);