Add allocate and copy style output buffer handling
Add a new macro `LOCAL_OUTPUT_ALLOC_WITH_COPY` to support the output buffer
handling of the multipart operations like `psa_cipher_update`. This will
allocate a local buffer and copy the content of the original buffer.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 00e4f2a..05467bd 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -182,6 +182,23 @@
} \
output_copy = LOCAL_OUTPUT_COPY_OF_##output.buffer;
+/* Allocate a copy of the buffer output and set the pointer output_copy to
+ * point to the start of the copy.
+ *
+ * Assumptions:
+ * - psa_status_t status exists
+ * - An exit label is declared
+ * - output is the name of a pointer to the buffer to be copied
+ * - LOCAL_OUTPUT_DECLARE(output, output_copy) has previously been called
+ */
+#define LOCAL_OUTPUT_ALLOC_WITH_COPY(output, length, output_copy) \
+ status = psa_crypto_local_output_alloc_with_copy(output, length, \
+ &LOCAL_OUTPUT_COPY_OF_##output); \
+ if (status != PSA_SUCCESS) { \
+ goto exit; \
+ } \
+ output_copy = LOCAL_OUTPUT_COPY_OF_##output.buffer;
+
/* Free the local output copy allocated previously by LOCAL_OUTPUT_ALLOC()
* after first copying back its contents to the original buffer.
*
@@ -5783,6 +5800,39 @@
return PSA_SUCCESS;
}
+psa_status_t psa_crypto_local_output_alloc_with_copy(uint8_t *output, size_t output_len,
+ psa_crypto_local_output_t *local_output)
+{
+ psa_status_t status;
+ *local_output = PSA_CRYPTO_LOCAL_OUTPUT_INIT;
+
+ if (output_len == 0) {
+ return PSA_SUCCESS;
+ }
+ local_output->buffer = mbedtls_calloc(output_len, 1);
+ if (local_output->buffer == NULL) {
+ /* Since we dealt with the zero-length case above, we know that
+ * a NULL return value means a failure of allocation. */
+ return PSA_ERROR_INSUFFICIENT_MEMORY;
+ }
+ local_output->length = output_len;
+ local_output->original = output;
+
+ status = psa_crypto_copy_input(output, output_len,
+ local_output->buffer, local_output->length);
+ if (status != PSA_SUCCESS) {
+ goto error;
+ }
+
+ return PSA_SUCCESS;
+
+error:
+ mbedtls_free(local_output->buffer);
+ local_output->buffer = NULL;
+ local_output->length = 0;
+ return status;
+}
+
psa_status_t psa_crypto_local_output_free(psa_crypto_local_output_t *local_output)
{
psa_status_t status;
diff --git a/library/psa_crypto_core.h b/library/psa_crypto_core.h
index 4731064..ae8af09 100644
--- a/library/psa_crypto_core.h
+++ b/library/psa_crypto_core.h
@@ -560,6 +560,25 @@
psa_status_t psa_crypto_local_output_alloc(uint8_t *output, size_t output_len,
psa_crypto_local_output_t *local_output);
+/** Allocate a local copy of an output buffer and copy the contents into it.
+ *
+ * \note This allocates and copies a buffer
+ * whose contents will be copied back to the
+ * original in a future call to
+ * psa_crypto_local_output_free().
+ *
+ * \param[in] output Pointer to output buffer.
+ * \param[in] output_len Length of the output buffer.
+ * \param[out] local_output Pointer to a psa_crypto_local_output_t struct to
+ * populate with the local output copy.
+ * \return #PSA_SUCCESS, if the buffer was successfully
+ * copied.
+ * \return #PSA_ERROR_INSUFFICIENT_MEMORY, if a copy of
+ * the buffer cannot be allocated.
+ */
+psa_status_t psa_crypto_local_output_alloc_with_copy(uint8_t *output, size_t output_len,
+ psa_crypto_local_output_t *local_output);
+
/** Copy from a local copy of an output buffer back to the original, then
* free the local copy.
*