esp-idf/components/esp_http_client/lib/http_auth.c
Harshit Malpani 803ad150cf
feat(esp_http_client): SHA256 support in digest auth
Added support for using SHA256 algorithm while calculating
digest auth in HTTP client connection

Closes https://github.com/espressif/esp-idf/issues/12383
2023-12-15 11:32:57 +05:30

226 lines
6.6 KiB
C

/*
* SPDX-FileCopyrightText: 2015-2021 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <stdarg.h>
#include "sys/socket.h"
#include "esp_rom_md5.h"
#include "esp_tls_crypto.h"
#include "mbedtls/sha256.h"
#include "esp_log.h"
#include "esp_check.h"
#include "http_utils.h"
#include "http_auth.h"
#define MD5_MAX_LEN (33)
#define SHA256_LEN (32)
#define SHA256_HEX_LEN (65)
#define HTTP_AUTH_BUF_LEN (1024)
static const char *TAG = "HTTP_AUTH";
/**
* @brief This function hash a formatted string with MD5 and format the result as ascii characters
*
* @param md The buffer will hold the ascii result
* @param[in] fmt The format
*
* @return Length of the result
*/
static int md5_printf(char *md, const char *fmt, ...)
{
unsigned char *buf;
unsigned char digest[MD5_MAX_LEN];
int len, i;
md5_context_t md5_ctx;
va_list ap;
va_start(ap, fmt);
len = vasprintf((char **)&buf, fmt, ap);
if (buf == NULL) {
va_end(ap);
return ESP_FAIL;
}
esp_rom_md5_init(&md5_ctx);
esp_rom_md5_update(&md5_ctx, buf, len);
esp_rom_md5_final(digest, &md5_ctx);
for (i = 0; i < 16; ++i) {
sprintf(&md[i * 2], "%02x", (unsigned int)digest[i]);
}
va_end(ap);
free(buf);
return MD5_MAX_LEN;
}
/**
* @brief This function hash a formatted string with SHA256 and format the result as ascii characters
*
* @param sha The buffer will hold the ascii result
* @param[in] fmt The format
*
* @return Length of the result
*/
static int sha256_sprintf(char *sha, const char *fmt, ...)
{
unsigned char *buf;
unsigned char digest[SHA256_LEN];
int len, i;
va_list ap;
va_start(ap, fmt);
len = vasprintf((char **)&buf, fmt, ap);
if (buf == NULL) {
va_end(ap);
return ESP_FAIL;
}
int ret = 0;
mbedtls_sha256_context sha256;
mbedtls_sha256_init(&sha256);
if (mbedtls_sha256_starts(&sha256, 0) != 0) {
goto exit;
}
if (mbedtls_sha256_update(&sha256, buf, len) != 0) {
goto exit;
}
if (mbedtls_sha256_finish(&sha256, digest) != 0) {
goto exit;
}
for (i = 0; i < 32; ++i) {
sprintf(&sha[i * 2], "%02x", (unsigned int)digest[i]);
}
sha[SHA256_HEX_LEN - 1] = '\0';
ret = SHA256_HEX_LEN;
exit:
free(buf);
mbedtls_sha256_free(&sha256);
va_end(ap);
return ret;
}
char *http_auth_digest(const char *username, const char *password, esp_http_auth_data_t *auth_data)
{
char *ha1, *ha2 = NULL;
char *digest = NULL;
char *auth_str = NULL;
char *temp_auth_str = NULL;
esp_err_t ret = ESP_OK;
if (username == NULL ||
password == NULL ||
auth_data->nonce == NULL ||
auth_data->uri == NULL ||
auth_data->realm == NULL) {
return NULL;
}
int digest_size = MD5_MAX_LEN;
int (*digest_func)(char *digest, const char *fmt, ...) = md5_printf;
if (!memcmp(auth_data->algorithm, "SHA256", strlen("SHA256")) ||
!memcmp(auth_data->algorithm, "SHA-256", strlen("SHA-256"))) {
digest_size = SHA256_HEX_LEN;
digest_func = sha256_sprintf;
}
ha1 = calloc(1, digest_size);
ESP_GOTO_ON_FALSE(ha1, ESP_FAIL, _digest_exit, TAG, "Memory exhausted");
ha2 = calloc(1, digest_size);
ESP_GOTO_ON_FALSE(ha2, ESP_FAIL, _digest_exit, TAG, "Memory exhausted");
digest = calloc(1, digest_size);
ESP_GOTO_ON_FALSE(digest, ESP_FAIL, _digest_exit, TAG, "Memory exhausted");
if (digest_func(ha1, "%s:%s:%s", username, auth_data->realm, password) <= 0) {
goto _digest_exit;
}
ESP_LOGD(TAG, "%s %s %s %s", "Digest", username, auth_data->realm, password);
if ((strcasecmp(auth_data->algorithm, "md5-sess") == 0) ||
(strcasecmp(auth_data->algorithm, "SHA256") == 0) ||
(strcasecmp(auth_data->algorithm, "md5-sess") == 0)) {
if (digest_func(ha1, "%s:%s:%016llx", ha1, auth_data->nonce, auth_data->cnonce) <= 0) {
goto _digest_exit;
}
}
if (digest_func(ha2, "%s:%s", auth_data->method, auth_data->uri) <= 0) {
goto _digest_exit;
}
//support qop = auth
if (auth_data->qop && strcasecmp(auth_data->qop, "auth-int") == 0) {
if (digest_func(ha2, "%s:%s", ha2, "entity") <= 0) {
goto _digest_exit;
}
}
if (auth_data->qop) {
// response=digest_func(HA1:nonce:nonceCount:cnonce:qop:HA2)
if (digest_func(digest, "%s:%s:%08x:%016llx:%s:%s", ha1, auth_data->nonce, auth_data->nc, auth_data->cnonce, auth_data->qop, ha2) <= 0) {
goto _digest_exit;
}
} else {
// response=digest_func(HA1:nonce:HA2)
if (digest_func(digest, "%s:%s:%s", ha1, auth_data->nonce, ha2) <= 0) {
goto _digest_exit;
}
}
int rc = asprintf(&auth_str, "Digest username=\"%s\", realm=\"%s\", nonce=\"%s\", uri=\"%s\", algorithm=%s, "
"response=\"%s\", qop=%s, nc=%08x, cnonce=\"%016"PRIx64"\"",
username, auth_data->realm, auth_data->nonce, auth_data->uri, auth_data->algorithm, digest, auth_data->qop, auth_data->nc, auth_data->cnonce);
if (rc < 0) {
ESP_LOGE(TAG, "asprintf() returned: %d", rc);
ret = ESP_FAIL;
goto _digest_exit;
}
if (auth_data->opaque) {
rc = asprintf(&temp_auth_str, "%s, opaque=\"%s\"", auth_str, auth_data->opaque);
// Free the previous memory allocated for `auth_str`
free(auth_str);
if (rc < 0) {
ESP_LOGE(TAG, "asprintf() returned: %d", rc);
ret = ESP_FAIL;
goto _digest_exit;
}
auth_str = temp_auth_str;
}
_digest_exit:
free(ha1);
free(ha2);
free(digest);
return (ret == ESP_OK) ? auth_str : NULL;
}
char *http_auth_basic(const char *username, const char *password)
{
size_t out;
char *user_info = NULL;
char *digest = NULL;
esp_err_t ret = ESP_OK;
size_t n = 0;
if (asprintf(&user_info, "%s:%s", username, password) < 0) {
return NULL;
}
ESP_RETURN_ON_FALSE(user_info, NULL, TAG, "Memory exhausted");
esp_crypto_base64_encode(NULL, 0, &n, (const unsigned char *)user_info, strlen(user_info));
digest = calloc(1, 6 + n + 1);
ESP_GOTO_ON_FALSE(digest, ESP_FAIL, _basic_exit, TAG, "Memory exhausted");
strcpy(digest, "Basic ");
esp_crypto_base64_encode((unsigned char *)digest + 6, n, &out, (const unsigned char *)user_info, strlen(user_info));
_basic_exit:
free(user_info);
return (ret == ESP_OK) ? digest : NULL;
}