expat: add source of entropy

This commit is contained in:
Roland Dobai 2018-07-31 14:49:54 +02:00
parent 3c5af26506
commit ce3cb5c3aa
3 changed files with 83 additions and 1 deletions

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@ -5,7 +5,7 @@ COMPONENT_ADD_INCLUDEDIRS := expat/expat/lib port/include
COMPONENT_SRCDIRS := expat/expat/lib port
CFLAGS += -DHAVE_EXPAT_CONFIG_H -DXML_POOR_ENTROPY
CFLAGS += -DHAVE_EXPAT_CONFIG_H -DHAVE_GETRANDOM
# Temporary suppress "fallthrough" warnings until they are fixed in expat repo
CFLAGS += -Wno-implicit-fallthrough

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@ -0,0 +1,30 @@
// Copyright 2018 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef __SYS_RANDOM__
#define __SYS_RANDOM__
#include <sys/types.h>
#ifdef __cplusplus
extern "C" {
#endif
ssize_t getrandom(void *buf, size_t buflen, unsigned int flags);
#ifdef __cplusplus
} // extern "C"
#endif
#endif //__SYS_RANDOM__

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@ -0,0 +1,52 @@
// Copyright 2018 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <sys/random.h>
#include <sys/param.h>
#include <assert.h>
#include <errno.h>
#include <string.h>
#include "esp_system.h"
#include "esp_log.h"
static const char *TAG = "RANDOM";
ssize_t getrandom(void *buf, size_t buflen, unsigned int flags)
{
// Flags are ignored because:
// - esp_random is non-blocking so it works for both blocking and non-blocking calls,
// - don't have opportunity so set som other source of entropy.
ESP_LOGD(TAG, "getrandom(buf=0x%x, buflen=%d, flags=%u)", (int) buf, buflen, flags);
if (buf == NULL) {
errno = EFAULT;
ESP_LOGD(TAG, "getrandom returns -1 (EFAULT)");
return -1;
}
uint8_t *dst = (uint8_t *) buf;
ssize_t ret = 0;
while (ret < buflen) {
const uint32_t random = esp_random();
const int needed = buflen - ret;
const int copy_len = MIN(sizeof(random), needed);
memcpy(dst + ret, &random, copy_len);
ret += copy_len;
}
ESP_LOGD(TAG, "getrandom returns %d", ret);
return ret;
}