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Refactor platform cryptography, add tests

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This commit is contained in:
Jonathan Bennett
2024-08-10 22:38:05 -05:00
parent b573e0eacc
commit 1cfd5d12d2
11 changed files with 88 additions and 276 deletions
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42
src/mesh/CryptoEngine.cpp
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@@ -1,6 +1,7 @@
#include "CryptoEngine.h"
#include "NodeDB.h"
#include "RadioInterface.h"
#include "architecture.h"
#include "configuration.h"
#if !(MESHTASTIC_EXCLUDE_PKI)
@@ -188,14 +189,44 @@ void CryptoEngine::setKey(const CryptoKey &k)
*
* @param bytes is updated in place
*/
void CryptoEngine::encrypt(uint32_t fromNode, uint64_t packetId, size_t numBytes, uint8_t *bytes)
void CryptoEngine::encryptPacket(uint32_t fromNode, uint64_t packetId, size_t numBytes, uint8_t *bytes)
{
LOG_WARN("noop encryption!\n");
if (key.length > 0) {
initNonce(fromNode, packetId);
if (numBytes <= MAX_BLOCKSIZE) {
encryptAESCtr(key, nonce, numBytes, bytes);
} else {
LOG_ERROR("Packet too large for crypto engine: %d. noop encryption!\n", numBytes);
}
}
}
void CryptoEngine::decrypt(uint32_t fromNode, uint64_t packetId, size_t numBytes, uint8_t *bytes)
{
LOG_WARN("noop decryption!\n");
// For CTR, the implementation is the same
encryptPacket(fromNode, packetId, numBytes, bytes);
}
// Generic implementation of AES-CTR encryption.
void CryptoEngine::encryptAESCtr(CryptoKey _key, uint8_t *_nonce, size_t numBytes, uint8_t *bytes)
{
if (ctr) {
delete ctr;
ctr = nullptr;
}
if (_key.length == 16)
ctr = new CTR<AES128>();
else
ctr = new CTR<AES256>();
ctr->setKey(_key.bytes, _key.length);
static uint8_t scratch[MAX_BLOCKSIZE];
memcpy(scratch, bytes, numBytes);
memset(scratch + numBytes, 0,
sizeof(scratch) - numBytes); // Fill rest of buffer with zero (in case cypher looks at it)
ctr->setIV(_nonce, 16);
ctr->setCounterSize(4);
ctr->encrypt(bytes, scratch, numBytes);
}
/**
@@ -208,4 +239,7 @@ void CryptoEngine::initNonce(uint32_t fromNode, uint64_t packetId)
// use memcpy to avoid breaking strict-aliasing
memcpy(nonce, &packetId, sizeof(uint64_t));
memcpy(nonce + sizeof(uint64_t), &fromNode, sizeof(uint32_t));
}
}
#ifndef HAS_CUSTOM_CRYPTO_ENGINE
CryptoEngine *crypto = new CryptoEngine;
#endif