Remove un-necessarry HMAC implementation, use SDK provided implementation

This commit is contained in:
Rick Watson 2019-05-06 22:40:24 +01:00
parent 079f134aa9
commit a4220d631d
4 changed files with 36 additions and 219 deletions

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@ -6,13 +6,35 @@ void ArduinoJsonJWT::setSecret(String secret){
_secret = secret;
}
String ArduinoJsonJWT::sign(String &value) {
// create signature
Sha256.initHmac((uint8_t*) _secret.c_str(), _secret.length());
Sha256.print(value);
// trim and return
return encode(Sha256.resultHmac(), 32);
/*
* ESP32 uses mbedtls, ESP2866 uses bearssl.
*
* Both come with decent HMAC implmentations supporting sha256, as well as others.
*
* No need to pull in additional crypto libraries - lets use what we already have.
*/
String ArduinoJsonJWT::sign(String &payload) {
unsigned char hmacResult[32];
{
#if defined(ESP_PLATFORM)
mbedtls_md_context_t ctx;
mbedtls_md_type_t md_type = MBEDTLS_MD_SHA256;
mbedtls_md_init(&ctx);
mbedtls_md_setup(&ctx, mbedtls_md_info_from_type(md_type), 1);
mbedtls_md_hmac_starts(&ctx, (unsigned char *) _secret.c_str(), _secret.length());
mbedtls_md_hmac_update(&ctx, (unsigned char *) payload.c_str(), payload.length());
mbedtls_md_hmac_finish(&ctx, hmacResult);
mbedtls_md_free(&ctx);
#else
br_hmac_key_context keyCtx;
br_hmac_key_init(&keyCtx, &br_sha256_vtable, _secret.c_str(), _secret.length());
br_hmac_context hmacCtx;
br_hmac_init(&hmacCtx, &keyCtx, 0);
br_hmac_update(&hmacCtx, payload.c_str(), payload.length());
br_hmac_out(&hmacCtx, hmacResult);
#endif
}
return encode(hmacResult, 32);
}
String ArduinoJsonJWT::decode(unsigned char * value) {

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@ -1,12 +1,17 @@
#ifndef ArduinoJsonJWT_H
#define ArduinoJsonJWT_H
#include "sha256.h"
#include "base64.h"
#include <Arduino.h>
#include <ArduinoJson.h>
#if defined(ESP_PLATFORM)
#include <mbedtls/md.h>
#else
#include <bearssl/bearssl_hmac.h>
#endif
#define JWT_HEADER_SIZE 36
#define JWT_SIG_SIZE 43

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@ -1,168 +0,0 @@
#include "sha256.h"
#include <string.h>
uint32_t sha256K[] PROGMEM = {
0x428a2f98,0x71374491,0xb5c0fbcf,0xe9b5dba5,0x3956c25b,0x59f111f1,0x923f82a4,0xab1c5ed5,
0xd807aa98,0x12835b01,0x243185be,0x550c7dc3,0x72be5d74,0x80deb1fe,0x9bdc06a7,0xc19bf174,
0xe49b69c1,0xefbe4786,0x0fc19dc6,0x240ca1cc,0x2de92c6f,0x4a7484aa,0x5cb0a9dc,0x76f988da,
0x983e5152,0xa831c66d,0xb00327c8,0xbf597fc7,0xc6e00bf3,0xd5a79147,0x06ca6351,0x14292967,
0x27b70a85,0x2e1b2138,0x4d2c6dfc,0x53380d13,0x650a7354,0x766a0abb,0x81c2c92e,0x92722c85,
0xa2bfe8a1,0xa81a664b,0xc24b8b70,0xc76c51a3,0xd192e819,0xd6990624,0xf40e3585,0x106aa070,
0x19a4c116,0x1e376c08,0x2748774c,0x34b0bcb5,0x391c0cb3,0x4ed8aa4a,0x5b9cca4f,0x682e6ff3,
0x748f82ee,0x78a5636f,0x84c87814,0x8cc70208,0x90befffa,0xa4506ceb,0xbef9a3f7,0xc67178f2
};
#define BUFFER_SIZE 64
uint8_t sha256InitState[] PROGMEM = {
0x67,0xe6,0x09,0x6a, // H0
0x85,0xae,0x67,0xbb, // H1
0x72,0xf3,0x6e,0x3c, // H2
0x3a,0xf5,0x4f,0xa5, // H3
0x7f,0x52,0x0e,0x51, // H4
0x8c,0x68,0x05,0x9b, // H5
0xab,0xd9,0x83,0x1f, // H6
0x19,0xcd,0xe0,0x5b // H7
};
void Sha256Class::init(void) {
memcpy_P(state.b,sha256InitState,32);
byteCount = 0;
bufferOffset = 0;
}
uint32_t Sha256Class::ror32(uint32_t number, uint8_t bits) {
return ((number << (32-bits)) | (number >> bits));
}
void Sha256Class::hashBlock() {
uint8_t i;
uint32_t a,b,c,d,e,f,g,h,t1,t2;
a=state.w[0];
b=state.w[1];
c=state.w[2];
d=state.w[3];
e=state.w[4];
f=state.w[5];
g=state.w[6];
h=state.w[7];
for (i=0; i<64; i++) {
if (i>=16) {
t1 = buffer.w[i&15] + buffer.w[(i-7)&15];
t2 = buffer.w[(i-2)&15];
t1 += ror32(t2,17) ^ ror32(t2,19) ^ (t2>>10);
t2 = buffer.w[(i-15)&15];
t1 += ror32(t2,7) ^ ror32(t2,18) ^ (t2>>3);
buffer.w[i&15] = t1;
}
t1 = h;
t1 += ror32(e,6) ^ ror32(e,11) ^ ror32(e,25); // ∑1(e)
t1 += g ^ (e & (g ^ f)); // Ch(e,f,g)
t1 += pgm_read_dword(sha256K+i); // Ki
t1 += buffer.w[i&15]; // Wi
t2 = ror32(a,2) ^ ror32(a,13) ^ ror32(a,22); // ∑0(a)
t2 += ((b & c) | (a & (b | c))); // Maj(a,b,c)
h=g; g=f; f=e; e=d+t1; d=c; c=b; b=a; a=t1+t2;
}
state.w[0] += a;
state.w[1] += b;
state.w[2] += c;
state.w[3] += d;
state.w[4] += e;
state.w[5] += f;
state.w[6] += g;
state.w[7] += h;
}
void Sha256Class::addUncounted(uint8_t data) {
buffer.b[bufferOffset ^ 3] = data;
bufferOffset++;
if (bufferOffset == BUFFER_SIZE) {
hashBlock();
bufferOffset = 0;
}
}
size_t Sha256Class::write(uint8_t data) {
++byteCount;
addUncounted(data);
return 1;
}
void Sha256Class::pad() {
// Implement SHA-256 padding (fips180-2 §5.1.1)
// Pad with 0x80 followed by 0x00 until the end of the block
addUncounted(0x80);
while (bufferOffset != 56) addUncounted(0x00);
// Append length in the last 8 bytes
addUncounted(0); // We're only using 32 bit lengths
addUncounted(0); // But SHA-1 supports 64 bit lengths
addUncounted(0); // So zero pad the top bits
addUncounted(byteCount >> 29); // Shifting to multiply by 8
addUncounted(byteCount >> 21); // as SHA-1 supports bitstreams as well as
addUncounted(byteCount >> 13); // byte.
addUncounted(byteCount >> 5);
addUncounted(byteCount << 3);
}
uint8_t* Sha256Class::result(void) {
// Pad to complete the last block
pad();
// Swap byte order back
for (int i=0; i<8; i++) {
uint32_t a,b;
a=state.w[i];
b=a<<24;
b|=(a<<8) & 0x00ff0000;
b|=(a>>8) & 0x0000ff00;
b|=a>>24;
state.w[i]=b;
}
// Return pointer to hash (20 characters)
return state.b;
}
#define HMAC_IPAD 0x36
#define HMAC_OPAD 0x5c
uint8_t keyBuffer[BLOCK_LENGTH]; // K0 in FIPS-198a
uint8_t innerHash[HASH_LENGTH];
void Sha256Class::initHmac(const uint8_t* key, int keyLength) {
uint8_t i;
memset(keyBuffer,0,BLOCK_LENGTH);
if (keyLength > BLOCK_LENGTH) {
// Hash long keys
init();
for (;keyLength--;) write(*key++);
memcpy(keyBuffer,result(),HASH_LENGTH);
} else {
// Block length keys are used as is
memcpy(keyBuffer,key,keyLength);
}
// Start inner hash
init();
for (i=0; i<BLOCK_LENGTH; i++) {
write(keyBuffer[i] ^ HMAC_IPAD);
}
}
uint8_t* Sha256Class::resultHmac(void) {
uint8_t i;
// Complete inner hash
memcpy(innerHash,result(),HASH_LENGTH);
// Calculate outer hash
init();
for (i=0; i<BLOCK_LENGTH; i++) write(keyBuffer[i] ^ HMAC_OPAD);
for (i=0; i<HASH_LENGTH; i++) write(innerHash[i]);
return result();
}
Sha256Class Sha256;

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@ -1,42 +0,0 @@
#ifndef Sha256_h
#define Sha256_h
#include <inttypes.h>
#include "Print.h"
#define HASH_LENGTH 32
#define BLOCK_LENGTH 64
union _buffer {
uint8_t b[BLOCK_LENGTH];
uint32_t w[BLOCK_LENGTH/4];
};
union _state {
uint8_t b[HASH_LENGTH];
uint32_t w[HASH_LENGTH/4];
};
class Sha256Class : public Print
{
public:
void init(void);
void initHmac(const uint8_t* secret, int secretLength);
uint8_t* result(void);
uint8_t* resultHmac(void);
virtual size_t write(uint8_t);
using Print::write;
private:
void pad();
void addUncounted(uint8_t data);
void hashBlock();
uint32_t ror32(uint32_t number, uint8_t bits);
_buffer buffer;
uint8_t bufferOffset;
_state state;
uint32_t byteCount;
uint8_t keyBuffer[BLOCK_LENGTH];
uint8_t innerHash[HASH_LENGTH];
};
extern Sha256Class Sha256;
#endif