mirrors
/
enchive
mirror of https://github.com/skeeto/enchive.git
1
0
Fork 0
Code Issues Releases Wiki Activity

Add authentication checksum.

pull/2/head
Christopher Wellons 2017-03-03 11:22:36 -05:00
parent 813413d151
commit 5b50281100
5 changed files with 250 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
Makefile
View File

@ -3,13 +3,14 @@
CC = cc
CFLAGS = -ansi -pedantic -Wall -Wextra -O3 -g3
objects = enchive.o chacha.o curve25519-donna.o
objects = enchive.o chacha.o curve25519-donna.o sha256.o
enchive: $(objects)
$(CC) $(LDFLAGS) -o $@ $(objects) $(LDLIBS)
enchive.o: enchive.c
chacha.o: chacha.c
curve25519-donna.o: curve25519-donna.c
sha256.o: sha256.c
clean:
rm -f enchive $(objects)

58
enchive.c
View File

@ -4,8 +4,9 @@
#include <stdarg.h>
#define OPTPARSE_IMPLEMENTATION
#include "optparse.h"
#include "sha256.h"
#include "chacha.h"
#include "optparse.h"
int curve25519_donna(u8 *p, const u8 *s, const u8 *b);
@ -57,9 +58,12 @@ static void
symmetric_encrypt(FILE *in, FILE *out, u8 *key, u8 *iv)
{
static u8 buffer[2][64 * 1024];
u8 sha256[SHA256_BLOCK_SIZE];
SHA256_CTX hash[1];
chacha_ctx ctx[1];
chacha_keysetup(ctx, key, 256);
chacha_ivsetup(ctx, iv);
sha256_init(hash);
for (;;) {
size_t z = fread(buffer[0], 1, sizeof(buffer[0]), in);
@ -68,10 +72,60 @@ symmetric_encrypt(FILE *in, FILE *out, u8 *key, u8 *iv)
fatal("error reading source file");
break;
}
sha256_update(hash, buffer[0], z);
chacha_encrypt_bytes(ctx, buffer[0], buffer[1], z);
if (!fwrite(buffer[1], z, 1, out))
fatal("error writing destination file");
}
sha256_final(hash, sha256);
if (!fwrite(sha256, SHA224_BLOCK_SIZE, 1, out))
fatal("error writing checksum to destination file");
if (fflush(out))
fatal("error flushing to destination");
}
static void
symmetric_decrypt(FILE *in, FILE *out, u8 *key, u8 *iv)
{
static u8 buffer[2][64 * 1024];
u8 sha256[SHA256_BLOCK_SIZE];
SHA256_CTX hash[1];
chacha_ctx ctx[1];
chacha_keysetup(ctx, key, 256);
chacha_ivsetup(ctx, iv);
sha256_init(hash);
/* Always keep SHA224_BLOCK_SIZE bytes in the buffer. */
if (!(fread(buffer[0], SHA224_BLOCK_SIZE, 1, in))) {
if (ferror(in))
fatal("error initially reading source file");
else
fatal("source file missing checksum");
}
for (;;) {
u8 *p = buffer[0] + SHA224_BLOCK_SIZE;
size_t z = fread(p, 1, sizeof(buffer[0]) - SHA224_BLOCK_SIZE, in);
if (!z) {
if (ferror(in))
fatal("error reading source file");
break;
}
chacha_encrypt_bytes(ctx, buffer[0], buffer[1], z);
sha256_update(hash, buffer[1], z);
if (!fwrite(buffer[1], z, 1, out))
fatal("error writing destination file");
/* Move last SHA224_BLOCK_SIZE bytes to the front. */
memmove(buffer[0], buffer[0] + z, SHA224_BLOCK_SIZE);
}
if (fflush(out))
fatal("error flushing to destination");
sha256_final(hash, sha256);
if (memcmp(buffer[0], sha256, SHA224_BLOCK_SIZE) != 0)
fatal("checksum mismatch!");
}
static const char *
@ -193,7 +247,7 @@ command_extract(struct optparse *options)
if (!(fread(epublic, sizeof(epublic), 1, stdin)))
fatal("failed to read ephemeral key from archive");
compute_shared(shared, secret, epublic);
symmetric_encrypt(stdin, stdout, shared, iv);
symmetric_decrypt(stdin, stdout, shared, iv);
}
static void

1
machine.h
View File

@ -9,6 +9,7 @@
typedef uint8_t u8;
typedef uint16_t u16;
typedef uint32_t u32;
typedef uint64_t u64;
typedef int32_t s32;
typedef int64_t limb;

158
sha256.c Normal file
View File

@ -0,0 +1,158 @@
/*********************************************************************
* Filename: sha256.c
* Author: Brad Conte (brad AT bradconte.com)
* Copyright:
* Disclaimer: This code is presented "as is" without any guarantees.
* Details: Implementation of the SHA-256 hashing algorithm.
SHA-256 is one of the three algorithms in the SHA2
specification. The others, SHA-384 and SHA-512, are not
offered in this implementation.
Algorithm specification can be found here:
* http://csrc.nist.gov/publications/fips/fips180-2/fips180-2withchangenotice.pdf
This implementation uses little endian byte order.
*********************************************************************/
/*************************** HEADER FILES ***************************/
#include <stdlib.h>
#include <memory.h>
#include "sha256.h"
/****************************** MACROS ******************************/
#define ROTLEFT(a,b) (((a) << (b)) | ((a) >> (32-(b))))
#define ROTRIGHT(a,b) (((a) >> (b)) | ((a) << (32-(b))))
#define CH(x,y,z) (((x) & (y)) ^ (~(x) & (z)))
#define MAJ(x,y,z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
#define EP0(x) (ROTRIGHT(x,2) ^ ROTRIGHT(x,13) ^ ROTRIGHT(x,22))
#define EP1(x) (ROTRIGHT(x,6) ^ ROTRIGHT(x,11) ^ ROTRIGHT(x,25))
#define SIG0(x) (ROTRIGHT(x,7) ^ ROTRIGHT(x,18) ^ ((x) >> 3))
#define SIG1(x) (ROTRIGHT(x,17) ^ ROTRIGHT(x,19) ^ ((x) >> 10))
/**************************** VARIABLES *****************************/
static const u32 k[64] = {
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
};
/*********************** FUNCTION DEFINITIONS ***********************/
void sha256_transform(SHA256_CTX *ctx, const u8 data[])
{
u32 a, b, c, d, e, f, g, h, i, j, t1, t2, m[64];
for (i = 0, j = 0; i < 16; ++i, j += 4)
m[i] = (data[j] << 24) | (data[j + 1] << 16) | (data[j + 2] << 8) | (data[j + 3]);
for ( ; i < 64; ++i)
m[i] = SIG1(m[i - 2]) + m[i - 7] + SIG0(m[i - 15]) + m[i - 16];
a = ctx->state[0];
b = ctx->state[1];
c = ctx->state[2];
d = ctx->state[3];
e = ctx->state[4];
f = ctx->state[5];
g = ctx->state[6];
h = ctx->state[7];
for (i = 0; i < 64; ++i) {
t1 = h + EP1(e) + CH(e,f,g) + k[i] + m[i];
t2 = EP0(a) + MAJ(a,b,c);
h = g;
g = f;
f = e;
e = d + t1;
d = c;
c = b;
b = a;
a = t1 + t2;
}
ctx->state[0] += a;
ctx->state[1] += b;
ctx->state[2] += c;
ctx->state[3] += d;
ctx->state[4] += e;
ctx->state[5] += f;
ctx->state[6] += g;
ctx->state[7] += h;
}
void sha256_init(SHA256_CTX *ctx)
{
ctx->datalen = 0;
ctx->bitlen = 0;
ctx->state[0] = 0x6a09e667;
ctx->state[1] = 0xbb67ae85;
ctx->state[2] = 0x3c6ef372;
ctx->state[3] = 0xa54ff53a;
ctx->state[4] = 0x510e527f;
ctx->state[5] = 0x9b05688c;
ctx->state[6] = 0x1f83d9ab;
ctx->state[7] = 0x5be0cd19;
}
void sha256_update(SHA256_CTX *ctx, const u8 data[], size_t len)
{
u32 i;
for (i = 0; i < len; ++i) {
ctx->data[ctx->datalen] = data[i];
ctx->datalen++;
if (ctx->datalen == 64) {
sha256_transform(ctx, ctx->data);
ctx->bitlen += 512;
ctx->datalen = 0;
}
}
}
void sha256_final(SHA256_CTX *ctx, u8 hash[])
{
u32 i;
i = ctx->datalen;
/* Pad whatever data is left in the buffer. */
if (ctx->datalen < 56) {
ctx->data[i++] = 0x80;
while (i < 56)
ctx->data[i++] = 0x00;
}
else {
ctx->data[i++] = 0x80;
while (i < 64)
ctx->data[i++] = 0x00;
sha256_transform(ctx, ctx->data);
memset(ctx->data, 0, 56);
}
/* Append to the padding the total message's length in bits and transform. */
ctx->bitlen += ctx->datalen * 8;
ctx->data[63] = ctx->bitlen;
ctx->data[62] = ctx->bitlen >> 8;
ctx->data[61] = ctx->bitlen >> 16;
ctx->data[60] = ctx->bitlen >> 24;
ctx->data[59] = ctx->bitlen >> 32;
ctx->data[58] = ctx->bitlen >> 40;
ctx->data[57] = ctx->bitlen >> 48;
ctx->data[56] = ctx->bitlen >> 56;
sha256_transform(ctx, ctx->data);
/* Since this implementation uses little endian byte ordering and SHA uses big endian, */
/* reverse all the bytes when copying the final state to the output hash. */
for (i = 0; i < 4; ++i) {
hash[i] = (ctx->state[0] >> (24 - i * 8)) & 0x000000ff;
hash[i + 4] = (ctx->state[1] >> (24 - i * 8)) & 0x000000ff;
hash[i + 8] = (ctx->state[2] >> (24 - i * 8)) & 0x000000ff;
hash[i + 12] = (ctx->state[3] >> (24 - i * 8)) & 0x000000ff;
hash[i + 16] = (ctx->state[4] >> (24 - i * 8)) & 0x000000ff;
hash[i + 20] = (ctx->state[5] >> (24 - i * 8)) & 0x000000ff;
hash[i + 24] = (ctx->state[6] >> (24 - i * 8)) & 0x000000ff;
hash[i + 28] = (ctx->state[7] >> (24 - i * 8)) & 0x000000ff;
}
}

33
sha256.h Normal file
View File

@ -0,0 +1,33 @@
/*********************************************************************
* Filename: sha256.h
* Author: Brad Conte (brad AT bradconte.com)
* Copyright:
* Disclaimer: This code is presented "as is" without any guarantees.
* Details: Defines the API for the corresponding SHA1 implementation.
*********************************************************************/
#ifndef SHA256_H
#define SHA256_H
#include <stddef.h>
#include "machine.h"
#define SHA224_BLOCK_SIZE 28
#define SHA256_BLOCK_SIZE 32
typedef unsigned char BYTE;
typedef unsigned int WORD;
typedef struct {
u8 data[64];
u32 datalen;
u64 bitlen;
u32 state[8];
} SHA256_CTX;
void sha256_init(SHA256_CTX *ctx);
void sha256_update(SHA256_CTX *ctx, const u8 data[], size_t len);
void sha256_final(SHA256_CTX *ctx, u8 hash[]);
#endif /* SHA256_H */