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Code Issues Releases Wiki Activity

Fix ChaCha20 usage.

pull/2/head
Christopher Wellons 2017-03-03 13:35:48 -05:00
parent 41f92082aa
commit c74a3c27a5
2 changed files with 14 additions and 7 deletions
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2
chacha.h
View File

@ -3,6 +3,8 @@
#include "machine.h" #include "machine.h"
#define CHACHA_BLOCKLENGTH 64
typedef struct { typedef struct {
u32 input[16]; u32 input[16];
} chacha_ctx; } chacha_ctx;

19
enchive.c
View File

@ -9,8 +9,6 @@
#include "chacha.h" #include "chacha.h"
#include "optparse.h" #include "optparse.h"
#define BUFSIZE (16 * 4096)
int curve25519_donna(u8 *p, const u8 *s, const u8 *b); int curve25519_donna(u8 *p, const u8 *s, const u8 *b);
static void static void
@ -65,7 +63,7 @@ compute_shared(u8 *sh, const u8 *s, const u8 *p)
static void static void
symmetric_encrypt(FILE *in, FILE *out, u8 *key, u8 *iv) symmetric_encrypt(FILE *in, FILE *out, u8 *key, u8 *iv)
{ {
static u8 buffer[2][BUFSIZE]; static u8 buffer[2][CHACHA_BLOCKLENGTH * 1024];
u8 sha256[SHA256_BLOCK_SIZE]; u8 sha256[SHA256_BLOCK_SIZE];
SHA256_CTX hash[1]; SHA256_CTX hash[1];
chacha_ctx ctx[1]; chacha_ctx ctx[1];
@ -84,6 +82,8 @@ symmetric_encrypt(FILE *in, FILE *out, u8 *key, u8 *iv)
chacha_encrypt_bytes(ctx, buffer[0], buffer[1], z); chacha_encrypt_bytes(ctx, buffer[0], buffer[1], z);
if (!fwrite(buffer[1], z, 1, out)) if (!fwrite(buffer[1], z, 1, out))
fatal("error writing ciphertext file"); fatal("error writing ciphertext file");
if (z < sizeof(buffer[0]))
break;
} }
sha256_final(hash, sha256); sha256_final(hash, sha256);
@ -96,7 +96,7 @@ symmetric_encrypt(FILE *in, FILE *out, u8 *key, u8 *iv)
static void static void
symmetric_decrypt(FILE *in, FILE *out, u8 *key, u8 *iv) symmetric_decrypt(FILE *in, FILE *out, u8 *key, u8 *iv)
{ {
static u8 buffer[2][BUFSIZE]; static u8 buffer[2][CHACHA_BLOCKLENGTH * 1024 + SHA224_BLOCK_SIZE];
u8 sha256[SHA256_BLOCK_SIZE]; u8 sha256[SHA256_BLOCK_SIZE];
SHA256_CTX hash[1]; SHA256_CTX hash[1];
chacha_ctx ctx[1]; chacha_ctx ctx[1];
@ -111,6 +111,7 @@ symmetric_decrypt(FILE *in, FILE *out, u8 *key, u8 *iv)
else else
fatal("ciphertext file too short"); fatal("ciphertext file too short");
} }
for (;;) { for (;;) {
u8 *p = buffer[0] + SHA224_BLOCK_SIZE; u8 *p = buffer[0] + SHA224_BLOCK_SIZE;
size_t z = fread(p, 1, sizeof(buffer[0]) - SHA224_BLOCK_SIZE, in); size_t z = fread(p, 1, sizeof(buffer[0]) - SHA224_BLOCK_SIZE, in);
@ -122,17 +123,21 @@ symmetric_decrypt(FILE *in, FILE *out, u8 *key, u8 *iv)
chacha_encrypt_bytes(ctx, buffer[0], buffer[1], z); chacha_encrypt_bytes(ctx, buffer[0], buffer[1], z);
sha256_update(hash, buffer[1], z); sha256_update(hash, buffer[1], z);
if (!fwrite(buffer[1], z, 1, out)) if (!fwrite(buffer[1], z, 1, out))
fatal("error writing destination file"); fatal("error writing plaintext file");
/* Move last SHA224_BLOCK_SIZE bytes to the front. */ /* Move last SHA224_BLOCK_SIZE bytes to the front. */
memmove(buffer[0], buffer[0] + z, SHA224_BLOCK_SIZE); memmove(buffer[0], buffer[0] + z, SHA224_BLOCK_SIZE);
if (z < sizeof(buffer[0]) - SHA224_BLOCK_SIZE)
break;
} }
if (fflush(out))
fatal("error flushing to destination");
sha256_final(hash, sha256); sha256_final(hash, sha256);
if (memcmp(buffer[0], sha256, SHA224_BLOCK_SIZE) != 0) if (memcmp(buffer[0], sha256, SHA224_BLOCK_SIZE) != 0)
fatal("checksum mismatch!"); fatal("checksum mismatch!");
if (fflush(out))
fatal("error flushing to plaintext file");
} }
static void static void