jepler/ungeli
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Factor out nbd_decrypt_range

Browse source
This commit is contained in:
Jeff Epler 2013-11-30 10:21:55 -06:00
parent 53383590d1
commit a8dfe23a14
1 changed files with 24 additions and 18 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

42
ungeli.c
View file

@ -247,6 +247,27 @@ void test_eli_crypto_hmac() {
}
}
void eli_decrypt_range(int ifd, unsigned char *ob, uint64_t byteoffset, uint64_t count)
{
unsigned char bkey[ELI_MAXKEYLEN];
eli_key_fill(mkey, (byteoffset >> ELI_KEY_SHIFT)/ blocksize, bkey);
unsigned char biv[IVSIZE];
xtr_ivgen(biv, byteoffset);
unsigned char ib[count];
read_full(ifd, ib, count);
EVP_CIPHER_CTX ctx;
EVP_CIPHER_CTX_init(&ctx);
EVP_DecryptInit_ex(&ctx, EVP_aes_128_xts(), NULL, bkey, biv);
int out_len, final_out_len;
EVP_DecryptUpdate(&ctx, ob, &out_len, ib, count);
EVP_DecryptFinal_ex(&ctx, ob+out_len, &final_out_len);
EVP_CIPHER_CTX_cleanup(&ctx);
if((out_len + final_out_len) != count) fatal("EVP final_out_len");
}
int main(int argc, char **argv) {
test_eli_crypto_hmac();
@ -278,28 +299,13 @@ int main(int argc, char **argv) {
for(unsigned long long i=0; i<nblocks; i++)
{
unsigned char ob[blocksize];
uint64_t blockoffset = offset + i;
uint64_t byteoffset = blockoffset * blocksize;
unsigned char bkey[ELI_MAXKEYLEN];
eli_key_fill(mkey, (byteoffset >> ELI_KEY_SHIFT) / blocksize, bkey);
unsigned char biv[IVSIZE];
xtr_ivgen(biv, byteoffset);
unsigned char ib[blocksize];
read_full(ifd, ib, blocksize);
eli_decrypt_range(ifd, ob, byteoffset, blocksize);
EVP_CIPHER_CTX ctx;
EVP_CIPHER_CTX_init(&ctx);
EVP_DecryptInit_ex(&ctx, EVP_aes_128_xts(), NULL, bkey, biv);
unsigned char ob[blocksize];
int out_len, final_out_len;
EVP_DecryptUpdate(&ctx, ob, &out_len, ib, blocksize);
EVP_DecryptFinal_ex(&ctx, ob+out_len, &final_out_len);
EVP_CIPHER_CTX_cleanup(&ctx);
fprintf(stderr, "out_len=%d final_out_len=%d\n", out_len, final_out_len);
if((out_len + final_out_len) != blocksize) fatal("EVP final_out_len");
write_full(ofd, ob, blocksize);
}
return 0;