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repart: port to our home-grown hmac_sha256

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This reduces dependencies. The speed of the code here is uimportant, because we
hash only a tiny amount of input data.

Debian and Ubuntu currently build without repart, see
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=976959
> repart requires openssl and so far I tried to avoid linking against
> both gnutls and openssl.

Co-authored-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
This commit is contained in:
Kevin Kuehler 2021-10-20 12:21:18 +02:00 committed by Zbigniew Jędrzejewski-Szmek
parent 528da64a0c
commit ade99252e2
1 changed files with 8 additions and 15 deletions
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23
src/partition/repart.c
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@ -12,9 +12,6 @@
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <openssl/hmac.h>
#include <openssl/sha.h>
#include "sd-id128.h"
#include "alloc-util.h"
@ -38,6 +35,7 @@
#include "glyph-util.h"
#include "gpt.h"
#include "hexdecoct.h"
#include "hmac.h"
#include "id128-util.h"
#include "json.h"
#include "list.h"
@ -1519,7 +1517,7 @@ static int fdisk_set_disklabel_id_by_uuid(struct fdisk_context *c, sd_id128_t id
static int derive_uuid(sd_id128_t base, const char *token, sd_id128_t *ret) {
union {
unsigned char md[SHA256_DIGEST_LENGTH];
uint8_t md[SHA256_DIGEST_SIZE];
sd_id128_t id;
} result;
@ -1531,11 +1529,7 @@ static int derive_uuid(sd_id128_t base, const char *token, sd_id128_t *ret) {
* machine ID). We use the machine ID as key (and not as cleartext!) of the HMAC operation since it's
* the machine ID we don't want to leak. */
if (!HMAC(EVP_sha256(),
&base, sizeof(base),
(const unsigned char*) token, strlen(token),
result.md, NULL))
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "HMAC-SHA256 calculation failed.");
hmac_sha256(base.bytes, sizeof(base.bytes), token, strlen(token), result.md);
/* Take the first half, mark it as v4 UUID */
assert_cc(sizeof(result.md) == sizeof(result.id) * 2);
@ -3067,7 +3061,7 @@ static int partition_acquire_uuid(Context *context, Partition *p, sd_id128_t *re
uint64_t counter;
} _packed_ plaintext = {};
union {
unsigned char md[SHA256_DIGEST_LENGTH];
uint8_t md[SHA256_DIGEST_SIZE];
sd_id128_t id;
} result;
@ -3111,11 +3105,10 @@ static int partition_acquire_uuid(Context *context, Partition *p, sd_id128_t *re
plaintext.type_uuid = p->type_uuid;
plaintext.counter = htole64(k);
if (!HMAC(EVP_sha256(),
&context->seed, sizeof(context->seed),
(const unsigned char*) &plaintext, k == 0 ? sizeof(sd_id128_t) : sizeof(plaintext),
result.md, NULL))
return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "SHA256 calculation failed.");
hmac_sha256(context->seed.bytes, sizeof(context->seed.bytes),
&plaintext,
k == 0 ? sizeof(sd_id128_t) : sizeof(plaintext),
result.md);
/* Take the first half, mark it as v4 UUID */
assert_cc(sizeof(result.md) == sizeof(result.id) * 2);