@matheusbsbs / matheus-bagliano / commits / f6d27d2468

builtin/receive-pack: avoid hard-coded constants for push certs

Use the GIT_SHA1_RAWSZ and GIT_SHA1_HEXSZ macros instead of hard-coding the constants 20 and 40. Switch one use of 20 with a format specifier for a hex value to use the hex constant instead, as the original appears to have been a typo. At this point, avoid converting the hard-coded use of SHA-1 to use the_hash_algo. SHA-1, even if not collision resistant, is secure in the context in which it is used here, and the hash algorithm of the repo need not match what is used here. When we adopt a new hash algorithm, we can simply adopt the new algorithm wholesale here, as the nonce is opaque and its length and validity are entirely controlled by the server. Consequently, defer updating this code until that point. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

brian m. carlson committed May 2, 2018 at 00:25 UTC f6d27d2468ccf8e123f9bffde6466d673dba2317

1 file changed +3 -3

builtin/receive-pack.c

+3 -3

@@ -454,21 +454,21 @@ static void hmac_sha1(unsigned char *out,

454 /* RFC 2104 2. (6) & (7) */

455 git_SHA1_Init(&ctx);

456 git_SHA1_Update(&ctx, k_opad, sizeof(k_opad));

457 - git_SHA1_Update(&ctx, out, 20);

457 + git_SHA1_Update(&ctx, out, GIT_SHA1_RAWSZ);

458 git_SHA1_Final(out, &ctx);

459 }

460

461 static char *prepare_push_cert_nonce(const char *path, timestamp_t stamp)

462 {

463 struct strbuf buf = STRBUF_INIT;

464 - unsigned char sha1[20];

464 + unsigned char sha1[GIT_SHA1_RAWSZ];

465

466 strbuf_addf(&buf, "%s:%"PRItime, path, stamp);

467 hmac_sha1(sha1, buf.buf, buf.len, cert_nonce_seed, strlen(cert_nonce_seed));;

468 strbuf_release(&buf);

469

470 /* RFC 2104 5. HMAC-SHA1-80 */

471 - strbuf_addf(&buf, "%"PRItime"-%.*s", stamp, 20, sha1_to_hex(sha1));

471 + strbuf_addf(&buf, "%"PRItime"-%.*s", stamp, GIT_SHA1_HEXSZ, sha1_to_hex(sha1));

472 return strbuf_detach(&buf, NULL);

473 }

474