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| author | Junio C Hamano <gitster@pobox.com> | 2014-09-25 10:51:39 -0700 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2014-09-25 11:17:46 -0700 |
| commit | 2e35c0d646c433bdddade3fec92ecc1f0c4c39f9 (patch) | |
| tree | dbc4a2f08a495d92851740f741be2a03368523b7 | |
| parent | 21c48f1472b0dd6e31dcdc416da5e6709a3d88b9 (diff) | |
| download | git-jc/push-cert-hmac-optim.tar.gz | |
receive-pack: truncate hmac early and convert only necessary bytesjc/push-cert-hmac-optim
Instead of copying out 20-bytes of HMAC, format it into 40-bytes of
hex and then chomping it to 20-bytes output when generating a nonce,
copy out only HMAC_TRUNCATE (=10) bytes, convert it to text using
the new bin_to_hex() helper to do the same.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
| -rw-r--r-- | builtin/receive-pack.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c index 42f25a5103..e0e7c75811 100644 --- a/builtin/receive-pack.c +++ b/builtin/receive-pack.c @@ -287,6 +287,7 @@ static int copy_to_sideband(int in, int out, void *arg) } #define HMAC_BLOCK_SIZE 64 +#define HMAC_TRUNCATE 10 /* in bytes */ static void hmac_sha1(unsigned char *out, const char *key_in, size_t key_len, @@ -323,21 +324,23 @@ static void hmac_sha1(unsigned char *out, /* RFC 2104 2. (6) & (7) */ git_SHA1_Init(&ctx); git_SHA1_Update(&ctx, k_opad, sizeof(k_opad)); - git_SHA1_Update(&ctx, out, 20); + git_SHA1_Update(&ctx, out, HMAC_TRUNCATE); git_SHA1_Final(out, &ctx); } static char *prepare_push_cert_nonce(const char *path, unsigned long stamp) { struct strbuf buf = STRBUF_INIT; - unsigned char sha1[20]; + unsigned char hmac[HMAC_TRUNCATE]; + char hmac_trunc[HMAC_TRUNCATE * 2 + 1]; strbuf_addf(&buf, "%s:%lu", path, stamp); - hmac_sha1(sha1, buf.buf, buf.len, cert_nonce_seed, strlen(cert_nonce_seed));; + hmac_sha1(hmac, buf.buf, buf.len, cert_nonce_seed, strlen(cert_nonce_seed));; strbuf_release(&buf); /* RFC 2104 5. HMAC-SHA1-80 */ - strbuf_addf(&buf, "%lu-%.*s", stamp, 20, sha1_to_hex(sha1)); + bin_to_hex(hmac, HMAC_TRUNCATE, hmac_trunc); + strbuf_addf(&buf, "%lu-%s", stamp, hmac_trunc); return strbuf_detach(&buf, NULL); } |