[PATCH v2 25/42] builtin/receive-pack: avoid hard-coded constants for push certs
- From
brian m. carlson <sandals@crustytoothpaste.net>
- Date
- May 2, 2018, 00:25 UTC
- Message-ID
- <20180502002610.915892-26-sandals@crustytoothpaste.net>
- In-Reply-To
- <20180502002610.915892-1-sandals@crustytoothpaste.net>
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> --- builtin/receive-pack.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c index 4b68a28e92..6501d6b6cf 100644 --- a/builtin/receive-pack.c +++ b/builtin/receive-pack.c @@ -454,21 +454,21 @@ 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, GIT_SHA1_RAWSZ); git_SHA1_Final(out, &ctx); } static char *prepare_push_cert_nonce(const char *path, timestamp_t stamp) { struct strbuf buf = STRBUF_INIT; - unsigned char sha1[20]; + unsigned char sha1[GIT_SHA1_RAWSZ]; strbuf_addf(&buf, "%s:%"PRItime, path, stamp); hmac_sha1(sha1, buf.buf, buf.len, cert_nonce_seed, strlen(cert_nonce_seed));; strbuf_release(&buf); /* RFC 2104 5. HMAC-SHA1-80 */ - strbuf_addf(&buf, "%"PRItime"-%.*s", stamp, 20, sha1_to_hex(sha1)); + strbuf_addf(&buf, "%"PRItime"-%.*s", stamp, GIT_SHA1_HEXSZ, sha1_to_hex(sha1)); return strbuf_detach(&buf, NULL); }