static int auto_update_server_info;
static int auto_gc = 1;
static int fix_thin = 1;
+static int stateless_rpc;
+static const char *service_dir;
static const char *head_name;
static void *head_name_to_free;
static int sent_capabilities;
static int shallow_update;
static const char *alt_shallow_file;
-static int accept_push_cert = 1;
static struct strbuf push_cert = STRBUF_INIT;
static unsigned char push_cert_sha1[20];
static struct signature_check sigcheck;
+static const char *push_cert_nonce;
+static const char *cert_nonce_seed;
+
+static const char *NONCE_UNSOLICITED = "UNSOLICITED";
+static const char *NONCE_BAD = "BAD";
+static const char *NONCE_MISSING = "MISSING";
+static const char *NONCE_OK = "OK";
+static const char *NONCE_SLOP = "SLOP";
+static const char *nonce_status;
+static long nonce_stamp_slop;
+static unsigned long nonce_stamp_slop_limit;
static enum deny_action parse_deny_action(const char *var, const char *value)
{
return 0;
}
- if (strcmp(var, "receive.acceptpushcert") == 0) {
- accept_push_cert = git_config_bool(var, value);
+ if (strcmp(var, "receive.certnonceseed") == 0)
+ return git_config_string(&cert_nonce_seed, var, value);
+
+ if (strcmp(var, "receive.certnonceslop") == 0) {
+ nonce_stamp_slop_limit = git_config_ulong(var, value);
return 0;
}
"report-status delete-refs side-band-64k quiet");
if (prefer_ofs_delta)
strbuf_addstr(&cap, " ofs-delta");
- if (accept_push_cert)
- strbuf_addstr(&cap, " push-cert");
+ if (push_cert_nonce)
+ strbuf_addf(&cap, " push-cert=%s", push_cert_nonce);
strbuf_addf(&cap, " agent=%s", git_user_agent_sanitized());
packet_write(1, "%s %s%c%s\n",
sha1_to_hex(sha1), path, 0, cap.buf);
return 0;
}
+#define HMAC_BLOCK_SIZE 64
+
+static void hmac_sha1(unsigned char *out,
+ const char *key_in, size_t key_len,
+ const char *text, size_t text_len)
+{
+ unsigned char key[HMAC_BLOCK_SIZE];
+ unsigned char k_ipad[HMAC_BLOCK_SIZE];
+ unsigned char k_opad[HMAC_BLOCK_SIZE];
+ int i;
+ git_SHA_CTX ctx;
+
+ /* RFC 2104 2. (1) */
+ memset(key, '\0', HMAC_BLOCK_SIZE);
+ if (HMAC_BLOCK_SIZE < key_len) {
+ git_SHA1_Init(&ctx);
+ git_SHA1_Update(&ctx, key_in, key_len);
+ git_SHA1_Final(key, &ctx);
+ } else {
+ memcpy(key, key_in, key_len);
+ }
+
+ /* RFC 2104 2. (2) & (5) */
+ for (i = 0; i < sizeof(key); i++) {
+ k_ipad[i] = key[i] ^ 0x36;
+ k_opad[i] = key[i] ^ 0x5c;
+ }
+
+ /* RFC 2104 2. (3) & (4) */
+ git_SHA1_Init(&ctx);
+ git_SHA1_Update(&ctx, k_ipad, sizeof(k_ipad));
+ git_SHA1_Update(&ctx, text, text_len);
+ git_SHA1_Final(out, &ctx);
+
+ /* 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_Final(out, &ctx);
+}
+
+static char *prepare_push_cert_nonce(const char *path, unsigned long stamp)
+{
+ struct strbuf buf = STRBUF_INIT;
+ unsigned char sha1[20];
+
+ strbuf_addf(&buf, "%s:%lu", 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, "%lu-%.*s", stamp, 20, sha1_to_hex(sha1));
+ return strbuf_detach(&buf, NULL);
+}
+
+/*
+ * NEEDSWORK: reuse find_commit_header() from jk/commit-author-parsing
+ * after dropping "_commit" from its name and possibly moving it out
+ * of commit.c
+ */
+static char *find_header(const char *msg, size_t len, const char *key)
+{
+ int key_len = strlen(key);
+ const char *line = msg;
+
+ while (line && line < msg + len) {
+ const char *eol = strchrnul(line, '\n');
+
+ if ((msg + len <= eol) || line == eol)
+ return NULL;
+ if (line + key_len < eol &&
+ !memcmp(line, key, key_len) && line[key_len] == ' ') {
+ int offset = key_len + 1;
+ return xmemdupz(line + offset, (eol - line) - offset);
+ }
+ line = *eol ? eol + 1 : NULL;
+ }
+ return NULL;
+}
+
+static const char *check_nonce(const char *buf, size_t len)
+{
+ char *nonce = find_header(buf, len, "nonce");
+ unsigned long stamp, ostamp;
+ char *bohmac, *expect = NULL;
+ const char *retval = NONCE_BAD;
+
+ if (!nonce) {
+ retval = NONCE_MISSING;
+ goto leave;
+ } else if (!push_cert_nonce) {
+ retval = NONCE_UNSOLICITED;
+ goto leave;
+ } else if (!strcmp(push_cert_nonce, nonce)) {
+ retval = NONCE_OK;
+ goto leave;
+ }
+
+ if (!stateless_rpc) {
+ /* returned nonce MUST match what we gave out earlier */
+ retval = NONCE_BAD;
+ goto leave;
+ }
+
+ /*
+ * In stateless mode, we may be receiving a nonce issued by
+ * another instance of the server that serving the same
+ * repository, and the timestamps may not match, but the
+ * nonce-seed and dir should match, so we can recompute and
+ * report the time slop.
+ *
+ * In addition, when a nonce issued by another instance has
+ * timestamp within receive.certnonceslop seconds, we pretend
+ * as if we issued that nonce when reporting to the hook.
+ */
+
+ /* nonce is concat(<seconds-since-epoch>, "-", <hmac>) */
+ if (*nonce <= '0' || '9' < *nonce) {
+ retval = NONCE_BAD;
+ goto leave;
+ }
+ stamp = strtoul(nonce, &bohmac, 10);
+ if (bohmac == nonce || bohmac[0] != '-') {
+ retval = NONCE_BAD;
+ goto leave;
+ }
+
+ expect = prepare_push_cert_nonce(service_dir, stamp);
+ if (strcmp(expect, nonce)) {
+ /* Not what we would have signed earlier */
+ retval = NONCE_BAD;
+ goto leave;
+ }
+
+ /*
+ * By how many seconds is this nonce stale? Negative value
+ * would mean it was issued by another server with its clock
+ * skewed in the future.
+ */
+ ostamp = strtoul(push_cert_nonce, NULL, 10);
+ nonce_stamp_slop = (long)ostamp - (long)stamp;
+
+ if (nonce_stamp_slop_limit &&
+ abs(nonce_stamp_slop) <= nonce_stamp_slop_limit) {
+ /*
+ * Pretend as if the received nonce (which passes the
+ * HMAC check, so it is not a forged by third-party)
+ * is what we issued.
+ */
+ free((void *)push_cert_nonce);
+ push_cert_nonce = xstrdup(nonce);
+ retval = NONCE_OK;
+ } else {
+ retval = NONCE_SLOP;
+ }
+
+leave:
+ free(nonce);
+ free(expect);
+ return retval;
+}
+
static void prepare_push_cert_sha1(struct child_process *proc)
{
static int already_done;
strbuf_release(&gpg_output);
strbuf_release(&gpg_status);
+ nonce_status = check_nonce(push_cert.buf, bogs);
}
if (!is_null_sha1(push_cert_sha1)) {
argv_array_pushf(&env, "GIT_PUSH_CERT=%s", sha1_to_hex(push_cert_sha1));
argv_array_pushf(&env, "GIT_PUSH_CERT_KEY=%s",
sigcheck.key ? sigcheck.key : "");
argv_array_pushf(&env, "GIT_PUSH_CERT_STATUS=%c", sigcheck.result);
-
+ if (push_cert_nonce) {
+ argv_array_pushf(&env, "GIT_PUSH_CERT_NONCE=%s", push_cert_nonce);
+ argv_array_pushf(&env, "GIT_PUSH_CERT_NONCE_STATUS=%s", nonce_status);
+ if (nonce_status == NONCE_SLOP)
+ argv_array_pushf(&env, "GIT_PUSH_CERT_NONCE_SLOP=%ld",
+ nonce_stamp_slop);
+ }
proc->env = env.argv;
}
}
int cmd_receive_pack(int argc, const char **argv, const char *prefix)
{
int advertise_refs = 0;
- int stateless_rpc = 0;
int i;
- const char *dir = NULL;
struct command *commands;
struct sha1_array shallow = SHA1_ARRAY_INIT;
struct sha1_array ref = SHA1_ARRAY_INIT;
usage(receive_pack_usage);
}
- if (dir)
+ if (service_dir)
usage(receive_pack_usage);
- dir = arg;
+ service_dir = arg;
}
- if (!dir)
+ if (!service_dir)
usage(receive_pack_usage);
setup_path();
- if (!enter_repo(dir, 0))
- die("'%s' does not appear to be a git repository", dir);
+ if (!enter_repo(service_dir, 0))
+ die("'%s' does not appear to be a git repository", service_dir);
git_config(receive_pack_config, NULL);
+ if (cert_nonce_seed)
+ push_cert_nonce = prepare_push_cert_nonce(service_dir, time(NULL));
if (0 <= transfer_unpack_limit)
unpack_limit = transfer_unpack_limit;
packet_flush(1);
sha1_array_clear(&shallow);
sha1_array_clear(&ref);
+ free((void *)push_cert_nonce);
return 0;
}