Merge branch 'rs/plug-leak-in-bundle'
[gitweb.git] / builtin / receive-pack.c
index 431af393358a9e5693e8a89b10fdd9ed3f9e5939..f2f6c67359cb5941c2d57b6692ce1fbbc86edccc 100644 (file)
@@ -1,4 +1,5 @@
 #include "builtin.h"
+#include "lockfile.h"
 #include "pack.h"
 #include "refs.h"
 #include "pkt-line.h"
@@ -17,6 +18,7 @@
 #include "version.h"
 #include "tag.h"
 #include "gpg-interface.h"
+#include "sigchain.h"
 
 static const char receive_pack_usage[] = "git receive-pack <git-dir>";
 
@@ -43,15 +45,27 @@ static int prefer_ofs_delta = 1;
 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)
 {
@@ -135,8 +149,11 @@ static int receive_pack_config(const char *var, const char *value, void *cb)
                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;
        }
 
@@ -157,8 +174,8 @@ static void show_ref(const char *path, const unsigned char *sha1)
                              "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);
@@ -271,6 +288,168 @@ static int copy_to_sideband(int in, int out, void *arg)
        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;
@@ -305,6 +484,7 @@ static void prepare_push_cert_sha1(struct child_process *proc)
 
                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));
@@ -313,7 +493,13 @@ static void prepare_push_cert_sha1(struct child_process *proc)
                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;
        }
 }
@@ -321,7 +507,7 @@ static void prepare_push_cert_sha1(struct child_process *proc)
 typedef int (*feed_fn)(void *, const char **, size_t *);
 static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_state)
 {
-       struct child_process proc;
+       struct child_process proc = CHILD_PROCESS_INIT;
        struct async muxer;
        const char *argv[2];
        int code;
@@ -332,7 +518,6 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_sta
 
        argv[1] = NULL;
 
-       memset(&proc, 0, sizeof(proc));
        proc.argv = argv;
        proc.in = -1;
        proc.stdout_to_stderr = 1;
@@ -356,6 +541,8 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_sta
                return code;
        }
 
+       sigchain_push(SIGPIPE, SIG_IGN);
+
        while (1) {
                const char *buf;
                size_t n;
@@ -367,6 +554,9 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed, void *feed_sta
        close(proc.in);
        if (use_sideband)
                finish_async(&muxer);
+
+       sigchain_pop(SIGPIPE);
+
        return finish_command(&proc);
 }
 
@@ -418,7 +608,7 @@ static int run_receive_hook(struct command *commands, const char *hook_name,
 static int run_update_hook(struct command *cmd)
 {
        const char *argv[5];
-       struct child_process proc;
+       struct child_process proc = CHILD_PROCESS_INIT;
        int code;
 
        argv[0] = find_hook("update");
@@ -430,7 +620,6 @@ static int run_update_hook(struct command *cmd)
        argv[3] = sha1_to_hex(cmd->new_sha1);
        argv[4] = NULL;
 
-       memset(&proc, 0, sizeof(proc));
        proc.no_stdin = 1;
        proc.stdout_to_stderr = 1;
        proc.err = use_sideband ? -1 : 0;
@@ -543,7 +732,6 @@ static const char *update(struct command *cmd, struct shallow_info *si)
        const char *namespaced_name;
        unsigned char *old_sha1 = cmd->old_sha1;
        unsigned char *new_sha1 = cmd->new_sha1;
-       struct ref_lock *lock;
 
        /* only refs/... are allowed */
        if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
@@ -644,19 +832,27 @@ static const char *update(struct command *cmd, struct shallow_info *si)
                return NULL; /* good */
        }
        else {
+               struct strbuf err = STRBUF_INIT;
+               struct ref_transaction *transaction;
+
                if (shallow_update && si->shallow_ref[cmd->index] &&
                    update_shallow_ref(cmd, si))
                        return "shallow error";
 
-               lock = lock_any_ref_for_update(namespaced_name, old_sha1,
-                                              0, NULL);
-               if (!lock) {
-                       rp_error("failed to lock %s", name);
-                       return "failed to lock";
-               }
-               if (write_ref_sha1(lock, new_sha1, "push")) {
-                       return "failed to write"; /* error() already called */
+               transaction = ref_transaction_begin(&err);
+               if (!transaction ||
+                   ref_transaction_update(transaction, namespaced_name,
+                                          new_sha1, old_sha1, 0, 1, &err) ||
+                   ref_transaction_commit(transaction, "push", &err)) {
+                       ref_transaction_free(transaction);
+
+                       rp_error("%s", err.buf);
+                       strbuf_release(&err);
+                       return "failed to update ref";
                }
+
+               ref_transaction_free(transaction);
+               strbuf_release(&err);
                return NULL; /* good */
        }
 }
@@ -666,7 +862,7 @@ static void run_update_post_hook(struct command *commands)
        struct command *cmd;
        int argc;
        const char **argv;
-       struct child_process proc;
+       struct child_process proc = CHILD_PROCESS_INIT;
        char *hook;
 
        hook = find_hook("post-update");
@@ -689,7 +885,6 @@ static void run_update_post_hook(struct command *commands)
        }
        argv[argc] = NULL;
 
-       memset(&proc, 0, sizeof(proc));
        proc.no_stdin = 1;
        proc.stdout_to_stderr = 1;
        proc.err = use_sideband ? -1 : 0;
@@ -1039,7 +1234,7 @@ static const char *unpack(int err_fd, struct shallow_info *si)
        const char *hdr_err;
        int status;
        char hdr_arg[38];
-       struct child_process child;
+       struct child_process child = CHILD_PROCESS_INIT;
        int fsck_objects = (receive_fsck_objects >= 0
                            ? receive_fsck_objects
                            : transfer_fsck_objects >= 0
@@ -1061,7 +1256,6 @@ static const char *unpack(int err_fd, struct shallow_info *si)
                argv_array_pushl(&av, "--shallow-file", alt_shallow_file, NULL);
        }
 
-       memset(&child, 0, sizeof(child));
        if (ntohl(hdr.hdr_entries) < unpack_limit) {
                argv_array_pushl(&av, "unpack-objects", hdr_arg, NULL);
                if (quiet)
@@ -1248,9 +1442,7 @@ static int delete_only(struct command *commands)
 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;
@@ -1283,19 +1475,21 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 
                        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;
@@ -1340,5 +1534,6 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
                packet_flush(1);
        sha1_array_clear(&shallow);
        sha1_array_clear(&ref);
+       free((void *)push_cert_nonce);
        return 0;
 }