@matheusbsbs / matheus-bagliano / commits / daebaa7813

upload/receive-pack: allow hiding ref hierarchies

A repository may have refs that are only used for its internal bookkeeping purposes that should not be exposed to the others that come over the network. Teach upload-pack to omit some refs from its initial advertisement by paying attention to the uploadpack.hiderefs multi-valued configuration variable. Do the same to receive-pack via the receive.hiderefs variable. As a convenient short-hand, allow using transfer.hiderefs to set the value to both of these variables. Any ref that is under the hierarchies listed on the value of these variable is excluded from responses to requests made by "ls-remote", "fetch", etc. (for upload-pack) and "push" (for receive-pack). Because these hidden refs do not count as OUR_REF, an attempt to fetch objects at the tip of them will be rejected, and because these refs do not get advertised, "git push :" will not see local branches that have the same name as them as "matching" ones to be sent. An attempt to update/delete these hidden refs with an explicit refspec, e.g. "git push origin :refs/hidden/22", is rejected. This is not a new restriction. To the pusher, it would appear that there is no such ref, so its push request will conclude with "Now that I sent you all the data, it is time for you to update the refs. I saw that the ref did not exist when I started pushing, and I want the result to point at this commit". The receiving end will apply the compare-and-swap rule to this request and rejects the push with "Well, your update request conflicts with somebody else; I see there is such a ref.", which is the right thing to do. Otherwise a push to a hidden ref will always be "the last one wins", which is not a good default. Signed-off-by: Junio C Hamano <gitster@pobox.com>

Junio C Hamano committed Jan 18, 2013 at 16:08 UTC daebaa78137d59693a808c1f0bdec0ecb40fc12e

7 files changed +146 -1

Documentation/config.txt

+23

@@ -1845,6 +1845,15 @@ receive.denyNonFastForwards::

1845 even if that push is forced. This configuration variable is

1846 set when initializing a shared repository.

1847

1848 +receive.hiderefs::

1849 + String(s) `receive-pack` uses to decide which refs to omit

1850 + from its initial advertisement. Use more than one

1851 + definitions to specify multiple prefix strings. A ref that

1852 + are under the hierarchies listed on the value of this

1853 + variable is excluded, and is hidden when responding to `git

1854 + push`, and an attempt to update or delete a hidden ref by

1855 + `git push` is rejected.

1856 +

1857 receive.updateserverinfo::

1858 If set to true, git-receive-pack will run git-update-server-info

1859 after receiving data from git-push and updating refs.

@@ -2057,11 +2066,25 @@ transfer.fsckObjects::

2066 not set, the value of this variable is used instead.

2067 Defaults to false.

2068

2069 +transfer.hiderefs::

2070 + This variable can be used to set both `receive.hiderefs`

2071 + and `uploadpack.hiderefs` at the same time to the same

2072 + values. See entries for these other variables.

2073 +

2074 transfer.unpackLimit::

2075 When `fetch.unpackLimit` or `receive.unpackLimit` are

2076 not set, the value of this variable is used instead.

2077 The default value is 100.

2078

2079 +uploadpack.hiderefs::

2080 + String(s) `upload-pack` uses to decide which refs to omit

2081 + from its initial advertisement. Use more than one

2082 + definitions to specify multiple prefix strings. A ref that

2083 + are under the hierarchies listed on the value of this

2084 + variable is excluded, and is hidden from `git ls-remote`,

2085 + `git fetch`, etc. An attempt to fetch a hidden ref by `git

2086 + fetch` will fail.

2087 +

2088 url.<base>.insteadOf::

2089 Any URL that starts with this value will be rewritten to

2090 start, instead, with <base>. In cases where some site serves a

builtin/receive-pack.c

+24

@@ -59,6 +59,11 @@ static enum deny_action parse_deny_action(const char *var, const char *value)

60 static int receive_pack_config(const char *var, const char *value, void *cb)

61 {

62 + int status = parse_hide_refs_config(var, value, "receive");

63 +

64 + if (status)

65 + return status;

66 +

67 if (strcmp(var, "receive.denydeletes") == 0) {

68 deny_deletes = git_config_bool(var, value);

69 return 0;

@@ -119,6 +124,9 @@ static int receive_pack_config(const char *var, const char *value, void *cb)

124

125 static void show_ref(const char *path, const unsigned char *sha1)

126 {

127 + if (ref_is_hidden(path))

128 + return;

129 +

130 if (sent_capabilities)

131 packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);

132 else

@@ -688,6 +696,20 @@ static int iterate_receive_command_list(void *cb_data, unsigned char sha1[20])

696 return -1; /* end of list */

697 }

698

699 +static void reject_updates_to_hidden(struct command *commands)

700 +{

701 + struct command *cmd;

702 +

703 + for (cmd = commands; cmd; cmd = cmd->next) {

704 + if (cmd->error_string || !ref_is_hidden(cmd->ref_name))

705 + continue;

706 + if (is_null_sha1(cmd->new_sha1))

707 + cmd->error_string = "deny deleting a hidden ref";

708 + else

709 + cmd->error_string = "deny updating a hidden ref";

710 + }

711 +}

712 +

713 static void execute_commands(struct command *commands, const char *unpacker_error)

714 {

715 struct command *cmd;

@@ -704,6 +726,8 @@ static void execute_commands(struct command *commands, const char *unpacker_erro

726 0, &cmd))

727 set_connectivity_errors(commands);

728

729 + reject_updates_to_hidden(commands);

730 +

731 if (run_receive_hook(commands, pre_receive_hook, 0)) {

732 for (cmd = commands; cmd; cmd = cmd->next) {

733 if (!cmd->error_string)

refs.c

+44

@@ -3,6 +3,7 @@

3 #include "object.h"

4 #include "tag.h"

5 #include "dir.h"

6 +#include "string-list.h"

8 /*

9 * Make sure "ref" is something reasonable to have under ".git/refs/";

@@ -2556,3 +2557,46 @@ char *shorten_unambiguous_ref(const char *refname, int strict)

2557 free(short_name);

2558 return xstrdup(refname);

2559 }

2560 +

2561 +static struct string_list *hide_refs;

2562 +

2563 +int parse_hide_refs_config(const char *var, const char *value, const char *section)

2564 +{

2565 + if (!strcmp("transfer.hiderefs", var) ||

2566 + /* NEEDSWORK: use parse_config_key() once both are merged */

2567 + (!prefixcmp(var, section) && var[strlen(section)] == '.' &&

2568 + !strcmp(var + strlen(section), ".hiderefs"))) {

2569 + char *ref;

2570 + int len;

2571 +

2572 + if (!value)

2573 + return config_error_nonbool(var);

2574 + ref = xstrdup(value);

2575 + len = strlen(ref);

2576 + while (len && ref[len - 1] == '/')

2577 + ref[--len] = '\0';

2578 + if (!hide_refs) {

2579 + hide_refs = xcalloc(1, sizeof(*hide_refs));

2580 + hide_refs->strdup_strings = 1;

2581 + }

2582 + string_list_append(hide_refs, ref);

2583 + }

2584 + return 0;

2585 +}

2586 +

2587 +int ref_is_hidden(const char *refname)

2588 +{

2589 + struct string_list_item *item;

2590 +

2591 + if (!hide_refs)

2592 + return 0;

2593 + for_each_string_list_item(item, hide_refs) {

2594 + int len;

2595 + if (prefixcmp(refname, item->string))

2596 + continue;

2597 + len = strlen(item->string);

2598 + if (!refname[len] || refname[len] == '/')

2599 + return 1;

2600 + }

2601 + return 0;

2602 +}

refs.h

@@ -147,4 +147,7 @@ int update_ref(const char *action, const char *refname,

147 const unsigned char *sha1, const unsigned char *oldval,

148 int flags, enum action_on_err onerr);

149

150 +extern int parse_hide_refs_config(const char *var, const char *value, const char *);

151 +extern int ref_is_hidden(const char *);

152 +

153 #endif /* REFS_H */

t/t5512-ls-remote.sh

+12

@@ -126,4 +126,16 @@ test_expect_success 'Report match with --exit-code' '

126 test_cmp expect actual

127 '

128

129 +for configsection in transfer uploadpack

130 +do

131 + test_expect_success "Hide some refs with $configsection.hiderefs" '

132 + test_config $configsection.hiderefs refs/tags &&

133 + git ls-remote . >actual &&

134 + test_unconfig $configsection.hiderefs &&

135 + git ls-remote . |

136 + sed -e "/ refs\/tags\//d" >expect &&

137 + test_cmp expect actual

138 + '

139 +done

140 +

141 test_done

t/t5516-fetch-push.sh

+27

@@ -1037,4 +1037,31 @@ test_expect_success 'push --prune refspec' '

1037 ! check_push_result $the_first_commit tmp/foo tmp/bar

1038 '

1039

1040 +for configsection in transfer receive

1041 +do

1042 + test_expect_success "push to update a ref hidden by $configsection.hiderefs" '

1043 + mk_test heads/master hidden/one hidden/two hidden/three &&

1044 + (

1045 + cd testrepo &&

1046 + git config $configsection.hiderefs refs/hidden

1047 + ) &&

1048 +

1049 + # push to unhidden ref succeeds normally

1050 + git push testrepo master:refs/heads/master &&

1051 + check_push_result $the_commit heads/master &&

1052 +

1053 + # push to update a hidden ref should fail

1054 + test_must_fail git push testrepo master:refs/hidden/one &&

1055 + check_push_result $the_first_commit hidden/one &&

1056 +

1057 + # push to delete a hidden ref should fail

1058 + test_must_fail git push testrepo :refs/hidden/two &&

1059 + check_push_result $the_first_commit hidden/two &&

1060 +

1061 + # idempotent push to update a hidden ref should fail

1062 + test_must_fail git push testrepo $the_first_commit:refs/hidden/three &&

1063 + check_push_result $the_first_commit hidden/three

1064 + '

1065 +done

1066 +

1067 test_done

upload-pack.c

+13 -1

@@ -12,6 +12,7 @@

12 #include "run-command.h"

13 #include "sigchain.h"

14 #include "version.h"

15 +#include "string-list.h"

17 static const char upload_pack_usage[] = "git upload-pack [--strict] [--timeout=<n>] <dir>";

@@ -719,9 +720,13 @@ static void receive_needs(void)

720 free(shallows.objects);

721 }

722

723 +/* return non-zero if the ref is hidden, otherwise 0 */

724 static int mark_our_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)

725 {

726 struct object *o = lookup_unknown_object(sha1);

727 +

728 + if (ref_is_hidden(refname))

729 + return 1;

730 if (!o)

731 die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1));

732 o->flags |= OUR_REF;

@@ -736,7 +741,8 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo

741 const char *refname_nons = strip_namespace(refname);

742 unsigned char peeled[20];

743

739 - mark_our_ref(refname, sha1, flag, cb_data);

744 + if (mark_our_ref(refname, sha1, flag, cb_data))

745 + return 0;

746

747 if (capabilities)

748 packet_write(1, "%s %s%c%s%s agent=%s\n",

@@ -773,6 +779,11 @@ static void upload_pack(void)

779 }

780 }

781

782 +static int upload_pack_config(const char *var, const char *value, void *unused)

783 +{

784 + return parse_hide_refs_config(var, value, "uploadpack");

785 +}

786 +

787 int main(int argc, char **argv)

788 {

789 char *dir;

@@ -824,6 +835,7 @@ int main(int argc, char **argv)

835 die("'%s' does not appear to be a git repository", dir);

836 if (is_repository_shallow())

837 die("attempt to fetch/clone from a shallow repository");

838 + git_config(upload_pack_config, NULL);

839 if (getenv("GIT_DEBUG_SEND_PACK"))

840 debug_fd = atoi(getenv("GIT_DEBUG_SEND_PACK"));

841 upload_pack();