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bmwillgitster
bmwill
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connect: tell server that the client understands v1
Teach the connection logic to tell a serve that it understands protocol v1. This is done in 2 different ways for the builtin transports, both of which ultimately set 'GIT_PROTOCOL' to 'version=1' on the server. 1. git:// A normal request to git-daemon is structured as "command path/to/repo\0host=..\0" and due to a bug introduced in 49ba83f (Add virtualization support to git-daemon, 2006-09-19) we aren't able to place any extra arguments (separated by NULs) besides the host otherwise the parsing of those arguments would enter an infinite loop. This bug was fixed in 73bb33a (daemon: Strictly parse the "extra arg" part of the command, 2009-06-04) but a check was put in place to disallow extra arguments so that new clients wouldn't trigger this bug in older servers. In order to get around this limitation git-daemon was taught to recognize additional request arguments hidden behind a second NUL byte. Requests can then be structured like: "command path/to/repo\0host=..\0\0version=1\0key=value\0". git-daemon can then parse out the extra arguments and set 'GIT_PROTOCOL' accordingly. By placing these extra arguments behind a second NUL byte we can skirt around both the infinite loop bug in 49ba83f (Add virtualization support to git-daemon, 2006-09-19) as well as the explicit disallowing of extra arguments introduced in 73bb33a (daemon: Strictly parse the "extra arg" part of the command, 2009-06-04) because both of these versions of git-daemon check for a single NUL byte after the host argument before terminating the argument parsing. 2. ssh://, file:// Set 'GIT_PROTOCOL' environment variable with the desired protocol version. With the file:// transport, 'GIT_PROTOCOL' can be set explicitly in the locally running git-upload-pack or git-receive-pack processes. With the ssh:// transport and OpenSSH compliant ssh programs, 'GIT_PROTOCOL' can be sent across ssh by using '-o SendEnv=GIT_PROTOCOL' and having the server whitelist this environment variable. Signed-off-by: Brandon Williams <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
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‎connect.c

Lines changed: 32 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -871,6 +871,7 @@ struct child_process *git_connect(int fd[2], const char *url,
871871
printf("Diag: path=%s\n", path ? path : "NULL");
872872
conn = NULL;
873873
} else if (protocol == PROTO_GIT) {
874+
struct strbuf request = STRBUF_INIT;
874875
/*
875876
* Set up virtual host information based on where we will
876877
* connect, unless the user has overridden us in
@@ -898,13 +899,25 @@ struct child_process *git_connect(int fd[2], const char *url,
898899
* Note: Do not add any other headers here! Doing so
899900
* will cause older git-daemon servers to crash.
900901
*/
901-
packet_write_fmt(fd[1],
902-
"%s %s%chost=%s%c",
903-
prog, path, 0,
904-
target_host, 0);
902+
strbuf_addf(&request,
903+
"%s %s%chost=%s%c",
904+
prog, path, 0,
905+
target_host, 0);
906+
907+
/* If using a new version put that stuff here after a second null byte */
908+
if (get_protocol_version_config() > 0) {
909+
strbuf_addch(&request, '\0');
910+
strbuf_addf(&request, "version=%d%c",
911+
get_protocol_version_config(), '\0');
912+
}
913+
914+
packet_write(fd[1], request.buf, request.len);
915+
905916
free(target_host);
917+
strbuf_release(&request);
906918
} else {
907919
struct strbuf cmd = STRBUF_INIT;
920+
const char *const *var;
908921

909922
conn = xmalloc(sizeof(*conn));
910923
child_process_init(conn);
@@ -917,7 +930,9 @@ struct child_process *git_connect(int fd[2], const char *url,
917930
sq_quote_buf(&cmd, path);
918931

919932
/* remove repo-local variables from the environment */
920-
conn->env = local_repo_env;
933+
for (var = local_repo_env; *var; var++)
934+
argv_array_push(&conn->env_array, *var);
935+
921936
conn->use_shell = 1;
922937
conn->in = conn->out = -1;
923938
if (protocol == PROTO_SSH) {
@@ -971,6 +986,14 @@ struct child_process *git_connect(int fd[2], const char *url,
971986
}
972987

973988
argv_array_push(&conn->args, ssh);
989+
990+
if (get_protocol_version_config() > 0) {
991+
argv_array_push(&conn->args, "-o");
992+
argv_array_push(&conn->args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
993+
argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
994+
get_protocol_version_config());
995+
}
996+
974997
if (flags & CONNECT_IPV4)
975998
argv_array_push(&conn->args, "-4");
976999
else if (flags & CONNECT_IPV6)
@@ -985,6 +1008,10 @@ struct child_process *git_connect(int fd[2], const char *url,
9851008
argv_array_push(&conn->args, ssh_host);
9861009
} else {
9871010
transport_check_allowed("file");
1011+
if (get_protocol_version_config() > 0) {
1012+
argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1013+
get_protocol_version_config());
1014+
}
9881015
}
9891016
argv_array_push(&conn->args, cmd.buf);
9901017

‎t/t5700-protocol-v1.sh

Lines changed: 223 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,223 @@
1+
#!/bin/sh
2+
3+
test_description='test git wire-protocol transition'
4+
5+
TEST_NO_CREATE_REPO=1
6+
7+
. ./test-lib.sh
8+
9+
# Test protocol v1 with 'git://' transport
10+
#
11+
. "$TEST_DIRECTORY"/lib-git-daemon.sh
12+
start_git_daemon --export-all --enable=receive-pack
13+
daemon_parent=$GIT_DAEMON_DOCUMENT_ROOT_PATH/parent
14+
15+
test_expect_success 'create repo to be served by git-daemon' '
16+
git init "$daemon_parent" &&
17+
test_commit -C "$daemon_parent" one
18+
'
19+
20+
test_expect_success 'clone with git:// using protocol v1' '
21+
GIT_TRACE_PACKET=1 git -c protocol.version=1 \
22+
clone "$GIT_DAEMON_URL/parent" daemon_child 2>log &&
23+
24+
git -C daemon_child log -1 --format=%s >actual &&
25+
git -C "$daemon_parent" log -1 --format=%s >expect &&
26+
test_cmp expect actual &&
27+
28+
# Client requested to use protocol v1
29+
grep "clone> .*\\\0\\\0version=1\\\0$" log &&
30+
# Server responded using protocol v1
31+
grep "clone< version 1" log
32+
'
33+
34+
test_expect_success 'fetch with git:// using protocol v1' '
35+
test_commit -C "$daemon_parent" two &&
36+
37+
GIT_TRACE_PACKET=1 git -C daemon_child -c protocol.version=1 \
38+
fetch 2>log &&
39+
40+
git -C daemon_child log -1 --format=%s origin/master >actual &&
41+
git -C "$daemon_parent" log -1 --format=%s >expect &&
42+
test_cmp expect actual &&
43+
44+
# Client requested to use protocol v1
45+
grep "fetch> .*\\\0\\\0version=1\\\0$" log &&
46+
# Server responded using protocol v1
47+
grep "fetch< version 1" log
48+
'
49+
50+
test_expect_success 'pull with git:// using protocol v1' '
51+
GIT_TRACE_PACKET=1 git -C daemon_child -c protocol.version=1 \
52+
pull 2>log &&
53+
54+
git -C daemon_child log -1 --format=%s >actual &&
55+
git -C "$daemon_parent" log -1 --format=%s >expect &&
56+
test_cmp expect actual &&
57+
58+
# Client requested to use protocol v1
59+
grep "fetch> .*\\\0\\\0version=1\\\0$" log &&
60+
# Server responded using protocol v1
61+
grep "fetch< version 1" log
62+
'
63+
64+
test_expect_success 'push with git:// using protocol v1' '
65+
test_commit -C daemon_child three &&
66+
67+
# Push to another branch, as the target repository has the
68+
# master branch checked out and we cannot push into it.
69+
GIT_TRACE_PACKET=1 git -C daemon_child -c protocol.version=1 \
70+
push origin HEAD:client_branch 2>log &&
71+
72+
git -C daemon_child log -1 --format=%s >actual &&
73+
git -C "$daemon_parent" log -1 --format=%s client_branch >expect &&
74+
test_cmp expect actual &&
75+
76+
# Client requested to use protocol v1
77+
grep "push> .*\\\0\\\0version=1\\\0$" log &&
78+
# Server responded using protocol v1
79+
grep "push< version 1" log
80+
'
81+
82+
stop_git_daemon
83+
84+
# Test protocol v1 with 'file://' transport
85+
#
86+
test_expect_success 'create repo to be served by file:// transport' '
87+
git init file_parent &&
88+
test_commit -C file_parent one
89+
'
90+
91+
test_expect_success 'clone with file:// using protocol v1' '
92+
GIT_TRACE_PACKET=1 git -c protocol.version=1 \
93+
clone "file://$(pwd)/file_parent" file_child 2>log &&
94+
95+
git -C file_child log -1 --format=%s >actual &&
96+
git -C file_parent log -1 --format=%s >expect &&
97+
test_cmp expect actual &&
98+
99+
# Server responded using protocol v1
100+
grep "clone< version 1" log
101+
'
102+
103+
test_expect_success 'fetch with file:// using protocol v1' '
104+
test_commit -C file_parent two &&
105+
106+
GIT_TRACE_PACKET=1 git -C file_child -c protocol.version=1 \
107+
fetch 2>log &&
108+
109+
git -C file_child log -1 --format=%s origin/master >actual &&
110+
git -C file_parent log -1 --format=%s >expect &&
111+
test_cmp expect actual &&
112+
113+
# Server responded using protocol v1
114+
grep "fetch< version 1" log
115+
'
116+
117+
test_expect_success 'pull with file:// using protocol v1' '
118+
GIT_TRACE_PACKET=1 git -C file_child -c protocol.version=1 \
119+
pull 2>log &&
120+
121+
git -C file_child log -1 --format=%s >actual &&
122+
git -C file_parent log -1 --format=%s >expect &&
123+
test_cmp expect actual &&
124+
125+
# Server responded using protocol v1
126+
grep "fetch< version 1" log
127+
'
128+
129+
test_expect_success 'push with file:// using protocol v1' '
130+
test_commit -C file_child three &&
131+
132+
# Push to another branch, as the target repository has the
133+
# master branch checked out and we cannot push into it.
134+
GIT_TRACE_PACKET=1 git -C file_child -c protocol.version=1 \
135+
push origin HEAD:client_branch 2>log &&
136+
137+
git -C file_child log -1 --format=%s >actual &&
138+
git -C file_parent log -1 --format=%s client_branch >expect &&
139+
test_cmp expect actual &&
140+
141+
# Server responded using protocol v1
142+
grep "push< version 1" log
143+
'
144+
145+
# Test protocol v1 with 'ssh://' transport
146+
#
147+
test_expect_success 'setup ssh wrapper' '
148+
GIT_SSH="$GIT_BUILD_DIR/t/helper/test-fake-ssh" &&
149+
export GIT_SSH &&
150+
export TRASH_DIRECTORY &&
151+
>"$TRASH_DIRECTORY"/ssh-output
152+
'
153+
154+
expect_ssh () {
155+
test_when_finished '(cd "$TRASH_DIRECTORY" && rm -f ssh-expect && >ssh-output)' &&
156+
echo "ssh: -o SendEnv=GIT_PROTOCOL myhost $1 '$PWD/ssh_parent'" >"$TRASH_DIRECTORY/ssh-expect" &&
157+
(cd "$TRASH_DIRECTORY" && test_cmp ssh-expect ssh-output)
158+
}
159+
160+
test_expect_success 'create repo to be served by ssh:// transport' '
161+
git init ssh_parent &&
162+
test_commit -C ssh_parent one
163+
'
164+
165+
test_expect_success 'clone with ssh:// using protocol v1' '
166+
GIT_TRACE_PACKET=1 git -c protocol.version=1 \
167+
clone "ssh://myhost:$(pwd)/ssh_parent" ssh_child 2>log &&
168+
expect_ssh git-upload-pack &&
169+
170+
git -C ssh_child log -1 --format=%s >actual &&
171+
git -C ssh_parent log -1 --format=%s >expect &&
172+
test_cmp expect actual &&
173+
174+
# Server responded using protocol v1
175+
grep "clone< version 1" log
176+
'
177+
178+
test_expect_success 'fetch with ssh:// using protocol v1' '
179+
test_commit -C ssh_parent two &&
180+
181+
GIT_TRACE_PACKET=1 git -C ssh_child -c protocol.version=1 \
182+
fetch 2>log &&
183+
expect_ssh git-upload-pack &&
184+
185+
git -C ssh_child log -1 --format=%s origin/master >actual &&
186+
git -C ssh_parent log -1 --format=%s >expect &&
187+
test_cmp expect actual &&
188+
189+
# Server responded using protocol v1
190+
grep "fetch< version 1" log
191+
'
192+
193+
test_expect_success 'pull with ssh:// using protocol v1' '
194+
GIT_TRACE_PACKET=1 git -C ssh_child -c protocol.version=1 \
195+
pull 2>log &&
196+
expect_ssh git-upload-pack &&
197+
198+
git -C ssh_child log -1 --format=%s >actual &&
199+
git -C ssh_parent log -1 --format=%s >expect &&
200+
test_cmp expect actual &&
201+
202+
# Server responded using protocol v1
203+
grep "fetch< version 1" log
204+
'
205+
206+
test_expect_success 'push with ssh:// using protocol v1' '
207+
test_commit -C ssh_child three &&
208+
209+
# Push to another branch, as the target repository has the
210+
# master branch checked out and we cannot push into it.
211+
GIT_TRACE_PACKET=1 git -C ssh_child -c protocol.version=1 \
212+
push origin HEAD:client_branch 2>log &&
213+
expect_ssh git-receive-pack &&
214+
215+
git -C ssh_child log -1 --format=%s >actual &&
216+
git -C ssh_parent log -1 --format=%s client_branch >expect &&
217+
test_cmp expect actual &&
218+
219+
# Server responded using protocol v1
220+
grep "push< version 1" log
221+
'
222+
223+
test_done

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