remote-curl: error on incomplete packet

Currently, remote-curl acts as a proxy and blindly forwards packets
between an HTTP server and fetch-pack. In the case of a stateless RPC
connection where the connection is terminated with a partially written
packet, remote-curl will blindly send the partially written packet
before waiting on more input from fetch-pack. Meanwhile, fetch-pack will
read the partial packet and continue reading, expecting more input. This
results in a deadlock between the two processes.

For a stateless connection, inspect packets before sending them and
error out if a packet line packet is incomplete.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

5 files changed, 50 insertions, 0 deletions

diff --git a/t/lib-httpd.sh b/t/lib-httpd.sh
index 1449ee9..d2edfa4 100644
--- a/t/lib-httpd.sh
+++ b/t/lib-httpd.sh
@@ -129,6 +129,8 @@ install_script () {
 prepare_httpd() {
 	mkdir -p "$HTTPD_DOCUMENT_ROOT_PATH"
 	cp "$TEST_PATH"/passwd "$HTTPD_ROOT_PATH"
+	install_script incomplete-length-upload-pack-v2-http.sh
+	install_script incomplete-body-upload-pack-v2-http.sh
 	install_script broken-smart-http.sh
 	install_script error-smart-http.sh
 	install_script error.sh
diff --git a/t/lib-httpd/apache.conf b/t/lib-httpd/apache.conf
index 994e529..afa91e3 100644
--- a/t/lib-httpd/apache.conf
+++ b/t/lib-httpd/apache.conf
@@ -117,6 +117,8 @@ Alias /auth/dumb/ www/auth/dumb/
 	SetEnv GIT_EXEC_PATH ${GIT_EXEC_PATH}
 	SetEnv GIT_HTTP_EXPORT_ALL
 </LocationMatch>
+ScriptAlias /smart/incomplete_length/git-upload-pack incomplete-length-upload-pack-v2-http.sh/
+ScriptAlias /smart/incomplete_body/git-upload-pack incomplete-body-upload-pack-v2-http.sh/
 ScriptAliasMatch /error_git_upload_pack/(.*)/git-upload-pack error.sh/
 ScriptAliasMatch /smart_*[^/]*/(.*) ${GIT_EXEC_PATH}/git-http-backend/$1
 ScriptAlias /broken_smart/ broken-smart-http.sh/
@@ -126,6 +128,12 @@ ScriptAliasMatch /one_time_perl/(.*) apply-one-time-perl.sh/$1
 <Directory ${GIT_EXEC_PATH}>
 	Options FollowSymlinks
 </Directory>
+<Files incomplete-length-upload-pack-v2-http.sh>
+	Options ExecCGI
+</Files>
+<Files incomplete-body-upload-pack-v2-http.sh>
+	Options ExecCGI
+</Files>
 <Files broken-smart-http.sh>
 	Options ExecCGI
 </Files>
diff --git a/t/lib-httpd/incomplete-body-upload-pack-v2-http.sh b/t/lib-httpd/incomplete-body-upload-pack-v2-http.sh
new file mode 100644
index 0000000..90e73ef
--- /dev/null
+++ b/t/lib-httpd/incomplete-body-upload-pack-v2-http.sh
@@ -0,0 +1,3 @@
+printf "Content-Type: text/%s\n" "application/x-git-upload-pack-result"
+echo
+printf "%s%s" "0079" "45"
diff --git a/t/lib-httpd/incomplete-length-upload-pack-v2-http.sh b/t/lib-httpd/incomplete-length-upload-pack-v2-http.sh
new file mode 100644
index 0000000..dce552e
--- /dev/null
+++ b/t/lib-httpd/incomplete-length-upload-pack-v2-http.sh
@@ -0,0 +1,3 @@
+printf "Content-Type: text/%s\n" "application/x-git-upload-pack-result"
+echo
+printf "%s" "00"
diff --git a/t/t5702-protocol-v2.sh b/t/t5702-protocol-v2.sh
index 5039e66..4eb81ba 100755
--- a/t/t5702-protocol-v2.sh
+++ b/t/t5702-protocol-v2.sh
@@ -586,6 +586,40 @@ test_expect_success 'clone with http:// using protocol v2' '
 	! grep "Send header: Transfer-Encoding: chunked" log
 '
 
+test_expect_success 'clone repository with http:// using protocol v2 with incomplete pktline length' '
+	test_when_finished "rm -f log" &&
+
+	git init "$HTTPD_DOCUMENT_ROOT_PATH/incomplete_length" &&
+	test_commit -C "$HTTPD_DOCUMENT_ROOT_PATH/incomplete_length" file &&
+
+	test_must_fail env GIT_TRACE_PACKET="$(pwd)/log" GIT_TRACE_CURL="$(pwd)/log" git -c protocol.version=2 \
+		clone "$HTTPD_URL/smart/incomplete_length" incomplete_length_child 2>err &&
+
+	# Client requested to use protocol v2
+	grep "Git-Protocol: version=2" log &&
+	# Server responded using protocol v2
+	grep "git< version 2" log &&
+	# Client reported appropriate failure
+	test_i18ngrep "bytes of length header were received" err
+'
+
+test_expect_success 'clone repository with http:// using protocol v2 with incomplete pktline body' '
+	test_when_finished "rm -f log" &&
+
+	git init "$HTTPD_DOCUMENT_ROOT_PATH/incomplete_body" &&
+	test_commit -C "$HTTPD_DOCUMENT_ROOT_PATH/incomplete_body" file &&
+
+	test_must_fail env GIT_TRACE_PACKET="$(pwd)/log" GIT_TRACE_CURL="$(pwd)/log" git -c protocol.version=2 \
+		clone "$HTTPD_URL/smart/incomplete_body" incomplete_body_child 2>err &&
+
+	# Client requested to use protocol v2
+	grep "Git-Protocol: version=2" log &&
+	# Server responded using protocol v2
+	grep "git< version 2" log &&
+	# Client reported appropriate failure
+	test_i18ngrep "bytes of body are still expected" err
+'
+
 test_expect_success 'clone big repository with http:// using protocol v2' '
 	test_when_finished "rm -f log" &&