credential: add WWW-Authenticate header to cred requests

mjcheetham · gitster · commit 026012ce26e8 · 2023-01-20T16:04:00.000-08:00
Add the value of the WWW-Authenticate response header to credential requests. Credential helpers that understand and support HTTP authentication and authorization can use this standard header (RFC 2616 Section 14.47 [1]) to generate valid credentials. WWW-Authenticate headers can contain information pertaining to the authority, authentication mechanism, or extra parameters/scopes that are required. The current I/O format for credential helpers only allows for unique names for properties/attributes, so in order to transmit multiple header values (with a specific order) we introduce a new convention whereby a C-style array syntax is used in the property name to denote multiple ordered values for the same property. In this case we send multiple `wwwauth[]` properties where the order that the repeated attributes appear in the conversation reflects the order that the WWW-Authenticate headers appeared in the HTTP response. Add a set of tests to exercise the HTTP authentication header parsing and the interop with credential helpers. Credential helpers will receive WWW-Authenticate information in credential requests. [1] https://datatracker.ietf.org/doc/html/rfc2616#section-14.47 Signed-off-by: Matthew John Cheetham <mjcheetham@outlook.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/git-credential.txt b/Documentation/git-credential.txt
@@ -113,7 +113,13 @@ separated by an `=` (equals) sign, followed by a newline.
 The key may contain any bytes except `=`, newline, or NUL. The value may
 contain any bytes except newline or NUL.
 
-In both cases, all bytes are treated as-is (i.e., there is no quoting,
+Attributes with keys that end with C-style array brackets `[]` can have
+multiple values. Each instance of a multi-valued attribute forms an
+ordered list of values - the order of the repeated attributes defines
+the order of the values. An empty multi-valued attribute (`key[]=\n`)
+acts to clear any previous entries and reset the list.
+
+In all cases, all bytes are treated as-is (i.e., there is no quoting,
 and one cannot transmit a value with newline or NUL in it). The list of
 attributes is terminated by a blank line or end-of-file.
 
@@ -160,6 +166,17 @@ empty string.
 Components which are missing from the URL (e.g., there is no
 username in the example above) will be left unset.
 
+`wwwauth[]`::
+
+	When an HTTP response is received by Git that includes one or more
+	'WWW-Authenticate' authentication headers, these will be passed by Git
+	to credential helpers.
++
+Each 'WWW-Authenticate' header value is passed as a multi-valued
+attribute 'wwwauth[]', where the order of the attributes is the same as
+they appear in the HTTP response. This attribute is 'one-way' from Git
+to pass additional information to credential helpers.
+
 Unrecognised attributes are silently discarded.
 
 GIT
diff --git a/credential.c b/credential.c
@@ -263,13 +263,24 @@ static void credential_write_item(FILE *fp, const char *key, const char *value,
 	fprintf(fp, "%s=%s\n", key, value);
 }
 
+static void credential_write_strvec(FILE *fp, const char *key,
+				    const struct strvec *vec)
+{
+	char *full_key = xstrfmt("%s[]", key);
+	for (size_t i = 0; i < vec->nr; i++) {
+		credential_write_item(fp, full_key, vec->v[i], 0);
+	}
+	free(full_key);
+}
+
 void credential_write(const struct credential *c, FILE *fp)
 {
 	credential_write_item(fp, "protocol", c->protocol, 1);
 	credential_write_item(fp, "host", c->host, 1);
 	credential_write_item(fp, "path", c->path, 0);
 	credential_write_item(fp, "username", c->username, 0);
 	credential_write_item(fp, "password", c->password, 0);
+	credential_write_strvec(fp, "wwwauth", &c->wwwauth_headers);
 }
 
 static int run_credential_helper(struct credential *c,
diff --git a/t/lib-credential-helper.sh b/t/lib-credential-helper.sh
@@ -0,0 +1,27 @@
+setup_credential_helper() {
+	test_expect_success 'setup credential helper' '
+		CREDENTIAL_HELPER="$TRASH_DIRECTORY/credential-helper.sh" &&
+		export CREDENTIAL_HELPER &&
+		echo $CREDENTIAL_HELPER &&
+
+		write_script "$CREDENTIAL_HELPER" <<-\EOF
+		cmd=$1
+		teefile=$cmd-query.cred
+		catfile=$cmd-reply.cred
+		sed -n -e "/^$/q" -e "p" >> $teefile
+		if test "$cmd" = "get"; then
+			cat $catfile
+		fi
+		EOF
+	'
+}
+
+set_credential_reply() {
+	cat >"$TRASH_DIRECTORY/$1-reply.cred"
+}
+
+expect_credential_query() {
+	cat >"$TRASH_DIRECTORY/$1-expect.cred" &&
+	test_cmp "$TRASH_DIRECTORY/$1-expect.cred" \
+		 "$TRASH_DIRECTORY/$1-query.cred"
+}
diff --git a/t/t5556-http-auth.sh b/t/t5556-http-auth.sh
@@ -4,6 +4,7 @@ test_description='test http auth header and credential helper interop'
 
 TEST_NO_CREATE_REPO=1
 . ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-credential-helper.sh
 
 test_set_port GIT_TEST_HTTP_PROTOCOL_PORT
 
@@ -33,6 +34,8 @@ test_expect_success 'setup repos' '
 	git -C "$REPO_DIR" branch -M main
 '
 
+setup_credential_helper
+
 run_http_server_worker() {
 	(
 		cd "$REPO_DIR"
@@ -101,6 +104,7 @@ per_test_cleanup () {
 	stop_http_server &&
 	rm -f OUT.* &&
 	rm -f IN.* &&
+	rm -f *.cred &&
 	rm -f auth.config
 }
 
@@ -218,4 +222,242 @@ test_expect_success 'http auth anonymous no challenge' '
 	git ls-remote $ORIGIN_URL
 '
 
+test_expect_success 'http auth www-auth headers to credential helper basic valid' '
+	test_when_finished "per_test_cleanup" &&
+	# base64("alice:secret-passwd")
+	USERPASS64=YWxpY2U6c2VjcmV0LXBhc3N3ZA== &&
+	export USERPASS64 &&
+
+	cat >auth.config <<-EOF &&
+	[auth]
+		challenge = basic:realm=\"example.com\"
+		token = basic:$USERPASS64
+	EOF
+
+	start_http_server --auth-config="$TRASH_DIRECTORY/auth.config" &&
+
+	set_credential_reply get <<-EOF &&
+	protocol=http
+	host=$HOST_PORT
+	username=alice
+	password=secret-passwd
+	EOF
+
+	git -c "credential.helper=!\"$CREDENTIAL_HELPER\"" ls-remote $ORIGIN_URL &&
+
+	expect_credential_query get <<-EOF &&
+	protocol=http
+	host=$HOST_PORT
+	wwwauth[]=basic realm="example.com"
+	EOF
+
+	expect_credential_query store <<-EOF
+	protocol=http
+	host=$HOST_PORT
+	username=alice
+	password=secret-passwd
+	EOF
+'
+
+test_expect_success 'http auth www-auth headers to credential helper ignore case valid' '
+	test_when_finished "per_test_cleanup" &&
+	# base64("alice:secret-passwd")
+	USERPASS64=YWxpY2U6c2VjcmV0LXBhc3N3ZA== &&
+	export USERPASS64 &&
+
+	cat >auth.config <<-EOF &&
+	[auth]
+		challenge = basic:realm=\"example.com\"
+		token = basic:$USERPASS64
+		extraHeader = wWw-aUtHeNtIcAtE: bEaRer auThoRiTy=\"id.example.com\"
+	EOF
+
+	start_http_server --auth-config="$TRASH_DIRECTORY/auth.config" &&
+
+	set_credential_reply get <<-EOF &&
+	protocol=http
+	host=$HOST_PORT
+	username=alice
+	password=secret-passwd
+	EOF
+
+	git -c "credential.helper=!\"$CREDENTIAL_HELPER\"" ls-remote $ORIGIN_URL &&
+
+	expect_credential_query get <<-EOF &&
+	protocol=http
+	host=$HOST_PORT
+	wwwauth[]=basic realm="example.com"
+	wwwauth[]=bEaRer auThoRiTy="id.example.com"
+	EOF
+
+	expect_credential_query store <<-EOF
+	protocol=http
+	host=$HOST_PORT
+	username=alice
+	password=secret-passwd
+	EOF
+'
+
+test_expect_success 'http auth www-auth headers to credential helper continuation hdr' '
+	test_when_finished "per_test_cleanup" &&
+	# base64("alice:secret-passwd")
+	USERPASS64=YWxpY2U6c2VjcmV0LXBhc3N3ZA== &&
+	export USERPASS64 &&
+
+	cat >auth.config <<-EOF &&
+	[auth]
+		challenge = "bearer:authority=\"id.example.com\"\\n    q=1\\n \\t p=0"
+		challenge = basic:realm=\"example.com\"
+		token = basic:$USERPASS64
+	EOF
+
+	start_http_server --auth-config="$TRASH_DIRECTORY/auth.config" &&
+
+	set_credential_reply get <<-EOF &&
+	protocol=http
+	host=$HOST_PORT
+	username=alice
+	password=secret-passwd
+	EOF
+
+	git -c "credential.helper=!\"$CREDENTIAL_HELPER\"" ls-remote $ORIGIN_URL &&
+
+	expect_credential_query get <<-EOF &&
+	protocol=http
+	host=$HOST_PORT
+	wwwauth[]=bearer authority="id.example.com" q=1 p=0
+	wwwauth[]=basic realm="example.com"
+	EOF
+
+	expect_credential_query store <<-EOF
+	protocol=http
+	host=$HOST_PORT
+	username=alice
+	password=secret-passwd
+	EOF
+'
+
+test_expect_success 'http auth www-auth headers to credential helper empty continuation hdrs' '
+	test_when_finished "per_test_cleanup" &&
+	# base64("alice:secret-passwd")
+	USERPASS64=YWxpY2U6c2VjcmV0LXBhc3N3ZA== &&
+	export USERPASS64 &&
+
+	cat >auth.config <<-EOF &&
+	[auth]
+		challenge = basic:realm=\"example.com\"
+		token = basic:$USERPASS64
+		extraheader = "WWW-Authenticate:"
+		extraheader = " "
+		extraheader = " bearer authority=\"id.example.com\""
+	EOF
+
+	start_http_server --auth-config="$TRASH_DIRECTORY/auth.config" &&
+
+	set_credential_reply get <<-EOF &&
+	protocol=http
+	host=$HOST_PORT
+	username=alice
+	password=secret-passwd
+	EOF
+
+	git -c "credential.helper=!\"$CREDENTIAL_HELPER\"" ls-remote $ORIGIN_URL &&
+
+	expect_credential_query get <<-EOF &&
+	protocol=http
+	host=$HOST_PORT
+	wwwauth[]=basic realm="example.com"
+	wwwauth[]=bearer authority="id.example.com"
+	EOF
+
+	expect_credential_query store <<-EOF
+	protocol=http
+	host=$HOST_PORT
+	username=alice
+	password=secret-passwd
+	EOF
+'
+
+test_expect_success 'http auth www-auth headers to credential helper custom schemes' '
+	test_when_finished "per_test_cleanup" &&
+	# base64("alice:secret-passwd")
+	USERPASS64=YWxpY2U6c2VjcmV0LXBhc3N3ZA== &&
+	export USERPASS64 &&
+
+	cat >auth.config <<-EOF &&
+	[auth]
+		challenge = "foobar:alg=test widget=1"
+		challenge = "bearer:authority=\"id.example.com\" q=1 p=0"
+		challenge = basic:realm=\"example.com\"
+		token = basic:$USERPASS64
+	EOF
+
+	start_http_server --auth-config="$TRASH_DIRECTORY/auth.config" &&
+
+	set_credential_reply get <<-EOF &&
+	protocol=http
+	host=$HOST_PORT
+	username=alice
+	password=secret-passwd
+	EOF
+
+	git -c "credential.helper=!\"$CREDENTIAL_HELPER\"" ls-remote $ORIGIN_URL &&
+
+	expect_credential_query get <<-EOF &&
+	protocol=http
+	host=$HOST_PORT
+	wwwauth[]=foobar alg=test widget=1
+	wwwauth[]=bearer authority="id.example.com" q=1 p=0
+	wwwauth[]=basic realm="example.com"
+	EOF
+
+	expect_credential_query store <<-EOF
+	protocol=http
+	host=$HOST_PORT
+	username=alice
+	password=secret-passwd
+	EOF
+'
+
+test_expect_success 'http auth www-auth headers to credential helper invalid' '
+	test_when_finished "per_test_cleanup" &&
+	# base64("alice:secret-passwd")
+	USERPASS64=YWxpY2U6c2VjcmV0LXBhc3N3ZA== &&
+	export USERPASS64 &&
+
+	cat >auth.config <<-EOF &&
+	[auth]
+		challenge = "bearer:authority=\"id.example.com\" q=1 p=0"
+		challenge = basic:realm=\"example.com\"
+		token = basic:$USERPASS64
+	EOF
+
+	start_http_server --auth-config="$TRASH_DIRECTORY/auth.config" &&
+
+	set_credential_reply get <<-EOF &&
+	protocol=http
+	host=$HOST_PORT
+	username=alice
+	password=invalid-passwd
+	EOF
+
+	test_must_fail git -c "credential.helper=!\"$CREDENTIAL_HELPER\"" ls-remote $ORIGIN_URL &&
+
+	expect_credential_query get <<-EOF &&
+	protocol=http
+	host=$HOST_PORT
+	wwwauth[]=bearer authority="id.example.com" q=1 p=0
+	wwwauth[]=basic realm="example.com"
+	EOF
+
+	expect_credential_query erase <<-EOF
+	protocol=http
+	host=$HOST_PORT
+	username=alice
+	password=invalid-passwd
+	wwwauth[]=bearer authority="id.example.com" q=1 p=0
+	wwwauth[]=basic realm="example.com"
+	EOF
+'
+
 test_done
