main/git: security fixes for CVE-2015-7545

6 files changed, 895 insertions, 4 deletions

diff --git a/main/git/APKBUILD b/main/git/APKBUILD
index be15aa6104..2398db8cc9 100644
--- a/main/git/APKBUILD
+++ b/main/git/APKBUILD
@@ -2,7 +2,7 @@
 # Maintainer: Natanael Copa <ncopa@alpinelinux.org>
 pkgname=git
 pkgver=2.4.1
-pkgrel=0
+pkgrel=1
 pkgdesc="A distributed version control system"
 url="http://git.or.cz/"
 arch="all"
@@ -32,6 +32,12 @@ source="git-$pkgver.tar.gz::https://github.com/git/git/archive/v$pkgver.tar.gz
 	bb-tar.patch
 	git-daemon.initd
 	git-daemon.confd
+
+	transport-add-protocol-whitelist-env-var.patch
+	submodule-allow-only-certain-protocols-for-submodule-fetches.patch
+	transport-refactor-protocol-whitelist-code.patch
+	http-limit-redirection-to-protocol-whitelist.patch
+	http-limit-redirection-depth.patch
 	"
 
 _makeopts="
@@ -204,12 +210,27 @@ _git_perl() {
 md5sums="14f0f4f1f904a97b09506ef7b7e60cc8  git-2.4.1.tar.gz
 e63a201556c4f089de790805c09a2e5b  bb-tar.patch
 75b9d8f33fbec38a8e0e06baf5165b19  git-daemon.initd
-2258e95d389ccc6de0b5111d53d9eed6  git-daemon.confd"
+2258e95d389ccc6de0b5111d53d9eed6  git-daemon.confd
+10390d958548a9bf8291fde68df73f6f  transport-add-protocol-whitelist-env-var.patch
+89b2fea6eb092beebc986874a90f7794  submodule-allow-only-certain-protocols-for-submodule-fetches.patch
+9d47666f2b8ea580661421c38b154bda  transport-refactor-protocol-whitelist-code.patch
+3cfe1fa926109de1ad99880d98380355  http-limit-redirection-to-protocol-whitelist.patch
+4f80de546d40e04d3e05d6556609a11a  http-limit-redirection-depth.patch"
 sha256sums="a41e45202363be7b3e6d88688d27a08a6be200ed096da113ba603c51651911d2  git-2.4.1.tar.gz
 cb6319f47d81605e199771350154cbed0a6e85ef9042a689f2b405c64039f49c  bb-tar.patch
 7918837f77b4cebce70b600b2f6da00e4c0df6b946f4ff5671c797c37b2ffc4f  git-daemon.initd
-aaa80bd059db549dadf4c4e27a9aa41a4b5def844f8e563c493bc8513dcd981e  git-daemon.confd"
+aaa80bd059db549dadf4c4e27a9aa41a4b5def844f8e563c493bc8513dcd981e  git-daemon.confd
+ab15c0fdfe6ff3ab990b68e65ebb4beeaddd46cf52b78ed794b0fa659ff576af  transport-add-protocol-whitelist-env-var.patch
+8d3e21cec854d275e8cd6a3d9697411c01a224e818f365864fdc9e123e79c060  submodule-allow-only-certain-protocols-for-submodule-fetches.patch
+94b5421675dc023191526284372c3a08db0561366324d2ac8e9ec7c7042eeac9  transport-refactor-protocol-whitelist-code.patch
+408ddfa018cb98c71252cfe80b6e1f3c89f8d60082c8cddc160226b84494672a  http-limit-redirection-to-protocol-whitelist.patch
+d67b5e2e8e5fc2e74644e64753237f8ec9aa1620d911bdf0dc5a2c28e2d21733  http-limit-redirection-depth.patch"
 sha512sums="6cd12f21193a051f6f4a0ef4aea54e84e72c340c117a773f097167093fde718ce45c6c32a91b601178a18a836214481976a18d7f3081679cb57247df9fdc6bf2  git-2.4.1.tar.gz
 6fa088a753c2a697e8dbef2032ed63e8c2a0553a41cff2fcff893c2f35c51d2c697054cc921c23ee606f77b93d0f340df85220b15e1c470bd352f7fba3986cd0  bb-tar.patch
 1e707250d133d56100f0311e7c2610920d6d81809c425ebf3e6acb4a289b958707a90dc38e1c17720da6dc2758dd84bf957fe6aed3854eacea79226eb616e885  git-daemon.initd
-9640f8078d68ed2678e5249da3f946fc21f50e858b94127a4221de73c6132101afcd46bc1fe33861e9a7f731c0dc9591915b8ebf376b8e690cd7135703966509  git-daemon.confd"
+9640f8078d68ed2678e5249da3f946fc21f50e858b94127a4221de73c6132101afcd46bc1fe33861e9a7f731c0dc9591915b8ebf376b8e690cd7135703966509  git-daemon.confd
+7ef30c73d747eff3b8159d9c7b5b65e722e48cf56a63fb2abcab99c89047a012a0291a45202dfbe54a260b0fd6be76b33df299ff1171a6bd0ba26cff66dbfc22  transport-add-protocol-whitelist-env-var.patch
+4af8c72fbdaf422a976af492e357ff12cfc6762d1e94290317d89725c66b32fdd9aeb1134eca697490e06e8c718c6d68a8bc16ea65405085af253680218592f2  submodule-allow-only-certain-protocols-for-submodule-fetches.patch
+88fb2412790fd1317da21c4eb684139e7010def355eda05d4939c153c1e15a3ad7f0413c629e907b3a667d700084fdd39b03213515be0ec8fb94e53548a5bba6  transport-refactor-protocol-whitelist-code.patch
+747b48a49e62b5a91ad6cbb6e4d845628eb3781e6ba05b3c402e4ba75f0f93f4fe2db23b3879706035172424b9c66ec950cdd732758b06e194634734b621d8ef  http-limit-redirection-to-protocol-whitelist.patch
+c223b6d1d4a1cd1e97cc5ad2ae0c312525d5432904a77c7d207c11b12df8a9603a047d0731cf33b18fdb67165ec816477b77aafa09261e2cd7b83cd954e39163  http-limit-redirection-depth.patch"
diff --git a/main/git/http-limit-redirection-depth.patch b/main/git/http-limit-redirection-depth.patch
new file mode 100644
index 0000000000..b03ce34eca
--- /dev/null
+++ b/main/git/http-limit-redirection-depth.patch
@@ -0,0 +1,64 @@
+From b258116462399b318c86165c61a5c7123043cfd4 Mon Sep 17 00:00:00 2001
+From: Blake Burkhart <bburky@bburky.com>
+Date: Tue, 22 Sep 2015 18:06:20 -0400
+Subject: http: limit redirection depth
+
+By default, libcurl will follow circular http redirects
+forever. Let's put a cap on this so that somebody who can
+trigger an automated fetch of an arbitrary repository (e.g.,
+for CI) cannot convince git to loop infinitely.
+
+The value chosen is 20, which is the same default that
+Firefox uses.
+
+Signed-off-by: Jeff King <peff@peff.net>
+Signed-off-by: Junio C Hamano <gitster@pobox.com>
+---
+ http.c                        | 1 +
+ t/lib-httpd/apache.conf       | 3 +++
+ t/t5812-proto-disable-http.sh | 4 ++++
+ 3 files changed, 8 insertions(+)
+
+diff --git a/http.c b/http.c
+index 5a57bcc..00e3fc8 100644
+--- a/http.c
++++ b/http.c
+@@ -352,6 +352,7 @@ static CURL *get_curl_handle(void)
+ 	}
+ 
+ 	curl_easy_setopt(result, CURLOPT_FOLLOWLOCATION, 1);
++	curl_easy_setopt(result, CURLOPT_MAXREDIRS, 20);
+ #if LIBCURL_VERSION_NUM >= 0x071301
+ 	curl_easy_setopt(result, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
+ #elif LIBCURL_VERSION_NUM >= 0x071101
+diff --git a/t/lib-httpd/apache.conf b/t/lib-httpd/apache.conf
+index 68ef8ad..7d15e6d 100644
+--- a/t/lib-httpd/apache.conf
++++ b/t/lib-httpd/apache.conf
+@@ -121,6 +121,9 @@ RewriteRule ^/smart-redir-auth/(.*)$ /auth/smart/$1 [R=301]
+ RewriteRule ^/smart-redir-limited/(.*)/info/refs$ /smart/$1/info/refs [R=301]
+ RewriteRule ^/ftp-redir/(.*)$ ftp://localhost:1000/$1 [R=302]
+ 
++RewriteRule ^/loop-redir/x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-(.*) /$1 [R=302]
++RewriteRule ^/loop-redir/(.*)$ /loop-redir/x-$1 [R=302]
++
+ <IfDefine SSL>
+ LoadModule ssl_module modules/mod_ssl.so
+ 
+diff --git a/t/t5812-proto-disable-http.sh b/t/t5812-proto-disable-http.sh
+index 6a4f816..0d105d5 100755
+--- a/t/t5812-proto-disable-http.sh
++++ b/t/t5812-proto-disable-http.sh
+@@ -25,5 +25,9 @@ test_expect_success 'curl redirects respect whitelist' '
+ 	}
+ '
+ 
++test_expect_success 'curl limits redirects' '
++	test_must_fail git clone "$HTTPD_URL/loop-redir/smart/repo.git"
++'
++
+ stop_httpd
+ test_done
+-- 
+cgit v0.11.2
+
diff --git a/main/git/http-limit-redirection-to-protocol-whitelist.patch b/main/git/http-limit-redirection-to-protocol-whitelist.patch
new file mode 100644
index 0000000000..f723847e40
--- /dev/null
+++ b/main/git/http-limit-redirection-to-protocol-whitelist.patch
@@ -0,0 +1,145 @@
+From f4113cac0c88b4f36ee6f3abf3218034440a68e3 Mon Sep 17 00:00:00 2001
+From: Blake Burkhart <bburky@bburky.com>
+Date: Tue, 22 Sep 2015 18:06:04 -0400
+Subject: http: limit redirection to protocol-whitelist
+
+Previously, libcurl would follow redirection to any protocol
+it was compiled for support with. This is desirable to allow
+redirection from HTTP to HTTPS. However, it would even
+successfully allow redirection from HTTP to SFTP, a protocol
+that git does not otherwise support at all. Furthermore
+git's new protocol-whitelisting could be bypassed by
+following a redirect within the remote helper, as it was
+only enforced at transport selection time.
+
+This patch limits redirects within libcurl to HTTP, HTTPS,
+FTP and FTPS. If there is a protocol-whitelist present, this
+list is limited to those also allowed by the whitelist. As
+redirection happens from within libcurl, it is impossible
+for an HTTP redirect to a protocol implemented within
+another remote helper.
+
+When the curl version git was compiled with is too old to
+support restrictions on protocol redirection, we warn the
+user if GIT_ALLOW_PROTOCOL restrictions were requested. This
+is a little inaccurate, as even without that variable in the
+environment, we would still restrict SFTP, etc, and we do
+not warn in that case. But anything else means we would
+literally warn every time git accesses an http remote.
+
+This commit includes a test, but it is not as robust as we
+would hope. It redirects an http request to ftp, and checks
+that curl complained about the protocol, which means that we
+are relying on curl's specific error message to know what
+happened. Ideally we would redirect to a working ftp server
+and confirm that we can clone without protocol restrictions,
+and not with them. But we do not have a portable way of
+providing an ftp server, nor any other protocol that curl
+supports (https is the closest, but we would have to deal
+with certificates).
+
+[jk: added test and version warning]
+
+Signed-off-by: Jeff King <peff@peff.net>
+Signed-off-by: Junio C Hamano <gitster@pobox.com>
+---
+ Documentation/git.txt         |  5 -----
+ http.c                        | 17 +++++++++++++++++
+ t/lib-httpd/apache.conf       |  1 +
+ t/t5812-proto-disable-http.sh |  9 +++++++++
+ 4 files changed, 27 insertions(+), 5 deletions(-)
+
+diff --git a/Documentation/git.txt b/Documentation/git.txt
+index b6a12b3..41a09ca 100644
+--- a/Documentation/git.txt
++++ b/Documentation/git.txt
+@@ -1071,11 +1071,6 @@ GIT_ICASE_PATHSPECS::
+ 
+ 	  - any external helpers are named by their protocol (e.g., use
+ 	    `hg` to allow the `git-remote-hg` helper)
+-+
+-Note that this controls only git's internal protocol selection.
+-If libcurl is used (e.g., by the `http` transport), it may
+-redirect to other protocols. There is not currently any way to
+-restrict this.
+ 
+ 
+ Discussion[[Discussion]]
+diff --git a/http.c b/http.c
+index 6798620..5a57bcc 100644
+--- a/http.c
++++ b/http.c
+@@ -8,6 +8,7 @@
+ #include "credential.h"
+ #include "version.h"
+ #include "pkt-line.h"
+-#include "gettext.h"
++#include "transport.h"
++#include "gettext.h"
+ 
+ int active_requests;
+ int http_is_verbose;
+@@ -303,6 +304,7 @@ static void set_curl_keepalive(CURL *c)
+ static CURL *get_curl_handle(void)
+ {
+ 	CURL *result = curl_easy_init();
++	long allowed_protocols = 0;
+ 
+ 	if (!result)
+ 		die("curl_easy_init failed");
+@@ -355,6 +357,21 @@ static CURL *get_curl_handle(void)
+ #elif LIBCURL_VERSION_NUM >= 0x071101
+ 	curl_easy_setopt(result, CURLOPT_POST301, 1);
+ #endif
++#if LIBCURL_VERSION_NUM >= 0x071304
++	if (is_transport_allowed("http"))
++		allowed_protocols |= CURLPROTO_HTTP;
++	if (is_transport_allowed("https"))
++		allowed_protocols |= CURLPROTO_HTTPS;
++	if (is_transport_allowed("ftp"))
++		allowed_protocols |= CURLPROTO_FTP;
++	if (is_transport_allowed("ftps"))
++		allowed_protocols |= CURLPROTO_FTPS;
++	curl_easy_setopt(result, CURLOPT_REDIR_PROTOCOLS, allowed_protocols);
++#else
++	if (transport_restrict_protocols())
++		warning("protocol restrictions not applied to curl redirects because\n"
++			"your curl version is too old (>= 7.19.4)");
++#endif
+ 
+ 	if (getenv("GIT_CURL_VERBOSE"))
+ 		curl_easy_setopt(result, CURLOPT_VERBOSE, 1);
+diff --git a/t/lib-httpd/apache.conf b/t/lib-httpd/apache.conf
+index 0b81a00..68ef8ad 100644
+--- a/t/lib-httpd/apache.conf
++++ b/t/lib-httpd/apache.conf
+@@ -119,6 +119,7 @@ RewriteRule ^/smart-redir-perm/(.*)$ /smart/$1 [R=301]
+ RewriteRule ^/smart-redir-temp/(.*)$ /smart/$1 [R=302]
+ RewriteRule ^/smart-redir-auth/(.*)$ /auth/smart/$1 [R=301]
+ RewriteRule ^/smart-redir-limited/(.*)/info/refs$ /smart/$1/info/refs [R=301]
++RewriteRule ^/ftp-redir/(.*)$ ftp://localhost:1000/$1 [R=302]
+ 
+ <IfDefine SSL>
+ LoadModule ssl_module modules/mod_ssl.so
+diff --git a/t/t5812-proto-disable-http.sh b/t/t5812-proto-disable-http.sh
+index dd5001c..6a4f816 100755
+--- a/t/t5812-proto-disable-http.sh
++++ b/t/t5812-proto-disable-http.sh
+@@ -16,5 +16,14 @@ test_expect_success 'create git-accessible repo' '
+ 
+ test_proto "smart http" http "$HTTPD_URL/smart/repo.git"
+ 
++test_expect_success 'curl redirects respect whitelist' '
++	test_must_fail env GIT_ALLOW_PROTOCOL=http:https \
++		git clone "$HTTPD_URL/ftp-redir/repo.git" 2>stderr &&
++	{
++		test_i18ngrep "ftp.*disabled" stderr ||
++		test_i18ngrep "your curl version is too old"
++	}
++'
++
+ stop_httpd
+ test_done
+-- 
+cgit v0.11.2
+
diff --git a/main/git/submodule-allow-only-certain-protocols-for-submodule-fetches.patch b/main/git/submodule-allow-only-certain-protocols-for-submodule-fetches.patch
new file mode 100644
index 0000000000..14a2fbd0f9
--- /dev/null
+++ b/main/git/submodule-allow-only-certain-protocols-for-submodule-fetches.patch
@@ -0,0 +1,107 @@
+From 33cfccbbf35a56e190b79bdec5c85457c952a021 Mon Sep 17 00:00:00 2001
+From: Jeff King <peff@peff.net>
+Date: Wed, 16 Sep 2015 13:13:12 -0400
+Subject: submodule: allow only certain protocols for submodule fetches
+
+Some protocols (like git-remote-ext) can execute arbitrary
+code found in the URL. The URLs that submodules use may come
+from arbitrary sources (e.g., .gitmodules files in a remote
+repository). Let's restrict submodules to fetching from a
+known-good subset of protocols.
+
+Note that we apply this restriction to all submodule
+commands, whether the URL comes from .gitmodules or not.
+This is more restrictive than we need to be; for example, in
+the tests we run:
+
+  git submodule add ext::...
+
+which should be trusted, as the URL comes directly from the
+command line provided by the user. But doing it this way is
+simpler, and makes it much less likely that we would miss a
+case. And since such protocols should be an exception
+(especially because nobody who clones from them will be able
+to update the submodules!), it's not likely to inconvenience
+anyone in practice.
+
+Reported-by: Blake Burkhart <bburky@bburky.com>
+Signed-off-by: Jeff King <peff@peff.net>
+Signed-off-by: Junio C Hamano <gitster@pobox.com>
+---
+ git-submodule.sh            |  9 +++++++++
+ t/t5815-submodule-protos.sh | 43 +++++++++++++++++++++++++++++++++++++++++++
+ 2 files changed, 52 insertions(+)
+ create mode 100755 t/t5815-submodule-protos.sh
+
+diff --git a/git-submodule.sh b/git-submodule.sh
+index 36797c3..78c2740 100755
+--- a/git-submodule.sh
++++ b/git-submodule.sh
+@@ -22,6 +22,15 @@ require_work_tree
+ wt_prefix=$(git rev-parse --show-prefix)
+ cd_to_toplevel
+ 
++# Restrict ourselves to a vanilla subset of protocols; the URLs
++# we get are under control of a remote repository, and we do not
++# want them kicking off arbitrary git-remote-* programs.
++#
++# If the user has already specified a set of allowed protocols,
++# we assume they know what they're doing and use that instead.
++: ${GIT_ALLOW_PROTOCOL=file:git:http:https:ssh}
++export GIT_ALLOW_PROTOCOL
++
+ command=
+ branch=
+ force=
+diff --git a/t/t5815-submodule-protos.sh b/t/t5815-submodule-protos.sh
+new file mode 100755
+index 0000000..06f55a1
+--- /dev/null
++++ b/t/t5815-submodule-protos.sh
+@@ -0,0 +1,43 @@
++#!/bin/sh
++
++test_description='test protocol whitelisting with submodules'
++. ./test-lib.sh
++. "$TEST_DIRECTORY"/lib-proto-disable.sh
++
++setup_ext_wrapper
++setup_ssh_wrapper
++
++test_expect_success 'setup repository with submodules' '
++	mkdir remote &&
++	git init remote/repo.git &&
++	(cd remote/repo.git && test_commit one) &&
++	# submodule-add should probably trust what we feed it on the cmdline,
++	# but its implementation is overly conservative.
++	GIT_ALLOW_PROTOCOL=ssh git submodule add remote:repo.git ssh-module &&
++	GIT_ALLOW_PROTOCOL=ext git submodule add "ext::fake-remote %S repo.git" ext-module &&
++	git commit -m "add submodules"
++'
++
++test_expect_success 'clone with recurse-submodules fails' '
++	test_must_fail git clone --recurse-submodules . dst
++'
++
++test_expect_success 'setup individual updates' '
++	rm -rf dst &&
++	git clone . dst &&
++	git -C dst submodule init
++'
++
++test_expect_success 'update of ssh allowed' '
++	git -C dst submodule update ssh-module
++'
++
++test_expect_success 'update of ext not allowed' '
++	test_must_fail git -C dst submodule update ext-module
++'
++
++test_expect_success 'user can override whitelist' '
++	GIT_ALLOW_PROTOCOL=ext git -C dst submodule update ext-module
++'
++
++test_done
+-- 
+cgit v0.11.2
+
diff --git a/main/git/transport-add-protocol-whitelist-env-var.patch b/main/git/transport-add-protocol-whitelist-env-var.patch
new file mode 100644
index 0000000000..01f8ff1514
--- /dev/null
+++ b/main/git/transport-add-protocol-whitelist-env-var.patch
@@ -0,0 +1,447 @@
+From a5adaced2e13c135d5d9cc65be9eb95aa3bacedf Mon Sep 17 00:00:00 2001
+From: Jeff King <peff@peff.net>
+Date: Wed, 16 Sep 2015 13:12:52 -0400
+Subject: transport: add a protocol-whitelist environment variable
+
+If we are cloning an untrusted remote repository into a
+sandbox, we may also want to fetch remote submodules in
+order to get the complete view as intended by the other
+side. However, that opens us up to attacks where a malicious
+user gets us to clone something they would not otherwise
+have access to (this is not necessarily a problem by itself,
+but we may then act on the cloned contents in a way that
+exposes them to the attacker).
+
+Ideally such a setup would sandbox git entirely away from
+high-value items, but this is not always practical or easy
+to set up (e.g., OS network controls may block multiple
+protocols, and we would want to enable some but not others).
+
+We can help this case by providing a way to restrict
+particular protocols. We use a whitelist in the environment.
+This is more annoying to set up than a blacklist, but
+defaults to safety if the set of protocols git supports
+grows). If no whitelist is specified, we continue to default
+to allowing all protocols (this is an "unsafe" default, but
+since the minority of users will want this sandboxing
+effect, it is the only sensible one).
+
+A note on the tests: ideally these would all be in a single
+test file, but the git-daemon and httpd test infrastructure
+is an all-or-nothing proposition rather than a test-by-test
+prerequisite. By putting them all together, we would be
+unable to test the file-local code on machines without
+apache.
+
+Signed-off-by: Jeff King <peff@peff.net>
+Signed-off-by: Junio C Hamano <gitster@pobox.com>
+---
+ Documentation/git.txt          | 32 ++++++++++++++
+ connect.c                      |  5 +++
+ t/lib-proto-disable.sh         | 96 ++++++++++++++++++++++++++++++++++++++++++
+ t/t5810-proto-disable-local.sh | 14 ++++++
+ t/t5811-proto-disable-git.sh   | 20 +++++++++
+ t/t5812-proto-disable-http.sh  | 20 +++++++++
+ t/t5813-proto-disable-ssh.sh   | 20 +++++++++
+ t/t5814-proto-disable-ext.sh   | 18 ++++++++
+ transport-helper.c             |  2 +
+ transport.c                    | 21 ++++++++-
+ transport.h                    |  7 +++
+ 11 files changed, 254 insertions(+), 1 deletion(-)
+ create mode 100644 t/lib-proto-disable.sh
+ create mode 100755 t/t5810-proto-disable-local.sh
+ create mode 100755 t/t5811-proto-disable-git.sh
+ create mode 100755 t/t5812-proto-disable-http.sh
+ create mode 100755 t/t5813-proto-disable-ssh.sh
+ create mode 100755 t/t5814-proto-disable-ext.sh
+
+diff --git a/Documentation/git.txt b/Documentation/git.txt
+index a62ed6f..b6a12b3 100644
+--- a/Documentation/git.txt
++++ b/Documentation/git.txt
+@@ -1045,6 +1045,38 @@ GIT_ICASE_PATHSPECS::
+ 	an operation has touched every ref (e.g., because you are
+ 	cloning a repository to make a backup).
+ 
++`GIT_ALLOW_PROTOCOL`::
++	If set, provide a colon-separated list of protocols which are
++	allowed to be used with fetch/push/clone. This is useful to
++	restrict recursive submodule initialization from an untrusted
++	repository. Any protocol not mentioned will be disallowed (i.e.,
++	this is a whitelist, not a blacklist). If the variable is not
++	set at all, all protocols are enabled.  The protocol names
++	currently used by git are:
++
++	  - `file`: any local file-based path (including `file://` URLs,
++	    or local paths)
++
++	  - `git`: the anonymous git protocol over a direct TCP
++	    connection (or proxy, if configured)
++
++	  - `ssh`: git over ssh (including `host:path` syntax,
++	    `git+ssh://`, etc).
++
++	  - `rsync`: git over rsync
++
++	  - `http`: git over http, both "smart http" and "dumb http".
++	    Note that this does _not_ include `https`; if you want both,
++	    you should specify both as `http:https`.
++
++	  - any external helpers are named by their protocol (e.g., use
++	    `hg` to allow the `git-remote-hg` helper)
+++
++Note that this controls only git's internal protocol selection.
++If libcurl is used (e.g., by the `http` transport), it may
++redirect to other protocols. There is not currently any way to
++restrict this.
++
+ 
+ Discussion[[Discussion]]
+ ------------------------
+diff --git a/connect.c b/connect.c
+index 14c924b..bd4b50e 100644
+--- a/connect.c
++++ b/connect.c
+@@ -9,6 +9,7 @@
+ #include "url.h"
+ #include "string-list.h"
+ #include "sha1-array.h"
++#include "transport.h"
+ 
+ static char *server_capabilities;
+ static const char *parse_feature_value(const char *, const char *, int *);
+@@ -694,6 +695,8 @@ struct child_process *git_connect(int fd[2], const char *url,
+ 		else
+ 			target_host = xstrdup(hostandport);
+ 
++		transport_check_allowed("git");
++
+ 		/* These underlying connection commands die() if they
+ 		 * cannot connect.
+ 		 */
+@@ -727,6 +730,7 @@ struct child_process *git_connect(int fd[2], const char *url,
+ 			int putty;
+ 			char *ssh_host = hostandport;
+ 			const char *port = NULL;
++			transport_check_allowed("ssh");
+ 			get_host_and_port(&ssh_host, &port);
+ 
+ 			if (!port)
+@@ -768,6 +772,7 @@ struct child_process *git_connect(int fd[2], const char *url,
+ 			/* remove repo-local variables from the environment */
+ 			conn->env = local_repo_env;
+ 			conn->use_shell = 1;
++			transport_check_allowed("file");
+ 		}
+ 		argv_array_push(&conn->args, cmd.buf);
+ 
+diff --git a/t/lib-proto-disable.sh b/t/lib-proto-disable.sh
+new file mode 100644
+index 0000000..b0917d9
+--- /dev/null
++++ b/t/lib-proto-disable.sh
+@@ -0,0 +1,96 @@
++# Test routines for checking protocol disabling.
++
++# test cloning a particular protocol
++#   $1 - description of the protocol
++#   $2 - machine-readable name of the protocol
++#   $3 - the URL to try cloning
++test_proto () {
++	desc=$1
++	proto=$2
++	url=$3
++
++	test_expect_success "clone $1 (enabled)" '
++		rm -rf tmp.git &&
++		(
++			GIT_ALLOW_PROTOCOL=$proto &&
++			export GIT_ALLOW_PROTOCOL &&
++			git clone --bare "$url" tmp.git
++		)
++	'
++
++	test_expect_success "fetch $1 (enabled)" '
++		(
++			cd tmp.git &&
++			GIT_ALLOW_PROTOCOL=$proto &&
++			export GIT_ALLOW_PROTOCOL &&
++			git fetch
++		)
++	'
++
++	test_expect_success "push $1 (enabled)" '
++		(
++			cd tmp.git &&
++			GIT_ALLOW_PROTOCOL=$proto &&
++			export GIT_ALLOW_PROTOCOL &&
++			git push origin HEAD:pushed
++		)
++	'
++
++	test_expect_success "push $1 (disabled)" '
++		(
++			cd tmp.git &&
++			GIT_ALLOW_PROTOCOL=none &&
++			export GIT_ALLOW_PROTOCOL &&
++			test_must_fail git push origin HEAD:pushed
++		)
++	'
++
++	test_expect_success "fetch $1 (disabled)" '
++		(
++			cd tmp.git &&
++			GIT_ALLOW_PROTOCOL=none &&
++			export GIT_ALLOW_PROTOCOL &&
++			test_must_fail git fetch
++		)
++	'
++
++	test_expect_success "clone $1 (disabled)" '
++		rm -rf tmp.git &&
++		(
++			GIT_ALLOW_PROTOCOL=none &&
++			export GIT_ALLOW_PROTOCOL &&
++			test_must_fail git clone --bare "$url" tmp.git
++		)
++	'
++}
++
++# set up an ssh wrapper that will access $host/$repo in the
++# trash directory, and enable it for subsequent tests.
++setup_ssh_wrapper () {
++	test_expect_success 'setup ssh wrapper' '
++		write_script ssh-wrapper <<-\EOF &&
++		echo >&2 "ssh: $*"
++		host=$1; shift
++		cd "$TRASH_DIRECTORY/$host" &&
++		eval "$*"
++		EOF
++		GIT_SSH="$PWD/ssh-wrapper" &&
++		export GIT_SSH &&
++		export TRASH_DIRECTORY
++	'
++}
++
++# set up a wrapper that can be used with remote-ext to
++# access repositories in the "remote" directory of trash-dir,
++# like "ext::fake-remote %S repo.git"
++setup_ext_wrapper () {
++	test_expect_success 'setup ext wrapper' '
++		write_script fake-remote <<-\EOF &&
++		echo >&2 "fake-remote: $*"
++		cd "$TRASH_DIRECTORY/remote" &&
++		eval "$*"
++		EOF
++		PATH=$TRASH_DIRECTORY:$PATH &&
++		export TRASH_DIRECTORY
++	'
++}
+diff --git a/t/t5810-proto-disable-local.sh b/t/t5810-proto-disable-local.sh
+new file mode 100755
+index 0000000..563592d
+--- /dev/null
++++ b/t/t5810-proto-disable-local.sh
+@@ -0,0 +1,14 @@
++#!/bin/sh
++
++test_description='test disabling of local paths in clone/fetch'
++. ./test-lib.sh
++. "$TEST_DIRECTORY/lib-proto-disable.sh"
++
++test_expect_success 'setup repository to clone' '
++	test_commit one
++'
++
++test_proto "file://" file "file://$PWD"
++test_proto "path" file .
++
++test_done
+diff --git a/t/t5811-proto-disable-git.sh b/t/t5811-proto-disable-git.sh
+new file mode 100755
+index 0000000..8ac6b2a
+--- /dev/null
++++ b/t/t5811-proto-disable-git.sh
+@@ -0,0 +1,20 @@
++#!/bin/sh
++
++test_description='test disabling of git-over-tcp in clone/fetch'
++. ./test-lib.sh
++. "$TEST_DIRECTORY/lib-proto-disable.sh"
++. "$TEST_DIRECTORY/lib-git-daemon.sh"
++start_git_daemon
++
++test_expect_success 'create git-accessible repo' '
++	bare="$GIT_DAEMON_DOCUMENT_ROOT_PATH/repo.git" &&
++	test_commit one &&
++	git --bare init "$bare" &&
++	git push "$bare" HEAD &&
++	>"$bare/git-daemon-export-ok" &&
++	git -C "$bare" config daemon.receivepack true
++'
++
++test_proto "git://" git "$GIT_DAEMON_URL/repo.git"
++
++test_done
+diff --git a/t/t5812-proto-disable-http.sh b/t/t5812-proto-disable-http.sh
+new file mode 100755
+index 0000000..dd5001c
+--- /dev/null
++++ b/t/t5812-proto-disable-http.sh
+@@ -0,0 +1,20 @@
++#!/bin/sh
++
++test_description='test disabling of git-over-http in clone/fetch'
++. ./test-lib.sh
++. "$TEST_DIRECTORY/lib-proto-disable.sh"
++. "$TEST_DIRECTORY/lib-httpd.sh"
++start_httpd
++
++test_expect_success 'create git-accessible repo' '
++	bare="$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
++	test_commit one &&
++	git --bare init "$bare" &&
++	git push "$bare" HEAD &&
++	git -C "$bare" config http.receivepack true
++'
++
++test_proto "smart http" http "$HTTPD_URL/smart/repo.git"
++
++stop_httpd
++test_done
+diff --git a/t/t5813-proto-disable-ssh.sh b/t/t5813-proto-disable-ssh.sh
+new file mode 100755
+index 0000000..ad877d7
+--- /dev/null
++++ b/t/t5813-proto-disable-ssh.sh
+@@ -0,0 +1,20 @@
++#!/bin/sh
++
++test_description='test disabling of git-over-ssh in clone/fetch'
++. ./test-lib.sh
++. "$TEST_DIRECTORY/lib-proto-disable.sh"
++
++setup_ssh_wrapper
++
++test_expect_success 'setup repository to clone' '
++	test_commit one &&
++	mkdir remote &&
++	git init --bare remote/repo.git &&
++	git push remote/repo.git HEAD
++'
++
++test_proto "host:path" ssh "remote:repo.git"
++test_proto "ssh://" ssh "ssh://remote/$PWD/remote/repo.git"
++test_proto "git+ssh://" ssh "git+ssh://remote/$PWD/remote/repo.git"
++
++test_done
+diff --git a/t/t5814-proto-disable-ext.sh b/t/t5814-proto-disable-ext.sh
+new file mode 100755
+index 0000000..9d6f7df
+--- /dev/null
++++ b/t/t5814-proto-disable-ext.sh
+@@ -0,0 +1,18 @@
++#!/bin/sh
++
++test_description='test disabling of remote-helper paths in clone/fetch'
++. ./test-lib.sh
++. "$TEST_DIRECTORY/lib-proto-disable.sh"
++
++setup_ext_wrapper
++
++test_expect_success 'setup repository to clone' '
++	test_commit one &&
++	mkdir remote &&
++	git init --bare remote/repo.git &&
++	git push remote/repo.git HEAD
++'
++
++test_proto "remote-helper" ext "ext::fake-remote %S repo.git"
++
++test_done
+diff --git a/transport-helper.c b/transport-helper.c
+index 7dc4a44..0b5362c 100644
+--- a/transport-helper.c
++++ b/transport-helper.c
+@@ -1038,6 +1038,8 @@ int transport_helper_init(struct transport *transport, const char *name)
+ 	struct helper_data *data = xcalloc(1, sizeof(*data));
+ 	data->name = name;
+ 
++	transport_check_allowed(name);
++
+ 	if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
+ 		debug = 1;
+ 
+diff --git a/transport.c b/transport.c
+index 88bde1d..94fe865 100644
+--- a/transport.c
++++ b/transport.c
+@@ -909,6 +909,20 @@ static int external_specification_len(const char *url)
+ 	return strchr(url, ':') - url;
+ }
+ 
++void transport_check_allowed(const char *type)
++{
++	struct string_list allowed = STRING_LIST_INIT_DUP;
++	const char *v = getenv("GIT_ALLOW_PROTOCOL");
++
++	if (!v)
++		return;
++
++	string_list_split(&allowed, v, ':', -1);
++	if (!unsorted_string_list_has_string(&allowed, type))
++		die("transport '%s' not allowed", type);
++	string_list_clear(&allowed, 0);
++}
++
+ struct transport *transport_get(struct remote *remote, const char *url)
+ {
+ 	const char *helper;
+@@ -940,12 +954,14 @@ struct transport *transport_get(struct remote *remote, const char *url)
+ 	if (helper) {
+ 		transport_helper_init(ret, helper);
+ 	} else if (starts_with(url, "rsync:")) {
++		transport_check_allowed("rsync");
+ 		ret->get_refs_list = get_refs_via_rsync;
+ 		ret->fetch = fetch_objs_via_rsync;
+ 		ret->push = rsync_transport_push;
+ 		ret->smart_options = NULL;
+ 	} else if (url_is_local_not_ssh(url) && is_file(url) && is_bundle(url, 1)) {
+ 		struct bundle_transport_data *data = xcalloc(1, sizeof(*data));
++		transport_check_allowed("file");
+ 		ret->data = data;
+ 		ret->get_refs_list = get_refs_from_bundle;
+ 		ret->fetch = fetch_refs_from_bundle;
+@@ -957,7 +973,10 @@ struct transport *transport_get(struct remote *remote, const char *url)
+ 		|| starts_with(url, "ssh://")
+ 		|| starts_with(url, "git+ssh://")
+ 		|| starts_with(url, "ssh+git://")) {
+-		/* These are builtin smart transports. */
++		/*
++		 * These are builtin smart transports; "allowed" transports
++		 * will be checked individually in git_connect.
++		 */
+ 		struct git_transport_data *data = xcalloc(1, sizeof(*data));
+ 		ret->data = data;
+ 		ret->set_option = NULL;
+diff --git a/transport.h b/transport.h
+index 3e0091e..f7df6ec 100644
+--- a/transport.h
++++ b/transport.h
+@@ -132,6 +132,13 @@ struct transport {
+ /* Returns a transport suitable for the url */
+ struct transport *transport_get(struct remote *, const char *);
+ 
++/*
++ * Check whether a transport is allowed by the environment,
++ * and die otherwise. type should generally be the URL scheme,
++ * as described in Documentation/git.txt
++ */
++void transport_check_allowed(const char *type);
++
+ /* Transport options which apply to git:// and scp-style URLs */
+ 
+ /* The program to use on the remote side to send a pack */
+-- 
+cgit v0.11.2
+
diff --git a/main/git/transport-refactor-protocol-whitelist-code.patch b/main/git/transport-refactor-protocol-whitelist-code.patch
new file mode 100644
index 0000000000..b28c78a776
--- /dev/null
+++ b/main/git/transport-refactor-protocol-whitelist-code.patch
@@ -0,0 +1,107 @@
+From 5088d3b38775f8ac12d7f77636775b16059b67ef Mon Sep 17 00:00:00 2001
+From: Jeff King <peff@peff.net>
+Date: Tue, 22 Sep 2015 18:03:49 -0400
+Subject: transport: refactor protocol whitelist code
+
+The current callers only want to die when their transport is
+prohibited. But future callers want to query the mechanism
+without dying.
+
+Let's break out a few query functions, and also save the
+results in a static list so we don't have to re-parse for
+each query.
+
+Based-on-a-patch-by: Blake Burkhart <bburky@bburky.com>
+Signed-off-by: Jeff King <peff@peff.net>
+Signed-off-by: Junio C Hamano <gitster@pobox.com>
+---
+ transport.c | 38 ++++++++++++++++++++++++++++++--------
+ transport.h | 15 +++++++++++++--
+ 2 files changed, 43 insertions(+), 10 deletions(-)
+
+diff --git a/transport.c b/transport.c
+index 94fe865..647d2c2 100644
+--- a/transport.c
++++ b/transport.c
+@@ -909,18 +909,40 @@ static int external_specification_len(const char *url)
+ 	return strchr(url, ':') - url;
+ }
+ 
+-void transport_check_allowed(const char *type)
++static const struct string_list *protocol_whitelist(void)
+ {
+-	struct string_list allowed = STRING_LIST_INIT_DUP;
+-	const char *v = getenv("GIT_ALLOW_PROTOCOL");
++	static int enabled = -1;
++	static struct string_list allowed = STRING_LIST_INIT_DUP;
++
++	if (enabled < 0) {
++		const char *v = getenv("GIT_ALLOW_PROTOCOL");
++		if (v) {
++			string_list_split(&allowed, v, ':', -1);
++			string_list_sort(&allowed);
++			enabled = 1;
++		} else {
++			enabled = 0;
++		}
++	}
+ 
+-	if (!v)
+-		return;
++	return enabled ? &allowed : NULL;
++}
++
++int is_transport_allowed(const char *type)
++{
++	const struct string_list *allowed = protocol_whitelist();
++	return !allowed || string_list_has_string(allowed, type);
++}
+ 
+-	string_list_split(&allowed, v, ':', -1);
+-	if (!unsorted_string_list_has_string(&allowed, type))
++void transport_check_allowed(const char *type)
++{
++	if (!is_transport_allowed(type))
+ 		die("transport '%s' not allowed", type);
+-	string_list_clear(&allowed, 0);
++}
++
++int transport_restrict_protocols(void)
++{
++	return !!protocol_whitelist();
+ }
+ 
+ struct transport *transport_get(struct remote *remote, const char *url)
+diff --git a/transport.h b/transport.h
+index f7df6ec..ed84da2 100644
+--- a/transport.h
++++ b/transport.h
+@@ -133,12 +133,23 @@ struct transport {
+ struct transport *transport_get(struct remote *, const char *);
+ 
+ /*
++ * Check whether a transport is allowed by the environment. Type should
++ * generally be the URL scheme, as described in Documentation/git.txt
++ */
++int is_transport_allowed(const char *type);
++
++/*
+  * Check whether a transport is allowed by the environment,
+- * and die otherwise. type should generally be the URL scheme,
+- * as described in Documentation/git.txt
++ * and die otherwise.
+  */
+ void transport_check_allowed(const char *type);
+ 
++/*
++ * Returns true if the user has attempted to turn on protocol
++ * restrictions at all.
++ */
++int transport_restrict_protocols(void);
++
+ /* Transport options which apply to git:// and scp-style URLs */
+ 
+ /* The program to use on the remote side to send a pack */
+-- 
+cgit v0.11.2
+