git/t/t5551-http-fetch-smart.sh
Jeff King 6628eb41db http: always update the base URL for redirects
If a malicious server redirects the initial ref
advertisement, it may be able to leak sha1s from other,
unrelated servers that the client has access to. For
example, imagine that Alice is a git user, she has access to
a private repository on a server hosted by Bob, and Mallory
runs a malicious server and wants to find out about Bob's
private repository.

Mallory asks Alice to clone an unrelated repository from her
over HTTP. When Alice's client contacts Mallory's server for
the initial ref advertisement, the server issues an HTTP
redirect for Bob's server. Alice contacts Bob's server and
gets the ref advertisement for the private repository. If
there is anything to fetch, she then follows up by asking
the server for one or more sha1 objects. But who is the
server?

If it is still Mallory's server, then Alice will leak the
existence of those sha1s to her.

Since commit c93c92f30 (http: update base URLs when we see
redirects, 2013-09-28), the client usually rewrites the base
URL such that all further requests will go to Bob's server.
But this is done by textually matching the URL. If we were
originally looking for "http://mallory/repo.git/info/refs",
and we got pointed at "http://bob/other.git/info/refs", then
we know that the right root is "http://bob/other.git".

If the redirect appears to change more than just the root,
we punt and continue to use the original server. E.g.,
imagine the redirect adds a URL component that Bob's server
will ignore, like "http://bob/other.git/info/refs?dummy=1".

We can solve this by aborting in this case rather than
silently continuing to use Mallory's server. In addition to
protecting from sha1 leakage, it's arguably safer and more
sane to refuse a confusing redirect like that in general.
For example, part of the motivation in c93c92f30 is
avoiding accidentally sending credentials over clear http,
just to get a response that says "try again over https". So
even in a non-malicious case, we'd prefer to err on the side
of caution.

The downside is that it's possible this will break a
legitimate but complicated server-side redirection scheme.
The setup given in the newly added test does work, but it's
convoluted enough that we don't need to care about it. A
more plausible case would be a server which redirects a
request for "info/refs?service=git-upload-pack" to just
"info/refs" (because it does not do smart HTTP, and for some
reason really dislikes query parameters).  Right now we
would transparently downgrade to dumb-http, but with this
patch, we'd complain (and the user would have to set
GIT_SMART_HTTP=0 to fetch).

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-12-06 12:32:48 -08:00

307 lines
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Executable file

#!/bin/sh
test_description='test smart fetching over http via http-backend'
. ./test-lib.sh
. "$TEST_DIRECTORY"/lib-httpd.sh
start_httpd
test_expect_success 'setup repository' '
git config push.default matching &&
echo content >file &&
git add file &&
git commit -m one
'
test_expect_success 'create http-accessible bare repository' '
mkdir "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
(cd "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
git --bare init
) &&
git remote add public "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
git push public master:master
'
setup_askpass_helper
cat >exp <<EOF
> GET /smart/repo.git/info/refs?service=git-upload-pack HTTP/1.1
> Accept: */*
> Accept-Encoding: gzip
> Pragma: no-cache
< HTTP/1.1 200 OK
< Pragma: no-cache
< Cache-Control: no-cache, max-age=0, must-revalidate
< Content-Type: application/x-git-upload-pack-advertisement
> POST /smart/repo.git/git-upload-pack HTTP/1.1
> Accept-Encoding: gzip
> Content-Type: application/x-git-upload-pack-request
> Accept: application/x-git-upload-pack-result
> Content-Length: xxx
< HTTP/1.1 200 OK
< Pragma: no-cache
< Cache-Control: no-cache, max-age=0, must-revalidate
< Content-Type: application/x-git-upload-pack-result
EOF
test_expect_success 'clone http repository' '
GIT_CURL_VERBOSE=1 git clone --quiet $HTTPD_URL/smart/repo.git clone 2>err &&
test_cmp file clone/file &&
tr '\''\015'\'' Q <err |
sed -e "
s/Q\$//
/^[*] /d
/^$/d
/^< $/d
/^[^><]/{
s/^/> /
}
/^> User-Agent: /d
/^> Host: /d
/^> POST /,$ {
/^> Accept: [*]\\/[*]/d
}
s/^> Content-Length: .*/> Content-Length: xxx/
/^> 00..want /d
/^> 00.*done/d
/^< Server: /d
/^< Expires: /d
/^< Date: /d
/^< Content-Length: /d
/^< Transfer-Encoding: /d
" >act &&
test_cmp exp act
'
test_expect_success 'fetch changes via http' '
echo content >>file &&
git commit -a -m two &&
git push public &&
(cd clone && git pull) &&
test_cmp file clone/file
'
cat >exp <<EOF
GET /smart/repo.git/info/refs?service=git-upload-pack HTTP/1.1 200
POST /smart/repo.git/git-upload-pack HTTP/1.1 200
GET /smart/repo.git/info/refs?service=git-upload-pack HTTP/1.1 200
POST /smart/repo.git/git-upload-pack HTTP/1.1 200
EOF
test_expect_success 'used upload-pack service' '
sed -e "
s/^.* \"//
s/\"//
s/ [1-9][0-9]*\$//
s/^GET /GET /
" >act <"$HTTPD_ROOT_PATH"/access.log &&
test_cmp exp act
'
test_expect_success 'follow redirects (301)' '
git clone $HTTPD_URL/smart-redir-perm/repo.git --quiet repo-p
'
test_expect_success 'follow redirects (302)' '
git clone $HTTPD_URL/smart-redir-temp/repo.git --quiet repo-t
'
test_expect_success 'redirects re-root further requests' '
git clone $HTTPD_URL/smart-redir-limited/repo.git repo-redir-limited
'
test_expect_success 're-rooting dies on insane schemes' '
test_must_fail git clone $HTTPD_URL/insane-redir/repo.git insane
'
test_expect_success 'clone from password-protected repository' '
echo two >expect &&
set_askpass user@host pass@host &&
git clone --bare "$HTTPD_URL/auth/smart/repo.git" smart-auth &&
expect_askpass both user@host &&
git --git-dir=smart-auth log -1 --format=%s >actual &&
test_cmp expect actual
'
test_expect_success 'clone from auth-only-for-push repository' '
echo two >expect &&
set_askpass wrong &&
git clone --bare "$HTTPD_URL/auth-push/smart/repo.git" smart-noauth &&
expect_askpass none &&
git --git-dir=smart-noauth log -1 --format=%s >actual &&
test_cmp expect actual
'
test_expect_success 'clone from auth-only-for-objects repository' '
echo two >expect &&
set_askpass user@host pass@host &&
git clone --bare "$HTTPD_URL/auth-fetch/smart/repo.git" half-auth &&
expect_askpass both user@host &&
git --git-dir=half-auth log -1 --format=%s >actual &&
test_cmp expect actual
'
test_expect_success 'no-op half-auth fetch does not require a password' '
set_askpass wrong &&
git --git-dir=half-auth fetch &&
expect_askpass none
'
test_expect_success 'redirects send auth to new location' '
set_askpass user@host pass@host &&
git -c credential.useHttpPath=true \
clone $HTTPD_URL/smart-redir-auth/repo.git repo-redir-auth &&
expect_askpass both user@host auth/smart/repo.git
'
test_expect_success 'disable dumb http on server' '
git --git-dir="$HTTPD_DOCUMENT_ROOT_PATH/repo.git" \
config http.getanyfile false
'
test_expect_success 'GIT_SMART_HTTP can disable smart http' '
(GIT_SMART_HTTP=0 &&
export GIT_SMART_HTTP &&
cd clone &&
test_must_fail git fetch)
'
test_expect_success 'invalid Content-Type rejected' '
test_must_fail git clone $HTTPD_URL/broken_smart/repo.git 2>actual &&
grep "not valid:" actual
'
test_expect_success 'create namespaced refs' '
test_commit namespaced &&
git push public HEAD:refs/namespaces/ns/refs/heads/master &&
git --git-dir="$HTTPD_DOCUMENT_ROOT_PATH/repo.git" \
symbolic-ref refs/namespaces/ns/HEAD refs/namespaces/ns/refs/heads/master
'
test_expect_success 'smart clone respects namespace' '
git clone "$HTTPD_URL/smart_namespace/repo.git" ns-smart &&
echo namespaced >expect &&
git --git-dir=ns-smart/.git log -1 --format=%s >actual &&
test_cmp expect actual
'
test_expect_success 'dumb clone via http-backend respects namespace' '
git --git-dir="$HTTPD_DOCUMENT_ROOT_PATH/repo.git" \
config http.getanyfile true &&
GIT_SMART_HTTP=0 git clone \
"$HTTPD_URL/smart_namespace/repo.git" ns-dumb &&
echo namespaced >expect &&
git --git-dir=ns-dumb/.git log -1 --format=%s >actual &&
test_cmp expect actual
'
cat >cookies.txt <<EOF
127.0.0.1 FALSE /smart_cookies/ FALSE 0 othername othervalue
EOF
cat >expect_cookies.txt <<EOF
127.0.0.1 FALSE /smart_cookies/ FALSE 0 othername othervalue
127.0.0.1 FALSE /smart_cookies/repo.git/info/ FALSE 0 name value
EOF
test_expect_success 'cookies stored in http.cookiefile when http.savecookies set' '
git config http.cookiefile cookies.txt &&
git config http.savecookies true &&
git ls-remote $HTTPD_URL/smart_cookies/repo.git master &&
tail -3 cookies.txt >cookies_tail.txt &&
test_cmp expect_cookies.txt cookies_tail.txt
'
test_expect_success 'transfer.hiderefs works over smart-http' '
test_commit hidden &&
test_commit visible &&
git push public HEAD^:refs/heads/a HEAD:refs/heads/b &&
git --git-dir="$HTTPD_DOCUMENT_ROOT_PATH/repo.git" \
config transfer.hiderefs refs/heads/a &&
git clone --bare "$HTTPD_URL/smart/repo.git" hidden.git &&
test_must_fail git -C hidden.git rev-parse --verify a &&
git -C hidden.git rev-parse --verify b
'
# create an arbitrary number of tags, numbered from tag-$1 to tag-$2
create_tags () {
rm -f marks &&
for i in $(test_seq "$1" "$2")
do
# don't use here-doc, because it requires a process
# per loop iteration
echo "commit refs/heads/too-many-refs-$1" &&
echo "mark :$i" &&
echo "committer git <git@example.com> $i +0000" &&
echo "data 0" &&
echo "M 644 inline bla.txt" &&
echo "data 4" &&
echo "bla" &&
# make every commit dangling by always
# rewinding the branch after each commit
echo "reset refs/heads/too-many-refs-$1" &&
echo "from :$1"
done | git fast-import --export-marks=marks &&
# now assign tags to all the dangling commits we created above
tag=$(perl -e "print \"bla\" x 30") &&
sed -e "s|^:\([^ ]*\) \(.*\)$|\2 refs/tags/$tag-\1|" <marks >>packed-refs
}
test_expect_success 'create 2,000 tags in the repo' '
(
cd "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
create_tags 1 2000
)
'
test_expect_success CMDLINE_LIMIT \
'clone the 2,000 tag repo to check OS command line overflow' '
run_with_limited_cmdline git clone $HTTPD_URL/smart/repo.git too-many-refs &&
(
cd too-many-refs &&
git for-each-ref refs/tags >actual &&
test_line_count = 2000 actual
)
'
test_expect_success 'large fetch-pack requests can be split across POSTs' '
GIT_CURL_VERBOSE=1 git -c http.postbuffer=65536 \
clone --bare "$HTTPD_URL/smart/repo.git" split.git 2>err &&
grep "^> POST" err >posts &&
test_line_count = 2 posts
'
test_expect_success EXPENSIVE 'http can handle enormous ref negotiation' '
(
cd "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
create_tags 2001 50000
) &&
git -C too-many-refs fetch -q --tags &&
(
cd "$HTTPD_DOCUMENT_ROOT_PATH/repo.git" &&
create_tags 50001 100000
) &&
git -C too-many-refs fetch -q --tags &&
git -C too-many-refs for-each-ref refs/tags >tags &&
test_line_count = 100000 tags
'
test_expect_success 'custom http headers' '
test_must_fail git -c http.extraheader="x-magic-two: cadabra" \
fetch "$HTTPD_URL/smart_headers/repo.git" &&
git -c http.extraheader="x-magic-one: abra" \
-c http.extraheader="x-magic-two: cadabra" \
fetch "$HTTPD_URL/smart_headers/repo.git" &&
git update-index --add --cacheinfo 160000,$(git rev-parse HEAD),sub &&
git config -f .gitmodules submodule.sub.path sub &&
git config -f .gitmodules submodule.sub.url \
"$HTTPD_URL/smart_headers/repo.git" &&
git submodule init sub &&
test_must_fail git submodule update sub &&
git -c http.extraheader="x-magic-one: abra" \
-c http.extraheader="x-magic-two: cadabra" \
submodule update sub
'
stop_httpd
test_done