summaryrefslogtreecommitdiff
path: root/t/lib-httpd
diff options
context:
space:
mode:
authorJeff King <peff@peff.net>2016-12-06 18:24:35 (GMT)
committerJunio C Hamano <gitster@pobox.com>2016-12-06 20:32:48 (GMT)
commit6628eb41db5189c0cdfdced6d8697e7c813c5f0f (patch)
tree13687858956d652416c34309e39ac5f61f42b9e9 /t/lib-httpd
parent986d7f4d37124e1ab7dcc99587f0d6d1deeedd9c (diff)
downloadgit-6628eb41db5189c0cdfdced6d8697e7c813c5f0f.zip
git-6628eb41db5189c0cdfdced6d8697e7c813c5f0f.tar.gz
git-6628eb41db5189c0cdfdced6d8697e7c813c5f0f.tar.bz2
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>
Diffstat (limited to 't/lib-httpd')
-rw-r--r--t/lib-httpd/apache.conf8
1 files changed, 8 insertions, 0 deletions
diff --git a/t/lib-httpd/apache.conf b/t/lib-httpd/apache.conf
index 018a83a..9a355fb 100644
--- a/t/lib-httpd/apache.conf
+++ b/t/lib-httpd/apache.conf
@@ -132,6 +132,14 @@ 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-$1 [R=302]
+# The first rule issues a client-side redirect to something
+# that _doesn't_ look like a git repo. The second rule is a
+# server-side rewrite, so that it turns out the odd-looking
+# thing _is_ a git repo. The "[PT]" tells Apache to match
+# the usual ScriptAlias rules for /smart.
+RewriteRule ^/insane-redir/(.*)$ /intern-redir/$1/foo [R=301]
+RewriteRule ^/intern-redir/(.*)/foo$ /smart/$1 [PT]
+
# Apache 2.2 does not understand <RequireAll>, so we use RewriteCond.
# And as RewriteCond does not allow testing for non-matches, we match
# the desired case first (one has abra, two has cadabra), and let it