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>
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>
We set CURLOPT_PROXYAUTH to use the most secure authentication
method available only when the user has set configuration variables
to specify a proxy. However, libcurl also supports specifying a
proxy through environment variables. In that case libcurl defaults
to only using the Basic proxy authentication method, because we do
not use CURLOPT_PROXYAUTH.
Set CURLOPT_PROXYAUTH to always use the most secure authentication
method available, even when there is no git configuration telling us
to use a proxy. This allows the user to use environment variables to
configure a proxy that requires an authentication method different
from Basic.
Signed-off-by: Enrique A. Tobis <etobis@twosigma.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The cleanup function is used in 4 places now and it's always safe to
free up the memory as well.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Calling setlocale(LC_MESSAGES, ...) directly from http.c, without
including <locale.h>, was causing compilation warnings. Move the
helper function to gettext.c that already includes the header and
where locale-related issues are handled.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We did not check the curl library version before using
CURLOPT_PROXYAUTH feature that may not exist.
* tc/missing-http-proxyauth:
http: support curl < 7.10.7
A broken pack .idx file in the receiving repository prevented the
dumb http transport from fetching a good copy of it from the other
side.
* jk/dumb-http-idx-fetch-fix:
dumb-http: do not pass NULL path to parse_pack_index
Using environment variable LANGUAGE and friends on the client side,
HTTP-based transports now send Accept-Language when making requests.
* ye/http-accept-language:
http: add Accept-Language header if possible
A broken pack .idx file in the receiving repository prevented the
dumb http transport from fetching a good copy of it from the other
side.
* jk/dumb-http-idx-fetch-fix:
dumb-http: do not pass NULL path to parse_pack_index
Mark file-local symbols as "static", and drop functions that nobody
uses.
* jc/unused-symbols:
shallow.c: make check_shallow_file_for_update() static
remote.c: make clear_cas_option() static
urlmatch.c: make match_urls() static
revision.c: make save_parents() and free_saved_parents() static
line-log.c: make line_log_data_init() static
pack-bitmap.c: make pack_bitmap_filename() static
prompt.c: remove git_getpass() nobody uses
http.c: make finish_active_slot() and handle_curl_result() static
Commit dd61399 introduced support for http proxies that require
authentication but it relies on the CURL_PROXYAUTH option which was
added in curl 7.10.7.
This makes sure proxy authentication is only enabled if libcurl can
support it.
Signed-off-by: Tom G. Christensen <tgc@statsbiblioteket.dk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add an Accept-Language header which indicates the user's preferred
languages defined by $LANGUAGE, $LC_ALL, $LC_MESSAGES and $LANG.
Examples:
LANGUAGE= -> ""
LANGUAGE=ko:en -> "Accept-Language: ko, en;q=0.9, *;q=0.1"
LANGUAGE=ko LANG=en_US.UTF-8 -> "Accept-Language: ko, *;q=0.1"
LANGUAGE= LANG=en_US.UTF-8 -> "Accept-Language: en-US, *;q=0.1"
This gives git servers a chance to display remote error messages in
the user's preferred language.
Limit the number of languages to 1,000 because q-value must not be
smaller than 0.001, and limit the length of Accept-Language header to
4,000 bytes for some HTTP servers which cannot accept such long header.
Signed-off-by: Yi EungJun <eungjun.yi@navercorp.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Once upon a time, dumb http always fetched .idx files
directly into their final location, and then checked their
validity with parse_pack_index. This was refactored in
commit 750ef42 (http-fetch: Use temporary files for
pack-*.idx until verified, 2010-04-19), which uses the
following logic:
1. If we have the idx already in place, see if it's
valid (using parse_pack_index). If so, use it.
2. Otherwise, fetch the .idx to a tempfile, check
that, and if so move it into place.
3. Either way, fetch the pack itself if necessary.
However, it got step 1 wrong. We pass a NULL path parameter
to parse_pack_index, so an existing .idx file always looks
broken. Worse, we do not treat this broken .idx as an
opportunity to re-fetch, but instead return an error,
ignoring the pack entirely. This can lead to a dumb-http
fetch failing to retrieve the necessary objects.
This doesn't come up much in practice, because it must be a
packfile that we found out about (and whose .idx we stored)
during an earlier dumb-http fetch, but whose packfile we
_didn't_ fetch. I.e., we did a partial clone of a
repository, didn't need some packfiles, and now a followup
fetch needs them.
Discovery and tests by Charles Bailey <charles@hashpling.org>.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
They used to be used directly by remote-curl.c for the smart-http
protocol. But they got wrapped by run_one_slot() in beed336 (http:
never use curl_easy_perform, 2014-02-18). Any future users are
expected to follow that route.
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Apache servers using mod_auth_kerb can be configured to allow the user
to authenticate either using Negotiate (using the Kerberos ticket) or
Basic authentication (using the Kerberos password). Often, one will
want to use Negotiate authentication if it is available, but fall back
to Basic authentication if the ticket is missing or expired.
However, libcurl will try very hard to use something other than Basic
auth, even over HTTPS. If Basic and something else are offered, libcurl
will never attempt to use Basic, even if the other option fails.
Teach the HTTP client code to stop trying authentication mechanisms that
don't use a password (currently Negotiate) after the first failure,
since if they failed the first time, they will never succeed.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
CodingGuidelines states that the first #include in C files should be
git-compat-util.h or another header file that includes it, such as
cache.h or builtin.h.
Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Unless there is a good reason, we should use die() rather than
fprintf/exit. We can also shorten the message to match other curl init
failures (and match our usual lowercase no-full-stop style).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Most struct child_process variables are cleared using memset first after
declaration. Provide a macro, CHILD_PROCESS_INIT, that can be used to
initialize them statically instead. That's shorter, doesn't require a
function call and is slightly more readable (especially given that we
already have STRBUF_INIT, ARGV_ARRAY_INIT etc.).
Helped-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* jk/skip-prefix:
http-push: refactor parsing of remote object names
imap-send: use skip_prefix instead of using magic numbers
use skip_prefix to avoid repeated calculations
git: avoid magic number with skip_prefix
fetch-pack: refactor parsing in get_ack
fast-import: refactor parsing of spaces
stat_opt: check extra strlen call
daemon: use skip_prefix to avoid magic numbers
fast-import: use skip_prefix for parsing input
use skip_prefix to avoid repeating strings
use skip_prefix to avoid magic numbers
transport-helper: avoid reading past end-of-string
fast-import: fix read of uninitialized argv memory
apply: use skip_prefix instead of raw addition
refactor skip_prefix to return a boolean
avoid using skip_prefix as a boolean
daemon: mark some strings as const
parse_diff_color_slot: drop ofs parameter
In some cases, we use starts_with to check for a prefix, and
then use an already-calculated prefix length to advance a
pointer past the prefix. There are no magic numbers or
duplicated strings here, but we can still make the code
simpler and more obvious by using skip_prefix.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
extract_content_type() could not extract a charset parameter if the
parameter is not the first one and there is a whitespace and a following
semicolon just before the parameter. For example:
text/plain; format=fixed ;charset=utf-8
And it also could not handle correctly some other cases, such as:
text/plain; charset=utf-8; format=fixed
text/plain; some-param="a long value with ;semicolons;"; charset=utf-8
Thanks-to: Jeff King <peff@peff.net>
Signed-off-by: Yi EungJun <eungjun.yi@navercorp.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is specified by RFC 2616 as the default if no "charset"
parameter is given.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since the previous commit, we now give a sanitized,
shortened version of the content-type header to any callers
who ask for it.
This patch adds back a way for them to cleanly access
specific parameters to the type. We could easily extract all
parameters and make them available via a string_list, but:
1. That complicates the interface and memory management.
2. In practice, no planned callers care about anything
except the charset.
This patch therefore goes with the simplest thing, and we
can expand or change the interface later if it becomes
necessary.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we get a content-type from curl, we get the whole
header line, including any parameters, and without any
normalization (like downcasing or whitespace) applied.
If we later try to match it with strcmp() or even
strcasecmp(), we may get false negatives.
This could cause two visible behaviors:
1. We might fail to recognize a smart-http server by its
content-type.
2. We might fail to relay text/plain error messages to
users (especially if they contain a charset parameter).
This patch teaches the http code to extract and normalize
just the type/subtype portion of the string. This is
technically passing out less information to the callers, who
can no longer see the parameters. But none of the current
callers cares, and a future patch will add back an
easier-to-use method for accessing those parameters.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* mh/object-code-cleanup:
sha1_file.c: document a bunch of functions defined in the file
sha1_file_name(): declare to return a const string
find_pack_entry(): document last_found_pack
replace_object: use struct members instead of an array
Change the return value of sha1_file_name() to (const char *).
(Callers have no business mucking about here.) Change callers
accordingly, deleting a few superfluous temporary variables along the
way.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We currently don't reuse http connections when fetching via
the smart-http protocol. This is bad because the TCP
handshake introduces latency, and especially because SSL
connection setup may be non-trivial.
We can fix it by consistently using curl's "multi"
interface. The reason is rather complicated:
Our http code has two ways of being used: queuing many
"slots" to be fetched in parallel, or fetching a single
request in a blocking manner. The parallel code is built on
curl's "multi" interface. Most of the single-request code
uses http_request, which is built on top of the parallel
code (we just feed it one slot, and wait until it finishes).
However, one could also accomplish the single-request scheme
by avoiding curl's multi interface entirely and just using
curl_easy_perform. This is simpler, and is used by post_rpc
in the smart-http protocol.
It does work to use the same curl handle in both contexts,
as long as it is not at the same time. However, internally
curl may not share all of the cached resources between both
contexts. In particular, a connection formed using the
"multi" code will go into a reuse pool connected to the
"multi" object. Further requests using the "easy" interface
will not be able to reuse that connection.
The smart http protocol does ref discovery via http_request,
which uses the "multi" interface, and then follows up with
the "easy" interface for its rpc calls. As a result, we make
two HTTP connections rather than reusing a single one.
We could teach the ref discovery to use the "easy"
interface. But it is only once we have done this discovery
that we know whether the protocol will be smart or dumb. If
it is dumb, then our further requests, which want to fetch
objects in parallel, will not be able to reuse the same
connection.
Instead, this patch switches post_rpc to build on the
parallel interface, which means that we use it consistently
everywhere. It's a little more complicated to use, but since
we have the infrastructure already, it doesn't add any code;
we can just factor out the relevant bits from http_request.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Remove a few duplicate implementations of prefix/suffix comparison
functions, and rename them to starts_with and ends_with.
* cc/starts-n-ends-with:
replace {pre,suf}fixcmp() with {starts,ends}_with()
strbuf: introduce starts_with() and ends_with()
builtin/remote: remove postfixcmp() and use suffixcmp() instead
environment: normalize use of prefixcmp() by removing " != 0"
Leaving only the function definitions and declarations so that any
new topic in flight can still make use of the old functions, replace
existing uses of the prefixcmp() and suffixcmp() with new API
functions.
The change can be recreated by mechanically applying this:
$ git grep -l -e prefixcmp -e suffixcmp -- \*.c |
grep -v strbuf\\.c |
xargs perl -pi -e '
s|!prefixcmp\(|starts_with\(|g;
s|prefixcmp\(|!starts_with\(|g;
s|!suffixcmp\(|ends_with\(|g;
s|suffixcmp\(|!ends_with\(|g;
'
on the result of preparatory changes in this series.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Issue "100 Continue" responses to help use of GSS-Negotiate
authentication scheme over HTTP transport when needed.
* bc/http-100-continue:
remote-curl: fix large pushes with GSSAPI
remote-curl: pass curl slot_results back through run_slot
http: return curl's AUTHAVAIL via slot_results
Callers of the http code may want to know which auth types
were available for the previous request. But after finishing
with the curl slot, they are not supposed to look at the
curl handle again. We already handle returning other
information via the slot_results struct; let's add a flag to
check the available auth.
Note that older versions of curl did not support this, so we
simply return 0 (something like "-1" would be worse, as the
value is a bitflag and we might accidentally set a flag).
This is sufficient for the callers planned in this series,
who only trigger some optional behavior if particular bits
are set, and can live with a fake "no bits" answer.
Signed-off-by: Jeff King <peff@peff.net>
Handle the case where http transport gets redirected during the
authorization request better.
* jk/http-auth-redirects:
http.c: Spell the null pointer as NULL
remote-curl: rewrite base url from info/refs redirects
remote-curl: store url as a strbuf
remote-curl: make refs_url a strbuf
http: update base URLs when we see redirects
http: provide effective url to callers
http: hoist credential request out of handle_curl_result
http: refactor options to http_get_*
http_request: factor out curlinfo_strbuf
http_get_file: style fixes
Commit 1bbcc224 ("http: refactor options to http_get_*", 28-09-2013)
changed the type of final 'options' argument of the http_get_file()
function from an int to an 'struct http_get_options' pointer.
However, it neglected to update the (single) call site. Since this
call was passing '0' to that argument, it was (correctly) being
interpreted as a null pointer. Change to argument to NULL.
Noticed by sparse. ("Using plain integer as NULL pointer")
Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Acked-by: Jeff King <peff@peff.net>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit a15d069 taught git to use curl's SOCKOPTFUNCTION hook
to turn on TCP keepalives. However, modern versions of curl
have a TCP_KEEPALIVE option, which can do this for us. As an
added bonus, the curl code knows how to turn on keepalive
for a much wider variety of platforms. The only downside to
using this option is that not everybody has a new enough curl.
Let's split our keepalive options into three conditionals:
1. With curl 7.25.0 and newer, we rely on curl to do it
right.
2. With older curl that still knows SOCKOPTFUNCTION, we
use the code from a15d069.
3. Otherwise, we are out of luck, and the call is a no-op.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If a caller asks the http_get_* functions to go to a
particular URL and we end up elsewhere due to a redirect,
the effective_url field can tell us where we went.
It would be nice to remember this redirect and short-cut
further requests for two reasons:
1. It's more efficient. Otherwise we spend an extra http
round-trip to the server for each subsequent request,
just to get redirected.
2. If we end up with an http 401 and are going to ask for
credentials, it is to feed them to the redirect target.
If the redirect is an http->https upgrade, this means
our credentials may be provided on the http leg, just
to end up redirected to https. And if the redirect
crosses server boundaries, then curl will drop the
credentials entirely as it follows the redirect.
However, it, it is not enough to simply record the effective
URL we saw and use that for subsequent requests. We were
originally fed a "base" url like:
http://example.com/foo.git
and we want to figure out what the new base is, even though
the URLs we see may be:
original: http://example.com/foo.git/info/refs
effective: http://example.com/bar.git/info/refs
Subsequent requests will not be for "info/refs", but for
other paths relative to the base. We must ask the caller to
pass in the original base, and we must pass the redirected
base back to the caller (so that it can generate more URLs
from it). Furthermore, we need to feed the new base to the
credential code, so that requests to credential helpers (or
to the user) match the URL we will be requesting.
This patch teaches http_request_reauth to do this munging.
Since it is the caller who cares about making more URLs, it
seems at first glance that callers could simply check
effective_url themselves and handle it. However, since we
need to update the credential struct before the second
re-auth request, we have to do it inside http_request_reauth.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
When we ask curl to access a URL, it may follow one or more
redirects to reach the final location. We have no idea
this has happened, as curl takes care of the details and
simply returns the final content to us.
The final URL that we ended up with can be accessed via
CURLINFO_EFFECTIVE_URL. Let's make that optionally available
to callers of http_get_*, so that they can make further
decisions based on the redirection.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
When we are handling a curl response code in http_request or
in the remote-curl RPC code, we use the handle_curl_result
helper to translate curl's response into an easy-to-use
code. When we see an HTTP 401, we do one of two things:
1. If we already had a filled-in credential, we mark it as
rejected, and then return HTTP_NOAUTH to indicate to
the caller that we failed.
2. If we didn't, then we ask for a new credential and tell
the caller HTTP_REAUTH to indicate that they may want
to try again.
Rejecting in the first case makes sense; it is the natural
result of the request we just made. However, prompting for
more credentials in the second step does not always make
sense. We do not know for sure that the caller is going to
make a second request, and nor are we sure that it will be
to the same URL. Logically, the prompt belongs not to the
request we just finished, but to the request we are (maybe)
about to make.
In practice, it is very hard to trigger any bad behavior.
Currently, if we make a second request, it will always be to
the same URL (even in the face of redirects, because curl
handles the redirects internally). And we almost always
retry on HTTP_REAUTH these days. The one exception is if we
are streaming a large RPC request to the server (e.g., a
pushed packfile), in which case we cannot restart. It's
extremely unlikely to see a 401 response at this stage,
though, as we would typically have seen it when we sent a
probe request, before streaming the data.
This patch drops the automatic prompt out of case 2, and
instead requires the caller to do it. This is a few extra
lines of code, and the bug it fixes is unlikely to come up
in practice. But it is conceptually cleaner, and paves the
way for better handling of credentials across redirects.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
This is a follow up to commit e47a8583 (enable SO_KEEPALIVE for
connected TCP sockets, 2011-12-06).
Sockets may never receive notification of some link errors,
causing "git fetch" or similar processes to hang forever.
Enabling keepalive messages allows hung processes to error out
after a few minutes/hours depending on the keepalive settings of
the system.
I noticed this problem with some non-interactive cronjobs getting
hung when talking to HTTP servers.
Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Over time, the http_get_strbuf function has grown several
optional parameters. We now have a bitfield with multiple
boolean options, as well as an optional strbuf for returning
the content-type of the response. And a future patch in this
series is going to add another strbuf option.
Treating these as separate arguments has a few downsides:
1. Most call sites need to add extra NULLs and 0s for the
options they aren't interested in.
2. The http_get_* functions are actually wrappers around
2 layers of low-level implementation functions. We have
to pass these options through individually.
3. The http_get_strbuf wrapper learned these options, but
nobody bothered to do so for http_get_file, even though
it is backed by the same function that does understand
the options.
Let's consolidate the options into a single struct. For the
common case of the default options, we'll allow callers to
simply pass a NULL for the options struct.
The resulting code is often a few lines longer, but it ends
up being easier to read (and to change as we add new
options, since we do not need to update each call site).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
When we retrieve the content-type of an http response, curl
gives us a pointer to internal storage, which we then copy
into a strbuf. Let's factor out the get-and-copy routine,
which can be used for getting other curl info.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Besides being ugly, the extra parentheses are idiomatic for
suppressing compiler warnings when we are assigning within a
conditional. We aren't doing that here, and they just
confuse the reader.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Allow section.<urlpattern>.var configuration variables to be
treated as a "virtual" section.var given a URL, and use the
mechanism to enhance http.* configuration variables.
This is a reroll of Kyle J. McKay's work.
* jc/url-match:
builtin/config.c: compilation fix
config: "git config --get-urlmatch" parses section.<url>.key
builtin/config: refactor collect_config()
config: parse http.<url>.<variable> using urlmatch
config: add generic callback wrapper to parse section.<url>.key
config: add helper to normalize and match URLs
http.c: fix parsing of http.sslCertPasswordProtected variable
Use the urlmatch_config_entry() to wrap the underlying
http_options() two-level variable parser in order to set
http.<variable> to the value with the most specific URL in the
configuration.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Kyle J. McKay <mackyle@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The existing code triggers only when the configuration variable is
set to true. Once the variable is set to true in a more generic
configuration file (e.g. ~/.gitconfig), it cannot be overriden to
false in the repository specific one (e.g. .git/config).
Signed-off-by: Junio C Hamano <gitster@pobox.com>
