* ew/http-walker:
list: avoid incompatibility with *BSD sys/queue.h
http-walker: reduce O(n) ops with doubly-linked list
http: avoid disconnecting on 404s for loose objects
http-walker: remove unused parameter from fetch_object
The previous commit made HTTP redirects more obvious and
tightened up the default behavior. However, there's another
way for a server to ask a git client to fetch arbitrary
content: by having an http-alternates file (or a regular
alternates file, which is used as a backup).
Similar to the HTTP redirect case, a malicious server can
claim to have refs pointing at object X, return a 404 when
the client asks for X, but point to some other URL via
http-alternates, which the client will transparently fetch.
The end result is that it looks from the user's perspective
like the objects came from the malicious server, as the
other URL is not mentioned at all.
Worse, because we feed the new URL to curl ourselves, the
usual protocol restrictions do not kick in (neither curl's
default of disallowing file://, nor the protocol
whitelisting in f4113cac0 (http: limit redirection to
protocol-whitelist, 2015-09-22).
Let's apply the same rules here as we do for HTTP redirects.
Namely:
- unless http.followRedirects is set to "always", we will
not follow remote redirects from http-alternates (or
alternates) at all
- set CURLOPT_PROTOCOLS alongside CURLOPT_REDIR_PROTOCOLS
restrict ourselves to a known-safe set and respect any
user-provided whitelist.
- mention alternate object stores on stderr so that the
user is aware another source of objects may be involved
The first item may prove to be too restrictive. The most
common use of alternates is to point to another path on the
same server. While it's possible for a single-server
redirect to be an attack, it takes a fairly obscure setup
(victim and evil repository on the same host, host speaks
dumb http, and evil repository has access to edit its own
http-alternates file).
So we could make the checks more specific, and only cover
cross-server redirects. But that means parsing the URLs
ourselves, rather than letting curl handle them. This patch
goes for the simpler approach. Given that they are only used
with dumb http, http-alternates are probably pretty rare.
And there's an escape hatch: the user can allow redirects on
a specific server by setting http.<url>.followRedirects to
"always".
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We instruct curl to always follow HTTP redirects. This is
convenient, but it creates opportunities for malicious
servers to create confusing situations. For instance,
imagine Alice is a git user with access to a private
repository on Bob's server. Mallory runs her own server and
wants to access objects from Bob's repository.
Mallory may try a few tricks that involve asking Alice to
clone from her, build on top, and then push the result:
1. Mallory may simply redirect all fetch requests to Bob's
server. Git will transparently follow those redirects
and fetch Bob's history, which Alice may believe she
got from Mallory. The subsequent push seems like it is
just feeding Mallory back her own objects, but is
actually leaking Bob's objects. There is nothing in
git's output to indicate that Bob's repository was
involved at all.
The downside (for Mallory) of this attack is that Alice
will have received Bob's entire repository, and is
likely to notice that when building on top of it.
2. If Mallory happens to know the sha1 of some object X in
Bob's repository, she can instead build her own history
that references that object. She then runs a dumb http
server, and Alice's client will fetch each object
individually. When it asks for X, Mallory redirects her
to Bob's server. The end result is that Alice obtains
objects from Bob, but they may be buried deep in
history. Alice is less likely to notice.
Both of these attacks are fairly hard to pull off. There's a
social component in getting Mallory to convince Alice to
work with her. Alice may be prompted for credentials in
accessing Bob's repository (but not always, if she is using
a credential helper that caches). Attack (1) requires a
certain amount of obliviousness on Alice's part while making
a new commit. Attack (2) requires that Mallory knows a sha1
in Bob's repository, that Bob's server supports dumb http,
and that the object in question is loose on Bob's server.
But we can probably make things a bit more obvious without
any loss of functionality. This patch does two things to
that end.
First, when we encounter a whole-repo redirect during the
initial ref discovery, we now inform the user on stderr,
making attack (1) much more obvious.
Second, the decision to follow redirects is now
configurable. The truly paranoid can set the new
http.followRedirects to false to avoid any redirection
entirely. But for a more practical default, we will disallow
redirects only after the initial ref discovery. This is
enough to thwart attacks similar to (2), while still
allowing the common use of redirects at the repository
level. Since c93c92f30 (http: update base URLs when we see
redirects, 2013-09-28) we re-root all further requests from
the redirect destination, which should generally mean that
no further redirection is necessary.
As an escape hatch, in case there really is a server that
needs to redirect individual requests, the user can set
http.followRedirects to "true" (and this can be done on a
per-server basis via http.*.followRedirects config).
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The discover_refs() function has a local "options" variable
to hold the http_get_options we pass to http_get_strbuf().
But this shadows the global "struct options" that holds our
program-level options, which cannot be accessed from this
function.
Let's give the local one a more descriptive name so we can
tell the two apart.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
This function looks for a common tail between what we asked
for and where we were redirected to, but it open-codes the
comparison. We can avoid some confusing subtractions by
using strip_suffix_mem().
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A small doc update.
* hv/doc-commit-reference-style:
SubmittingPatches: use gitk's "Copy commit summary" format
SubmittingPatches: document how to reference previous commits
A small test clean-up for a topic introduced in v2.9.1 and later.
* sg/reflog-past-root:
t1410: remove superfluous 'git reflog' from the 'walk past root' test
Correct an age-old calco (is that a typo-like word for calc)
in the documentation.
* ls/packet-line-protocol-doc-fix:
pack-protocol: fix maximum pkt-line size
The tempfile (hence its user lockfile) API lets the caller to open
a file descriptor to a temporary file, write into it and then
finalize it by first closing the filehandle and then either
removing or renaming the temporary file. When the process spawns a
subprocess after obtaining the file descriptor, and if the
subprocess has not exited when the attempt to remove or rename is
made, the last step fails on Windows, because the subprocess has
the file descriptor still open. Open tempfile with O_CLOEXEC flag
to avoid this (on Windows, this is mapped to O_NOINHERIT).
* bw/mingw-avoid-inheriting-fd-to-lockfile:
mingw: ensure temporary file handles are not inherited by child processes
t6026-merge-attr: child processes must not inherit index.lock handles
The "git -c var[=val] cmd" facility to append a configuration
variable definition at the end of the search order was described in
git(1) manual page, but not in git-config(1), which was more likely
place for people to look for when they ask "can I make a one-shot
override, and if so how?"
* dg/document-git-c-in-git-config-doc:
doc: mention `git -c` in git-config(1)
On Windows, help.browser configuration variable used to be ignored,
which has been corrected.
* js/no-html-bypass-on-windows:
Revert "display HTML in default browser using Windows' shell API"
"git difftool" by default ignores the error exit from the backend
commands it spawns, because often they signal that they found
differences by exiting with a non-zero status code just like "diff"
does; the exit status codes 126 and above however are special in
that they are used to signal that the command is not executable,
does not exist, or killed by a signal. "git difftool" has been
taught to notice these exit status codes.
* jk/difftool-command-not-found:
difftool: always honor fatal error exit codes
"git checkout --detach <branch>" used to give the same advice
message as that is issued when "git checkout <tag>" (or anything
that is not a branch name) is given, but asking with "--detach" is
an explicit enough sign that the user knows what is going on. The
advice message has been squelched in this case.
* sb/checkout-explit-detach-no-advice:
checkout: do not mention detach advice for explicit --detach option
When "git merge-recursive" works on history with many criss-cross
merges in "verbose" mode, the names the command assigns to the
virtual merge bases could have overwritten each other by unintended
reuse of the same piece of memory.
* rs/pull-signed-tag:
commit: use FLEX_ARRAY in struct merge_remote_desc
merge-recursive: fix verbose output for multiple base trees
commit: factor out set_merge_remote_desc()
commit: use xstrdup() in get_merge_parent()
The "t/" hierarchy is prone to get an unusual pathname; "make test"
has been taught to make sure they do not contain paths that cannot
be checked out on Windows (and the mechanism can be reusable to
catch pathnames that are not portable to other platforms as need
arises).
* js/test-lint-pathname:
t/Makefile: ensure that paths are valid on platforms we care
"git mv dir non-existing-dir/" did not work in some environments
the same way as existing mainstream platforms. The code now moves
"dir" to "non-existing-dir", without relying on rename("A", "B/")
that strips the trailing slash of '/'.
* js/mv-dir-to-new-directory:
git mv: do not keep slash in `git mv dir non-existing-dir/`
"import-tars" fast-import script (in contrib/) used to ignore a
hardlink target and replaced it with an empty file, which has been
corrected to record the same blob as the other file the hardlink is
shared with.
* js/import-tars-hardlinks:
import-tars: support hard links
"git push --force-with-lease" already had enough logic to allow
ensuring that such a push results in creation of a ref (i.e. the
receiving end did not have another push from sideways that would be
discarded by our force-pushing), but didn't expose this possibility
to the users. It does so now.
* jk/push-force-with-lease-creation:
t5533: make it pass on case-sensitive filesystems
push: allow pushing new branches with --force-with-lease
push: add shorthand for --force-with-lease branch creation
Documentation/git-push: fix placeholder formatting
The reflog output format is documented better, and a new format
--date=unix to report the seconds-since-epoch (without timezone)
has been added.
* jk/reflog-date:
date: clarify --date=raw description
date: add "unix" format
date: document and test "raw-local" mode
doc/pretty-formats: explain shortening of %gd
doc/pretty-formats: describe index/time formats for %gd
doc/rev-list-options: explain "-g" output formats
doc/rev-list-options: clarify "commit@{Nth}" for "-g" option
"git merge" with renormalization did not work well with
merge-recursive, due to "safer crlf" conversion kicking in when it
shouldn't.
* jc/renormalize-merge-kill-safer-crlf:
merge: avoid "safer crlf" during recording of merge results
convert: unify the "auto" handling of CRLF
There are certain house-keeping tasks that need to be performed at
the very beginning of any Git program, and programs that are not
built-in commands had to do them exactly the same way as "git"
potty does. It was easy to make mistakes in one-off standalone
programs (like test helpers). A common "main()" function that
calls cmd_main() of individual program has been introduced to
make it harder to make mistakes.
* jk/common-main:
mingw: declare main()'s argv as const
common-main: call git_setup_gettext()
common-main: call restore_sigpipe_to_default()
common-main: call sanitize_stdfds()
common-main: call git_extract_argv0_path()
add an extra level of indirection to main()
According to LARGE_PACKET_MAX in pkt-line.h the maximal length of a
pkt-line packet is 65520 bytes. The pkt-line header takes 4 bytes and
therefore the pkt-line data component must not exceed 65516 bytes.
Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update the suggestion in 175d38ca ("SubmittingPatches: document how
to reference previous commits", 2016-07-28) on the format to refer
to a commit to match what gitk has been giving since last year with
its "Copy commit summary" command; also mention this as one of the
ways to obtain a commit reference in this format.
Signed-off-by: Beat Bolli <dev+git@drbeat.li>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When the index is locked and child processes inherit the handle to
said lock and the parent process wants to remove the lock before the
child process exits, on Windows there is a problem: it won't work
because files cannot be deleted if a process holds a handle on them.
The symptom:
Rename from 'xxx/.git/index.lock' to 'xxx/.git/index' failed.
Should I try again? (y/n)
Spawning child processes with bInheritHandles==FALSE would not work
because no file handles would be inherited, not even the hStdXxx
handles in STARTUPINFO (stdin/stdout/stderr).
Opening every file with O_NOINHERIT does not work, either, as e.g.
git-upload-pack expects inherited file handles.
This leaves us with the only way out: creating temp files with the
O_NOINHERIT flag. This flag is Windows-specific, however. For our
purposes, it is equivalent to O_CLOEXEC (which does not exist on
Windows), so let's just open temporary files with the O_CLOEXEC flag and
map that flag to O_NOINHERIT on Windows.
As Eric Wong pointed out, we need to be careful to handle the case where
the Linux headers used to compile Git support O_CLOEXEC but the Linux
kernel used to run Git does not: it returns an EINVAL.
This fixes the test that we just introduced to demonstrate the problem.
Signed-off-by: Ben Wijen <ben@wijen.net>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since 4804aab (help (Windows): Display HTML in default browser using
Windows' shell API, 2008-07-13), Git for Windows used to call
`ShellExecute()` to launch the default Windows handler for `.html`
files.
The idea was to avoid going through a shell script, for performance
reasons.
However, this change ignores the `help.browser` config setting. Together
with browsing help not being a performance-critical operation, let's
just revert that patch.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
On Windows, a file cannot be removed unless all file handles to it have
been released. Hence it is particularly important to close handles when
spawning children (which would probably not even know that they hold on
to those handles).
The example chosen for this test is a custom merge driver that indeed
has no idea that it blocks the deletion of index.lock. The full use case
is a daemon that lives on after the merge, with subsequent invocations
handing off to the daemon, thereby avoiding hefty start-up costs. We
simulate this behavior by simply sleeping one second.
Note that the test only fails on Windows, due to the file locking issue.
Since we have no way to say "expect failure with MINGW, success
otherwise", we simply skip this test on Windows for now.
Signed-off-by: Ben Wijen <ben@wijen.net>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To reference previous commits people used to put just the
abbreviated SHA-1 into commit messages. This is what has evolved as
a more stable format for referencing commits. So lets document it
for everyone to look-up when needed.
Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Some pathnames that are okay on ext4 and on HFS+ cannot be checked
out on Windows. Tests that want to see operations on such paths on
filesystems that support them must do so behind appropriate test
prerequisites, and must not include them in the source tree (instead
they should create them when they run). Otherwise, the source tree
cannot even be checked out.
Make sure that double-quotes, asterisk, colon, greater/less-than,
question-mark, backslash, tab, vertical-bar, as well as any non-ASCII
characters never appear in the pathnames with a new test-lint-* target
as part of a `make test`. To that end, we call `git ls-files` (ensuring
that the paths are quoted properly), relying on the fact that paths
containing non-ASCII characters are quoted within double-quotes.
In case that the source code does not actually live in a Git
repository (e.g. when extracted from a .zip file), or that the `git`
executable cannot be executed, we simply ignore the error for now; In
that case, our trusty Continuous Integration will be the last line of
defense and catch any problematic file name.
Noticed when a topic wanted to add a pathname with '>' in it. A
check like this will prevent a similar problems from happening in the
future.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
At the moment difftool's "trust exit code" logic always suppresses the
exit status of the diff utility we invoke. This is useful because we
don't want to exit just because diff returned "1" because the files
differ, but it's confusing if the shell returns an error because the
selected diff utility is not found.
POSIX specifies 127 as the exit status for "command not found", 126 for
"command found but is not executable" and values greater than 128 if the
command terminated because it received a signal [1] and at least bash
and dash follow this specification, while diff utilities generally use
"1" for the exit status we want to ignore.
Handle any value of 126 or greater as a special value indicating that
some form of fatal error occurred.
[1] http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_08_02
Signed-off-by: John Keeping <john@keeping.me.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a user asked for a detached HEAD specifically with `--detach`,
we do not need to give advice on what a detached HEAD state entails as
we can assume they know what they're getting into as they asked for it.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The test added in 71abeb753f (reflog: continue walking the reflog
past root commits, 2016-06-03) contains an unnecessary 'git reflog'
execution, which was part of my debug/tracing instrumentation that I
somehow didn't manage to remove before submitting.
Signed-off-by: SZEDER Gábor <szeder@ira.uka.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Use the macro FLEX_ALLOC_MEM instead of open-coding it. This shortens
and simplifies the code a bit.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert the name member of struct merge_remote_desc to a FLEX_ARRAY and
use FLEX_ALLOC_STR to build the struct. This halves the number of
memory allocations, saves the storage for a pointer and avoids an
indirection when reading the name.
Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
One of the indirect callers of make_virtual_commit() passes the result of
oid_to_hex() as the name, i.e. a pointer to a static buffer. Since the
function uses that string pointer directly in building a struct
merge_remote_desc, multiple entries can end up sharing the same name
inadvertently.
Fix that by calling set_merge_remote_desc(), which creates a copy of the
string, instead of building the struct by hand.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Export a helper function for allocating, populating and attaching a
merge_remote_desc to a commit.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Handle allocation errors for the name member just like we already do
for the struct merge_remote_desc itself.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
handle_message_id() duplicates the contents of the strbuf that is passed
to it. Its only caller proceeds to release the strbuf immediately after
that. Reuse it instead and make that change of object ownership more
obvious by inlining this short function.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This section is about "The FLEXPTR_* variants", so use FLEXPTR_ALLOC_STR
in the example.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git difftool <paths>..." started in a subdirectory failed to
interpret the paths relative to that directory, which has been
fixed.
* jk/difftool-in-subdir:
difftool: use Git::* functions instead of passing around state
difftool: avoid $GIT_DIR and $GIT_WORK_TREE
difftool: fix argument handling in subdirs
Not-so-recent rewrite of "git am" that started making internal
calls into the commit machinery had an unintended regression, in
that no matter how many seconds it took to apply many patches, the
resulting committer timestamp for the resulting commits were all
the same.
* jk/reset-ident-time-per-commit:
am: reset cached ident date for each patch
