In order to prevent a valid push certificate for pushing into an
repository from getting replayed in a different push operation, send
a nonce string from the receive-pack process and have the signer
include it in the push certificate. The receiving end uses an HMAC
hash of the path to the repository it serves and the current time
stamp, hashed with a secret seed (the secret seed does not have to
be per-repository but can be defined in /etc/gitconfig) to generate
the nonce, in order to ensure that a random third party cannot forge
a nonce that looks like it originated from it.
The original nonce is exported as GIT_PUSH_CERT_NONCE for the hooks
to examine and match against the value on the "nonce" header in the
certificate to notice a replay, but returned "nonce" header in the
push certificate is examined by receive-pack and the result is
exported as GIT_PUSH_CERT_NONCE_STATUS, whose value would be "OK"
if the nonce recorded in the certificate matches what we expect, so
that the hooks can more easily check.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Record the URL of the intended recipient for a push (after
anonymizing it if it has authentication material) on a new "pushee
URL" header. Because the networking configuration (SSH-tunnels,
proxies, etc.) on the pushing user's side varies, the receiving
repository may not know the single canonical URL all the pushing
users would refer it as (besides, many sites allow pushing over
ssh://host/path and https://host/path protocols to the same
repository but with different local part of the path). So this
value may not be reliably used for replay-attack prevention
purposes, but this will still serve as a human readable hint to
identify the repository the certificate refers to.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With the interim protocol, we used to send the update commands even
though we already send a signed copy of the same information when
push certificate is in use. Update the send-pack/receive-pack pair
not to do so.
The notable thing on the receive-pack side is that it makes sure
that there is no command sent over the traditional protocol packet
outside the push certificate. Otherwise a pusher can claim to be
pushing one set of ref updates in the signed certificate while
issuing commands to update unrelated refs, and such an update will
evade later audits.
Finally, start documenting the protocol.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We would want to update the interim protocol so that we do not send
the usual update commands when the push certificate feature is in
use, as the same information is in the certificate. Once that
happens, the push-cert packet may become the only protocol command,
but then there is no packet to put the feature request behind, like
we always did.
As we have prepared the receiving end that understands the push-cert
feature to accept the feature request on the first protocol packet
(other than "shallow ", which was an unfortunate historical mistake
that has to come before everything else), we can give the feature
request on the push-cert packet instead of the first update protocol
packet, in preparation for the next step to actually update to the
final protocol.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Reusing the GPG signature check helpers we already have, verify
the signature in receive-pack and give the results to the hooks
via GIT_PUSH_CERT_{SIGNER,KEY,STATUS} environment variables.
Policy decisions, such as accepting or rejecting a good signature by
a key that is not fully trusted, is left to the hook and kept
outside of the core.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
While signed tags and commits assert that the objects thusly signed
came from you, who signed these objects, there is not a good way to
assert that you wanted to have a particular object at the tip of a
particular branch. My signing v2.0.1 tag only means I want to call
the version v2.0.1, and it does not mean I want to push it out to my
'master' branch---it is likely that I only want it in 'maint', so
the signature on the object alone is insufficient.
The only assurance to you that 'maint' points at what I wanted to
place there comes from your trust on the hosting site and my
authentication with it, which cannot easily audited later.
Introduce a mechanism that allows you to sign a "push certificate"
(for the lack of better name) every time you push, asserting that
what object you are pushing to update which ref that used to point
at what other object. Think of it as a cryptographic protection for
ref updates, similar to signed tags/commits but working on an
orthogonal axis.
The basic flow based on this mechanism goes like this:
1. You push out your work with "git push --signed".
2. The sending side learns where the remote refs are as usual,
together with what protocol extension the receiving end
supports. If the receiving end does not advertise the protocol
extension "push-cert", an attempt to "git push --signed" fails.
Otherwise, a text file, that looks like the following, is
prepared in core:
certificate version 0.1
pusher Junio C Hamano <gitster@pobox.com> 1315427886 -0700
7339ca65... 21580ecb... refs/heads/master
3793ac56... 12850bec... refs/heads/next
The file begins with a few header lines, which may grow as we
gain more experience. The 'pusher' header records the name of
the signer (the value of user.signingkey configuration variable,
falling back to GIT_COMMITTER_{NAME|EMAIL}) and the time of the
certificate generation. After the header, a blank line follows,
followed by a copy of the protocol message lines.
Each line shows the old and the new object name at the tip of
the ref this push tries to update, in the way identical to how
the underlying "git push" protocol exchange tells the ref
updates to the receiving end (by recording the "old" object
name, the push certificate also protects against replaying). It
is expected that new command packet types other than the
old-new-refname kind will be included in push certificate in the
same way as would appear in the plain vanilla command packets in
unsigned pushes.
The user then is asked to sign this push certificate using GPG,
formatted in a way similar to how signed tag objects are signed,
and the result is sent to the other side (i.e. receive-pack).
In the protocol exchange, this step comes immediately before the
sender tells what the result of the push should be, which in
turn comes before it sends the pack data.
3. When the receiving end sees a push certificate, the certificate
is written out as a blob. The pre-receive hook can learn about
the certificate by checking GIT_PUSH_CERT environment variable,
which, if present, tells the object name of this blob, and make
the decision to allow or reject this push. Additionally, the
post-receive hook can also look at the certificate, which may be
a good place to log all the received certificates for later
audits.
Because a push certificate carry the same information as the usual
command packets in the protocol exchange, we can omit the latter
when a push certificate is in use and reduce the protocol overhead.
This however is not included in this patch to make it easier to
review (in other words, the series at this step should never be
released without the remainder of the series, as it implements an
interim protocol that will be incompatible with the final one).
As such, the documentation update for the protocol is left out of
this step.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Everywhere else we use PKT-LINE to denote the pkt-line formatted
data, but "shallow/deepen" messages are described with PKT_LINE().
Fix them.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Our signed-tag objects set the standard format used by Git to store
GPG-signed payload (i.e. the payload followed by its detached
signature) [*1*], and it made sense to have a helper to find the
boundary between the payload and its signature in tag.c back then.
Newer code added later to parse other kinds of objects that learned
to use the same format to store GPG-signed payload (e.g. signed
commits), however, kept using the helper from the same location.
Move it to gpg-interface; the helper is no longer about signed tag,
but it is how our code and data interact with GPG.
[Reference]
*1* http://thread.gmane.org/gmane.linux.kernel/297998/focus=1383
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Earlier, ffb6d7d5 (Move commit GPG signature verification to
commit.c, 2013-03-31) moved this helper that used to be in pretty.c
(i.e. the output code path) to commit.c for better reusability.
It was a good first step in the right direction, but still suffers
from a myopic view that commits will be the only thing we would ever
want to sign---we would actually want to be able to reuse it even
wider.
The function interprets what GPG said; gpg-interface is obviously a
better place. Move it there.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We use it to make sure that the feature request is sent only once on
the very first request packet (ignoring the "shallow " line, which
was an unfortunate mistake we cannot retroactively fix with existing
receive-pack already deployed in the field) and we set it to "true"
with cmds_sent++, not because we care about the actual number of
updates sent but because it is merely an idiomatic way.
Set it explicitly to one to clarify that the code that uses this
variable only cares about its zero-ness.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The main loop over remote_refs list inspects the ref status
to see if we need to generate pack data (i.e. a delete-only push
does not need to send any additional data), resets it to "expecting
the status report" state, and formats the actual update commands
to be sent.
Split the former two out of the main loop, as it will become
conditional in later steps.
Besides, we should have code that does real thing here, before the
"Finally, tell the other end!" part ;-)
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The variable counts how many non-deleting command is being sent, but
is only checked with 0-ness to decide if we need to send the pack
data.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Similar to the previous one for send-pack, make it easier and
cleaner to add to capability advertisement.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A run of 'var ? " var" : ""' fed to a long printf string in a deeply
nested block was hard to read. Move it outside the loop and format
it into a strbuf.
As an added bonus, the trick to add "agent=<agent-name>" by using
two conditionals is replaced by a more readable version.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We tried to avoid sending one extra byte, NUL and nothing behind it
to signal there is no protocol capabilities being sent, on the first
command packet on the wire, but it just made the code look ugly.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A new helper function ref_update_to_be_sent() decides for each ref
if the update is to be sent based on the status previously set by
set_ref_status_for_push() and also if this is a mirrored push.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
20e8b465 (refactor ref status logic for pushing, 2010-01-08)
restructured the code to set status for each ref to be pushed, but
did not quite go far enough. We inspect the status set earlier by
set_refs_status_for_push() and then perform yet another update to
the status of a ref with an otherwise OK status to be deleted to
mark it with REF_STATUS_REJECT_NODELETE when the protocol tells us
never to delete.
Split the latter into a separate loop that comes before we enter the
per-ref loop. This way we would have one less condition to check in
the main loop.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make a helper function to accept a line of a protocol message and
queue an update command out of the code from read_head_info().
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This piece of code reads object names of shallow boundaries, not
old_sha1[], i.e. the current value the ref points at, which is to be
replaced by what is in new_sha1[].
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Ideally, we should have also allowed the first "shallow" to carry
the feature request trailer, but that is water under the bridge
now. This makes the next step to factor out the queuing of commands
easier to review.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
An "update" command in the protocol exchange consists of 40-hex old
object name, SP, 40-hex new object name, SP, and a refname, but the
first instance is further followed by a NUL with feature requests.
The command structure, which has a flex-array member that stores the
refname at the end, was allocated based on the whole length of the
update command, without excluding the trailing feature requests.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make tests pass on msysgit by mostly disabling ones that are
infeasible on that platform.
* sk/mingw-tests-workaround:
t800[12]: work around MSys limitation
t9902: mingw-specific fix for gitfile link files
t4210: skip command-line encoding tests on mingw
MinGW: disable legacy encoding tests
t0110/MinGW: skip tests that pass arbitrary bytes on the command line
MinGW: Skip test redirecting to fd 4
Most of these are battle-tested in msysgit and are needed to
complete what has been merged to 'master' already.
* sk/mingw-uni-fix-more:
Win32: enable color output in Windows cmd.exe
Win32: patch Windows environment on startup
Win32: keep the environment sorted
Win32: use low-level memory allocation during initialization
Win32: reduce environment array reallocations
Win32: don't copy the environment twice when spawning child processes
Win32: factor out environment block creation
Win32: unify environment function names
Win32: unify environment case-sensitivity
Win32: fix environment memory leaks
Win32: Unicode environment (incoming)
Win32: Unicode environment (outgoing)
Revert "Windows: teach getenv to do a case-sensitive search"
tests: do not pass iso8859-1 encoded parameter
The test case "--amend option copies authorship" specifies that the
git-commit option `--amend` uses the authorship of the replaced
commit for the new commit. Add the omitted check that this property
actually holds.
Signed-off-by: Fabian Ruch <bafain@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* maint:
t4013: test diff-tree's --stdin commit formatting
diff-tree: avoid lookup_unknown_object
object_as_type: set commit index
alloc: factor out commit index
add object_as_type helper for casting objects
parse_object_buffer: do not set object type
move setting of object->type to alloc_* functions
alloc: write out allocator definitions
alloc.c: remove the alloc_raw_commit_node() function
Once upon a time, git-log was just "rev-list | diff-tree",
and we did not bother to test it separately. These days git-log
is implemented internally, but we want to make sure that the
rev-list to diff-tree pipeline continues to function. Let's
add a basic sanity test.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This has been illegal since cbdffe4 (check_ref_format(): tighten
refname rules, 2009-03-21), but we never tested it.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* jk/alloc-commit-id-maint:
diff-tree: avoid lookup_unknown_object
object_as_type: set commit index
alloc: factor out commit index
add object_as_type helper for casting objects
parse_object_buffer: do not set object type
move setting of object->type to alloc_* functions
alloc: write out allocator definitions
alloc.c: remove the alloc_raw_commit_node() function
We generally want to avoid lookup_unknown_object, because it
results in allocating more memory for the object than may be
strictly necessary.
In this case, it is used to check whether we have an
already-parsed object before calling parse_object, to save
us from reading the object from disk. Using lookup_object
would be fine for that purpose, but we can take it a step
further. Since this code was written, parse_object already
learned the "check lookup_object" optimization, so we can
simply call parse_object directly.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The point of the "index" field of struct commit is that
every allocated commit would have one. It is supposed to be
an invariant that whenever object->type is set to
OBJ_COMMIT, we have a unique index.
Commit 969eba6 (commit: push commit_index update into
alloc_commit_node, 2014-06-10) covered this case for
newly-allocated commits. However, we may also allocate an
"unknown" object via lookup_unknown_object, and only later
convert it to a commit. We must make sure that we set the
commit index when we switch the type field.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We keep a static counter to set the commit index on newly
allocated objects. However, since we also need to set the
index on any_objects which are converted to commits, let's
make the counter available as a public function.
While we're moving it, let's make sure the counter is
allocated as an unsigned integer to match the index field in
"struct commit".
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we call lookup_commit, lookup_tree, etc, the logic goes
something like:
1. Look for an existing object struct. If we don't have
one, allocate and return a new one.
2. Double check that any object we have is the expected
type (and complain and return NULL otherwise).
3. Convert an object with type OBJ_NONE (from a prior
call to lookup_unknown_object) to the expected type.
We can encapsulate steps 2 and 3 in a helper function which
checks whether we have the expected object type, converts
OBJ_NONE as appropriate, and returns the object.
Not only does this shorten the code, but it also provides
one central location for converting OBJ_NONE objects into
objects of other types. Future patches will use that to
enforce type-specific invariants.
Since this is a refactoring, we would want it to behave
exactly as the current code. It takes a little reasoning to
see that this is the case:
- for lookup_{commit,tree,etc} functions, we are just
pulling steps 2 and 3 into a function that does the same
thing.
- for the call in peel_object, we currently only do step 3
(but we want to consolidate it with the others, as
mentioned above). However, step 2 is a noop here, as the
surrounding conditional makes sure we have OBJ_NONE
(which we want to keep to avoid an extraneous call to
sha1_object_info).
- for the call in lookup_commit_reference_gently, we are
currently doing step 2 but not step 3. However, step 3
is a noop here. The object we got will have just come
from deref_tag, which must have figured out the type for
each object in order to know when to stop peeling.
Therefore the type will never be OBJ_NONE.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The only way that "obj" can be non-NULL is if it came from
one of the lookup_* functions. These functions always ensure
that the object has the expected type (and return NULL
otherwise), so there is no need for us to set the type.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "struct object" type implements basic object
polymorphism. Individual instances are allocated as
concrete types (or as a union type that can store any
object), and a "struct object *" can be cast into its real
type after examining its "type" enum. This means it is
dangerous to have a type field that does not match the
allocation (e.g., setting the type field of a "struct blob"
to "OBJ_COMMIT" would mean that a reader might read past the
allocated memory).
In most of the current code this is not a problem; the first
thing we do after allocating an object is usually to set its
type field by passing it to create_object. However, the
virtual commits we create in merge-recursive.c do not ever
get their type set. This does not seem to have caused
problems in practice, though (presumably because we always
pass around a "struct commit" pointer and never even look at
the type).
We can fix this oversight and also make it harder for future
code to get it wrong by setting the type directly in the
object allocation functions.
This will also make it easier to fix problems with commit
index allocation, as we know that any object allocated by
alloc_commit_node will meet the invariant that an object
with an OBJ_COMMIT type field will have a unique index
number.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Because the allocator functions for tree, blobs, etc are all
very similar, we originally used a macro to avoid repeating
ourselves. Since the prior commit, though, the heavy lifting
is done by an inline helper function. The macro does still
save us a few lines, but at some readability cost. It
obfuscates the function definitions (and makes them hard to
find via grep).
Much worse, though, is the fact that it isn't used
consistently for all allocators. Somebody coming later may
be tempted to modify DEFINE_ALLOCATOR, but they would miss
alloc_commit_node, which is treated specially.
Let's just drop the macro and write everything out
explicitly.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In order to encapsulate the setting of the unique commit index, commit
969eba63 ("commit: push commit_index update into alloc_commit_node",
10-06-2014) introduced a (logically private) intermediary allocator
function. However, this function (alloc_raw_commit_node()) was declared
as a public function, which undermines its entire purpose.
Introduce an inline function, alloc_node(), which implements the main
logic of the allocator used by DEFINE_ALLOCATOR, and redefine the macro
in terms of the new function. In addition, use the new function in the
implementation of the alloc_commit_node() allocator, rather than the
intermediary allocator, which can now be removed.
Noticed by sparse ("symbol 'alloc_raw_commit_node' was not declared.
Should it be static?").
Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git rebase --fork-point" did not filter out patch-identical
commits correctly.
* jk/rebase-am-fork-point:
rebase: omit patch-identical commits with --fork-point
rebase--am: use --cherry-pick instead of --ignore-if-in-upstream
"git replace" learned a "--graft" option to rewrite parents of a
commit.
* cc/replace-graft:
replace: add test for --graft with a mergetag
replace: check mergetags when using --graft
replace: add test for --graft with signed commit
replace: remove signature when using --graft
contrib: add convert-grafts-to-replace-refs.sh
Documentation: replace: add --graft option
replace: add test for --graft
replace: add --graft option
replace: cleanup redirection style in tests
* jk/stable-prio-queue:
t5539: update a flaky test
paint_down_to_common: use prio_queue
prio-queue: make output stable with respect to insertion
prio-queue: factor out compare and swap operations
When parsing "index" lines from a git-diff, we look for a
space followed by the mode. If we don't have a space, then
we set our pointer to the end-of-line. However, we don't
double-check that our end-of-line pointer is valid (e.g., if
we got a truncated diff input), which could lead to some
wrap-around pointer arithmetic.
In most cases this would probably get caught by our "40 <
len" check later in the function, but to be on the safe
side, let's just use strchrnul to treat end-of-string the
same as end-of-line.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
