Commit graph

312 commits

Author SHA1 Message Date
Jiang Xin f65003b4c4 receive-pack: gently write messages to proc-receive
Johannes found a flaky hang in `t5411/test-0013-bad-protocol.sh` in the
osx-clang job of the CI/PR builds, and ran into an issue when using
the `--stress` option with the following error messages:

    fatal: unable to write flush packet: Broken pipe
    send-pack: unexpected disconnect while reading sideband packet
    fatal: the remote end hung up unexpectedly

In this test case, the "proc-receive" hook sends an error message and
dies earlier. While "receive-pack" on the other side of the pipe
should forward the error message of the "proc-receive" hook to the
client side, but it fails to do so. This is because "receive-pack"
uses `packet_write_fmt()` and `packet_flush()` to write pkt-line
message to "proc-receive" hook, and these functions die immediately
when pipe is broken. Using "gently" forms for these functions will get
more predicable output.

Add more "--die-*" options to test helper to test different stages of
the protocol between "receive-pack" and "proc-receive" hook.

Reported-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-11 12:46:56 -08:00
Junio C Hamano 6c430a647c Merge branch 'jx/proc-receive-hook'
"git receive-pack" that accepts requests by "git push" learned to
outsource most of the ref updates to the new "proc-receive" hook.

* jx/proc-receive-hook:
  doc: add documentation for the proc-receive hook
  transport: parse report options for tracking refs
  t5411: test updates of remote-tracking branches
  receive-pack: new config receive.procReceiveRefs
  doc: add document for capability report-status-v2
  New capability "report-status-v2" for git-push
  receive-pack: feed report options to post-receive
  receive-pack: add new proc-receive hook
  t5411: add basic test cases for proc-receive hook
  transport: not report a non-head push as a branch
2020-09-25 15:25:39 -07:00
Jiang Xin 31e8595a11 receive-pack: new config receive.procReceiveRefs
Add a new multi-valued config variable "receive.procReceiveRefs"
for `receive-pack` command, like the follows:

    git config --system --add receive.procReceiveRefs refs/for
    git config --system --add receive.procReceiveRefs refs/drafts

If the specific prefix strings given by the config variables match the
reference names of the commands which are sent from git client to
`receive-pack`, these commands will be executed by an external hook
(named "proc-receive"), instead of the internal `execute_commands`
function.

For example, if it is set to "refs/for", pushing to a reference such as
"refs/for/master" will not create or update reference "refs/for/master",
but may create or update a pull request directly by running the hook
"proc-receive".

Optional modifiers can be provided in the beginning of the value to
filter commands for specific actions: create (a), modify (m),
delete (d). A `!` can be included in the modifiers to negate the
reference prefix entry. E.g.:

    git config --system --add receive.procReceiveRefs ad:refs/heads
    git config --system --add receive.procReceiveRefs !:refs/heads

Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-27 12:47:47 -07:00
Jiang Xin 63518a574a New capability "report-status-v2" for git-push
The new introduced "proc-receive" hook may handle a command for a
pseudo-reference with a zero-old as its old-oid, while the hook may
create or update a reference with different name, different new-oid,
and different old-oid (the reference may exist already with a non-zero
old-oid).  Current "report-status" protocol cannot report the status for
such reference rewrite.

Add new capability "report-status-v2" and new report protocol which is
not backward compatible for report of git-push.

If a user pushes to a pseudo-reference "refs/for/master/topic", and
"receive-pack" creates two new references "refs/changes/23/123/1" and
"refs/changes/24/124/1", for client without the knowledge of
"report-status-v2", "receive-pack" will only send "ok/ng" directives in
the report, such as:

    ok ref/for/master/topic

But for client which has the knowledge of "report-status-v2",
"receive-pack" will use "option" directives to report more attributes
for the reference given by the above "ok/ng" directive.

    ok refs/for/master/topic
    option refname refs/changes/23/123/1
    option new-oid <new-oid>
    ok refs/for/master/topic
    option refname refs/changes/24/124/1
    option new-oid <new-oid>

The client will report two new created references to the end user.

Suggested-by: Junio C Hamano <gitster@pobox.com>
Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-27 12:47:47 -07:00
Jiang Xin 195d6eaea3 receive-pack: feed report options to post-receive
When commands are fed to the "post-receive" hook, report options will
be parsed and the real old-oid, new-oid, reference name will feed to
the "post-receive" hook.

Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-27 12:47:47 -07:00
Jiang Xin 15d3af5e22 receive-pack: add new proc-receive hook
Git calls an internal `execute_commands` function to handle commands
sent from client to `git-receive-pack`.  Regardless of what references
the user pushes, git creates or updates the corresponding references if
the user has write-permission.  A contributor who has no
write-permission, cannot push to the repository directly.  So, the
contributor has to write commits to an alternate location, and sends
pull request by emails or by other ways.  We call this workflow as a
distributed workflow.

It would be more convenient to work in a centralized workflow like what
Gerrit provided for some cases.  For example, a read-only user who
cannot push to a branch directly can run the following `git push`
command to push commits to a pseudo reference (has a prefix "refs/for/",
not "refs/heads/") to create a code review.

    git push origin \
        HEAD:refs/for/<branch-name>/<session>

The `<branch-name>` in the above example can be as simple as "master",
or a more complicated branch name like "foo/bar".  The `<session>` in
the above example command can be the local branch name of the client
side, such as "my/topic".

We cannot implement a centralized workflow elegantly by using
"pre-receive" + "post-receive", because Git will call the internal
function "execute_commands" to create references (even the special
pseudo reference) between these two hooks.  Even though we can delete
the temporarily created pseudo reference via the "post-receive" hook,
having a temporary reference is not safe for concurrent pushes.

So, add a filter and a new handler to support this kind of workflow.
The filter will check the prefix of the reference name, and if the
command has a special reference name, the filter will turn a specific
field (`run_proc_receive`) on for the command.  Commands with this filed
turned on will be executed by a new handler (a hook named
"proc-receive") instead of the internal `execute_commands` function.
We can use this "proc-receive" command to create pull requests or send
emails for code review.

Suggested by Junio, this "proc-receive" hook reads the commands,
push-options (optional), and send result using a protocol in pkt-line
format.  In the following example, the letter "S" stands for
"receive-pack" and letter "H" stands for the hook.

    # Version and features negotiation.
    S: PKT-LINE(version=1\0push-options atomic...)
    S: flush-pkt
    H: PKT-LINE(version=1\0push-options...)
    H: flush-pkt

    # Send commands from server to the hook.
    S: PKT-LINE(<old-oid> <new-oid> <ref>)
    S: ... ...
    S: flush-pkt
    # Send push-options only if the 'push-options' feature is enabled.
    S: PKT-LINE(push-option)
    S: ... ...
    S: flush-pkt

    # Receive result from the hook.
    # OK, run this command successfully.
    H: PKT-LINE(ok <ref>)
    # NO, I reject it.
    H: PKT-LINE(ng <ref> <reason>)
    # Fall through, let 'receive-pack' to execute it.
    H: PKT-LINE(ok <ref>)
    H: PKT-LINE(option fall-through)
    # OK, but has an alternate reference.  The alternate reference name
    # and other status can be given in options
    H: PKT-LINE(ok <ref>)
    H: PKT-LINE(option refname <refname>)
    H: PKT-LINE(option old-oid <old-oid>)
    H: PKT-LINE(option new-oid <new-oid>)
    H: PKT-LINE(option forced-update)
    H: ... ...
    H: flush-pkt

After receiving a command, the hook will execute the command, and may
create/update different reference.  For example, a command for a pseudo
reference "refs/for/master/topic" may create/update different reference
such as "refs/pull/123/head".  The alternate reference name and other
status are given in option lines.

The list of commands returned from "proc-receive" will replace the
relevant commands that are sent from user to "receive-pack", and
"receive-pack" will continue to run the "execute_commands" function and
other routines.  Finally, the result of the execution of these commands
will be reported to end user.

The reporting function from "receive-pack" to "send-pack" will be
extended in latter commit just like what the "proc-receive" hook reports
to "receive-pack".

Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-27 12:47:47 -07:00
Jeff King d70a9eb611 strvec: rename struct fields
The "argc" and "argv" names made sense when the struct was argv_array,
but now they're just confusing. Let's rename them to "nr" (which we use
for counts elsewhere) and "v" (which is rather terse, but reads well
when combined with typical variable names like "args.v").

Note that we have to update all of the callers immediately. Playing
tricks with the preprocessor is hard here, because we wouldn't want to
rewrite unrelated tokens.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-30 19:18:06 -07:00
Jeff King f6d8942b1f strvec: fix indentation in renamed calls
Code which split an argv_array call across multiple lines, like:

  argv_array_pushl(&args, "one argument",
                   "another argument", "and more",
		   NULL);

was recently mechanically renamed to use strvec, which results in
mis-matched indentation like:

  strvec_pushl(&args, "one argument",
                   "another argument", "and more",
		   NULL);

Let's fix these up to align the arguments with the opening paren. I did
this manually by sifting through the results of:

  git jump grep 'strvec_.*,$'

and liberally applying my editor's auto-format. Most of the changes are
of the form shown above, though I also normalized a few that had
originally used a single-tab indentation (rather than our usual style of
aligning with the open paren). I also rewrapped a couple of obvious
cases (e.g., where previously too-long lines became short enough to fit
on one), but I wasn't aggressive about it. In cases broken to three or
more lines, the grouping of arguments is sometimes meaningful, and it
wasn't worth my time or reviewer time to ponder each case individually.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28 15:02:18 -07:00
Jeff King 22f9b7f3f5 strvec: convert builtin/ callers away from argv_array name
We eventually want to drop the argv_array name and just use strvec
consistently. There's no particular reason we have to do it all at once,
or care about interactions between converted and unconverted bits.
Because of our preprocessor compat layer, the names are interchangeable
to the compiler (so even a definition and declaration using different
names is OK).

This patch converts all of the files in builtin/ to keep the diff to a
manageable size.

The conversion was done purely mechanically with:

  git ls-files '*.c' '*.h' |
  xargs perl -i -pe '
    s/ARGV_ARRAY/STRVEC/g;
    s/argv_array/strvec/g;
  '

and then selectively staging files with "git add builtin/". We'll deal
with any indentation/style fallouts separately.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28 15:02:18 -07:00
Jeff King dbbcd44fb4 strvec: rename files from argv-array to strvec
This requires updating #include lines across the code-base, but that's
all fairly mechanical, and was done with:

  git ls-files '*.c' '*.h' |
  xargs perl -i -pe 's/argv-array.h/strvec.h/'

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28 15:02:17 -07:00
Junio C Hamano 12210859da Merge branch 'bc/sha-256-part-2'
SHA-256 migration work continues.

* bc/sha-256-part-2: (44 commits)
  remote-testgit: adapt for object-format
  bundle: detect hash algorithm when reading refs
  t5300: pass --object-format to git index-pack
  t5704: send object-format capability with SHA-256
  t5703: use object-format serve option
  t5702: offer an object-format capability in the test
  t/helper: initialize the repository for test-sha1-array
  remote-curl: avoid truncating refs with ls-remote
  t1050: pass algorithm to index-pack when outside repo
  builtin/index-pack: add option to specify hash algorithm
  remote-curl: detect algorithm for dumb HTTP by size
  builtin/ls-remote: initialize repository based on fetch
  t5500: make hash independent
  serve: advertise object-format capability for protocol v2
  connect: parse v2 refs with correct hash algorithm
  connect: pass full packet reader when parsing v2 refs
  Documentation/technical: document object-format for protocol v2
  t1302: expect repo format version 1 for SHA-256
  builtin/show-index: provide options to determine hash algo
  t5302: modernize test formatting
  ...
2020-07-06 22:09:13 -07:00
brian m. carlson bb095d0875 builtin/receive-pack: detect when the server doesn't support our hash
Detect when the server doesn't support our hash algorithm and abort.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-27 10:07:06 -07:00
brian m. carlson bf30dbf826 remote: advertise the object-format capability on the server side
Advertise the current hash algorithm in use by using the object-format
capability as part of the ref advertisement.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-27 10:07:06 -07:00
Junio C Hamano 896833b268 Merge branch 'tb/shallow-cleanup'
Code cleanup.

* tb/shallow-cleanup:
  shallow: use struct 'shallow_lock' for additional safety
  shallow.h: document '{commit,rollback}_shallow_file'
  shallow: extract a header file for shallow-related functions
  commit: make 'commit_graft_pos' non-static
2020-05-13 12:19:18 -07:00
Junio C Hamano b9bcd76a9a Merge branch 'cb/avoid-colliding-with-netbsd-hmac'
The <stdlib.h> header on NetBSD brings in its own definition of
hmac() function (eek), which conflicts with our own and unrelated
function with the same name.  Our function has been renamed to work
around the issue.

* cb/avoid-colliding-with-netbsd-hmac:
  builtin/receive-pack: avoid generic function name hmac()
2020-05-08 14:25:09 -07:00
Carlo Marcelo Arenas Belón 3013118eb8 builtin/receive-pack: avoid generic function name hmac()
fabec2c5c3 (builtin/receive-pack: switch to use the_hash_algo, 2019-08-18)
renames hmac_sha1 to hmac, as it was updated to use the hash function used
by git (which won't be sha1 in the future).

hmac() is provided by NetBSD >= 8 libc and therefore conflicts as shown by :

builtin/receive-pack.c:421:13: error: conflicting types for 'hmac'
 static void hmac(unsigned char *out,
             ^~~~
In file included from ./git-compat-util.h:172:0,
                 from ./builtin.h:4,
                 from builtin/receive-pack.c:1:
/usr/include/stdlib.h:305:10: note: previous declaration of 'hmac' was here
 ssize_t  hmac(const char *, const void *, size_t, const void *, size_t, void *,
          ^~~~

Rename it again to hmac_hash to reflect it will use the git's defined hash
function and avoid the conflict, while at it update a comment to better
describe the HMAC function that was used.

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-05 11:26:25 -07:00
Junio C Hamano 2b4ff3d3dc Merge branch 'tb/reset-shallow'
Fix in-core inconsistency after fetching into a shallow repository
that broke the code to write out commit-graph.

* tb/reset-shallow:
  shallow.c: use '{commit,rollback}_shallow_file'
  t5537: use test_write_lines and indented heredocs for readability
2020-05-01 13:39:51 -07:00
Taylor Blau cac4b8e22e shallow: use struct 'shallow_lock' for additional safety
In previous patches, the functions 'commit_shallow_file' and
'rollback_shallow_file' were introduced to reset the shallowness
validity checks on a repository after potentially modifying
'.git/shallow'.

These functions can be made safer by wrapping the 'struct lockfile *' in
a new type, 'shallow_lock', so that they cannot be called with a raw
lock (and potentially misused by other code that happens to possess a
lockfile, but has nothing to do with shallowness).

This patch introduces that type as a thin wrapper around 'struct
lockfile', and updates the two aforementioned functions and their
callers to use it.

Suggested-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-30 14:19:13 -07:00
Taylor Blau 120ad2b0f1 shallow: extract a header file for shallow-related functions
There are many functions in commit.h that are more related to shallow
repositories than they are to any sort of generic commit machinery.
Likely this began when there were only a few shallow-related functions,
and commit.h seemed a reasonable enough place to put them.

But, now there are a good number of shallow-related functions, and
placing them all in 'commit.h' doesn't make sense.

This patch extracts a 'shallow.h', which takes all of the declarations
from 'commit.h' for functions which already exist in 'shallow.c'. We
will bring the remaining shallow-related functions defined in 'commit.c'
in a subsequent patch.

For now, move only the ones that already are implemented in 'shallow.c',
and update the necessary includes.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-30 14:19:13 -07:00
Junio C Hamano 2abd648b17 Merge branch 'bc/constant-memequal'
Validation of push certificate has been made more robust against
timing attacks.

* bc/constant-memequal:
  receive-pack: compilation fix
  builtin/receive-pack: use constant-time comparison for HMAC value
2020-04-28 15:49:57 -07:00
Taylor Blau 37b9dcabfc shallow.c: use '{commit,rollback}_shallow_file'
In bd0b42aed3 (fetch-pack: do not take shallow lock unnecessarily,
2019-01-10), the author noted that 'is_repository_shallow' produces
visible side-effect(s) by setting 'is_shallow' and 'shallow_stat'.

This is a problem for e.g., fetching with '--update-shallow' in a
shallow repository with 'fetch.writeCommitGraph' enabled, since the
update to '.git/shallow' will cause Git to think that the repository
isn't shallow when it is, thereby circumventing the commit-graph
compatibility check.

This causes problems in shallow repositories with at least shallow refs
that have at least one ancestor (since the client won't have those
objects, and therefore can't take the reachability closure over commits
when writing a commit-graph).

Address this by introducing thin wrappers over 'commit_lock_file' and
'rollback_lock_file' for use specifically when the lock is held over
'.git/shallow'. These wrappers (appropriately called
'commit_shallow_file' and 'rollback_shallow_file') call into their
respective functions in 'lockfile.h', but additionally reset validity
checks used by the shallow machinery.

Replace each instance of 'commit_lock_file' and 'rollback_lock_file'
with 'commit_shallow_file' and 'rollback_shallow_file' when the lock
being held is over the '.git/shallow' file.

As a result, 'prune_shallow' can now only be called once (since
'check_shallow_file_for_update' will die after calling
'reset_repository_shallow'). But, this is OK since we only call
'prune_shallow' at most once per process.

Helped-by: Jonathan Tan <jonathantanmy@google.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-24 13:56:39 -07:00
Junio C Hamano 719483e547 receive-pack: compilation fix
We do not use C99 "for loop initial declaration" in our codebase
(yet), but one snuck in.

Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-22 08:55:11 -07:00
brian m. carlson edc6dccf81 builtin/receive-pack: use constant-time comparison for HMAC value
When we're comparing a push cert nonce, we currently do so using strcmp.
Most implementations of strcmp short-circuit and exit as soon as they
know whether two values are equal.  This, however, is a problem when
we're comparing the output of HMAC, as it leaks information in the time
taken about how much of the two values match if they do indeed differ.

In our case, the nonce is used to prevent replay attacks against our
server via the embedded timestamp and replay attacks using requests from
a different server via the HMAC.  Push certs, which contain the nonces,
are signed, so an attacker cannot tamper with the nonces without
breaking validation of the signature.  They can, of course, create their
own signatures with invalid nonces, but they can also create their own
signatures with valid nonces, so there's nothing to be gained.  Thus,
there is no security problem.

Even though it doesn't appear that there are any negative consequences
from the current technique, for safety and to encourage good practices,
let's use a constant time comparison function for nonce verification.
POSIX does not provide one, but they are easy to write.

The technique we use here is also used in NaCl and the Go standard
library and relies on the fact that bitwise or and xor are constant time
on all known architectures.

We need not be concerned about exiting early if the actual and expected
lengths differ, since the standard cryptographic assumption is that
everyone, including an attacker, knows the format of and algorithm used
in our nonces (and in any event, they have the source code and can
determine it easily).  As a result, we assume everyone knows how long
our nonces should be.  This philosophy is also taken by the Go standard
library and other cryptographic libraries when performing constant time
comparisons on HMAC values.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-09 18:17:27 -07:00
Jeff King fe299ec5ae oid_array: rename source file from sha1-array
We renamed the actual data structure in 910650d2f8 (Rename sha1_array to
oid_array, 2017-03-31), but the file is still called sha1-array. Besides
being slightly confusing, it makes it more annoying to grep for leftover
occurrences of "sha1" in various files, because the header is included
in so many places.

Let's complete the transition by renaming the source and header files
(and fixing up a few comment references).

I kept the "-" in the name, as that seems to be our style; cf.
fc1395f4a4 (sha1_file.c: rename to use dash in file name, 2018-04-10).
We also have oidmap.h and oidset.h without any punctuation, but those
are "struct oidmap" and "struct oidset" in the code. We _could_ make
this "oidarray" to match, but somehow it looks uglier to me because of
the length of "array" (plus it would be a very invasive patch for little
gain).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-30 10:59:08 -07:00
Hariom Verma 4ef346482d receive.denyCurrentBranch: respect all worktrees
The receive.denyCurrentBranch config option controls what happens if
you push to a branch that is checked out into a non-bare repository.
By default, it rejects it. It can be disabled via `ignore` or `warn`.
Another yet trickier option is `updateInstead`.

However, this setting was forgotten when the git worktree command was
introduced: only the main worktree's current branch is respected.

With this change, all worktrees are respected.

That change also leads to revealing another bug,
i.e. `receive.denyCurrentBranch = true` was ignored when pushing into a
non-bare repository's unborn current branch using ref namespaces. As
`is_ref_checked_out()` returns 0 which means `receive-pack` does not get
into conditional statement to switch `deny_current_branch` accordingly
(ignore, warn, refuse, unconfigured, updateInstead).

receive.denyCurrentBranch uses the function `refs_resolve_ref_unsafe()`
(called via `resolve_refdup()`) to resolve the symbolic ref HEAD, but
that function fails when HEAD does not point at a valid commit.
As we replace the call to `refs_resolve_ref_unsafe()` with
`find_shared_symref()`, which has no problem finding the worktree for a
given branch even if it is unborn yet, this bug is fixed at the same
time: receive.denyCurrentBranch now also handles worktrees with unborn
branches as intended even while using ref namespaces.

Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Hariom Verma <hariom18599@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-24 11:14:43 -08:00
brian m. carlson fc06be3b7f builtin/receive-pack: replace sha1_to_hex
Since sha1_to_hex is limited to SHA-1, replace it with hash_to_hex.
Rename several variables to indicate that they can contain any hash.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-19 15:04:59 -07:00
brian m. carlson fabec2c5c3 builtin/receive-pack: switch to use the_hash_algo
The push cert code uses HMAC-SHA-1 to create a nonce.  This is a secure
use of SHA-1 which is not affected by its collision resistance (or lack
thereof).  However, it makes sense for us to use a better algorithm if
one is available, one which may even be more performant.  Futhermore,
until we have specialized functions for computing the hex value of an
arbitrary function, it simplifies the code greatly to use the same hash
algorithm everywhere.

Switch this code to use GIT_MAX_BLKSZ and the_hash_algo for computing
the push cert nonce, and rename the hmac_sha1 function to simply "hmac".

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-19 15:04:57 -07:00
Junio C Hamano 68e65ded5b Merge branch 'jk/check-connected-with-alternates'
The tips of refs from the alternate object store can be used as
starting point for reachability computation now.

* jk/check-connected-with-alternates:
  check_everything_connected: assume alternate ref tips are valid
  object-store.h: move for_each_alternate_ref() from transport.h
2019-07-19 11:30:21 -07:00
Junio C Hamano 5cb7c73589 Merge branch 'ds/close-object-store'
The commit-graph file is now part of the "files that the runtime
may keep open file descriptors on, all of which would need to be
closed when done with the object store", and the file descriptor to
an existing commit-graph file now is closed before "gc" finalizes a
new instance to replace it.

* ds/close-object-store:
  packfile: rename close_all_packs to close_object_store
  packfile: close commit-graph in close_all_packs
  commit-graph: use raw_object_store when closing
2019-07-09 15:25:37 -07:00
Jeff King 709dfa6990 object-store.h: move for_each_alternate_ref() from transport.h
There's nothing inherently transport-related about enumerating the
alternate ref tips. The code has lived in transport.[ch] because the
only use so far had been advertising available tips during transport.
But it could be used for more, and a future patch will teach rev-list to
access these refs.

Let's move it alongside the other alt-odb code, declaring it in
object-store.h with the implementation in sha1-file.c.

This lets us drop the inclusion of transport.h from receive-pack, which
perhaps shows how it was misplaced (though receive-pack is about
transporting objects, transport.h is mostly about the client side).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-07-01 09:47:29 -07:00
Derrick Stolee 2d511cfc0b packfile: rename close_all_packs to close_object_store
The close_all_packs() method is now responsible for more than just pack-files.
It also closes the commit-graph and the multi-pack-index. Rename the function
to be more descriptive of its larger role. The name also fits because the
input parameter is a raw_object_store.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-12 11:33:54 -07:00
Jeff King c95fc72f47 receive-pack: drop unused "commands" from prepare_shallow_update()
We pass in the list of proposed ref updates to prepare_shallow_update(),
but that function doesn't actually need it (and never has since its
inception in 0a1bc12b6e). Only its caller, update_shallow_info(), needs
to look at the command list.

Let's drop the unused parameter to reduce confusion.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-05-13 14:22:54 +09:00
Junio C Hamano 4751a1673c Merge branch 'ab/receive-pack-use-after-free-fix'
Memfix.

* ab/receive-pack-use-after-free-fix:
  receive-pack: fix use-after-free bug
2019-03-07 09:59:57 +09:00
Jeff Hostetler 6206286e49 trace2:data: add trace2 hook classification
Classify certain child processes as hooks.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-02-22 15:28:21 -08:00
Ævar Arnfjörð Bjarmason 9903623761 receive-pack: fix use-after-free bug
The resolve_ref_unsafe() function can, and sometimes will in the case
of this codepath, return the char * passed to it to the caller. In
this case we construct a strbuf, free it, and then continue using the
dst_name after that free().

The code being fixed dates back to da3efdb17b ("receive-pack: detect
aliased updates which can occur with symrefs", 2010-04-19). When it
was originally added it didn't have this bug, it was introduced when
it was subsequently modified to use strbuf in 6b01ecfe22 ("ref
namespaces: Support remote repositories via upload-pack and
receive-pack", 2011-07-08).

This is theoretically a security issue, the C standard makes no
guarantees that a value you use after free() hasn't been poked at or
changed by something else on the system, but in practice modern OSs
will have mapped the relevant page to this process, so nothing else
would have used it. We do no further allocations between the free()
and use-after-free, so we ourselves didn't corrupt or change the
value.

Jeff investigated that and found: "It probably would be an issue if
the allocation were larger. glibc at least will use mmap()/munmap()
after some cutoff[1], in which case we'd get a segfault from hitting
the unmapped page. But for small allocations, it just bumps brk() and
the memory is still available for further allocations after
free(). [...] If you had a sufficiently large refname you might be
able to trigger the bug [...]. I tried to push such a ref. I had to
manually make a packed-refs file with the long name to avoid
filesystem limits (though probably you could have a long a/b/c/ name
on ext4).  But the result can't actually be pushed, because it all has
to fit into a 64k pkt-line as part of the push protocol.".

An a alternative and more succinct way of implementing this would have
been to do the strbuf_release() at the end of check_aliased_update()
and use "goto out" instead of the early "return" statements. Hopefully
this approach of using a helper instead makes it easier to follow.

1. Jeff: "Weirdly, the mmap() cutoff on my glibc system is 135168
   bytes. Which is...2^17 + 2^12? 33 pages? I'm sure there's a good
   reason for that, but I didn't dig into it."

Reported-by: 王健强 <jianqiang.wang@securitygossip.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-02-20 15:02:12 -08:00
Masaya Suzuki 2d103c31c2 pack-protocol.txt: accept error packets in any context
In the Git pack protocol definition, an error packet may appear only in
a certain context. However, servers can face a runtime error (e.g. I/O
error) at an arbitrary timing. This patch changes the protocol to allow
an error packet to be sent instead of any packet.

Without this protocol spec change, when a server cannot process a
request, there's no way to tell that to a client. Since the server
cannot produce a valid response, it would be forced to cut a connection
without telling why. With this protocol spec change, the server can be
more gentle in this situation. An old client may see these error packets
as an unexpected packet, but this is not worse than having an unexpected
EOF.

Following this protocol spec change, the error packet handling code is
moved to pkt-line.c. Implementation wise, this implementation uses
pkt-line to communicate with a subprocess. Since this is not a part of
Git protocol, it's possible that a packet that is not supposed to be an
error packet is mistakenly parsed as an error packet. This error packet
handling is enabled only for the Git pack protocol parsing code
considering this.

Signed-off-by: Masaya Suzuki <masayasuzuki@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-02 13:05:30 -08:00
Masaya Suzuki 01f9ec64c8 Use packet_reader instead of packet_read_line
By using and sharing a packet_reader while handling a Git pack protocol
request, the same reader option is used throughout the code. This makes
it easy to set a reader option to the request parsing code.

Signed-off-by: Masaya Suzuki <masayasuzuki@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-02 13:05:27 -08:00
Junio C Hamano 4c7f544022 Merge branch 'jc/receive-deny-current-branch-fix'
The receive.denyCurrentBranch=updateInstead codepath kicked in even
when the push should have been rejected due to other reasons, such
as it does not fast-forward or the update-hook rejects it, which
has been corrected.

* jc/receive-deny-current-branch-fix:
  receive: denyCurrentBranch=updateinstead should not blindly update
2018-10-30 15:43:46 +09:00
Junio C Hamano b072a25fad receive: denyCurrentBranch=updateinstead should not blindly update
The handling of receive.denyCurrentBranch=updateInstead was added to
a switch statement that handles other values of the variable, but
all the other case arms only checked a condition to reject the
attempted push, or let later logic in the same function to still
intervene, so that a push that does not fast-forward (which is
checked after the switch statement in question) is still rejected.

But the handling of updateInstead incorrectly took immediate effect,
without giving other checks a chance to intervene.

Instead of calling update_worktree() that causes the side effect
immediately, just note the fact that we will need to call the
function later, and first give other checks a chance to reject the
request.  After the update-hook gets a chance to reject the push
(which happens as the last step in a series of checks), call
update_worktree() when we earlier detected the need to.

Reported-by: Rajesh Madamanchi
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-19 15:13:32 +09:00
Junio C Hamano 465e73fff3 Merge branch 'tb/filter-alternate-refs'
When pushing into a repository that borrows its objects from an
alternate object store, "git receive-pack" that responds to the
push request on the other side lists the tips of refs in the
alternate to reduce the amount of objects transferred.  This
sometimes is detrimental when the number of refs in the alternate
is absurdly large, in which case the bandwidth saved in potentially
fewer objects transferred is wasted in excessively large ref
advertisement.  The alternate refs that are advertised are now
configurable with a pair of configuration variables.

* tb/filter-alternate-refs:
  transport.c: introduce core.alternateRefsPrefixes
  transport.c: introduce core.alternateRefsCommand
  transport.c: extract 'fill_alternate_refs_command'
  transport: drop refnames from for_each_alternate_ref
2018-10-19 13:34:08 +09:00
Junio C Hamano 20e0ef6a03 Merge branch 'jk/check-everything-connected-is-long-gone'
Comment fix.

* jk/check-everything-connected-is-long-gone:
  receive-pack: update comment with check_everything_connected
2018-10-16 16:16:04 +09:00
Jeff King bdf4276c91 transport: drop refnames from for_each_alternate_ref
None of the current callers use the refname parameter we pass to their
callbacks. In theory somebody _could_ do so, but it's actually quite
weird if you think about it: it's a ref in somebody else's repository.
So the name has no meaning locally, and in fact there may be duplicates
if there are multiple alternates.

The users of this interface really only care about seeing some ref tips,
since that promises that the alternate has the full commit graph
reachable from there. So let's keep the information we pass back to the
bare minimum.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-09 14:30:02 +09:00
Jeff King 7987d2232d receive-pack: update comment with check_everything_connected
That function is now called "check_connected()", but we forgot to update
this comment in 7043c7071c (check_everything_connected: use a struct
with named options, 2016-07-15).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-25 13:32:08 -07:00
Junio C Hamano ae109a9789 Merge branch 'en/double-semicolon-fix'
Code clean-up.

* en/double-semicolon-fix:
  Remove superfluous trailing semicolons
2018-09-24 10:30:47 -07:00
Junio C Hamano 769af0fd9e Merge branch 'jk/cocci'
spatch transformation to replace boolean uses of !hashcmp() to
newly introduced oideq() is added, and applied, to regain
performance lost due to support of multiple hash algorithms.

* jk/cocci:
  show_dirstat: simplify same-content check
  read-cache: use oideq() in ce_compare functions
  convert hashmap comparison functions to oideq()
  convert "hashcmp() != 0" to "!hasheq()"
  convert "oidcmp() != 0" to "!oideq()"
  convert "hashcmp() == 0" to hasheq()
  convert "oidcmp() == 0" to oideq()
  introduce hasheq() and oideq()
  coccinelle: use <...> for function exclusion
2018-09-17 13:53:57 -07:00
Junio C Hamano 1b7a91da71 Merge branch 'ds/reachable'
The code for computing history reachability has been shuffled,
obtained a bunch of new tests to cover them, and then being
improved.

* ds/reachable:
  commit-reach: correct accidental #include of C file
  commit-reach: use can_all_from_reach
  commit-reach: make can_all_from_reach... linear
  commit-reach: replace ref_newer logic
  test-reach: test commit_contains
  test-reach: test can_all_from_reach_with_flags
  test-reach: test reduce_heads
  test-reach: test get_merge_bases_many
  test-reach: test is_descendant_of
  test-reach: test in_merge_bases
  test-reach: create new test tool for ref_newer
  commit-reach: move can_all_from_reach_with_flags
  upload-pack: generalize commit date cutoff
  upload-pack: refactor ok_to_give_up()
  upload-pack: make reachable() more generic
  commit-reach: move commit_contains from ref-filter
  commit-reach: move ref_newer from remote.c
  commit.h: remove method declarations
  commit-reach: move walk methods from commit.c
2018-09-17 13:53:52 -07:00
Elijah Newren c3b9bc94b9 Remove superfluous trailing semicolons
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-05 10:21:24 -07:00
Jeff King 4a7e27e957 convert "oidcmp() == 0" to oideq()
Using the more restrictive oideq() should, in the long run,
give the compiler more opportunities to optimize these
callsites. For now, this conversion should be a complete
noop with respect to the generated code.

The result is also perhaps a little more readable, as it
avoids the "zero is equal" idiom. Since it's so prevalent in
C, I think seasoned programmers tend not to even notice it
anymore, but it can sometimes make for awkward double
negations (e.g., we can drop a few !!oidcmp() instances
here).

This patch was generated almost entirely by the included
coccinelle patch. This mechanical conversion should be
completely safe, because we check explicitly for cases where
oidcmp() is compared to 0, which is what oideq() is doing
under the hood. Note that we don't have to catch "!oidcmp()"
separately; coccinelle's standard isomorphisms make sure the
two are treated equivalently.

I say "almost" because I did hand-edit the coccinelle output
to fix up a few style violations (it mostly keeps the
original formatting, but sometimes unwraps long lines).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-29 11:32:49 -07:00
Junio C Hamano 3a2a1dc170 Merge branch 'sb/object-store-lookup'
lookup_commit_reference() and friends have been updated to find
in-core object for a specific in-core repository instance.

* sb/object-store-lookup: (32 commits)
  commit.c: allow lookup_commit_reference to handle arbitrary repositories
  commit.c: allow lookup_commit_reference_gently to handle arbitrary repositories
  tag.c: allow deref_tag to handle arbitrary repositories
  object.c: allow parse_object to handle arbitrary repositories
  object.c: allow parse_object_buffer to handle arbitrary repositories
  commit.c: allow get_cached_commit_buffer to handle arbitrary repositories
  commit.c: allow set_commit_buffer to handle arbitrary repositories
  commit.c: migrate the commit buffer to the parsed object store
  commit-slabs: remove realloc counter outside of slab struct
  commit.c: allow parse_commit_buffer to handle arbitrary repositories
  tag: allow parse_tag_buffer to handle arbitrary repositories
  tag: allow lookup_tag to handle arbitrary repositories
  commit: allow lookup_commit to handle arbitrary repositories
  tree: allow lookup_tree to handle arbitrary repositories
  blob: allow lookup_blob to handle arbitrary repositories
  object: allow lookup_object to handle arbitrary repositories
  object: allow object_as_type to handle arbitrary repositories
  tag: add repository argument to deref_tag
  tag: add repository argument to parse_tag_buffer
  tag: add repository argument to lookup_tag
  ...
2018-08-02 15:30:42 -07:00
Junio C Hamano 6fc7de1a1f Merge branch 'hs/push-cert-check-cleanup'
Code clean-up.

* hs/push-cert-check-cleanup:
  gpg-interface: make parse_gpg_output static and remove from interface header
  builtin/receive-pack: use check_signature from gpg-interface
2018-07-24 14:50:48 -07:00