In general, Git tries not to arbitrarily limit what it will store, and
there are currently no limits at all on the size of the path we find in
a tree. In theory you could have one that is gigabytes long.
But in practice this freedom is not really helping anybody, and is
potentially harmful:
1. Most operating systems have much lower limits for the size of a
single pathname component (e.g., on Linux you'll generally get
ENAMETOOLONG for anything over 255 bytes). And while you _can_ use
Git in a way that never touches the filesystem (manipulating the
index and trees directly), it's still probably not a good idea to
have gigantic tree names. Many operations load and traverse them,
so any clever Git-as-a-database scheme is likely to perform poorly
in that case.
2. We still have a lot of code which assumes strings are reasonably
sized, and I won't be at all surprised if you can trigger some
interesting integer overflows with gigantic pathnames. Stopping
malicious trees from entering the repository provides an extra line
of defense, protecting downstream code.
This patch implements an fsck check so that such trees can be rejected
by transfer.fsckObjects. I've picked a reasonably high maximum depth
here (4096) that hopefully should not bother anybody in practice. I've
also made it configurable, as an escape hatch.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a new "const struct config_context *ctx" arg to config_fn_t to hold
additional information about the config iteration operation.
config_context has a "struct key_value_info kvi" member that holds
metadata about the config source being read (e.g. what kind of config
source it is, the filename, etc). In this series, we're only interested
in .kvi, so we could have just used "struct key_value_info" as an arg,
but config_context makes it possible to add/adjust members in the future
without changing the config_fn_t signature. We could also consider other
ways of organizing the args (e.g. moving the config name and value into
config_context or key_value_info), but in my experiments, the
incremental benefit doesn't justify the added complexity (e.g. a
config_fn_t will sometimes invoke another config_fn_t but with a
different config value).
In subsequent commits, the .kvi member will replace the global "struct
config_reader" in config.c, making config iteration a global-free
operation. It requires much more work for the machinery to provide
meaningful values of .kvi, so for now, merely change the signature and
call sites, pass NULL as a placeholder value, and don't rely on the arg
in any meaningful way.
Most of the changes are performed by
contrib/coccinelle/config_fn_ctx.pending.cocci, which, for every
config_fn_t:
- Modifies the signature to accept "const struct config_context *ctx"
- Passes "ctx" to any inner config_fn_t, if needed
- Adds UNUSED attributes to "ctx", if needed
Most config_fn_t instances are easily identified by seeing if they are
called by the various config functions. Most of the remaining ones are
manually named in the .cocci patch. Manual cleanups are still needed,
but the majority of it is trivial; it's either adjusting config_fn_t
that the .cocci patch didn't catch, or adding forward declarations of
"struct config_context ctx" to make the signatures make sense.
The non-trivial changes are in cases where we are invoking a config_fn_t
outside of config machinery, and we now need to decide what value of
"ctx" to pass. These cases are:
- trace2/tr2_cfg.c:tr2_cfg_set_fl()
This is indirectly called by git_config_set() so that the trace2
machinery can notice the new config values and update its settings
using the tr2 config parsing function, i.e. tr2_cfg_cb().
- builtin/checkout.c:checkout_main()
This calls git_xmerge_config() as a shorthand for parsing a CLI arg.
This might be worth refactoring away in the future, since
git_xmerge_config() can call git_default_config(), which can do much
more than just parsing.
Handle them by creating a KVI_INIT macro that initializes "struct
key_value_info" to a reasonable default, and use that to construct the
"ctx" arg.
Signed-off-by: Glen Choo <chooglen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Things should be able to depend on object.h without pulling in all of
cache.h. Move an enum to allow this.
Note that a couple files previously depended on things brought in
through cache.h indirectly (revision.h -> commit.h -> object.h ->
cache.h). As such, this change requires making existing dependencies
more explicit in half a dozen files. The inclusion of strbuf.h in
some headers if of particular note: these headers directly embedded a
strbuf in some new structs, meaning they should have been including
strbuf.h all along but were indirectly getting the necessary
definitions.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The fsck code has been slowly moving away from requiring an object
struct in commits like 103fb6d43b (fsck: accept an oid instead of a
"struct tag" for fsck_tag(), 2019-10-18), c5b4269b57 (fsck: accept an
oid instead of a "struct commit" for fsck_commit(), 2019-10-18), etc.
However, the only external interface that fsck.c provides is
fsck_object(), which requires an object struct, then promptly discards
everything except its oid and type. Let's factor out the post-discard
part of that function as fsck_buffer(), leaving fsck_object() as a thin
wrapper around it. That will provide more flexibility for callers which
may not have a struct.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Recently, a vulnerability was reported that can lead to an out-of-bounds
write when reading an unreasonably large gitattributes file. The root
cause of this error are multiple integer overflows in different parts of
the code when there are either too many lines, when paths are too long,
when attribute names are too long, or when there are too many attributes
declared for a pattern.
As all of these are related to size, it seems reasonable to restrict the
size of the gitattributes file via git-fsck(1). This allows us to both
stop distributing known-vulnerable objects via common hosting platforms
that have fsck enabled, and users to protect themselves by enabling the
`fetch.fsckObjects` config.
There are basically two checks:
1. We verify that size of the gitattributes file is smaller than
100MB.
2. We verify that the maximum line length does not exceed 2048
bytes.
With the preceding commits, both of these conditions would cause us to
either ignore the complete gitattributes file or blob in the first case,
or the specific line in the second case. Now with these consistency
checks added, we also grow the ability to stop distributing such files
in the first place when `receive.fsckObjects` is enabled.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The documentation lacks mention of specific <msg-id> that are supported.
While git-help --config will display a list of these options, often
developers' first instinct is to consult the git docs to find valid
config values.
Add a list of fsck error messages, and link to it from the git-fsck
documentation.
Signed-off-by: John Cai <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This error type has never been used since it was introduced at
159e7b08 (fsck: detect gitmodules files, 2018-05-02).
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2175a0c6 (fsck: stop checking tag->tagged, 2019-10-18) stopped
checking the tagged object referred to by a tag object, which is what the
error message BAD_TAG_OBJECT was for. Since then the BAD_TAG_OBJECT
message is no longer used anywhere.
Remove the BAD_TAG_OBJECT msg-id.
Signed-off-by: John Cai <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous commit un-broke the "badFileMode" check; before then it was
literally testing nothing. And as far as I can tell, it has been so
since the very initial version of fsck.
The current severity of "badFileMode" is just "warning". But in the
--strict mode used by transfer.fsckObjects, that is elevated to an
error. This will potentially cause hassle for users, because historical
objects with bad modes will suddenly start causing pushes to many server
operators to be rejected.
At the same time, these bogus modes aren't actually a big risk. Because
we canonicalize them everywhere besides fsck, they can't cause too much
mischief in the real world. The worst thing you can do is end up with
two almost-identical trees that have different hashes but are
interpreted the same. That will generally cause things to be inefficient
rather than wrong, and is a bug somebody working on a Git implementation
would want to fix, but probably not worth inconveniencing users by
refusing to push or fetch.
So let's downgrade this to "info" by default, which is our setting for
"mention this when fscking, but don't ever reject, even under strict
mode". If somebody really wants to be paranoid, they can still adjust
the level using config.
Suggested-by: Xavier Morel <xavier.morel@masklinn.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the commits merged in via 204333b015 (Merge branch
'jk/open-dotgitx-with-nofollow', 2021-03-22), we stopped following
symbolic links for .gitattributes, .gitignore, and .mailmap files.
Let's teach fsck to warn that these symlinks are not going to do
anything. Note that this is just a warning, and won't block the objects
via transfer.fsckObjects, since there are reported to be cases of this
in the wild (and even once fixed, they will continue to exist in the
commit history of those projects, but are not particularly dangerous).
Note that we won't add these to the existing gitmodules block in the
fsck code. The logic for gitmodules is a bit more complicated, as we
also check the content of non-symlink instances we find. But for these
new files, there is no content check; we're just looking at the name and
mode of the tree entry (and we can avoid even the complicated name
checks in the common case that the mode doesn't indicate a symlink).
We can reuse the test helper function we defined for .gitmodules, though
(it needs some slight adjustments for the fsck error code, and because
we don't block these symlinks via verify_path()).
Note that I didn't explicitly test the transfer.fsckObjects case here
(nor does the existing .gitmodules test that it blocks a push). The
translation of fsck severities to outcomes is covered in general in
t5504.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Refactor the check added in 5476e1efde (fetch-pack: print and use
dangling .gitmodules, 2021-02-22) to make use of us now passing the
"msg_id" to the user defined "error_func". We can now compare against
the FSCK_MSG_GITMODULES_MISSING instead of parsing the generated
message.
Let's also replace register_found_gitmodules() with directly
manipulating the "gitmodules_found" member. A recent commit moved it
into "fsck_options" so we could do this here.
I'm sticking this callback in fsck.c. Perhaps in the future we'd like
to accumulate such callbacks into another file (maybe fsck-cb.c,
similar to parse-options-cb.c?), but while we've got just the one
let's just put it into fsck.c.
A better alternative in this case would be some library some more
obvious library shared by fetch-pack.c ad builtin/index-pack.c, but
there isn't such a thing.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the gitmodules_{found,done} static variables added in
159e7b080b (fsck: detect gitmodules files, 2018-05-02) into the
fsck_options struct. It makes sense to keep all the context in the
same place.
This requires changing the recently added register_found_gitmodules()
function added in 5476e1efde (fetch-pack: print and use dangling
.gitmodules, 2021-02-22) to take fsck_options. That function will be
removed in a subsequent commit, but as it'll require the new
gitmodules_found attribute of "fsck_options" we need this intermediate
step first.
An earlier version of this patch removed the small amount of
duplication we now have between FSCK_OPTIONS_{DEFAULT,STRICT} with a
FSCK_OPTIONS_COMMON macro. I don't think such de-duplication is worth
it for this amount of copy/pasting.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change code I added in acf9de4c94 (mktag: use fsck instead of custom
verify_tag(), 2021-01-05) to make use of a new API function that takes
the fsck_msg_{id,type} types, instead of arbitrary strings that
we'll (hopefully) parse into those types.
At the time that the fsck_set_msg_type() API was introduced in
0282f4dced (fsck: offer a function to demote fsck errors to warnings,
2015-06-22) it was only intended to be used to parse user-supplied
data.
For things that are purely internal to the C code it makes sense to
have the compiler check these arguments, and to skip the sanity
checking of the data in fsck_set_msg_type() which is redundant to
checks we get from the compiler.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the fsck_error callback to also pass along the
fsck_msg_id. Before this change the only way to get the message id was
to parse it back out of the "message".
Let's pass it down explicitly for the benefit of callers that might
want to use it, as discussed in [1].
Passing the msg_type is now redundant, as you can always get it back
from the msg_id, but I'm not changing that convention. It's really
common to need the msg_type, and the report() function itself (which
calls "fsck_error") needs to call fsck_msg_type() to discover
it. Let's not needlessly re-do that work in the user callback.
1. https://lore.kernel.org/git/87blcja2ha.fsf@evledraar.gmail.com/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the FOREACH_FSCK_MSG_ID macro and the fsck_msg_id enum it helps
define from fsck.c to fsck.h. This is in preparation for having
non-static functions take the fsck_msg_id as an argument.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the values in the "enum fsck_msg_type" from being manually
assigned to using default C enum values.
This means we end up with a FSCK_IGNORE=0, which was previously
defined as "2".
I'm confident that nothing relies on these values, we always compare
them for equality. Let's not omit "0" so it won't be assumed that
we're using these as a boolean somewhere.
This also allows us to re-structure the fields to mark which are
"private" v.s. "public". See the preceding commit for a rationale for
not simply splitting these into two enums, namely that this is used
for both the private and public fsck API.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the FSCK_{FATAL,INFO,ERROR,WARN,IGNORE} defines into a new
fsck_msg_type enum.
These defines were originally introduced in:
- ba002f3b28 (builtin-fsck: move common object checking code to
fsck.c, 2008-02-25)
- f50c440730 (fsck: disallow demoting grave fsck errors to warnings,
2015-06-22)
- efaba7cc77 (fsck: optionally ignore specific fsck issues
completely, 2015-06-22)
- f27d05b170 (fsck: allow upgrading fsck warnings to errors,
2015-06-22)
The reason these were defined in two different places is because we
use FSCK_{IGNORE,INFO,FATAL} only in fsck.c, but FSCK_{ERROR,WARN} are
used by external callbacks.
Untangling that would take some more work, since we expose the new
"enum fsck_msg_type" to both. Similar to "enum object_type" it's not
worth structuring the API in such a way that only those who need
FSCK_{ERROR,WARN} pass around a different type.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rename variables in a function added in 0282f4dced (fsck: offer a
function to demote fsck errors to warnings, 2015-06-22).
It was needlessly confusing that it took a "msg_type" argument, but
then later declared another "msg_type" of a different type.
Let's rename that to "severity", and rename "id" to "msg_id" and
"msg_id" to "msg_id_str" etc. This will make a follow-up change
smaller.
While I'm at it properly indent the fsck_set_msg_type() argument list.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the fsck_walk_func to use an "enum object_type" instead of an
"int" type. The types are compatible, and ever since this was added in
355885d531 (add generic, type aware object chain walker, 2008-02-25)
we've used entries from object_type (OBJ_BLOB etc.).
So this doesn't really change anything as far as the generated code is
concerned, it just gives the compiler more information and makes this
easier to read.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Refactor the definitions of FSCK_OPTIONS_{DEFAULT,STRICT} to use
designated initializers. This allows us to omit those fields that
are initialized to 0 or NULL.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Refactor code I recently changed in 1f3299fda9 (fsck: make
fsck_config() re-usable, 2021-01-05) so that I could use fsck's config
callback in mktag in 1f3299fda9 (fsck: make fsck_config() re-usable,
2021-01-05).
I don't know what I was thinking in structuring the code this way, but
it clearly makes no sense to have an fsck_config_internal() at all
just so it can get a fsck_options when git_config() already supports
passing along some void* data.
Let's just make use of that instead, which gets us rid of the two
wrapper functions, and brings fsck's common config callback in line
with other such reusable config callbacks.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The approach to "fsck" the incoming objects in "index-pack" is
attractive for performance reasons (we have them already in core,
inflated and ready to be inspected), but fundamentally cannot be
applied fully when we receive more than one pack stream, as a tree
object in one pack may refer to a blob object in another pack as
".gitmodules", when we want to inspect blobs that are used as
".gitmodules" file, for example. Teach "index-pack" to emit
objects that must be inspected later and check them in the calling
"fetch-pack" process.
* jt/transfer-fsck-across-packs:
fetch-pack: print and use dangling .gitmodules
fetch-pack: with packfile URIs, use index-pack arg
http-fetch: allow custom index-pack args
http: allow custom index-pack args
Teach index-pack to print dangling .gitmodules links after its "keep" or
"pack" line instead of declaring an error, and teach fetch-pack to check
such lines printed.
This allows the tree side of the .gitmodules link to be in one packfile
and the blob side to be in another without failing the fsck check,
because it is now fetch-pack which checks such objects after all
packfiles have been downloaded and indexed (and not index-pack on an
individual packfile, as it is before this commit).
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the fsck_config() function from builtin/fsck.c to fsck.[ch]. This
allows for re-using it in other tools that expose fsck logic and want
to support its configuration variables.
A logical continuation of this change would be to use a common
function for all of {fetch,receive}.fsck.* and fsck.*. See
5d477a334a (fsck (receive-pack): allow demoting errors to warnings,
2015-06-22) and my own 1362df0d41 (fetch: implement fetch.fsck.*,
2018-07-27) for the relevant code.
However, those routines want to not parse the fsck.skipList into OIDs,
but rather pass them along with the --strict option to another
process. It would be possible to refactor that whole thing so we
support e.g. a "fetch." prefix, then just keep track of the skiplist
as a filename instead of parsing it, and learn to spew that all out
from our internal structures into something we can append to the
--strict option.
But instead I'm planning to re-use this in "mktag", which'll just
re-use these "fsck.*" variables as-is.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the validation logic in "mktag" to use fsck's fsck_tag()
instead of its own custom parser. Curiously the logic for both dates
back to the same commit[1]. Let's unify them so we're not maintaining
two sets functions to verify that a tag is OK.
The behavior of fsck_tag() and the old "mktag" code being removed here
is different in few aspects.
I think it makes sense to remove some of those checks, namely:
A. fsck only cares that the timezone matches [-+][0-9]{4}. The mktag
code disallowed values larger than 1400.
Yes there's currently no timezone with a greater offset[2], but
since we allow any number of non-offical timezones (e.g. +1234)
passing this through seems fine. Git also won't break in the
future if e.g. French Polynesia decides it needs to outdo the Line
Islands when it comes to timezone extravagance.
B. fsck allows missing author names such as "tagger <email>", mktag
wouldn't, but would allow e.g. "tagger [2 spaces] <email>" (but
not "tagger [1 space] <email>"). Now we allow all of these.
C. Like B, but "mktag" disallowed spaces in the <email> part, fsck
allows it.
In some ways fsck_tag() is stricter than "mktag" was, namely:
D. fsck disallows zero-padded dates, but mktag didn't care. So
e.g. the timestamp "0000000000 +0000" produces an error now. A
test in "t1006-cat-file.sh" relied on this, it's been changed to
use "hash-object" (without fsck) instead.
There was one check I deemed worth keeping by porting it over to
fsck_tag():
E. "mktag" did not allow any custom headers, and by extension (as an
empty commit is allowed) also forbade an extra stray trailing
newline after the headers it knew about.
Add a new check in the "ignore" category to fsck and use it. This
somewhat abuses the facility added in efaba7cc77 (fsck:
optionally ignore specific fsck issues completely, 2015-06-22).
This is somewhat of hack, but probably the least invasive change
we can make here. The fsck command will shuffle these categories
around, e.g. under --strict the "info" becomes a "warn" and "warn"
becomes "error". Existing users of fsck's (and others,
e.g. index-pack) --strict option rely on this.
So we need to put something into a category that'll be ignored by
all existing users of the API. Pretending that
fsck.extraHeaderEntry=error ("ignore" by default) was set serves
to do this for us.
1. ec4465adb3 (Add "tag" objects that can be used to sign other
objects., 2005-04-25)
2. https://en.wikipedia.org/wiki/List_of_UTC_time_offsets
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
None of the callbacks actually care about having a "struct object";
they're happy with just the oid and type information. So let's give
ourselves more flexibility to avoid having a "struct object" by just
passing the broken-down fields.
Note that the callback already takes a "type" field for the fsck message
type. We'll rename that to "msg_type" (and use "object_type" for the
object type) to make the distinction explicit.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We don't actually care about having object structs; we only need to look
up decorations by oid. Let's accept this more limited form, which will
give our callers more flexibility.
Note that the decoration API we rely on uses object structs itself (even
though it only looks at their oids). We can solve this by switching to
a kh_oid_map (we could also use the hashmap oidmap, but it's more
awkward for the simple case of just storing a void pointer).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit 90cf590f53 (fsck: optionally show more helpful info for broken
links, 2016-07-17) added a system for decorating objects with names. The
code is split across builtin/fsck.c (which gives the initial names) and
fsck.c (which adds to the names as it traverses the object graph). This
leads to some duplication, where both sites have near-identical
describe_object() functions (the difference being that the one in
builtin/fsck.c uses a circular array of buffers to allow multiple calls
in a single printf).
Let's provide a unified object_name API for fsck. That lets us drop the
duplication, as well as making the interface boundaries more clear
(which will let us refactor the implementation more in a future patch).
We'll leave describe_object() in builtin/fsck.c as a thin wrapper around
the new API, as it relies on a static global to make its many callers a
bit shorter.
We'll also convert the bare add_decoration() calls in builtin/fsck.c to
put_object_name(). This fixes two minor bugs:
1. We leak many small strings. add_decoration() has a last-one-wins
approach: it updates the decoration to the new string and returns
the old one. But we ignore the return value, leaking the old
string. This is quite common to trigger, since we look at reflogs:
the tip of any ref will be described both by looking at the actual
ref, as well as the latest reflog entry. So we'd always end up
leaking one of those strings.
2. The last-one-wins approach gives us lousy names. For instance, we
first look at all of the refs, and then all of the reflogs. So
rather than seeing "refs/heads/master", we're likely to overwrite
it with "HEAD@{12345678}". We're generally better off using the
first name we find.
And indeed, the test in t1450 expects this ugly HEAD@{} name. After
this patch, we've switched to using fsck_put_object_name()'s
first-one-wins semantics, and we output the more human-friendly
"refs/tags/julius" (and the test is updated accordingly).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The fsck_object() function takes in a buffer, but also a "struct
object". The rules for using these vary between types:
- for a commit, we'll use the provided buffer; if it's NULL, we'll
fall back to get_commit_buffer(), which loads from either an
in-memory cache or from disk. If the latter fails, we'd die(), which
is non-ideal for fsck.
- for a tag, a NULL buffer will fall back to loading the object from
disk (and failure would lead to an fsck error)
- for a tree, we _never_ look at the provided buffer, and always use
tree->buffer
- for a blob, we usually don't look at the buffer at all, unless it
has been marked as a .gitmodule file. In that case we check the
buffer given to us, or assume a NULL buffer is a very large blob
(and complain about it)
This is much more complex than it needs to be. It turns out that nobody
ever feeds a NULL buffer that isn't a blob:
- git-fsck calls fsck_object() only from fsck_obj(). That in turn is
called by one of:
- fsck_obj_buffer(), which is a callback to verify_pack(), which
unpacks everything except large blobs into a buffer (see
pack-check.c, lines 131-141).
- fsck_loose(), which hits a BUG() on non-blobs with a NULL buffer
(builtin/fsck.c, lines 639-640)
And in either case, we'll have just called parse_object_buffer()
anyway, which would segfault on a NULL buffer for commits or tags
(not for trees, but it would install a NULL tree->buffer which would
later cause a segfault)
- git-index-pack asserts that the buffer is non-NULL unless the object
is a blob (see builtin/index-pack.c, line 832)
- git-unpack-objects always writes a non-NULL buffer into its
obj_buffer hash, which is then fed to fsck_object(). (There is
actually a funny thing here where it does not store blob buffers at
all, nor does it call fsck on them; it does check any needed blobs
via fsck_finish() though).
Let's make the rules simpler, which reduces the amount of code and gives
us more flexibility in refactoring the fsck code. The new rules are:
- only blobs are allowed to pass a NULL buffer
- we always use the provided buffer, never pulling information from
the object struct
We don't have to adjust any callers, because they were already adhering
to these. Note that we do drop a few fsck identifiers for missing tags,
but that was all dead code (because nobody passed a NULL tag buffer).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the implementation of the skipList feature to use oidset
instead of oid_array to store SHA-1s for later lookup.
This list is parsed once on startup by fsck, fetch-pack or
receive-pack depending on the *.skipList config in use. I.e. only once
per invocation, but note that for "clone --recurse-submodules" each
submodule will re-parse the list, in addition to the main project, and
it will be re-parsed when checking .gitmodules blobs, see
fb16287719 ("fsck: check skiplist for object in fsck_blob()",
2018-06-27).
Memory usage is a bit higher, but we don't need to keep track of the
sort order anymore. Embed the oidset into struct fsck_options to make
its ownership clear (no hidden sharing) and avoid unnecessary pointer
indirection.
The cumulative impact on performance of this & the preceding change,
using the test setup described in the previous commit:
Test HEAD~2 HEAD~ HEAD
----------------------------------------------------------------------------------------------------------------
1450.3: fsck with 0 skipped bad commits 7.70(7.31+0.38) 7.72(7.33+0.38) +0.3% 7.70(7.30+0.40) +0.0%
1450.5: fsck with 1 skipped bad commits 7.84(7.47+0.37) 7.69(7.32+0.36) -1.9% 7.71(7.29+0.41) -1.7%
1450.7: fsck with 10 skipped bad commits 7.81(7.40+0.40) 7.94(7.57+0.36) +1.7% 7.92(7.55+0.37) +1.4%
1450.9: fsck with 100 skipped bad commits 7.81(7.42+0.38) 7.95(7.53+0.41) +1.8% 7.83(7.42+0.41) +0.3%
1450.11: fsck with 1000 skipped bad commits 7.99(7.62+0.36) 7.90(7.50+0.40) -1.1% 7.86(7.49+0.37) -1.6%
1450.13: fsck with 10000 skipped bad commits 7.98(7.57+0.40) 7.94(7.53+0.40) -0.5% 7.90(7.45+0.44) -1.0%
1450.15: fsck with 100000 skipped bad commits 7.97(7.57+0.39) 8.03(7.67+0.36) +0.8% 7.84(7.43+0.41) -1.6%
1450.17: fsck with 1000000 skipped bad commits 7.72(7.22+0.50) 7.28(7.07+0.20) -5.7% 7.13(6.87+0.25) -7.6%
Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
I looped over the toplevel header files, creating a temporary two-line C
program for each consisting of
#include "git-compat-util.h"
#include $HEADER
This patch is the result of manually fixing errors in compiling those
tiny programs.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In preparation for performing fsck checks on .gitmodules
files, this commit plumbs in the actual detection of the
files. Note that unlike most other fsck checks, this cannot
be a property of a single object: we must know that the
object is found at a ".gitmodules" path at the root tree of
a commit.
Since the fsck code only sees one object at a time, we have
to mark the related objects to fit the puzzle together. When
we see a commit we mark its tree as a root tree, and when
we see a root tree with a .gitmodules file, we mark the
corresponding blob to be checked.
In an ideal world, we'd check the objects in topological
order: commits followed by trees followed by blobs. In that
case we can avoid ever loading an object twice, since all
markings would be complete by the time we get to the marked
objects. And indeed, if we are checking a single packfile,
this is the order in which Git will generally write the
objects. But we can't count on that:
1. git-fsck may show us the objects in arbitrary order
(loose objects are fed in sha1 order, but we may also
have multiple packs, and we process each pack fully in
sequence).
2. The type ordering is just what git-pack-objects happens
to write now. The pack format does not require a
specific order, and it's possible that future versions
of Git (or a custom version trying to fool official
Git's fsck checks!) may order it differently.
3. We may not even be fscking all of the relevant objects
at once. Consider pushing with transfer.fsckObjects,
where one push adds a blob at path "foo", and then a
second push adds the same blob at path ".gitmodules".
The blob is not part of the second push at all, but we
need to mark and check it.
So in the general case, we need to make up to three passes
over the objects: once to make sure we've seen all commits,
then once to cover any trees we might have missed, and then
a final pass to cover any .gitmodules blobs we found in the
second pass.
We can simplify things a bit by loosening the requirement
that we find .gitmodules only at root trees. Technically
a file like "subdir/.gitmodules" is not parsed by Git, but
it's not unreasonable for us to declare that Git is aware of
all ".gitmodules" files and make them eligible for checking.
That lets us drop the root-tree requirement, which
eliminates one pass entirely. And it makes our worst case
much better: instead of potentially queueing every root tree
to be re-examined, the worst case is that we queue each
unique .gitmodules blob for a second look.
This patch just adds the boilerplate to find .gitmodules
files. The actual content checks will come in a subsequent
commit.
Signed-off-by: Jeff King <peff@peff.net>
Since this structure handles an array of object IDs, rename it to struct
oid_array. Also rename the accessor functions and the initialization
constant.
This commit was produced mechanically by providing non-Documentation
files to the following Perl one-liners:
perl -pi -E 's/struct sha1_array/struct oid_array/g'
perl -pi -E 's/\bsha1_array_/oid_array_/g'
perl -pi -E 's/SHA1_ARRAY_INIT/OID_ARRAY_INIT/g'
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We will need this in the next commit, where fsck will be taught to
optionally name the objects when reporting issues about them.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If fsck_options->name_objects is initialized, and if it already has
name(s) for the object(s) that are to be the starting point(s) for
fsck_walk(), then that function will now add names for the objects
that were walked.
This will be highly useful for teaching git-fsck to identify root causes
for broken links, which is the task for the next patch in this series.
Note that this patch opts for decorating the objects with plain strings
instead of full-blown structs (à la `struct rev_name` in the code of
the `git name-rev` command), for several reasons:
- the code is much simpler than if it had to work with structs that
describe arbitrarily long names such as "master~14^2~5:builtin/am.c",
- the string processing is actually quite light-weight compared to the
rest of fsck's operation,
- the caller of fsck_walk() is expected to provide names for the
starting points, and using plain and simple strings is just the
easiest way to do that.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The optional new config option `receive.fsck.skipList` specifies the path
to a file listing the names, i.e. SHA-1s, one per line, of objects that
are to be ignored by `git receive-pack` when `receive.fsckObjects = true`.
This is extremely handy in case of legacy repositories where it would
cause more pain to change incorrect objects than to live with them
(e.g. a duplicate 'author' line in an early commit object).
The intended use case is for server administrators to inspect objects
that are reported by `git push` as being too problematic to enter the
repository, and to add the objects' SHA-1 to a (preferably sorted) file
when the objects are legitimate, i.e. when it is determined that those
problematic objects should be allowed to enter the server.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
An fsck issue in a legacy repository might be so common that one would
like not to bother the user with mentioning it at all. With this change,
that is possible by setting the respective message type to "ignore".
This change "abuses" the missingEmail=warn test to verify that "ignore"
is also accepted and works correctly. And while at it, it makes sure
that multiple options work, too (they are passed to unpack-objects or
index-pack as a comma-separated list via the --strict=... command-line
option).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
For example, missing emails in commit and tag objects can be demoted to
mere warnings with
git config receive.fsck.missingemail=warn
The value is actually a comma-separated list.
In case that the same key is listed in multiple receive.fsck.<msg-id>
lines in the config, the latter configuration wins (this can happen for
example when both $HOME/.gitconfig and .git/config contain message type
settings).
As git receive-pack does not actually perform the checks, it hands off
the setting to index-pack or unpack-objects in the form of an optional
argument to the --strict option.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are legacy repositories out there whose older commits and tags
have issues that prevent pushing them when 'receive.fsckObjects' is set.
One real-life example is a commit object that has been hand-crafted to
list two authors.
Often, it is not possible to fix those issues without disrupting the
work with said repositories, yet it is still desirable to perform checks
by setting `receive.fsckObjects = true`. This commit is the first step
to allow demoting specific fsck issues to mere warnings.
The `fsck_set_msg_types()` function added by this commit parses a list
of settings in the form:
missingemail=warn,badname=warn,...
Unfortunately, the FSCK_WARN/FSCK_ERROR flag is only really heeded by
git fsck so far, but other call paths (e.g. git index-pack --strict)
error out *always* no matter what type was specified. Therefore, we need
to take extra care to set all message types to FSCK_ERROR by default in
those cases.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of specifying whether a message by the fsck machinery constitutes
an error or a warning, let's specify an identifier relating to the
concrete problem that was encountered. This is necessary for upcoming
support to be able to demote certain errors to warnings.
In the process, simplify the requirements on the calling code: instead of
having to handle full-blown varargs in every callback, we now send a
string buffer ready to be used by the callback.
We could use a simple enum for the message IDs here, but we want to
guarantee that the enum values are associated with the appropriate
message types (i.e. error or warning?). Besides, we want to introduce a
parser in the next commit that maps the string representation to the
enum value, hence we use the slightly ugly preprocessor construct that
is extensible for use with said parser.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Just like the diff machinery, we are about to introduce more settings,
therefore it makes sense to carry them around as a (pointer to a) struct
containing all of them.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When fsck'ing an incoming pack, we need to fsck objects that cannot be
read via read_sha1_file() because they are not local yet (and might even
be rejected if transfer.fsckobjects is set to 'true').
For commits, there is a hack in place: we basically cache commit
objects' buffers anyway, but the same is not true, say, for tag objects.
By refactoring fsck_object() to take the object buffer and size as
optional arguments -- optional, because we still fall back to the
previous method to look at the cached commit objects if the caller
passes NULL -- we prepare the machinery for the upcoming handling of tag
objects.
The assumption that such buffers are inherently NUL terminated is now
wrong, of course, hence we pass the size of the buffer so that we can
add a sanity check later, to prevent running past the end of the buffer.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We already have these checks in many printf-type functions that have
prototypes which are in header files. Add these same checks to some
more prototypes in header functions and to static functions in .c
files.
cc: Miklos Vajna <vmiklos@frugalware.org>
Signed-off-by: Tarmigan Casebolt <tarmigan+git@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The requirements are:
* it may not crash on NULL pointers
* a callback function is needed, as index-pack/unpack-objects
need to do different things
* the type information is needed to check the expected <-> real type
and print better error messages
Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Jeff King
Glen Choo
Elijah Newren
Junio C Hamano
Patrick Steinhardt
John Cai
Ævar Arnfjörð Bjarmason
Jonathan Tan
René Scharfe
brian m. carlson
Johannes Schindelin
Tarmigan Casebolt
Mike Ralphson
Martin Koegler