Similar as with the preceding commit, start ignoring gitattributes files
that are overly large to protect us against out-of-bounds reads and
writes caused by integer overflows. Unfortunately, we cannot just define
"overly large" in terms of any preexisting limits in the codebase.
Instead, we choose a very conservative limit of 100MB. This is plenty of
room for specifying gitattributes, and incidentally it is also the limit
for blob sizes for GitHub. While we don't want GitHub to dictate limits
here, it is still sensible to use this fact for an informed decision
given that it is hosting a huge set of repositories. Furthermore, over
at GitLab we scanned a subset of repositories for their root-level
attribute files. We found that 80% of them have a gitattributes file
smaller than 100kB, 99.99% have one smaller than 1MB, and only a single
repository had one that was almost 3MB in size. So enforcing a limit of
100MB seems to give us ample of headroom.
With this limit in place we can be reasonably sure that there is no easy
way to exploit the gitattributes file via integer overflows anymore.
Furthermore, it protects us against resource exhaustion caused by
allocating the in-memory data structures required to represent the
parsed attributes.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are two different code paths to read gitattributes: once via a
file, and once via the index. These two paths used to behave differently
because when reading attributes from a file, we used fgets(3P) with a
buffer size of 2kB. Consequentially, we silently truncate line lengths
when lines are longer than that and will then parse the remainder of the
line as a new pattern. It goes without saying that this is entirely
unexpected, but it's even worse that the behaviour depends on how the
gitattributes are parsed.
While this is simply wrong, the silent truncation saves us with the
recently discovered vulnerabilities that can cause out-of-bound writes
or reads with unreasonably long lines due to integer overflows. As the
common path is to read gitattributes via the worktree file instead of
via the index, we can assume that any gitattributes file that had lines
longer than that is already broken anyway. So instead of lifting the
limit here, we can double down on it to fix the vulnerabilities.
Introduce an explicit line length limit of 2kB that is shared across all
paths that read attributes and ignore any line that hits this limit
while printing a warning.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Several methods specify that they take a 'struct index_state' pointer
with the 'const' qualifier because they intend to only query the data,
not change it. However, we will be introducing a step very low in the
method stack that might modify a sparse-index to become a full index in
the case that our queries venture inside a sparse-directory entry.
This change only removes the 'const' qualifiers that are necessary for
the following change which will actually modify the implementation of
index_name_stage_pos().
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the documentation from Documentation/technical/api-gitattributes.txt
to attr.h as it's easier for the developers to find the usage
information beside the code instead of looking for it in another doc file.
Also documentation/technical/api-gitattributes.txt is removed because the
information it has is now redundant and it'll be hard to keep it up to
date and synchronized with the documentation in the header file.
Signed-off-by: Heba Waly <heba.waly@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git_check_attr() returns always 0.
Remove all the error handling code of the callers, which is never executed.
Change git_check_attr() to be a void function.
Signed-off-by: Torsten Bögershausen <tboegi@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Code hygiene improvement for the header files.
* en/incl-forward-decl:
Remove forward declaration of an enum
compat/precompose_utf8.h: use more common include guard style
urlmatch.h: fix include guard
Move definition of enum branch_track from cache.h to branch.h
alloc: make allocate_alloc_state and clear_alloc_state more consistent
Add missing includes and forward declarations
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>
Since attr checking API now take the index, there's no need to set an
index in advance with this call. Most call sites are straightforward
because they either pass the_index or NULL (which defaults back to
the_index previously). There's only one suspicious call site in
unpack-trees.c where it sets a different index.
This code in unpack-trees is about to check out entries from the
new/temporary index after merging is done in it. The attributes will
be used by entry.c code to do crlf conversion if needed. entry.c now
respects struct checkout's istate field, and this field is correctly
set in unpack-trees.c, there should be no regression from this change.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make the attr API take an index_state instead of assuming the_index in
attr code. All call sites are converted blindly to keep the patch
simple and retain current behavior. Individual call sites may receive
further updates to use the right index instead of the_index.
There is one ugly temporary workaround added in attr.c that needs some
more explanation.
Commit c24f3abace (apply: file commited with CRLF should roundtrip
diff and apply - 2017-08-19) forces one convert_to_git() call to NOT
read the index at all. But what do you know, we read it anyway by
falling back to the_index. When "istate" from convert_to_git is now
propagated down to read_attr_from_array() we will hit segfault
somewhere inside read_blob_data_from_index.
The right way of dealing with this is to kill "use_index" variable and
only follow "istate" but at this stage we are not ready for that:
while most git_attr_set_direction() calls just passes the_index to be
assigned to use_index, unpack-trees passes a different one which is
used by entry.c code, which has no way to know what index to use if we
delete use_index. So this has to be done later.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The pathspec mechanism is extended via the new
":(attr:eol=input)pattern/to/match" syntax to filter paths so that it
requires paths to not just match the given pattern but also have the
specified attrs attached for them to be chosen.
Based on a patch by Stefan Beller <sbeller@google.com>
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Move the 'git_attr_set_direction()' up to be closer to the variables
that it modifies as well as a small formatting by renaming the variable
'new' to 'new_direction' so that it is more descriptive.
Update the comment about how 'direction' is used to read the state of
the world. It should be noted that callers of
'git_attr_set_direction()' should ensure that other threads are not
making calls into the attribute system until after the call to
'git_attr_set_direction()' completes. This function essentially acts as
reset button for the attribute system and should be handled with care.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The last big hurdle towards a thread-safe API for the attribute system
is the reliance on a global attribute stack that is modified during each
call into the attribute system.
This patch removes this global stack and instead a stack is stored
locally in each attr_check instance. This opens up the opportunity for
future optimizations to customize the attribute stack for the attributes
that a particular attr_check struct is interested in.
One caveat with pushing the attribute stack into the attr_check
structure is that the attribute system now needs to keep track of all
active attr_check instances. Due to the direction mechanism the stack
needs to be dropped when the direction is switched. In order to ensure
correctness when the direction is changed the attribute system needs to
iterate through all active attr_check instances and drop each of their
stacks.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Currently there is a reliance on 'check_all_attr' which is a global
array of 'attr_check_item' items which is used to store the value of
each attribute during the collection process.
This patch eliminates this global and instead creates an array per
'attr_check' instance which is then used in the attribute collection
process. This brings the attribute system one step closer to being
thread-safe.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The current implementation of the attribute dictionary uses a custom
hashtable. This modernizes the dictionary by converting it to the builtin
'hashmap' structure.
Also, in order to enable a threaded API in the future add an
accompanying mutex which must be acquired prior to accessing the
dictionary of interned attributes.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since nobody uses the old API, make it file-scope static, and update
the documentation to describe the new API.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This updates the other two ways the attribute check is done via an
array of "struct attr_check_item" elements. These two niches
appear only in "git check-attr".
* The caller does not know offhand what attributes it wants to ask
about and cannot use attr_check_initl() to prepare the
attr_check structure.
* The caller may not know what attributes it wants to ask at all,
and instead wants to learn everything that the given path has.
Such a caller can call attr_check_alloc() to allocate an empty
attr_check, and then call attr_check_append() to add attribute names
one by one.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A common pattern to check N attributes for many paths is to
(1) prepare an array A of N attr_check_item items;
(2) call git_attr() to intern the N attribute names and fill A;
(3) repeatedly call git_check_attrs() for path with N and A;
A look-up for these N attributes for a single path P scans the
entire attr_stack, starting from the .git/info/attributes file and
then .gitattributes file in the directory the path P is in, going
upwards to find .gitattributes file found in parent directories.
An earlier commit 06a604e6 (attr: avoid heavy work when we know the
specified attr is not defined, 2014-12-28) tried to optimize out
this scanning for one trivial special case: when the attribute being
sought is known not to exist, we do not have to scan for it. While
this may be a cheap and effective heuristic, it would not work well
when N is (much) more than 1.
What we would want is a more customized way to skip irrelevant
entries in the attribute stack, and the definition of irrelevance
is tied to the set of attributes passed to git_check_attrs() call,
i.e. the set of attributes being sought. The data necessary for
this optimization needs to live alongside the set of attributes, but
a simple array of git_attr_check_elem simply does not have any place
for that.
Introduce "struct attr_check" that contains N, the number of
attributes being sought, and A, the array that holds N
attr_check_item items, and a function git_check_attr() that
takes a path P and this structure as its parameters. This structure
can later be extended to hold extra data necessary for optimization.
Also, to make it easier to write the first two steps in common
cases, introduce git_attr_check_initl() helper function, which takes
a NULL-terminated list of attribute names and initialize this
structure.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The traditional API to check attributes is to prepare an N-element
array of "struct git_attr_check" and pass N and the array to the
function "git_check_attr()" as arguments.
In preparation to revamp the API to pass a single structure, in
which these N elements are held, rename the type used for these
individual array elements to "struct attr_check_item" and rename
the function to "git_check_attrs()".
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It holds an interned string, and git_attr_name() is a way to peek
into it. Make sure the involved pointer types are pointer-to-const.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Found by running this command:
$ git ls-files -z|xargs -0 perl -0777 -n \
-e 'while (/\b(then?|[iao]n|i[fst]|but|f?or|at|and|[dt]o)\s+\1\b/gims)' \
-e ' {' \
-e ' $n = ($` =~ tr/\n/\n/ + 1);' \
-e ' ($v = $&) =~ s/\n/\\n/g;' \
-e ' print "$ARGV:$n:$v\n";' \
-e ' }'
Why not just git grep -E ...?
That wouldn't work then the doubled words are separated by a newline.
This is derived from a Makefile syntax-check rule in gnulib's maint.mk:
http://git.sv.gnu.org/cgit/gnulib.git/tree/top/maint.mk
Signed-off-by: Jim Meyering <meyering@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Suggested by: Junio Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a function, git_all_attrs(), that reports on all attributes that
are set on a path.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It will be present in any likely future reimplementation, and its
availability simplifies other code.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Without this patch at least IBM VisualAge C 5.0 (I have 5.0.2) on AIX
5.1 fails to compile git.
enum style is inconsistent already, with some enums declared on one
line, some over 3 lines with the enum values all on the middle line,
sometimes with 1 enum value per line... and independently of that the
trailing comma is sometimes present and other times absent, often
mixing with/without trailing comma styles in a single file, and
sometimes in consecutive enum declarations.
Clearly, omitting the comma is the more portable style, and this patch
changes all enum declarations to use the portable omitted dangling
comma style consistently.
Signed-off-by: Gary V. Vaughan <gary@thewrittenword.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function took (name, namelen) as its arguments, but all the public
callers wanted to pass a full string.
Demote the counted-string interface to an internal API status, and allow
public callers to just pass the string to the function.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This instructs attr mechanism, not to look into working .gitattributes
at all. Needed by tools that does not handle working directory, such
as "git archive".
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Traditionally we used .gitattributes file from the work tree if exists,
and otherwise read from the index as a fallback. When switching to a
branch that has an updated .gitattributes file, and entries in it give
different attributes to other paths being checked out, we should instead
read from the .gitattributes in the index.
This breaks a use case of fixing incorrect entries in the .gitattributes
in the work tree (without adding it to the index) and checking other paths
out, though.
$ edit .gitattributes ;# mark foo.dat as binary
$ rm foo.dat
$ git checkout foo.dat
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It was bothering me a lot that I abused small integer values
casted to (void *) to represent non string values in
gitattributes. This corrects it by making the type of attribute
values (const char *), and using the address of a few statically
allocated character buffer to denote true/false. Unset attributes
are represented as having NULLs as their values.
Added in-header documentation to explain how git_checkattr()
routine should be called.
Signed-off-by: Junio C Hamano <junkio@cox.net>
This allows you to define three values (and possibly more) to
each attribute: true, false, and unset.
Typically the handlers that notice and act on attribute values
treat "unset" attribute to mean "do your default thing"
(e.g. crlf that is unset would trigger "guess from contents"),
so being able to override a setting to an unset state is
actually useful.
- If you want to set the attribute value to true, have an entry
in .gitattributes file that mentions the attribute name; e.g.
*.o binary
- If you want to set the attribute value explicitly to false,
use '-'; e.g.
*.a -diff
- If you want to make the attribute value _unset_, perhaps to
override an earlier entry, use '!'; e.g.
*.a -diff
c.i.a !diff
This also allows string values to attributes, with the natural
syntax:
attrname=attrvalue
but you cannot use it, as nobody takes notice and acts on
it yet.
Signed-off-by: Junio C Hamano <junkio@cox.net>
This adds the basic infrastructure to assign attributes to
paths, in a way similar to what the exclusion mechanism does
based on $GIT_DIR/info/exclude and .gitignore files.
An attribute is just a simple string that does not contain any
whitespace. They can be specified in $GIT_DIR/info/attributes
file, and .gitattributes file in each directory.
Each line in these files defines a pattern matching rule.
Similar to the exclusion mechanism, a later match overrides an
earlier match in the same file, and entries from .gitattributes
file in the same directory takes precedence over the ones from
parent directories. Lines in $GIT_DIR/info/attributes file are
used as the lowest precedence default rules.
A line is either a comment (an empty line, or a line that begins
with a '#'), or a rule, which is a whitespace separated list of
tokens. The first token on the line is a shell glob pattern.
The rest are names of attributes, each of which can optionally
be prefixed with '!'. Such a line means "if a path matches this
glob, this attribute is set (or unset -- if the attribute name
is prefixed with '!'). For glob matching, the same "if the
pattern does not have a slash in it, the basename of the path is
matched with fnmatch(3) against the pattern, otherwise, the path
is matched with the pattern with FNM_PATHNAME" rule as the
exclusion mechanism is used.
This does not define what an attribute means. Tying an
attribute to various effects it has on git operation for paths
that have it will be specified separately.
Signed-off-by: Junio C Hamano <junkio@cox.net>
