The attribute subsystem learned to honor `attr.tree` configuration
that specifies which tree to read the .gitattributes files from.
* jc/attr-tree-config:
attr: add attr.tree for setting the treeish to read attributes from
attr: read attributes from HEAD when bare repo
44451a2 (attr: teach "--attr-source=<tree>" global option to "git",
2023-05-06) provided the ability to pass in a treeish as the attr
source. In the context of serving Git repositories as bare repos like we
do at GitLab however, it would be easier to point --attr-source to HEAD
for all commands by setting it once.
Add a new config attr.tree that allows this.
Signed-off-by: John Cai <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The motivation for 44451a2e5e (attr: teach "--attr-source=<tree>" global
option to "git" , 2023-05-06), was to make it possible to use
gitattributes with bare repositories.
To make it easier to read gitattributes in bare repositories however,
let's just make HEAD:.gitattributes the default. This is in line with
how mailmap works, 8c473cecfd (mailmap: default mailmap.blob in bare
repositories, 2012-12-13).
Signed-off-by: John Cai <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The files config.{h,c} contain functions that have to do with parsing,
but not config.
In order to further reduce all-in-one headers, separate out functions in
config.c that do not operate on config into its own file, parse.h,
and update the include directives in the .c files that need only such
functions accordingly.
Signed-off-by: Calvin Wan <calvinwan@google.com>
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach "git check-attr" work better with sparse-index.
* sl/sparse-check-attr:
check-attr: integrate with sparse-index
attr.c: read attributes in a sparse directory
t1092: add tests for 'git check-attr'
Before this patch, git check-attr was unable to read the attributes from
a .gitattributes file within a sparse directory. The original comment
was operating under the assumption that users are only interested in
files or directories inside the cones. Therefore, in the original code,
in the case of a cone-mode sparse-checkout, we didn't load the
.gitattributes file.
However, this behavior can lead to missing attributes for files inside
sparse directories, causing inconsistencies in file handling.
To resolve this, revise 'git check-attr' to allow attribute reading for
files in sparse directories from the corresponding .gitattributes files:
1.Utilize path_in_cone_mode_sparse_checkout() and index_name_pos_sparse
to check if a path falls within a sparse directory.
2.If path is inside a sparse directory, employ the value of
index_name_pos_sparse() to find the sparse directory containing path and
path relative to sparse directory. Proceed to read attributes from the
tree OID of the sparse directory using read_attr_from_blob().
3.If path is not inside a sparse directory，ensure that attributes are
fetched from the index blob with read_blob_data_from_index().
Change the test 'check-attr with pathspec outside sparse definition' to
'test_expect_success' to reflect that the attributes inside a sparse
directory can now be read. Ensure that the sparse index case works
correctly for git check-attr to illustrate the successful handling of
attributes within sparse directories.
Helped-by: Victoria Dye <vdye@github.com>
Signed-off-by: Shuqi Liang <cheskaqiqi@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Further shuffling of declarations across header files to streamline
file dependencies.
* cw/compat-util-header-cleanup:
git-compat-util: move alloc macros to git-compat-util.h
treewide: remove unnecessary includes for wrapper.h
kwset: move translation table from ctype
sane-ctype.h: create header for sane-ctype macros
git-compat-util: move wrapper.c funcs to its header
git-compat-util: move strbuf.c funcs to its header
alloc_nr, ALLOC_GROW, and ALLOC_GROW_BY are commonly used macros for
dynamic array allocation. Moving these macros to git-compat-util.h with
the other alloc macros focuses alloc.[ch] to allocation for Git objects
and additionally allows us to remove inclusions to alloc.h from files
that solely used the above macros.
Signed-off-by: Calvin Wan <calvinwan@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add more "git var" for toolsmiths to learn various locations Git is
configured with either via the configuration or hardcoded defaults.
* bc/more-git-var:
var: add config file locations
var: add attributes files locations
attr: expose and rename accessor functions
var: adjust memory allocation for strings
var: format variable structure with C99 initializers
var: add support for listing the shell
t: add a function to check executable bit
var: mark unused parameters in git_var callbacks
Right now, the functions which determine the current system and global
gitattributes files are not exposed. We'd like to use them in a future
commit, but they're not ideally named. Rename them to something more
suitable as a public interface, expose them, and document them.
Signed-off-by: brian m. carlson <bk2204@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The vast majority of files including object-store.h did not need dir.h
nor khash.h. Split the header into two files, and let most just depend
upon object-store-ll.h, while letting the two callers that need it
depend on the full object-store.h.
After this patch:
$ git grep -h include..object-store | sort | uniq -c
2 #include "object-store.h"
129 #include "object-store-ll.h"
Diff best viewed with `--color-moved`.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This also made it clear that several .c files that depended upon path.h
were missing a #include for it; add the missing includes while at it.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since this header showed up in some places besides just #include
statements, update/clean-up/remove those other places as well.
Note that compat/fsmonitor/fsm-path-utils-darwin.c previously got
away with violating the rule that all files must start with an include
of git-compat-util.h (or a short-list of alternate headers that happen
to include it first). This change exposed the violation and caused it
to stop building correctly; fix it by having it include
git-compat-util.h first, as per policy.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
For the functions defined in read-cache.c, move their declarations from
cache.h to a new header, read-cache-ll.h. Also move some related inline
functions from cache.h to read-cache.h. The purpose of the
read-cache-ll.h/read-cache.h split is that about 70% of the sites don't
need the inline functions and the extra headers they include.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git --attr-source=<tree> cmd $args" is a new way to have any
command to read attributes not from the working tree but from the
given tree object.
* jc/attr-source-tree:
attr: teach "--attr-source=<tree>" global option to "git"
Earlier, 47cfc9bd (attr: add flag `--source` to work with tree-ish,
2023-01-14) taught "git check-attr" the "--source=<tree>" option to
allow it to read attribute files from a tree-ish, but did so only
for the command. Just like "check-attr" users wanted a way to use
attributes from a tree-ish and not from the working tree files,
users of other commands (like "git diff") would benefit from the
same.
Undo most of the UI change the commit made, while keeping the
internal logic to read attributes from a given tree-ish. Expose the
internal logic via a new "--attr-source=<tree>" command line option
given to "git", so that it can be used with any git command that
runs as part of the main git process.
Additionally, add an environment variable GIT_ATTR_SOURCE that is set
when --attr-source is passed in, so that subprocesses use the same value
for the attributes source tree.
Signed-off-by: John Cai <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Dozens of files made use of gettext functions, without explicitly
including gettext.h. This made it more difficult to find which files
could remove a dependence on cache.h. Make C files explicitly include
gettext.h if they are using it.
However, while compat/fsmonitor/fsm-ipc-darwin.c should also gain an
include of gettext.h, it was left out to avoid conflicting with an
in-flight topic.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This allows us to replace includes of cache.h with includes of the much
smaller alloc.h in many places. It does mean that we also need to add
includes of alloc.h in a number of C files.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git check-attr" learned to take an optional tree-ish to read the
.gitattributes file from.
* kn/attr-from-tree:
attr: add flag `--source` to work with tree-ish
t0003: move setup for `--all` into new block
Code cleaning.
* rs/dup-array:
use DUP_ARRAY
add DUP_ARRAY
do full type check in BARF_UNLESS_COPYABLE
factor out BARF_UNLESS_COPYABLE
mingw: make argv2 in try_shell_exec() non-const
On platforms where `size_t` does not have the same width as `unsigned
long`, passing a pointer to the former when a pointer to the latter is
expected can lead to problems.
Windows and 32-bit Linux are among the affected platforms.
In this instance, we want to store the size of the blob that was read in
that variable. However, `read_blob_data_from_index()` passes that
pointer to `read_object_file()` which expects an `unsigned long *`.
Which means that on affected platforms, the variable is not fully
populated and part of its value is left uninitialized. (On Big-Endian
platforms, this problem would be even worse.)
The consequence is that depending on the uninitialized memory's
contents, we may erroneously reject perfectly fine attributes.
Let's address this by passing a pointer to a variable of the expected
data type.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The contents of the .gitattributes files may evolve over time, but "git
check-attr" always checks attributes against them in the working tree
and/or in the index. It may be beneficial to optionally allow the users
to check attributes taken from a commit other than HEAD against paths.
Add a new flag `--source` which will allow users to check the
attributes against a commit (actually any tree-ish would do). When the
user uses this flag, we go through the stack of .gitattributes files but
instead of checking the current working tree and/or in the index, we
check the blobs from the provided tree-ish object. This allows the
command to also be used in bare repositories.
Since we use a tree-ish object, the user can pass "--source
HEAD:subdirectory" and all the attributes will be looked up as if
subdirectory was the root directory of the repository.
We cannot simply use the `<rev>:<path>` syntax without the `--source`
flag, similar to how it is used in `git show` because any non-flag
parameter before `--` is treated as an attribute and any parameter after
`--` is treated as a pathname.
The change involves creating a new function `read_attr_from_blob`, which
given the path reads the blob for the path against the provided source and
parses the attributes line by line. This function is plugged into
`read_attr()` function wherein we go through the stack of attributes
files.
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Toon Claes <toon@iotcl.com>
Co-authored-by: toon@iotcl.com
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a semantic patch for replace ALLOC_ARRAY+COPY_ARRAY with DUP_ARRAY
to reduce code duplication and apply its results.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
When reading attributes from a file we use fgets(3P) with a buffer size
of 2048 bytes. This means that as soon as a line exceeds the buffer size
we split it up into multiple parts and parse each of them as a separate
pattern line. This is of course not what the user intended, and even
worse the behaviour is inconsistent with how we read attributes from the
index.
Fix this bug by converting the code to use `strbuf_getline()` instead.
This will indeed read in the whole line, which may theoretically lead to
an out-of-memory situation when the gitattributes file is huge. We're
about to reject any gitattributes files larger than 100MB in the next
commit though, which makes this less of a concern.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When parsing an attributes line, we need to allocate an array that holds
all attributes specified for the given file pattern. The calculation to
determine the number of bytes that need to be allocated was prone to an
overflow though when there was an unreasonable amount of attributes.
Harden the allocation by instead using the `st_` helper functions that
cause us to die when we hit an integer overflow.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Attributes have a field that tracks the position in the `all_attrs`
array they're stored inside. This field gets set via `hashmap_get_size`
when adding the attribute to the global map of attributes. But while the
field is of type `int`, the value returned by `hashmap_get_size` is an
`unsigned int`. It can thus happen that the value overflows, where we
would now dereference teh `all_attrs` array at an out-of-bounds value.
We do have a sanity check for this overflow via an assert that verifies
the index matches the new hashmap's size. But asserts are not a proper
mechanism to detect against any such overflows as they may not in fact
be compiled into production code.
Fix this by using an `unsigned int` to track the index and convert the
assert to a call `die()`.
Reported-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `struct attr_stack` tracks the stack of all patterns together with
their attributes. When parsing a gitattributes file that has more than
2^31 such patterns though we may trigger multiple out-of-bounds reads on
64 bit platforms. This is because while the `num_matches` variable is an
unsigned integer, we always use a signed integer to iterate over them.
I have not been able to reproduce this issue due to memory constraints
on my systems. But despite the out-of-bounds reads, the worst thing that
can seemingly happen is to call free(3P) with a garbage pointer when
calling `attr_stack_free()`.
Fix this bug by using unsigned integers to iterate over the array. While
this makes the iteration somewhat awkward when iterating in reverse, it
is at least better than knowingly running into an out-of-bounds read.
While at it, convert the call to `ALLOC_GROW` to use `ALLOC_GROW_BY`
instead.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is possible to trigger an integer overflow when parsing attribute
names when there are more than 2^31 of them for a single pattern. This
can either lead to us dying due to trying to request too many bytes:
blob=$(perl -e 'print "f" . " a=" x 2147483649' | git hash-object -w --stdin)
git update-index --add --cacheinfo 100644,$blob,.gitattributes
git attr-check --all file
=================================================================
==1022==ERROR: AddressSanitizer: requested allocation size 0xfffffff800000032 (0xfffffff800001038 after adjustments for alignment, red zones etc.) exceeds maximum supported size of 0x10000000000 (thread T0)
#0 0x7fd3efabf411 in __interceptor_calloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:77
#1 0x5563a0a1e3d3 in xcalloc wrapper.c:150
#2 0x5563a058d005 in parse_attr_line attr.c:384
#3 0x5563a058e661 in handle_attr_line attr.c:660
#4 0x5563a058eddb in read_attr_from_index attr.c:769
#5 0x5563a058ef12 in read_attr attr.c:797
#6 0x5563a058f24c in bootstrap_attr_stack attr.c:867
#7 0x5563a058f4a3 in prepare_attr_stack attr.c:902
#8 0x5563a05905da in collect_some_attrs attr.c:1097
#9 0x5563a059093d in git_all_attrs attr.c:1128
#10 0x5563a02f636e in check_attr builtin/check-attr.c:67
#11 0x5563a02f6c12 in cmd_check_attr builtin/check-attr.c:183
#12 0x5563a02aa993 in run_builtin git.c:466
#13 0x5563a02ab397 in handle_builtin git.c:721
#14 0x5563a02abb2b in run_argv git.c:788
#15 0x5563a02ac991 in cmd_main git.c:926
#16 0x5563a05432bd in main common-main.c:57
#17 0x7fd3ef82228f (/usr/lib/libc.so.6+0x2328f)
==1022==HINT: if you don't care about these errors you may set allocator_may_return_null=1
SUMMARY: AddressSanitizer: allocation-size-too-big /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:77 in __interceptor_calloc
==1022==ABORTING
Or, much worse, it can lead to an out-of-bounds write because we
underallocate and then memcpy(3P) into an array:
perl -e '
print "A " . "\rh="x2000000000;
print "\rh="x2000000000;
print "\rh="x294967294 . "\n"
' >.gitattributes
git add .gitattributes
git commit -am "evil attributes"
$ git clone --quiet /path/to/repo
=================================================================
==15062==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000002550 at pc 0x5555559884d5 bp 0x7fffffffbc60 sp 0x7fffffffbc58
WRITE of size 8 at 0x602000002550 thread T0
#0 0x5555559884d4 in parse_attr_line attr.c:393
#1 0x5555559884d4 in handle_attr_line attr.c:660
#2 0x555555988902 in read_attr_from_index attr.c:784
#3 0x555555988902 in read_attr_from_index attr.c:747
#4 0x555555988a1d in read_attr attr.c:800
#5 0x555555989b0c in bootstrap_attr_stack attr.c:882
#6 0x555555989b0c in prepare_attr_stack attr.c:917
#7 0x555555989b0c in collect_some_attrs attr.c:1112
#8 0x55555598b141 in git_check_attr attr.c:1126
#9 0x555555a13004 in convert_attrs convert.c:1311
#10 0x555555a95e04 in checkout_entry_ca entry.c:553
#11 0x555555d58bf6 in checkout_entry entry.h:42
#12 0x555555d58bf6 in check_updates unpack-trees.c:480
#13 0x555555d5eb55 in unpack_trees unpack-trees.c:2040
#14 0x555555785ab7 in checkout builtin/clone.c:724
#15 0x555555785ab7 in cmd_clone builtin/clone.c:1384
#16 0x55555572443c in run_builtin git.c:466
#17 0x55555572443c in handle_builtin git.c:721
#18 0x555555727872 in run_argv git.c:788
#19 0x555555727872 in cmd_main git.c:926
#20 0x555555721fa0 in main common-main.c:57
#21 0x7ffff73f1d09 in __libc_start_main ../csu/libc-start.c:308
#22 0x555555723f39 in _start (git+0x1cff39)
0x602000002552 is located 0 bytes to the right of 2-byte region [0x602000002550,0x602000002552) allocated by thread T0 here:
#0 0x7ffff768c037 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154
#1 0x555555d7fff7 in xcalloc wrapper.c:150
#2 0x55555598815f in parse_attr_line attr.c:384
#3 0x55555598815f in handle_attr_line attr.c:660
#4 0x555555988902 in read_attr_from_index attr.c:784
#5 0x555555988902 in read_attr_from_index attr.c:747
#6 0x555555988a1d in read_attr attr.c:800
#7 0x555555989b0c in bootstrap_attr_stack attr.c:882
#8 0x555555989b0c in prepare_attr_stack attr.c:917
#9 0x555555989b0c in collect_some_attrs attr.c:1112
#10 0x55555598b141 in git_check_attr attr.c:1126
#11 0x555555a13004 in convert_attrs convert.c:1311
#12 0x555555a95e04 in checkout_entry_ca entry.c:553
#13 0x555555d58bf6 in checkout_entry entry.h:42
#14 0x555555d58bf6 in check_updates unpack-trees.c:480
#15 0x555555d5eb55 in unpack_trees unpack-trees.c:2040
#16 0x555555785ab7 in checkout builtin/clone.c:724
#17 0x555555785ab7 in cmd_clone builtin/clone.c:1384
#18 0x55555572443c in run_builtin git.c:466
#19 0x55555572443c in handle_builtin git.c:721
#20 0x555555727872 in run_argv git.c:788
#21 0x555555727872 in cmd_main git.c:926
#22 0x555555721fa0 in main common-main.c:57
#23 0x7ffff73f1d09 in __libc_start_main ../csu/libc-start.c:308
SUMMARY: AddressSanitizer: heap-buffer-overflow attr.c:393 in parse_attr_line
Shadow bytes around the buggy address:
0x0c047fff8450: fa fa 00 02 fa fa 00 07 fa fa fd fd fa fa 00 00
0x0c047fff8460: fa fa 02 fa fa fa fd fd fa fa 00 06 fa fa 05 fa
0x0c047fff8470: fa fa fd fd fa fa 00 02 fa fa 06 fa fa fa 05 fa
0x0c047fff8480: fa fa 07 fa fa fa fd fd fa fa 00 01 fa fa 00 02
0x0c047fff8490: fa fa 00 03 fa fa 00 fa fa fa 00 01 fa fa 00 03
=>0x0c047fff84a0: fa fa 00 01 fa fa 00 02 fa fa[02]fa fa fa fa fa
0x0c047fff84b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff84c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff84d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff84e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff84f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
Shadow gap: cc
==15062==ABORTING
Fix this bug by using `size_t` instead to count the number of attributes
so that this value cannot reasonably overflow without running out of
memory before already.
Reported-by: Markus Vervier <markus.vervier@x41-dsec.de>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is possible to trigger an integer overflow when parsing attribute
names that are longer than 2^31 bytes because we assign the result of
strlen(3P) to an `int` instead of to a `size_t`. This can lead to an
abort in vsnprintf(3P) with the following reproducer:
blob=$(perl -e 'print "A " . "B"x2147483648 . "\n"' | git hash-object -w --stdin)
git update-index --add --cacheinfo 100644,$blob,.gitattributes
git check-attr --all path
BUG: strbuf.c:400: your vsnprintf is broken (returned -1)
But furthermore, assuming that the attribute name is even longer than
that, it can cause us to silently truncate the attribute and thus lead
to wrong results.
Fix this integer overflow by using a `size_t` instead. This fixes the
silent truncation of attribute names, but it only partially fixes the
BUG we hit: even though the initial BUG is fixed, we can still hit a BUG
when parsing invalid attribute lines via `report_invalid_attr()`.
This is due to an underlying design issue in vsnprintf(3P) which only
knows to return an `int`, and thus it may always overflow with large
inputs. This issue is benign though: the worst that can happen is that
the error message is misreported to be either truncated or too long, but
due to the buffer being NUL terminated we wouldn't ever do an
out-of-bounds read here.
Reported-by: Markus Vervier <markus.vervier@x41-dsec.de>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There is an out-of-bounds read possible when parsing gitattributes that
have an attribute that is 2^31+1 bytes long. This is caused due to an
integer overflow when we assign the result of strlen(3P) to an `int`,
where we use the wrapped-around value in a subsequent call to
memcpy(3P). The following code reproduces the issue:
blob=$(perl -e 'print "a" x 2147483649 . " attr"' | git hash-object -w --stdin)
git update-index --add --cacheinfo 100644,$blob,.gitattributes
git check-attr --all file
AddressSanitizer:DEADLYSIGNAL
=================================================================
==8451==ERROR: AddressSanitizer: SEGV on unknown address 0x7f93efa00800 (pc 0x7f94f1f8f082 bp 0x7ffddb59b3a0 sp 0x7ffddb59ab28 T0)
==8451==The signal is caused by a READ memory access.
#0 0x7f94f1f8f082 (/usr/lib/libc.so.6+0x176082)
#1 0x7f94f2047d9c in __interceptor_strspn /usr/src/debug/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:752
#2 0x560e190f7f26 in parse_attr_line attr.c:375
#3 0x560e190f9663 in handle_attr_line attr.c:660
#4 0x560e190f9ddd in read_attr_from_index attr.c:769
#5 0x560e190f9f14 in read_attr attr.c:797
#6 0x560e190fa24e in bootstrap_attr_stack attr.c:867
#7 0x560e190fa4a5 in prepare_attr_stack attr.c:902
#8 0x560e190fb5dc in collect_some_attrs attr.c:1097
#9 0x560e190fb93f in git_all_attrs attr.c:1128
#10 0x560e18e6136e in check_attr builtin/check-attr.c:67
#11 0x560e18e61c12 in cmd_check_attr builtin/check-attr.c:183
#12 0x560e18e15993 in run_builtin git.c:466
#13 0x560e18e16397 in handle_builtin git.c:721
#14 0x560e18e16b2b in run_argv git.c:788
#15 0x560e18e17991 in cmd_main git.c:926
#16 0x560e190ae2bd in main common-main.c:57
#17 0x7f94f1e3c28f (/usr/lib/libc.so.6+0x2328f)
#18 0x7f94f1e3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349)
#19 0x560e18e110e4 in _start ../sysdeps/x86_64/start.S:115
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/usr/lib/libc.so.6+0x176082)
==8451==ABORTING
Fix this bug by converting the variable to a `size_t` instead.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The function `git_attr_internal()` is called to upsert attributes into
the global map. And while all callers pass a `size_t`, the function
itself accepts an `int` as the attribute name's length. This can lead to
an integer overflow in case the attribute name is longer than `INT_MAX`.
Now this overflow seems harmless as the first thing we do is to call
`attr_name_valid()`, and that function only succeeds in case all chars
in the range of `namelen` match a certain small set of chars. We thus
can't do an out-of-bounds read as NUL is not part of that set and all
strings passed to this function are NUL-terminated. And furthermore, we
wouldn't ever read past the current attribute name anyway due to the
same reason. And if validation fails we will return early.
On the other hand it feels fragile to rely on this behaviour, even more
so given that we pass `namelen` to `FLEX_ALLOC_MEM()`. So let's instead
just do the correct thing here and accept a `size_t` as line length.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since its inception in d0bfd026a8 (Add basic infrastructure to assign
attributes to paths, 2007-04-12), the attribute code carries a little
bit of debug code that is conditionally compiled only when DEBUG_ATTR is
set. But since you have to know about it and make a special build of Git
to use it, it's not clear that it's helping anyone (and there are very
few mentions of it on the list over the years).
Meanwhile, it causes slight headaches. Since it's not built as part of a
regular compile, it's subject to bitrot. E.g., this was dealt with in
712efb1a42 (attr: make it build with DEBUG_ATTR again, 2013-01-15), and
it currently fails to build with DEVELOPER=1 since e810e06357 (attr:
tighten const correctness with git_attr and match_attr, 2017-01-27).
And it causes confusion with -Wunused-parameter; the "what" parameter of
fill_one() is unused in a normal build, but needed in a debug build.
Let's just get rid of this code (and the now-useless parameter).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Undoes 'jk/unused-annotation' topic and redoes it to work around
Coccinelle rules misfiring false positives in unrelated codepaths.
* ab/unused-annotation:
git-compat-util.h: use "deprecated" for UNUSED variables
git-compat-util.h: use "UNUSED", not "UNUSED(var)"
Annotate function parameters that are not used (but cannot be
removed for structural reasons), to prepare us to later compile
with -Wunused warning turned on.
* jk/unused-annotation:
is_path_owned_by_current_uid(): mark "report" parameter as unused
run-command: mark unused async callback parameters
mark unused read_tree_recursive() callback parameters
hashmap: mark unused callback parameters
config: mark unused callback parameters
streaming: mark unused virtual method parameters
transport: mark bundle transport_options as unused
refs: mark unused virtual method parameters
refs: mark unused reflog callback parameters
refs: mark unused each_ref_fn parameters
git-compat-util: add UNUSED macro
As reported in [1] the "UNUSED(var)" macro introduced in
2174b8c75d (Merge branch 'jk/unused-annotation' into next,
2022-08-24) breaks coccinelle's parsing of our sources in files where
it occurs.
Let's instead partially go with the approach suggested in [2] of
making this not take an argument. As noted in [1] "coccinelle" will
ignore such tokens in argument lists that it doesn't know about, and
it's less of a surprise to syntax highlighters.
This undoes the "help us notice when a parameter marked as unused is
actually use" part of 9b24034754 (git-compat-util: add UNUSED macro,
2022-08-19), a subsequent commit will further tweak the macro to
implement a replacement for that functionality.
1. https://lore.kernel.org/git/220825.86ilmg4mil.gmgdl@evledraar.gmail.com/
2. https://lore.kernel.org/git/220819.868rnk54ju.gmgdl@evledraar.gmail.com/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This field has not been used since the function was introduced in
b559263216 (exclude: split pathname matching code into a separate
function, 2012-10-15), though there was a brief period where it was
erroneously used and then reverted in ed4958477b (dir: fix pattern
matching on dirs, 2021-09-24) and 5ceb663e92 (dir: fix
directory-matching bug, 2021-11-02).
It's possible we'd eventually add a flag that makes it useful here, but
there are only a handful of callers. It would be easy to add back if
necessary, and in the meantime this makes the function interface less
misleading.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Hashmap comparison functions must conform to a particular callback
interface, but many don't use all of their parameters. Especially the
void cmp_data pointer, but some do not use keydata either (because they
can easily form a full struct to pass when doing lookups). Let's mark
these to make -Wunused-parameter happy.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Code clean-up.
* ab/refs-various-fixes:
refs debug: add a wrapper for "read_symbolic_ref"
packed-backend: remove stub BUG(...) functions
misc *.c: use designated initializers for struct assignments
refs: use designated initializers for "struct ref_iterator_vtable"
refs: use designated initializers for "struct ref_storage_be"
Change a few miscellaneous non-designated initializer assignments to
use designated initializers.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
