These calls to snprintf should always succeed, because their
input is small and fixed. Let's use xsnprintf to make sure
this is the case (and to make auditing for actual truncation
easier).
These could be candidates for turning into heap buffers, but
they fall into a few broad categories that make it not worth
doing:
- formatting single numbers is simple enough that we can
see the result should fit
- the size of a sha1 is likewise well-known, and I didn't
want to cause unnecessary conflicts with the ongoing
process to convert these constants to GIT_MAX_HEXSZ
- the interface for curl_errorstr is dictated by curl
Signed-off-by: Jeff King <peff@peff.net>
We'd prefer to avoid unchecked snprintf calls because
truncation can lead to unexpected results.
These are all cases where truncation shouldn't ever happen,
because the input to snprintf is fixed in size. That makes
them candidates for xsnprintf(), but it's simpler still to
just use the heap, and then nobody has to wonder if "100" is
big enough.
We'll use xstrfmt() where possible, and a strbuf when we need
the resulting size or to reuse the same buffer in a loop.
Signed-off-by: Jeff King <peff@peff.net>
After receive-pack reads the pack header from the client, it
feeds the already-read part to index-pack and unpack-objects
via their --pack-header command-line options. To do so, we
format it into a fixed buffer, then duplicate it into the
child's argv_array.
Our buffer is long enough to handle any possible input, so
this isn't wrong. But it's more complicated than it needs to
be; we can just argv_array_pushf() the final value and avoid
the intermediate copy. This drops the magic number and is
more efficient, too.
Note that we need to push to the argv_array in order, which
means we can't do the push until we are in the "unpack-objects
versus index-pack" conditional. Rather than duplicate the
slightly complicated format specifier, I pushed it into a
helper function.
Signed-off-by: Jeff King <peff@peff.net>
When name-rev needs to format an actual name, we do so into
a fixed-size buffer. That includes the actual ref tip, as
well as any traversal information. Since refs can exceed
1024 bytes, this means you can get a bogus result. E.g.,
doing:
git tag $(perl -e 'print join("/", 1..1024)')
git describe --contains HEAD^
results in ".../282/283", when it should be
".../1023/1024~1".
We can solve this by using a heap buffer. We'll use a
strbuf, which lets us write into the same buffer from our
loop without having to reallocate.
Signed-off-by: Jeff King <peff@peff.net>
We generate a reflog message that contains some fixed text
plus a branch name, and use a buffer of size PATH_MAX + 20.
This mostly works if you assume that refnames are shorter
than PATH_MAX, but:
1. That's not necessarily true. PATH_MAX is not always the
filesystem's limit.
2. The "20" is not sufficiently large for the fixed text
anyway.
Let's just switch to a heap buffer so we don't have to even
care.
Signed-off-by: Jeff King <peff@peff.net>
In create_branch() we write the reflog msg into a buffer in
the main function, but then use it only inside a
conditional. If you carefully follow the logic, you can
confirm that we never use the buffer uninitialized nor write
when it would not be used. But we can make this a lot more
obvious by simply moving the write step inside the
conditional.
Signed-off-by: Jeff King <peff@peff.net>
Like the previous commit, we'd like to avoid the assumption
that refs fit into PATH_MAX-sized buffers. These callsites
have an extra twist, though: they write the refnames using
mksnpath. This does two things beyond a regular snprintf:
1. It quietly writes "/bad-path/" when truncation occurs.
This saves the caller having to check the error code,
but if you aren't actually feeding the result to a
system call (and we aren't here), it's questionable.
2. It calls cleanup_path(), which removes leading
instances of "./". That's questionable when dealing
with refnames, as we could silently canonicalize a
syntactically bogus refname into a valid one.
Let's convert each case to use a strbuf. This is preferable
to xstrfmt() because we can reuse the same buffer as we
loop.
Signed-off-by: Jeff King <peff@peff.net>
Many functions which handle refs use a PATH_MAX-sized buffer
to do so. This is mostly reasonable as we have to write
loose refs into the filesystem, and at least on Linux the 4K
PATH_MAX is big enough that nobody would care. But:
1. The static PATH_MAX is not always the filesystem limit.
2. On other platforms, PATH_MAX may be much smaller.
3. As we move to alternate ref storage, we won't be bound
by filesystem limits.
Let's convert these to heap buffers so we don't have to
worry about truncation or size limits.
We may want to eventually constrain ref lengths for sanity
and to prevent malicious names, but we should do so
consistently across all platforms, and in a central place
(like the ref code).
Signed-off-by: Jeff King <peff@peff.net>
Part of the reflog content comes from the environment, which
can be much larger than our fixed buffer. Let's use a heap
buffer so we avoid truncating it.
Signed-off-by: Jeff King <peff@peff.net>
We format the tag header into a fixed 1024-byte buffer. But
since the tag-name and tagger ident can be arbitrarily
large, we may unceremoniously die with "tag header too big".
Let's just use a strbuf instead.
Note that it looks at first glance like we can just format
this directly into the "buf" strbuf where it will ultimately
go. But that buffer may already contain the tag message, and
we have no easy way to prepend formatted data to a strbuf
(we can only splice in an already-generated buffer). This
isn't a performance-critical path, so going through an extra
buffer isn't a big deal.
Signed-off-by: Jeff King <peff@peff.net>
To generate a patch id, we format the diff header into a
fixed-size buffer, and then feed the result to our sha1
computation. The fixed buffer has size '4*PATH_MAX + 20',
which in theory accommodates the four filenames plus some
extra data. Except:
1. The filenames may not be constrained to PATH_MAX. The
static value may not be a real limit on the current
filesystem. Moreover, we may compute patch-ids for
names stored only in git, without touching the current
filesystem at all.
2. The 20 bytes is not nearly enough to cover the
extra content we put in the buffer.
As a result, the data we feed to the sha1 computation may be
truncated, and it's possible that a commit with a very long
filename could erroneously collide in the patch-id space
with another commit. For instance, if one commit modified
"really-long-filename/foo" and another modified "bar" in the
same directory.
In practice this is unlikely. Because the filenames are
repeated, and because there's a single cutoff at the end of
the buffer, the offending filename would have to be on the
order of four times larger than PATH_MAX.
We could fix this by moving to a strbuf. However, we can
observe that the purpose of formatting this in the first
place is to feed it to git_SHA1_Update(). So instead, let's
just feed each part of the formatted string directly. This
actually ends up more readable, and we can even factor out
some duplicated bits from the various conditional branches.
Technically this may change the output of patch-id for very
long filenames, but it's not worth making an exception for
this in the --stable output. It was a bug, and one that only
affected an unlikely set of paths. And anyway, the exact
value would have varied from platform to platform depending
on the value of PATH_MAX, so there is no "stable" value.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since git_path_buf() is smart enough to replace "objects/"
with the correct object path, we can use it instead of
manually assembling the path. That's slightly shorter, and
will clean up any non-canonical bits in the path.
Signed-off-by: Jeff King <peff@peff.net>
The odb_mkstemp() function expects the caller to provide a
fixed buffer to write the resulting tempfile name into. But
it creates the template using snprintf without checking the
return value. This means we could silently truncate the
filename.
In practice, it's unlikely that the truncation would end in
the template-pattern that mkstemp needs to open the file. So
we'd probably end up failing either way, unless the path was
specially crafted.
The simplest fix would be to notice the truncation and die.
However, we can observe that most callers immediately
xstrdup() the result anyway. So instead, let's switch to
using a strbuf, which is easier for them (and isn't a big
deal for the other 2 callers, who can just strbuf_release
when they're done with it).
Note that many of the callers used static buffers, but this
was purely to avoid putting a large buffer on the stack. We
never passed the static buffers out of the function, so
there's no complicated memory handling we need to change.
Signed-off-by: Jeff King <peff@peff.net>
The odb_mkstemp function does not return an error; it dies
on failure instead. But many of its callers compare the
resulting descriptor against -1 and die themselves.
Mostly this is just pointless, but it does raise a question
when looking at the callers: if they show the results of the
"template" buffer after a failure, what's in it? The answer
is: it doesn't matter, because it cannot happen.
So let's make that clear by removing the bogus error checks.
In bitmap_writer_finish(), we can drop the error-handling
code entirely. In the other two cases, it's shared with the
open() in another code path; we can just move the
error-check next to that open() call.
And while we're at it, let's flesh out the function's
docstring a bit to make the error behavior clear.
Signed-off-by: Jeff King <peff@peff.net>
sha1dc/sha1.c wanted to check the endianness of the target platform
at compilation time and used a CPP macro with a rather overly
generic name, "BIGENDIAN", to pass the result of the check around
in the file. It wasn't prepared for the same macro set to 0
(false) by the platform to signal that the target is _not_ a big
endian box, and assumed that the endianness detection logic it has
alone would be the one that is setting the macro, resulting in a
breakage on Windows. This has been fixed by using a bit less
generic name for the same purpose.
* jk/sha1dc:
sha1dc: avoid CPP macro collisions
The name-hash used for detecting paths that are different only in
cases (which matter on case insensitive filesystems) has been
optimized to take advantage of multi-threading when it makes sense.
* jh/memihash-opt:
name-hash: add test-lazy-init-name-hash to .gitignore
name-hash: add perf test for lazy_init_name_hash
name-hash: add test-lazy-init-name-hash
name-hash: perf improvement for lazy_init_name_hash
hashmap: document memihash_cont, hashmap_disallow_rehash api
hashmap: add disallow_rehash setting
hashmap: allow memihash computation to be continued
name-hash: specify initial size for istate.dir_hash table
Code clean-up.
* jk/fast-import-cleanup:
pack.h: define largest possible encoded object size
encode_in_pack_object_header: respect output buffer length
fast-import: use xsnprintf for formatting headers
fast-import: use xsnprintf for writing sha1s
Recent enhancement to "git stash push" command to support pathspec
to allow only a subset of working tree changes to be stashed away
was found to be too chatty and exposed the internal implementation
detail (e.g. when it uses reset to match the index to HEAD before
doing other things, output from reset seeped out). These, and
other chattyness has been fixed.
* tg/stash-push-fixup:
stash: keep untracked files intact in stash -k
stash: pass the pathspec argument to git reset
stash: don't show internal implementation details
"git checkout" is taught the "--recurse-submodules" option.
* sb/checkout-recurse-submodules:
builtin/read-tree: add --recurse-submodules switch
builtin/checkout: add --recurse-submodules switch
entry.c: create submodules when interesting
unpack-trees: check if we can perform the operation for submodules
unpack-trees: pass old oid to verify_clean_submodule
update submodules: add submodule_move_head
submodule.c: get_super_prefix_or_empty
update submodules: move up prepare_submodule_repo_env
submodules: introduce check to see whether to touch a submodule
update submodules: add a config option to determine if submodules are updated
update submodules: add submodule config parsing
make is_submodule_populated gently
lib-submodule-update.sh: define tests for recursing into submodules
lib-submodule-update.sh: replace sha1 by hash
lib-submodule-update: teach test_submodule_content the -C <dir> flag
lib-submodule-update.sh: do not use ./. as submodule remote
lib-submodule-update.sh: reorder create_lib_submodule_repo
submodule--helper.c: remove duplicate code
connect_work_tree_and_git_dir: safely create leading directories
Code clean-up.
* jk/pack-name-cleanups:
index-pack: make pointer-alias fallbacks safer
replace snprintf with odb_pack_name()
odb_pack_keep(): stop generating keepfile name
sha1_file.c: make pack-name helper globally accessible
move odb_* declarations out of git-compat-util.h
A few unterminated here documents in tests were fixed, which in
turn revealed incorrect expectations the tests make. These tests
have been updated.
* st/verify-tag:
t7004, t7030: fix here-doc syntax errors
Recent versions of Git treats http alternates (used in dumb http
transport) just like HTTP redirects and requires the client to
enable following it, due to security concerns. But we forgot to
give a warning when we decide not to honor the alternates.
* ew/http-alternates-as-redirects-warning:
http: release strbuf on disabled alternates
http: inform about alternates-as-redirects behavior
"git filter-branch --prune-empty" drops a single-parent commit that
becomes a no-op, but did not drop a root commit whose tree is empty.
* dp/filter-branch-prune-empty:
p7000: add test for filter-branch with --prune-empty
filter-branch: fix --prune-empty on parentless commits
t7003: ensure --prune-empty removes entire branch when applicable
t7003: ensure --prune-empty can prune root commit
"git fetch" that requests a commit by object name, when the other
side does not allow such an request, failed without much
explanation.
* mm/fetch-show-error-message-on-unadvertised-object:
fetch-pack: add specific error for fetching an unadvertised object
fetch_refs_via_pack: call report_unmatched_refs
fetch-pack: move code to report unmatched refs to a function
"git branch @" created refs/heads/@ as a branch, and in general the
code that handled @{-1} and @{upstream} was a bit too loose in
disambiguating.
* jk/interpret-branch-name:
checkout: restrict @-expansions when finding branch
strbuf_check_ref_format(): expand only local branches
branch: restrict @-expansions when deleting
t3204: test git-branch @-expansion corner cases
interpret_branch_name: allow callers to restrict expansions
strbuf_branchname: add docstring
strbuf_branchname: drop return value
interpret_branch_name: move docstring to header file
interpret_branch_name(): handle auto-namelen for @{-1}
A few tests were run conditionally under (rare) conditions where
they cannot be run (like running cvs tests under 'root' account).
* ab/cond-skip-tests:
gitweb tests: skip tests when we don't have Time::HiRes
gitweb tests: change confusing "skip_all" phrasing
cvs tests: skip tests that call "cvs commit" when running as root
user.email that consists of only cruft chars should consistently
error out, but didn't.
* jk/ident-empty:
ident: do not ignore empty config name/email
ident: reject all-crud ident name
ident: handle NULL email when complaining of empty name
ident: mark error messages for translation
"git repack --depth=<n>" for a long time busted the specified depth
when reusing delta from existing packs. This has been corrected.
* jk/delta-chain-limit:
pack-objects: convert recursion to iteration in break_delta_chain()
pack-objects: enforce --depth limit in reused deltas
Teach the "debug" helper used in the test framework that allows a
command to run under "gdb" to make the session interactive.
* sg/test-with-stdin:
tests: make the 'test_pause' helper work in non-verbose mode
tests: create an interactive gdb session with the 'debug' helper
