All but one of the callers of make_traverse_path() allocate a new heap
buffer to store the path. Let's give them an easy way to write to a
strbuf, which saves them from computing the length themselves (which is
especially tricky when they want to add to the path). It will also make
it easier for us to change the make_traverse_path() interface in a
future patch to improve its bounds-checking.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We assume that if setup_traverse_info() is passed a non-empty "base"
string, that string is pointing into a tree object and we can read the
object oid by skipping past the trailing NUL.
As it turns out, this is not true for either of the two calls, and we
may end up reading garbage bytes:
1. In git-merge-tree, our base string is either empty (in which case
we'd never run this code), or it comes from our traverse_path()
helper. The latter overallocates a buffer by the_hash_algo->rawsz
bytes, but then fills it with only make_traverse_path(), leaving
those extra bytes uninitialized (but part of a legitimate heap
buffer).
2. In unpack_trees(), we pass o->prefix, which is some arbitrary
string from the caller. In "git read-tree --prefix=foo", for
instance, it will point to the command-line parameter, and we'll
read 20 bytes past the end of the string.
Interestingly, tools like ASan do not detect (2) because the process
argv is part of a big pre-allocated buffer. So we're reading trash, but
it's trash that's probably part of the next argument, or the
environment.
You can convince it to fail by putting something like this at the
beginning of common-main.c's main() function:
{
int i;
for (i = 0; i < argc; i++)
argv[i] = xstrdup_or_null(argv[i]);
}
That puts the arguments into their own heap buffers, so running:
make SANITIZE=address test
will find problems when "read-tree --prefix" is used (e.g., in t3030).
Doubly interesting, even with the hackery above, this does not fail
prior to ea82b2a085 (tree-walk: store object_id in a separate member,
2019-01-15). That commit switched setup_traverse_info() to actually
copying the hash, rather than simply pointing to it. That pointer was
always pointing to garbage memory, but that commit started actually
dereferencing the bytes, which is what triggers ASan.
That also implies that nobody actually cares about reading these oid
bytes anyway (or at least no path covered by our tests). And manual
inspection of the code backs that up (I'll follow this patch with some
cleanups that show definitively this is the case, but they're quite
invasive, so it's worth doing this fix on its own).
So let's drop the bogus hashcpy(), along with the confusing oversizing
in merge-tree.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
All callers of fill_tree_descriptor() have been converted to object_id
already, so convert that function as well. As a nice side-effect we get
rid of NULL checks in tree-diff.c, as fill_tree_descriptor() already
does them for us.
Helped-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Reviewed-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When an error is encountered, it calls add_rejected_file() which either
- directly displays the error message and stops if in plumbing mode
(i.e. if show_all_errors is not initialized at 1)
- or stores it so that it will be displayed at the end with display_error_msgs(),
Storing the files by error type permits to have a list of files for
which there is the same error instead of having a serie of almost
identical errors.
As each bind_overlap error combines a file and an old file, a list cannot be
done, therefore, theses errors are not stored but directly displayed.
Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Most of them are still stubs, but the procedure to build the HTML
documentation, maintaining the index and installing the end product are
there.
I placed names of people who are likely to know the most about the topic
in the stub files, so that volunteers will know whom to ask questions as
needed.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
