Commit f1c0e3946e (apply: reject patches larger than ~1 GiB, 2022-10-25)
added a limit on the size of patch that apply will process to avoid
integer overflows. The implementation re-used the existing error message
for when we are unable to read the patch. This is unfortunate because (a) it
does not signal to the user that the patch is being rejected because it
is too large and (b) it uses error_errno() without setting errno.
This patch adds a specific error message for the case when a patch is
too large. It also updates the existing message to make it clearer that
it is the patch that cannot be read rather than any other file and marks
both messages for translation. The "git apply" prefix is also dropped to
match most of the rest of the error messages in apply.c (there are still
a few error messages that prefixed with "git apply" and are not marked
for translation after this patch). The test added in f1c0e3946e is
updated accordingly.
Reported-by: Premek Vysoky <Premek.Vysoky@microsoft.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The apply code is not prepared to handle extremely large files. It uses
"int" in some places, and "unsigned long" in others.
This combination leads to unfortunate problems when switching between
the two types. Using "int" prevents us from handling large files, since
large offsets will wrap around and spill into small negative values,
which can result in wrong behavior (like accessing the patch buffer with
a negative offset).
Converting from "unsigned long" to "int" also has truncation problems
even on LLP64 platforms where "long" is the same size as "int", since
the former is unsigned but the latter is not.
To avoid potential overflow and truncation issues in `git apply`, apply
similar treatment as in dcd1742e56 (xdiff: reject files larger than
~1GB, 2015-09-24), where the xdiff code was taught to reject large
files for similar reasons.
The maximum size was chosen somewhat arbitrarily, but picking a value
just shy of a gigabyte allows us to double it without overflowing 2^31-1
(after which point our value would wrap around to a negative number).
To give ourselves a bit of extra margin, the maximum patch size is a MiB
smaller than a full GiB, which gives us some slop in case we allocate
"(records + 1) * sizeof(int)" or similar.
Luckily, the security implications of these conversion issues are
relatively uninteresting, because a victim needs to be convinced to
apply a malicious patch.
Reported-by: 정재우 <thebound7@gmail.com>
Suggested-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Phillip Wood
Taylor Blau