t5313: test bounds-checks of corrupted/malicious pack/idx files
Our on-disk .pack and .idx files may reference other data by
offset. We should make sure that we are not fooled by
corrupt data into accessing memory outside of our mmap'd
boundaries.
This patch adds a series of tests for offsets found in .pack
and .idx files. For the most part we get this right, but
there are two tests of .idx files marked as failures: we do
not bounds-check offsets in the v2 index's extended offset
table, nor do we handle .idx offsets that overflow a signed
off_t.
With these tests, we should have good coverage of all
offsets found in these files. Note that this doesn't cover
.bitmap files, which may have similar bugs.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>