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#!/bin/sh
test_description='bounds-checking of access to mmapped on-disk file formats'
. ./test-lib.sh
clear_base () {
test_when_finished 'restore_base' &&
rm -f $base
}
restore_base () {
cp base-backup/* .git/objects/pack/
}
do_pack () {
pack_objects=$1; shift
sha1=$(
for i in $pack_objects
do
echo $i
done | git pack-objects "$@" .git/objects/pack/pack
) &&
pack=.git/objects/pack/pack-$sha1.pack &&
idx=.git/objects/pack/pack-$sha1.idx &&
chmod +w $pack $idx &&
test_when_finished 'rm -f "$pack" "$idx"'
}
munge () {
printf "$3" | dd of="$1" bs=1 conv=notrunc seek=$2
}
# Offset in a v2 .idx to its initial and extended offset tables. For an index
# with "nr" objects, this is:
#
# magic(4) + version(4) + fan-out(4*256) + sha1s(20*nr) + crc(4*nr),
#
# for the initial, and another ofs(4*nr) past that for the extended.
#
ofs_table () {
echo $((4 + 4 + 4*256 + $(test_oid rawsz)*$1 + 4*$1))
}
extended_table () {
echo $(($(ofs_table "$1") + 4*$1))
}
test_expect_success 'setup' '
test_oid_init &&
test_oid_cache <<-EOF
oid000 sha1:1485
oid000 sha256:4222
oidfff sha1:74
oidfff sha256:1350
EOF
'
test_expect_success 'set up base packfile and variables' '
# the hash of this content starts with ff, which
# makes some later computations much simpler
echo $(test_oid oidfff) >file &&
git add file &&
git commit -m base &&
git repack -ad &&
base=$(echo .git/objects/pack/*) &&
chmod +w $base &&
mkdir base-backup &&
cp $base base-backup/ &&
object=$(git rev-parse HEAD:file)
'
test_expect_success 'pack/index object count mismatch' '
do_pack $object &&
munge $pack 8 "\377\0\0\0" &&
clear_base &&
# We enumerate the objects from the completely-fine
# .idx, but notice later that the .pack is bogus
# and fail to show any data.
echo "$object missing" >expect &&
git cat-file --batch-all-objects --batch-check >actual &&
test_cmp expect actual &&
# ...and here fail to load the object (without segfaulting),
# but fallback to a good copy if available.
test_must_fail git cat-file blob $object &&
restore_base &&
git cat-file blob $object >actual &&
test_cmp file actual &&
# ...and make sure that index-pack --verify, which has its
# own reading routines, does not segfault.
test_must_fail git index-pack --verify $pack
'
test_expect_success 'matched bogus object count' '
do_pack $object &&
munge $pack 8 "\377\0\0\0" &&
munge $idx $((255 * 4)) "\377\0\0\0" &&
clear_base &&
# Unlike above, we should notice early that the .idx is totally
# bogus, and not even enumerate its contents.
git cat-file --batch-all-objects --batch-check >actual &&
test_must_be_empty actual &&
# But as before, we can do the same object-access checks.
test_must_fail git cat-file blob $object &&
restore_base &&
git cat-file blob $object >actual &&
test_cmp file actual &&
test_must_fail git index-pack --verify $pack
'
# Note that we cannot check the fallback case for these
# further .idx tests, as we notice the problem in functions
# whose interface doesn't allow an error return (like use_pack()),
# and thus we just die().
#
# There's also no point in doing enumeration tests, as
# we are munging offsets here, which are about looking up
# specific objects.
test_expect_success 'bogus object offset (v1)' '
do_pack $object --index-version=1 &&
munge $idx $((4 * 256)) "\377\0\0\0" &&
clear_base &&
test_must_fail git cat-file blob $object &&
test_must_fail git index-pack --verify $pack
'
test_expect_success 'bogus object offset (v2, no msb)' '
do_pack $object --index-version=2 &&
munge $idx $(ofs_table 1) "\0\377\0\0" &&
clear_base &&
test_must_fail git cat-file blob $object &&
test_must_fail git index-pack --verify $pack
'
test_expect_success 'bogus offset into v2 extended table' '
do_pack $object --index-version=2 &&
munge $idx $(ofs_table 1) "\377\0\0\0" &&
clear_base &&
test_must_fail git cat-file blob $object &&
test_must_fail git index-pack --verify $pack
'
test_expect_success 'bogus offset inside v2 extended table' '
# We need two objects here, so we can plausibly require
# an extended table (if the first object were larger than 2^31).
#
# Note that the value is important here. We want $object as
# the second entry in sorted-hash order. The hash of this object starts
# with "000", which sorts before that of $object (which starts
# with "fff").
second=$(test_oid oid000 | git hash-object -w --stdin) &&
do_pack "$object $second" --index-version=2 &&
# We have to make extra room for the table, so we cannot
# just munge in place as usual.
{
dd if=$idx bs=1 count=$(($(ofs_table 2) + 4)) &&
printf "\200\0\0\0" &&
printf "\377\0\0\0\0\0\0\0" &&
dd if=$idx bs=1 skip=$(extended_table 2)
} >tmp &&
mv tmp "$idx" &&
clear_base &&
test_must_fail git cat-file blob $object &&
test_must_fail git index-pack --verify $pack
'
test_expect_success 'bogus OFS_DELTA in packfile' '
# Generate a pack with a delta in it.
base=$(test-tool genrandom foo 3000 | git hash-object --stdin -w) &&
delta=$(test-tool genrandom foo 2000 | git hash-object --stdin -w) &&
do_pack "$base $delta" --delta-base-offset &&
rm -f .git/objects/??/* &&
# Double check that we have the delta we expect.
echo $base >expect &&
echo $delta | git cat-file --batch-check="%(deltabase)" >actual &&
test_cmp expect actual &&
# Now corrupt it. We assume the varint size for the delta is small
# enough to fit in the first byte (which it should be, since it
# is a pure deletion from the base), and that original ofs_delta
# takes 2 bytes (which it should, as it should be ~3000).
ofs=$(git show-index <$idx | grep $delta | cut -d" " -f1) &&
munge $pack $(($ofs + 1)) "\177\377" &&
test_must_fail git cat-file blob $delta >/dev/null
'
test_done
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