git/t/t5303-pack-corruption-resilience.sh
Jeff King 50b72ede05 t5303: drop "count=1" from corruption dd
This test corrupts pack objects by using "dd" with a seek
command. It passes "count=1 bs=1" to munge just a single
byte. However, the test added in commit b3118bdc wants to
munge two bytes, and the second byte of corruption is
silently ignored.

This turned out not to impact the test, however. The idea
was to reduce the "size of this entry" part of the header so
that zlib runs out of input bytes while inflating the entry.
That header is two bytes long, and the test reduced the
value of both bytes; since we experience the problem if we
are off by even 1 byte, it is sufficient to munge only the
first one.

Even though the test would have worked with only a single
byte munged, and we could simply tweak the test to use a
single byte, it makes sense to lift this 1-byte restriction
from do_corrupt_object. It will allow future tests that do
need to change multiple bytes to do so.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-06-14 14:56:08 -07:00

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#!/bin/sh
#
# Copyright (c) 2008 Nicolas Pitre
#
test_description='resilience to pack corruptions with redundant objects'
. ./test-lib.sh
# Note: the test objects are created with knowledge of their pack encoding
# to ensure good code path coverage, and to facilitate direct alteration
# later on. The assumed characteristics are:
#
# 1) blob_2 is a delta with blob_1 for base and blob_3 is a delta with blob2
# for base, such that blob_3 delta depth is 2;
#
# 2) the bulk of object data is uncompressible so the text part remains
# visible;
#
# 3) object header is always 2 bytes.
create_test_files() {
test-genrandom "foo" 2000 > file_1 &&
test-genrandom "foo" 1800 > file_2 &&
test-genrandom "foo" 1800 > file_3 &&
echo " base " >> file_1 &&
echo " delta1 " >> file_2 &&
echo " delta delta2 " >> file_3 &&
test-genrandom "bar" 150 >> file_2 &&
test-genrandom "baz" 100 >> file_3
}
create_new_pack() {
rm -rf .git &&
git init &&
blob_1=`git hash-object -t blob -w file_1` &&
blob_2=`git hash-object -t blob -w file_2` &&
blob_3=`git hash-object -t blob -w file_3` &&
pack=`printf "$blob_1\n$blob_2\n$blob_3\n" |
git pack-objects $@ .git/objects/pack/pack` &&
pack=".git/objects/pack/pack-${pack}" &&
git verify-pack -v ${pack}.pack
}
do_repack() {
pack=`printf "$blob_1\n$blob_2\n$blob_3\n" |
git pack-objects $@ .git/objects/pack/pack` &&
pack=".git/objects/pack/pack-${pack}"
}
do_corrupt_object() {
ofs=`git show-index < ${pack}.idx | grep $1 | cut -f1 -d" "` &&
ofs=$(($ofs + $2)) &&
chmod +w ${pack}.pack &&
dd of=${pack}.pack bs=1 conv=notrunc seek=$ofs &&
test_must_fail git verify-pack ${pack}.pack
}
printf '\0' > zero
test_expect_success \
'initial setup validation' \
'create_test_files &&
create_new_pack &&
git prune-packed &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'create corruption in header of first object' \
'do_corrupt_object $blob_1 0 < zero &&
test_must_fail git cat-file blob $blob_1 > /dev/null &&
test_must_fail git cat-file blob $blob_2 > /dev/null &&
test_must_fail git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... but having a loose copy allows for full recovery' \
'mv ${pack}.idx tmp &&
git hash-object -t blob -w file_1 &&
mv tmp ${pack}.idx &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... and loose copy of first delta allows for partial recovery' \
'git prune-packed &&
test_must_fail git cat-file blob $blob_2 > /dev/null &&
mv ${pack}.idx tmp &&
git hash-object -t blob -w file_2 &&
mv tmp ${pack}.idx &&
test_must_fail git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'create corruption in data of first object' \
'create_new_pack &&
git prune-packed &&
chmod +w ${pack}.pack &&
"$PERL_PATH" -i.bak -pe "s/ base /abcdef/" ${pack}.pack &&
test_must_fail git cat-file blob $blob_1 > /dev/null &&
test_must_fail git cat-file blob $blob_2 > /dev/null &&
test_must_fail git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... but having a loose copy allows for full recovery' \
'mv ${pack}.idx tmp &&
git hash-object -t blob -w file_1 &&
mv tmp ${pack}.idx &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... and loose copy of second object allows for partial recovery' \
'git prune-packed &&
test_must_fail git cat-file blob $blob_2 > /dev/null &&
mv ${pack}.idx tmp &&
git hash-object -t blob -w file_2 &&
mv tmp ${pack}.idx &&
test_must_fail git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'create corruption in header of first delta' \
'create_new_pack &&
git prune-packed &&
do_corrupt_object $blob_2 0 < zero &&
git cat-file blob $blob_1 > /dev/null &&
test_must_fail git cat-file blob $blob_2 > /dev/null &&
test_must_fail git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... but having a loose copy allows for full recovery' \
'mv ${pack}.idx tmp &&
git hash-object -t blob -w file_2 &&
mv tmp ${pack}.idx &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... and then a repack "clears" the corruption' \
'do_repack &&
git prune-packed &&
git verify-pack ${pack}.pack &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'create corruption in data of first delta' \
'create_new_pack &&
git prune-packed &&
chmod +w ${pack}.pack &&
"$PERL_PATH" -i.bak -pe "s/ delta1 /abcdefgh/" ${pack}.pack &&
git cat-file blob $blob_1 > /dev/null &&
test_must_fail git cat-file blob $blob_2 > /dev/null &&
test_must_fail git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... but having a loose copy allows for full recovery' \
'mv ${pack}.idx tmp &&
git hash-object -t blob -w file_2 &&
mv tmp ${pack}.idx &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... and then a repack "clears" the corruption' \
'do_repack &&
git prune-packed &&
git verify-pack ${pack}.pack &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'corruption in delta base reference of first delta (OBJ_REF_DELTA)' \
'create_new_pack &&
git prune-packed &&
do_corrupt_object $blob_2 2 < zero &&
git cat-file blob $blob_1 > /dev/null &&
test_must_fail git cat-file blob $blob_2 > /dev/null &&
test_must_fail git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... but having a loose copy allows for full recovery' \
'mv ${pack}.idx tmp &&
git hash-object -t blob -w file_2 &&
mv tmp ${pack}.idx &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... and then a repack "clears" the corruption' \
'do_repack &&
git prune-packed &&
git verify-pack ${pack}.pack &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'corruption #0 in delta base reference of first delta (OBJ_OFS_DELTA)' \
'create_new_pack --delta-base-offset &&
git prune-packed &&
do_corrupt_object $blob_2 2 < zero &&
git cat-file blob $blob_1 > /dev/null &&
test_must_fail git cat-file blob $blob_2 > /dev/null &&
test_must_fail git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... but having a loose copy allows for full recovery' \
'mv ${pack}.idx tmp &&
git hash-object -t blob -w file_2 &&
mv tmp ${pack}.idx &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... and then a repack "clears" the corruption' \
'do_repack --delta-base-offset &&
git prune-packed &&
git verify-pack ${pack}.pack &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'corruption #1 in delta base reference of first delta (OBJ_OFS_DELTA)' \
'create_new_pack --delta-base-offset &&
git prune-packed &&
printf "\001" | do_corrupt_object $blob_2 2 &&
git cat-file blob $blob_1 > /dev/null &&
test_must_fail git cat-file blob $blob_2 > /dev/null &&
test_must_fail git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... but having a loose copy allows for full recovery' \
'mv ${pack}.idx tmp &&
git hash-object -t blob -w file_2 &&
mv tmp ${pack}.idx &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... and then a repack "clears" the corruption' \
'do_repack --delta-base-offset &&
git prune-packed &&
git verify-pack ${pack}.pack &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'... and a redundant pack allows for full recovery too' \
'do_corrupt_object $blob_2 2 < zero &&
git cat-file blob $blob_1 > /dev/null &&
test_must_fail git cat-file blob $blob_2 > /dev/null &&
test_must_fail git cat-file blob $blob_3 > /dev/null &&
mv ${pack}.idx tmp &&
git hash-object -t blob -w file_1 &&
git hash-object -t blob -w file_2 &&
printf "$blob_1\n$blob_2\n" | git pack-objects .git/objects/pack/pack &&
git prune-packed &&
mv tmp ${pack}.idx &&
git cat-file blob $blob_1 > /dev/null &&
git cat-file blob $blob_2 > /dev/null &&
git cat-file blob $blob_3 > /dev/null'
test_expect_success \
'corrupting header to have too small output buffer fails unpack' \
'create_new_pack &&
git prune-packed &&
printf "\262\001" | do_corrupt_object $blob_1 0 &&
test_must_fail git cat-file blob $blob_1 > /dev/null &&
test_must_fail git cat-file blob $blob_2 > /dev/null &&
test_must_fail git cat-file blob $blob_3 > /dev/null'
test_done