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a1283866 JK |
1 | #!/bin/sh |
2 | ||
3 | test_description='bounds-checking of access to mmapped on-disk file formats' | |
4 | . ./test-lib.sh | |
5 | ||
6 | clear_base () { | |
7 | test_when_finished 'restore_base' && | |
8 | rm -f $base | |
9 | } | |
10 | ||
11 | restore_base () { | |
12 | cp base-backup/* .git/objects/pack/ | |
13 | } | |
14 | ||
15 | do_pack () { | |
16 | pack_objects=$1; shift | |
17 | sha1=$( | |
18 | for i in $pack_objects | |
19 | do | |
20 | echo $i | |
21 | done | git pack-objects "$@" .git/objects/pack/pack | |
22 | ) && | |
23 | pack=.git/objects/pack/pack-$sha1.pack && | |
24 | idx=.git/objects/pack/pack-$sha1.idx && | |
25 | chmod +w $pack $idx && | |
26 | test_when_finished 'rm -f "$pack" "$idx"' | |
27 | } | |
28 | ||
29 | munge () { | |
30 | printf "$3" | dd of="$1" bs=1 conv=notrunc seek=$2 | |
31 | } | |
32 | ||
33 | # Offset in a v2 .idx to its initial and extended offset tables. For an index | |
34 | # with "nr" objects, this is: | |
35 | # | |
36 | # magic(4) + version(4) + fan-out(4*256) + sha1s(20*nr) + crc(4*nr), | |
37 | # | |
38 | # for the initial, and another ofs(4*nr) past that for the extended. | |
39 | # | |
40 | ofs_table () { | |
41 | echo $((4 + 4 + 4*256 + 20*$1 + 4*$1)) | |
42 | } | |
43 | extended_table () { | |
44 | echo $(($(ofs_table "$1") + 4*$1)) | |
45 | } | |
46 | ||
47 | test_expect_success 'set up base packfile and variables' ' | |
48 | # the hash of this content starts with ff, which | |
49 | # makes some later computations much simpler | |
50 | echo 74 >file && | |
51 | git add file && | |
52 | git commit -m base && | |
53 | git repack -ad && | |
54 | base=$(echo .git/objects/pack/*) && | |
55 | chmod +w $base && | |
56 | mkdir base-backup && | |
57 | cp $base base-backup/ && | |
58 | object=$(git rev-parse HEAD:file) | |
59 | ' | |
60 | ||
61 | test_expect_success 'pack/index object count mismatch' ' | |
62 | do_pack $object && | |
63 | munge $pack 8 "\377\0\0\0" && | |
64 | clear_base && | |
65 | ||
66 | # We enumerate the objects from the completely-fine | |
67 | # .idx, but notice later that the .pack is bogus | |
68 | # and fail to show any data. | |
69 | echo "$object missing" >expect && | |
70 | git cat-file --batch-all-objects --batch-check >actual && | |
71 | test_cmp expect actual && | |
72 | ||
73 | # ...and here fail to load the object (without segfaulting), | |
74 | # but fallback to a good copy if available. | |
75 | test_must_fail git cat-file blob $object && | |
76 | restore_base && | |
77 | git cat-file blob $object >actual && | |
78 | test_cmp file actual && | |
79 | ||
80 | # ...and make sure that index-pack --verify, which has its | |
81 | # own reading routines, does not segfault. | |
82 | test_must_fail git index-pack --verify $pack | |
83 | ' | |
84 | ||
85 | test_expect_success 'matched bogus object count' ' | |
86 | do_pack $object && | |
87 | munge $pack 8 "\377\0\0\0" && | |
88 | munge $idx $((255 * 4)) "\377\0\0\0" && | |
89 | clear_base && | |
90 | ||
91 | # Unlike above, we should notice early that the .idx is totally | |
92 | # bogus, and not even enumerate its contents. | |
93 | >expect && | |
94 | git cat-file --batch-all-objects --batch-check >actual && | |
95 | test_cmp expect actual && | |
96 | ||
97 | # But as before, we can do the same object-access checks. | |
98 | test_must_fail git cat-file blob $object && | |
99 | restore_base && | |
100 | git cat-file blob $object >actual && | |
101 | test_cmp file actual && | |
102 | ||
103 | test_must_fail git index-pack --verify $pack | |
104 | ' | |
105 | ||
106 | # Note that we cannot check the fallback case for these | |
107 | # further .idx tests, as we notice the problem in functions | |
108 | # whose interface doesn't allow an error return (like use_pack()), | |
109 | # and thus we just die(). | |
110 | # | |
111 | # There's also no point in doing enumeration tests, as | |
112 | # we are munging offsets here, which are about looking up | |
113 | # specific objects. | |
114 | ||
115 | test_expect_success 'bogus object offset (v1)' ' | |
116 | do_pack $object --index-version=1 && | |
117 | munge $idx $((4 * 256)) "\377\0\0\0" && | |
118 | clear_base && | |
119 | test_must_fail git cat-file blob $object && | |
120 | test_must_fail git index-pack --verify $pack | |
121 | ' | |
122 | ||
123 | test_expect_success 'bogus object offset (v2, no msb)' ' | |
124 | do_pack $object --index-version=2 && | |
125 | munge $idx $(ofs_table 1) "\0\377\0\0" && | |
126 | clear_base && | |
127 | test_must_fail git cat-file blob $object && | |
128 | test_must_fail git index-pack --verify $pack | |
129 | ' | |
130 | ||
47fe3f6e | 131 | test_expect_success 'bogus offset into v2 extended table' ' |
a1283866 JK |
132 | do_pack $object --index-version=2 && |
133 | munge $idx $(ofs_table 1) "\377\0\0\0" && | |
134 | clear_base && | |
135 | test_must_fail git cat-file blob $object && | |
136 | test_must_fail git index-pack --verify $pack | |
137 | ' | |
138 | ||
13e0b0d3 | 139 | test_expect_success 'bogus offset inside v2 extended table' ' |
a1283866 JK |
140 | # We need two objects here, so we can plausibly require |
141 | # an extended table (if the first object were larger than 2^31). | |
142 | do_pack "$object $(git rev-parse HEAD)" --index-version=2 && | |
143 | ||
144 | # We have to make extra room for the table, so we cannot | |
145 | # just munge in place as usual. | |
146 | { | |
147 | dd if=$idx bs=1 count=$(($(ofs_table 2) + 4)) && | |
148 | printf "\200\0\0\0" && | |
149 | printf "\377\0\0\0\0\0\0\0" && | |
150 | dd if=$idx bs=1 skip=$(extended_table 2) | |
151 | } >tmp && | |
152 | mv tmp "$idx" && | |
153 | clear_base && | |
154 | test_must_fail git cat-file blob $object && | |
155 | test_must_fail git index-pack --verify $pack | |
156 | ' | |
157 | ||
158 | test_expect_success 'bogus OFS_DELTA in packfile' ' | |
159 | # Generate a pack with a delta in it. | |
160 | base=$(test-genrandom foo 3000 | git hash-object --stdin -w) && | |
161 | delta=$(test-genrandom foo 2000 | git hash-object --stdin -w) && | |
162 | do_pack "$base $delta" --delta-base-offset && | |
163 | rm -f .git/objects/??/* && | |
164 | ||
165 | # Double check that we have the delta we expect. | |
166 | echo $base >expect && | |
167 | echo $delta | git cat-file --batch-check="%(deltabase)" >actual && | |
168 | test_cmp expect actual && | |
169 | ||
170 | # Now corrupt it. We assume the varint size for the delta is small | |
171 | # enough to fit in the first byte (which it should be, since it | |
172 | # is a pure deletion from the base), and that original ofs_delta | |
173 | # takes 2 bytes (which it should, as it should be ~3000). | |
174 | ofs=$(git show-index <$idx | grep $delta | cut -d" " -f1) && | |
175 | munge $pack $(($ofs + 1)) "\177\377" && | |
176 | test_must_fail git cat-file blob $delta >/dev/null | |
177 | ' | |
178 | ||
179 | test_done |