t7700: demonstrate mishandling of objects in packs with a .keep file
[git/dscho.git] / pack-check.c
blobf596bf2db5e0a0065e6856b8caa3ded8a134f74d
1 #include "cache.h"
2 #include "pack.h"
3 #include "pack-revindex.h"
5 struct idx_entry
7 off_t offset;
8 const unsigned char *sha1;
9 unsigned int nr;
12 static int compare_entries(const void *e1, const void *e2)
14 const struct idx_entry *entry1 = e1;
15 const struct idx_entry *entry2 = e2;
16 if (entry1->offset < entry2->offset)
17 return -1;
18 if (entry1->offset > entry2->offset)
19 return 1;
20 return 0;
23 int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
24 off_t offset, off_t len, unsigned int nr)
26 const uint32_t *index_crc;
27 uint32_t data_crc = crc32(0, Z_NULL, 0);
29 do {
30 unsigned int avail;
31 void *data = use_pack(p, w_curs, offset, &avail);
32 if (avail > len)
33 avail = len;
34 data_crc = crc32(data_crc, data, avail);
35 offset += avail;
36 len -= avail;
37 } while (len);
39 index_crc = p->index_data;
40 index_crc += 2 + 256 + p->num_objects * (20/4) + nr;
42 return data_crc != ntohl(*index_crc);
45 static int verify_packfile(struct packed_git *p,
46 struct pack_window **w_curs)
48 off_t index_size = p->index_size;
49 const unsigned char *index_base = p->index_data;
50 SHA_CTX ctx;
51 unsigned char sha1[20], *pack_sig;
52 off_t offset = 0, pack_sig_ofs = p->pack_size - 20;
53 uint32_t nr_objects, i;
54 int err = 0;
55 struct idx_entry *entries;
57 /* Note that the pack header checks are actually performed by
58 * use_pack when it first opens the pack file. If anything
59 * goes wrong during those checks then the call will die out
60 * immediately.
63 SHA1_Init(&ctx);
64 while (offset < pack_sig_ofs) {
65 unsigned int remaining;
66 unsigned char *in = use_pack(p, w_curs, offset, &remaining);
67 offset += remaining;
68 if (offset > pack_sig_ofs)
69 remaining -= (unsigned int)(offset - pack_sig_ofs);
70 SHA1_Update(&ctx, in, remaining);
72 SHA1_Final(sha1, &ctx);
73 pack_sig = use_pack(p, w_curs, pack_sig_ofs, NULL);
74 if (hashcmp(sha1, pack_sig))
75 err = error("%s SHA1 checksum mismatch",
76 p->pack_name);
77 if (hashcmp(index_base + index_size - 40, pack_sig))
78 err = error("%s SHA1 does not match its inddex",
79 p->pack_name);
80 unuse_pack(w_curs);
82 /* Make sure everything reachable from idx is valid. Since we
83 * have verified that nr_objects matches between idx and pack,
84 * we do not do scan-streaming check on the pack file.
86 nr_objects = p->num_objects;
87 entries = xmalloc((nr_objects + 1) * sizeof(*entries));
88 entries[nr_objects].offset = pack_sig_ofs;
89 /* first sort entries by pack offset, since unpacking them is more efficient that way */
90 for (i = 0; i < nr_objects; i++) {
91 entries[i].sha1 = nth_packed_object_sha1(p, i);
92 if (!entries[i].sha1)
93 die("internal error pack-check nth-packed-object");
94 entries[i].offset = nth_packed_object_offset(p, i);
95 entries[i].nr = i;
97 qsort(entries, nr_objects, sizeof(*entries), compare_entries);
99 for (i = 0; i < nr_objects; i++) {
100 void *data;
101 enum object_type type;
102 unsigned long size;
104 if (p->index_version > 1) {
105 off_t offset = entries[i].offset;
106 off_t len = entries[i+1].offset - offset;
107 unsigned int nr = entries[i].nr;
108 if (check_pack_crc(p, w_curs, offset, len, nr))
109 err = error("index CRC mismatch for object %s "
110 "from %s at offset %"PRIuMAX"",
111 sha1_to_hex(entries[i].sha1),
112 p->pack_name, (uintmax_t)offset);
114 data = unpack_entry(p, entries[i].offset, &type, &size);
115 if (!data) {
116 err = error("cannot unpack %s from %s at offset %"PRIuMAX"",
117 sha1_to_hex(entries[i].sha1), p->pack_name,
118 (uintmax_t)entries[i].offset);
119 break;
121 if (check_sha1_signature(entries[i].sha1, data, size, typename(type))) {
122 err = error("packed %s from %s is corrupt",
123 sha1_to_hex(entries[i].sha1), p->pack_name);
124 free(data);
125 break;
127 free(data);
129 free(entries);
131 return err;
134 int verify_pack(struct packed_git *p)
136 off_t index_size;
137 const unsigned char *index_base;
138 SHA_CTX ctx;
139 unsigned char sha1[20];
140 int err = 0;
141 struct pack_window *w_curs = NULL;
143 if (open_pack_index(p))
144 return error("packfile %s index not opened", p->pack_name);
145 index_size = p->index_size;
146 index_base = p->index_data;
148 /* Verify SHA1 sum of the index file */
149 SHA1_Init(&ctx);
150 SHA1_Update(&ctx, index_base, (unsigned int)(index_size - 20));
151 SHA1_Final(sha1, &ctx);
152 if (hashcmp(sha1, index_base + index_size - 20))
153 err = error("Packfile index for %s SHA1 mismatch",
154 p->pack_name);
156 /* Verify pack file */
157 err |= verify_packfile(p, &w_curs);
158 unuse_pack(&w_curs);
160 return err;