Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
tag: v1.7.7.7
Fetching contributors…

Cannot retrieve contributors at this time

file 171 lines (151 sloc) 4.684 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171
#include "cache.h"
#include "pack.h"
#include "pack-revindex.h"

struct idx_entry {
off_t offset;
const unsigned char *sha1;
unsigned int nr;
};

static int compare_entries(const void *e1, const void *e2)
{
const struct idx_entry *entry1 = e1;
const struct idx_entry *entry2 = e2;
if (entry1->offset < entry2->offset)
return -1;
if (entry1->offset > entry2->offset)
return 1;
return 0;
}

int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
off_t offset, off_t len, unsigned int nr)
{
const uint32_t *index_crc;
uint32_t data_crc = crc32(0, NULL, 0);

do {
unsigned long avail;
void *data = use_pack(p, w_curs, offset, &avail);
if (avail > len)
avail = len;
data_crc = crc32(data_crc, data, avail);
offset += avail;
len -= avail;
} while (len);

index_crc = p->index_data;
index_crc += 2 + 256 + p->num_objects * (20/4) + nr;

return data_crc != ntohl(*index_crc);
}

static int verify_packfile(struct packed_git *p,
struct pack_window **w_curs)
{
off_t index_size = p->index_size;
const unsigned char *index_base = p->index_data;
git_SHA_CTX ctx;
unsigned char sha1[20], *pack_sig;
off_t offset = 0, pack_sig_ofs = 0;
uint32_t nr_objects, i;
int err = 0;
struct idx_entry *entries;

/* Note that the pack header checks are actually performed by
* use_pack when it first opens the pack file. If anything
* goes wrong during those checks then the call will die out
* immediately.
*/

git_SHA1_Init(&ctx);
do {
unsigned long remaining;
unsigned char *in = use_pack(p, w_curs, offset, &remaining);
offset += remaining;
if (!pack_sig_ofs)
pack_sig_ofs = p->pack_size - 20;
if (offset > pack_sig_ofs)
remaining -= (unsigned int)(offset - pack_sig_ofs);
git_SHA1_Update(&ctx, in, remaining);
} while (offset < pack_sig_ofs);
git_SHA1_Final(sha1, &ctx);
pack_sig = use_pack(p, w_curs, pack_sig_ofs, NULL);
if (hashcmp(sha1, pack_sig))
err = error("%s SHA1 checksum mismatch",
p->pack_name);
if (hashcmp(index_base + index_size - 40, pack_sig))
err = error("%s SHA1 does not match its index",
p->pack_name);
unuse_pack(w_curs);

/* Make sure everything reachable from idx is valid. Since we
* have verified that nr_objects matches between idx and pack,
* we do not do scan-streaming check on the pack file.
*/
nr_objects = p->num_objects;
entries = xmalloc((nr_objects + 1) * sizeof(*entries));
entries[nr_objects].offset = pack_sig_ofs;
/* first sort entries by pack offset, since unpacking them is more efficient that way */
for (i = 0; i < nr_objects; i++) {
entries[i].sha1 = nth_packed_object_sha1(p, i);
if (!entries[i].sha1)
die("internal error pack-check nth-packed-object");
entries[i].offset = nth_packed_object_offset(p, i);
entries[i].nr = i;
}
qsort(entries, nr_objects, sizeof(*entries), compare_entries);

for (i = 0; i < nr_objects; i++) {
void *data;
enum object_type type;
unsigned long size;

if (p->index_version > 1) {
off_t offset = entries[i].offset;
off_t len = entries[i+1].offset - offset;
unsigned int nr = entries[i].nr;
if (check_pack_crc(p, w_curs, offset, len, nr))
err = error("index CRC mismatch for object %s "
"from %s at offset %"PRIuMAX"",
sha1_to_hex(entries[i].sha1),
p->pack_name, (uintmax_t)offset);
}
data = unpack_entry(p, entries[i].offset, &type, &size);
if (!data) {
err = error("cannot unpack %s from %s at offset %"PRIuMAX"",
sha1_to_hex(entries[i].sha1), p->pack_name,
(uintmax_t)entries[i].offset);
break;
}
if (check_sha1_signature(entries[i].sha1, data, size, typename(type))) {
err = error("packed %s from %s is corrupt",
sha1_to_hex(entries[i].sha1), p->pack_name);
free(data);
break;
}
free(data);
}
free(entries);

return err;
}

int verify_pack_index(struct packed_git *p)
{
off_t index_size;
const unsigned char *index_base;
git_SHA_CTX ctx;
unsigned char sha1[20];
int err = 0;

if (open_pack_index(p))
return error("packfile %s index not opened", p->pack_name);
index_size = p->index_size;
index_base = p->index_data;

/* Verify SHA1 sum of the index file */
git_SHA1_Init(&ctx);
git_SHA1_Update(&ctx, index_base, (unsigned int)(index_size - 20));
git_SHA1_Final(sha1, &ctx);
if (hashcmp(sha1, index_base + index_size - 20))
err = error("Packfile index for %s SHA1 mismatch",
p->pack_name);
return err;
}

int verify_pack(struct packed_git *p)
{
int err = 0;
struct pack_window *w_curs = NULL;

err |= verify_pack_index(p);
if (!p->index_data)
return -1;

err |= verify_packfile(p, &w_curs);
unuse_pack(&w_curs);

return err;
}
Something went wrong with that request. Please try again.