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#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, Z_NULL, 0);
do {
unsigned int 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 int 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 inddex",
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;
}
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