| #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; |
| } |