diff options
Diffstat (limited to 'third_party/git/pack-check.c')
| -rw-r--r-- | third_party/git/pack-check.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/third_party/git/pack-check.c b/third_party/git/pack-check.c new file mode 100644 index 000000000000..2cc3603189b8 --- /dev/null +++ b/third_party/git/pack-check.c @@ -0,0 +1,204 @@ +#include "cache.h" +#include "repository.h" +#include "pack.h" +#include "pack-revindex.h" +#include "progress.h" +#include "packfile.h" +#include "object-store.h" + +struct idx_entry { + off_t offset; + union idx_entry_object { + const unsigned char *hash; + struct object_id *oid; + } oid; + 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 * (the_hash_algo->rawsz/4) + nr; + + return data_crc != ntohl(*index_crc); +} + +static int verify_packfile(struct repository *r, + struct packed_git *p, + struct pack_window **w_curs, + verify_fn fn, + struct progress *progress, uint32_t base_count) + +{ + off_t index_size = p->index_size; + const unsigned char *index_base = p->index_data; + git_hash_ctx ctx; + unsigned char hash[GIT_MAX_RAWSZ], *pack_sig; + off_t offset = 0, pack_sig_ofs = 0; + uint32_t nr_objects, i; + int err = 0; + struct idx_entry *entries; + + if (!is_pack_valid(p)) + return error("packfile %s cannot be accessed", p->pack_name); + + the_hash_algo->init_fn(&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 - the_hash_algo->rawsz; + if (offset > pack_sig_ofs) + remaining -= (unsigned int)(offset - pack_sig_ofs); + the_hash_algo->update_fn(&ctx, in, remaining); + } while (offset < pack_sig_ofs); + the_hash_algo->final_fn(hash, &ctx); + pack_sig = use_pack(p, w_curs, pack_sig_ofs, NULL); + if (!hasheq(hash, pack_sig)) + err = error("%s pack checksum mismatch", + p->pack_name); + if (!hasheq(index_base + index_size - the_hash_algo->hexsz, pack_sig)) + err = error("%s pack checksum 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; + ALLOC_ARRAY(entries, nr_objects + 1); + 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].oid.hash = nth_packed_object_sha1(p, i); + if (!entries[i].oid.hash) + 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, compare_entries); + + for (i = 0; i < nr_objects; i++) { + void *data; + enum object_type type; + unsigned long size; + off_t curpos; + int data_valid; + + 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"", + oid_to_hex(entries[i].oid.oid), + p->pack_name, (uintmax_t)offset); + } + + curpos = entries[i].offset; + type = unpack_object_header(p, w_curs, &curpos, &size); + unuse_pack(w_curs); + + if (type == OBJ_BLOB && big_file_threshold <= size) { + /* + * Let check_object_signature() check it with + * the streaming interface; no point slurping + * the data in-core only to discard. + */ + data = NULL; + data_valid = 0; + } else { + data = unpack_entry(r, p, entries[i].offset, &type, &size); + data_valid = 1; + } + + if (data_valid && !data) + err = error("cannot unpack %s from %s at offset %"PRIuMAX"", + oid_to_hex(entries[i].oid.oid), p->pack_name, + (uintmax_t)entries[i].offset); + else if (check_object_signature(entries[i].oid.oid, data, size, type_name(type))) + err = error("packed %s from %s is corrupt", + oid_to_hex(entries[i].oid.oid), p->pack_name); + else if (fn) { + int eaten = 0; + err |= fn(entries[i].oid.oid, type, size, data, &eaten); + if (eaten) + data = NULL; + } + if (((base_count + i) & 1023) == 0) + display_progress(progress, base_count + i); + free(data); + + } + display_progress(progress, base_count + i); + free(entries); + + return err; +} + +int verify_pack_index(struct packed_git *p) +{ + off_t index_size; + const unsigned char *index_base; + git_hash_ctx ctx; + unsigned char hash[GIT_MAX_RAWSZ]; + 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 */ + the_hash_algo->init_fn(&ctx); + the_hash_algo->update_fn(&ctx, index_base, (unsigned int)(index_size - the_hash_algo->rawsz)); + the_hash_algo->final_fn(hash, &ctx); + if (!hasheq(hash, index_base + index_size - the_hash_algo->rawsz)) + err = error("Packfile index for %s hash mismatch", + p->pack_name); + return err; +} + +int verify_pack(struct repository *r, struct packed_git *p, verify_fn fn, + struct progress *progress, uint32_t base_count) +{ + int err = 0; + struct pack_window *w_curs = NULL; + + err |= verify_pack_index(p); + if (!p->index_data) + return -1; + + err |= verify_packfile(r, p, &w_curs, fn, progress, base_count); + unuse_pack(&w_curs); + + return err; +} |