pack-check.c

   1 #define DISABLE_SIGN_COMPARE_WARNINGS
   2
   3 #include "git-compat-util.h"
   4 #include "environment.h"
   5 #include "hex.h"
   6 #include "repository.h"
   7 #include "pack.h"
   8 #include "progress.h"
   9 #include "packfile.h"
  10 #include "object-file.h"
  11 #include "odb.h"
  12
  13 struct idx_entry {
  14         off_t                offset;
  15         unsigned int nr;
  16 };
  17
  18 static int compare_entries(const void *e1, const void *e2)
  19 {
  20         const struct idx_entry *entry1 = e1;
  21         const struct idx_entry *entry2 = e2;
  22         if (entry1->offset < entry2->offset)
  23                 return -1;
  24         if (entry1->offset > entry2->offset)
  25                 return 1;
  26         return 0;
  27 }
  28
  29 int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
  30                    off_t offset, off_t len, unsigned int nr)
  31 {
  32         const uint32_t *index_crc;
  33         uint32_t data_crc = crc32(0, NULL, 0);
  34
  35         do {
  36                 unsigned long avail;
  37                 void *data = use_pack(p, w_curs, offset, &avail);
  38                 if (avail > len)
  39                         avail = len;
  40                 data_crc = crc32(data_crc, data, avail);
  41                 offset += avail;
  42                 len -= avail;
  43         } while (len);
  44
  45         index_crc = p->index_data;
  46         index_crc += 2 + 256 + (size_t)p->num_objects * (p->repo->hash_algo->rawsz/4) + nr;
  47
  48         return data_crc != ntohl(*index_crc);
  49 }
  50
  51 static int verify_packfile(struct repository *r,
  52                            struct packed_git *p,
  53                            struct pack_window **w_curs,
  54                            verify_fn fn,
  55                            struct progress *progress, uint32_t base_count)
  56
  57 {
  58         off_t index_size = p->index_size;
  59         const unsigned char *index_base = p->index_data;
  60         struct git_hash_ctx ctx;
  61         unsigned char hash[GIT_MAX_RAWSZ], *pack_sig;
  62         off_t offset = 0, pack_sig_ofs = 0;
  63         uint32_t nr_objects, i;
  64         int err = 0;
  65         struct idx_entry *entries;
  66
  67         if (!is_pack_valid(p))
  68                 return error("packfile %s cannot be accessed", p->pack_name);
  69
  70         r->hash_algo->init_fn(&ctx);
  71         do {
  72                 unsigned long remaining;
  73                 unsigned char *in = use_pack(p, w_curs, offset, &remaining);
  74                 offset += remaining;
  75                 if (!pack_sig_ofs)
  76                         pack_sig_ofs = p->pack_size - r->hash_algo->rawsz;
  77                 if (offset > pack_sig_ofs)
  78                         remaining -= (unsigned int)(offset - pack_sig_ofs);
  79                 git_hash_update(&ctx, in, remaining);
  80         } while (offset < pack_sig_ofs);
  81         git_hash_final(hash, &ctx);
  82         pack_sig = use_pack(p, w_curs, pack_sig_ofs, NULL);
  83         if (!hasheq(hash, pack_sig, r->hash_algo))
  84                 err = error("%s pack checksum mismatch",
  85                             p->pack_name);
  86         if (!hasheq(index_base + index_size - r->hash_algo->hexsz, pack_sig,
  87                     r->hash_algo))
  88                 err = error("%s pack checksum does not match its index",
  89                             p->pack_name);
  90         unuse_pack(w_curs);
  91
  92         /* Make sure everything reachable from idx is valid.  Since we
  93          * have verified that nr_objects matches between idx and pack,
  94          * we do not do scan-streaming check on the pack file.
  95          */
  96         nr_objects = p->num_objects;
  97         ALLOC_ARRAY(entries, nr_objects + 1);
  98         entries[nr_objects].offset = pack_sig_ofs;
  99         /* first sort entries by pack offset, since unpacking them is more efficient that way */
 100         for (i = 0; i < nr_objects; i++) {
 101                 entries[i].offset = nth_packed_object_offset(p, i);
 102                 entries[i].nr = i;
 103         }
 104         QSORT(entries, nr_objects, compare_entries);
 105
 106         for (i = 0; i < nr_objects; i++) {
 107                 void *data;
 108                 struct object_id oid;
 109                 enum object_type type;
 110                 unsigned long size;
 111                 off_t curpos;
 112                 int data_valid;
 113
 114                 if (nth_packed_object_id(&oid, p, entries[i].nr) < 0)
 115                         BUG("unable to get oid of object %lu from %s",
 116                             (unsigned long)entries[i].nr, p->pack_name);
 117
 118                 if (p->index_version > 1) {
 119                         off_t offset = entries[i].offset;
 120                         off_t len = entries[i+1].offset - offset;
 121                         unsigned int nr = entries[i].nr;
 122                         if (check_pack_crc(p, w_curs, offset, len, nr))
 123                                 err = error("index CRC mismatch for object %s "
 124                                             "from %s at offset %"PRIuMAX"",
 125                                             oid_to_hex(&oid),
 126                                             p->pack_name, (uintmax_t)offset);
 127                 }
 128
 129                 curpos = entries[i].offset;
 130                 type = unpack_object_header(p, w_curs, &curpos, &size);
 131                 unuse_pack(w_curs);
 132
 133                 if (type == OBJ_BLOB &&
 134                     repo_settings_get_big_file_threshold(r) <= size) {
 135                         /*
 136                          * Let stream_object_signature() check it with
 137                          * the streaming interface; no point slurping
 138                          * the data in-core only to discard.
 139                          */
 140                         data = NULL;
 141                         data_valid = 0;
 142                 } else {
 143                         data = unpack_entry(r, p, entries[i].offset, &type, &size);
 144                         data_valid = 1;
 145                 }
 146
 147                 if (data_valid && !data)
 148                         err = error("cannot unpack %s from %s at offset %"PRIuMAX"",
 149                                     oid_to_hex(&oid), p->pack_name,
 150                                     (uintmax_t)entries[i].offset);
 151                 else if (data && check_object_signature(r, &oid, data, size,
 152                                                         type) < 0)
 153                         err = error("packed %s from %s is corrupt",
 154                                     oid_to_hex(&oid), p->pack_name);
 155                 else if (!data && stream_object_signature(r, &oid) < 0)
 156                         err = error("packed %s from %s is corrupt",
 157                                     oid_to_hex(&oid), p->pack_name);
 158                 else if (fn) {
 159                         int eaten = 0;
 160                         err |= fn(&oid, type, size, data, &eaten);
 161                         if (eaten)
 162                                 data = NULL;
 163                 }
 164                 if (((base_count + i) & 1023) == 0)
 165                         display_progress(progress, base_count + i);
 166                 free(data);
 167
 168         }
 169         display_progress(progress, base_count + i);
 170         free(entries);
 171
 172         return err;
 173 }
 174
 175 int verify_pack_index(struct packed_git *p)
 176 {
 177         int err = 0;
 178
 179         if (open_pack_index(p))
 180                 return error("packfile %s index not opened", p->pack_name);
 181
 182         /* Verify SHA1 sum of the index file */
 183         if (!hashfile_checksum_valid(p->repo->hash_algo, p->index_data, p->index_size))
 184                 err = error("Packfile index for %s hash mismatch",
 185                             p->pack_name);
 186         return err;
 187 }
 188
 189 int verify_pack(struct repository *r, struct packed_git *p, verify_fn fn,
 190                 struct progress *progress, uint32_t base_count)
 191 {
 192         int err = 0;
 193         struct pack_window *w_curs = NULL;
 194
 195         err |= verify_pack_index(p);
 196         if (!p->index_data)
 197                 return -1;
 198
 199         err |= verify_packfile(r, p, &w_curs, fn, progress, base_count);
 200         unuse_pack(&w_curs);
 201
 202         return err;
 203 }