pack-check.c

   1 #include "cache.h"
   2 #include "pack.h"
   3 #include "pack-revindex.h"
   4 #include "progress.h"
   5 #include "packfile.h"
   6 #include "object-store.h"
   7
   8 struct idx_entry {
   9         off_t                offset;
  10         union idx_entry_object {
  11                 const unsigned char *hash;
  12                 struct object_id *oid;
  13         } oid;
  14         unsigned int nr;
  15 };
  16
  17 static int compare_entries(const void *e1, const void *e2)
  18 {
  19         const struct idx_entry *entry1 = e1;
  20         const struct idx_entry *entry2 = e2;
  21         if (entry1->offset < entry2->offset)
  22                 return -1;
  23         if (entry1->offset > entry2->offset)
  24                 return 1;
  25         return 0;
  26 }
  27
  28 int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
  29                    off_t offset, off_t len, unsigned int nr)
  30 {
  31         const uint32_t *index_crc;
  32         uint32_t data_crc = crc32(0, NULL, 0);
  33
  34         do {
  35                 unsigned long avail;
  36                 void *data = use_pack(p, w_curs, offset, &avail);
  37                 if (avail > len)
  38                         avail = len;
  39                 data_crc = crc32(data_crc, data, avail);
  40                 offset += avail;
  41                 len -= avail;
  42         } while (len);
  43
  44         index_crc = p->index_data;
  45         index_crc += 2 + 256 + p->num_objects * (20/4) + nr;
  46
  47         return data_crc != ntohl(*index_crc);
  48 }
  49
  50 static int verify_packfile(struct packed_git *p,
  51                            struct pack_window **w_curs,
  52                            verify_fn fn,
  53                            struct progress *progress, uint32_t base_count)
  54
  55 {
  56         off_t index_size = p->index_size;
  57         const unsigned char *index_base = p->index_data;
  58         git_SHA_CTX ctx;
  59         unsigned char hash[GIT_MAX_RAWSZ], *pack_sig;
  60         off_t offset = 0, pack_sig_ofs = 0;
  61         uint32_t nr_objects, i;
  62         int err = 0;
  63         struct idx_entry *entries;
  64
  65         if (!is_pack_valid(p))
  66                 return error("packfile %s cannot be accessed", p->pack_name);
  67
  68         git_SHA1_Init(&ctx);
  69         do {
  70                 unsigned long remaining;
  71                 unsigned char *in = use_pack(p, w_curs, offset, &remaining);
  72                 offset += remaining;
  73                 if (!pack_sig_ofs)
  74                         pack_sig_ofs = p->pack_size - 20;
  75                 if (offset > pack_sig_ofs)
  76                         remaining -= (unsigned int)(offset - pack_sig_ofs);
  77                 git_SHA1_Update(&ctx, in, remaining);
  78         } while (offset < pack_sig_ofs);
  79         git_SHA1_Final(hash, &ctx);
  80         pack_sig = use_pack(p, w_curs, pack_sig_ofs, NULL);
  81         if (hashcmp(hash, pack_sig))
  82                 err = error("%s SHA1 checksum mismatch",
  83                             p->pack_name);
  84         if (hashcmp(index_base + index_size - 40, pack_sig))
  85                 err = error("%s SHA1 does not match its index",
  86                             p->pack_name);
  87         unuse_pack(w_curs);
  88
  89         /* Make sure everything reachable from idx is valid.  Since we
  90          * have verified that nr_objects matches between idx and pack,
  91          * we do not do scan-streaming check on the pack file.
  92          */
  93         nr_objects = p->num_objects;
  94         ALLOC_ARRAY(entries, nr_objects + 1);
  95         entries[nr_objects].offset = pack_sig_ofs;
  96         /* first sort entries by pack offset, since unpacking them is more efficient that way */
  97         for (i = 0; i < nr_objects; i++) {
  98                 entries[i].oid.hash = nth_packed_object_sha1(p, i);
  99                 if (!entries[i].oid.hash)
 100                         die("internal error pack-check nth-packed-object");
 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                 enum object_type type;
 109                 unsigned long size;
 110                 off_t curpos;
 111                 int data_valid;
 112
 113                 if (p->index_version > 1) {
 114                         off_t offset = entries[i].offset;
 115                         off_t len = entries[i+1].offset - offset;
 116                         unsigned int nr = entries[i].nr;
 117                         if (check_pack_crc(p, w_curs, offset, len, nr))
 118                                 err = error("index CRC mismatch for object %s "
 119                                             "from %s at offset %"PRIuMAX"",
 120                                             oid_to_hex(entries[i].oid.oid),
 121                                             p->pack_name, (uintmax_t)offset);
 122                 }
 123
 124                 curpos = entries[i].offset;
 125                 type = unpack_object_header(p, w_curs, &curpos, &size);
 126                 unuse_pack(w_curs);
 127
 128                 if (type == OBJ_BLOB && big_file_threshold <= size) {
 129                         /*
 130                          * Let check_sha1_signature() check it with
 131                          * the streaming interface; no point slurping
 132                          * the data in-core only to discard.
 133                          */
 134                         data = NULL;
 135                         data_valid = 0;
 136                 } else {
 137                         data = unpack_entry(p, entries[i].offset, &type, &size);
 138                         data_valid = 1;
 139                 }
 140
 141                 if (data_valid && !data)
 142                         err = error("cannot unpack %s from %s at offset %"PRIuMAX"",
 143                                     oid_to_hex(entries[i].oid.oid), p->pack_name,
 144                                     (uintmax_t)entries[i].offset);
 145                 else if (check_sha1_signature(entries[i].oid.hash, data, size, typename(type)))
 146                         err = error("packed %s from %s is corrupt",
 147                                     oid_to_hex(entries[i].oid.oid), p->pack_name);
 148                 else if (fn) {
 149                         int eaten = 0;
 150                         err |= fn(entries[i].oid.oid, type, size, data, &eaten);
 151                         if (eaten)
 152                                 data = NULL;
 153                 }
 154                 if (((base_count + i) & 1023) == 0)
 155                         display_progress(progress, base_count + i);
 156                 free(data);
 157
 158         }
 159         display_progress(progress, base_count + i);
 160         free(entries);
 161
 162         return err;
 163 }
 164
 165 int verify_pack_index(struct packed_git *p)
 166 {
 167         off_t index_size;
 168         const unsigned char *index_base;
 169         git_SHA_CTX ctx;
 170         unsigned char sha1[20];
 171         int err = 0;
 172
 173         if (open_pack_index(p))
 174                 return error("packfile %s index not opened", p->pack_name);
 175         index_size = p->index_size;
 176         index_base = p->index_data;
 177
 178         /* Verify SHA1 sum of the index file */
 179         git_SHA1_Init(&ctx);
 180         git_SHA1_Update(&ctx, index_base, (unsigned int)(index_size - 20));
 181         git_SHA1_Final(sha1, &ctx);
 182         if (hashcmp(sha1, index_base + index_size - 20))
 183                 err = error("Packfile index for %s SHA1 mismatch",
 184                             p->pack_name);
 185         return err;
 186 }
 187
 188 int verify_pack(struct packed_git *p, verify_fn fn,
 189                 struct progress *progress, uint32_t base_count)
 190 {
 191         int err = 0;
 192         struct pack_window *w_curs = NULL;
 193
 194         err |= verify_pack_index(p);
 195         if (!p->index_data)
 196                 return -1;
 197
 198         err |= verify_packfile(p, &w_curs, fn, progress, base_count);
 199         unuse_pack(&w_curs);
 200
 201         return err;
 202 }