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
   7 struct idx_entry {
   8         off_t                offset;
   9         union idx_entry_object {
  10                 const unsigned char *hash;
  11                 struct object_id *oid;
  12         } oid;
  13         unsigned int nr;
  14 };
  15
  16 static int compare_entries(const void *e1, const void *e2)
  17 {
  18         const struct idx_entry *entry1 = e1;
  19         const struct idx_entry *entry2 = e2;
  20         if (entry1->offset < entry2->offset)
  21                 return -1;
  22         if (entry1->offset > entry2->offset)
  23                 return 1;
  24         return 0;
  25 }
  26
  27 int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
  28                    off_t offset, off_t len, unsigned int nr)
  29 {
  30         const uint32_t *index_crc;
  31         uint32_t data_crc = crc32(0, NULL, 0);
  32
  33         do {
  34                 unsigned long avail;
  35                 void *data = use_pack(p, w_curs, offset, &avail);
  36                 if (avail > len)
  37                         avail = len;
  38                 data_crc = crc32(data_crc, data, avail);
  39                 offset += avail;
  40                 len -= avail;
  41         } while (len);
  42
  43         index_crc = p->index_data;
  44         index_crc += 2 + 256 + p->num_objects * (20/4) + nr;
  45
  46         return data_crc != ntohl(*index_crc);
  47 }
  48
  49 static int verify_packfile(struct packed_git *p,
  50                            struct pack_window **w_curs,
  51                            verify_fn fn,
  52                            struct progress *progress, uint32_t base_count)
  53
  54 {
  55         off_t index_size = p->index_size;
  56         const unsigned char *index_base = p->index_data;
  57         git_SHA_CTX ctx;
  58         unsigned char hash[GIT_MAX_RAWSZ], *pack_sig;
  59         off_t offset = 0, pack_sig_ofs = 0;
  60         uint32_t nr_objects, i;
  61         int err = 0;
  62         struct idx_entry *entries;
  63
  64         if (!is_pack_valid(p))
  65                 return error("packfile %s cannot be accessed", p->pack_name);
  66
  67         git_SHA1_Init(&ctx);
  68         do {
  69                 unsigned long remaining;
  70                 unsigned char *in = use_pack(p, w_curs, offset, &remaining);
  71                 offset += remaining;
  72                 if (!pack_sig_ofs)
  73                         pack_sig_ofs = p->pack_size - 20;
  74                 if (offset > pack_sig_ofs)
  75                         remaining -= (unsigned int)(offset - pack_sig_ofs);
  76                 git_SHA1_Update(&ctx, in, remaining);
  77         } while (offset < pack_sig_ofs);
  78         git_SHA1_Final(hash, &ctx);
  79         pack_sig = use_pack(p, w_curs, pack_sig_ofs, NULL);
  80         if (hashcmp(hash, pack_sig))
  81                 err = error("%s SHA1 checksum mismatch",
  82                             p->pack_name);
  83         if (hashcmp(index_base + index_size - 40, pack_sig))
  84                 err = error("%s SHA1 does not match its index",
  85                             p->pack_name);
  86         unuse_pack(w_curs);
  87
  88         /* Make sure everything reachable from idx is valid.  Since we
  89          * have verified that nr_objects matches between idx and pack,
  90          * we do not do scan-streaming check on the pack file.
  91          */
  92         nr_objects = p->num_objects;
  93         ALLOC_ARRAY(entries, nr_objects + 1);
  94         entries[nr_objects].offset = pack_sig_ofs;
  95         /* first sort entries by pack offset, since unpacking them is more efficient that way */
  96         for (i = 0; i < nr_objects; i++) {
  97                 entries[i].oid.hash = nth_packed_object_sha1(p, i);
  98                 if (!entries[i].oid.hash)
  99                         die("internal error pack-check nth-packed-object");
 100                 entries[i].offset = nth_packed_object_offset(p, i);
 101                 entries[i].nr = i;
 102         }
 103         QSORT(entries, nr_objects, compare_entries);
 104
 105         for (i = 0; i < nr_objects; i++) {
 106                 void *data;
 107                 enum object_type type;
 108                 unsigned long size;
 109                 off_t curpos;
 110                 int data_valid;
 111
 112                 if (p->index_version > 1) {
 113                         off_t offset = entries[i].offset;
 114                         off_t len = entries[i+1].offset - offset;
 115                         unsigned int nr = entries[i].nr;
 116                         if (check_pack_crc(p, w_curs, offset, len, nr))
 117                                 err = error("index CRC mismatch for object %s "
 118                                             "from %s at offset %"PRIuMAX"",
 119                                             oid_to_hex(entries[i].oid.oid),
 120                                             p->pack_name, (uintmax_t)offset);
 121                 }
 122
 123                 curpos = entries[i].offset;
 124                 type = unpack_object_header(p, w_curs, &curpos, &size);
 125                 unuse_pack(w_curs);
 126
 127                 if (type == OBJ_BLOB && big_file_threshold <= size) {
 128                         /*
 129                          * Let check_sha1_signature() check it with
 130                          * the streaming interface; no point slurping
 131                          * the data in-core only to discard.
 132                          */
 133                         data = NULL;
 134                         data_valid = 0;
 135                 } else {
 136                         data = unpack_entry(p, entries[i].offset, &type, &size);
 137                         data_valid = 1;
 138                 }
 139
 140                 if (data_valid && !data)
 141                         err = error("cannot unpack %s from %s at offset %"PRIuMAX"",
 142                                     oid_to_hex(entries[i].oid.oid), p->pack_name,
 143                                     (uintmax_t)entries[i].offset);
 144                 else if (check_sha1_signature(entries[i].oid.hash, data, size, typename(type)))
 145                         err = error("packed %s from %s is corrupt",
 146                                     oid_to_hex(entries[i].oid.oid), p->pack_name);
 147                 else if (fn) {
 148                         int eaten = 0;
 149                         err |= fn(entries[i].oid.oid, type, size, data, &eaten);
 150                         if (eaten)
 151                                 data = NULL;
 152                 }
 153                 if (((base_count + i) & 1023) == 0)
 154                         display_progress(progress, base_count + i);
 155                 free(data);
 156
 157         }
 158         display_progress(progress, base_count + i);
 159         free(entries);
 160
 161         return err;
 162 }
 163
 164 int verify_pack_index(struct packed_git *p)
 165 {
 166         off_t index_size;
 167         const unsigned char *index_base;
 168         git_SHA_CTX ctx;
 169         unsigned char sha1[20];
 170         int err = 0;
 171
 172         if (open_pack_index(p))
 173                 return error("packfile %s index not opened", p->pack_name);
 174         index_size = p->index_size;
 175         index_base = p->index_data;
 176
 177         /* Verify SHA1 sum of the index file */
 178         git_SHA1_Init(&ctx);
 179         git_SHA1_Update(&ctx, index_base, (unsigned int)(index_size - 20));
 180         git_SHA1_Final(sha1, &ctx);
 181         if (hashcmp(sha1, index_base + index_size - 20))
 182                 err = error("Packfile index for %s SHA1 mismatch",
 183                             p->pack_name);
 184         return err;
 185 }
 186
 187 int verify_pack(struct packed_git *p, verify_fn fn,
 188                 struct progress *progress, uint32_t base_count)
 189 {
 190         int err = 0;
 191         struct pack_window *w_curs = NULL;
 192
 193         err |= verify_pack_index(p);
 194         if (!p->index_data)
 195                 return -1;
 196
 197         err |= verify_packfile(p, &w_curs, fn, progress, base_count);
 198         unuse_pack(&w_curs);
 199
 200         return err;
 201 }