verify_pack.c

   1 #include "cache.h"
   2 #include "pack.h"
   3
   4 static int verify_packfile(struct packed_git *p)
   5 {
   6         unsigned long index_size = p->index_size;
   7         void *index_base = p->index_base;
   8         SHA_CTX ctx;
   9         unsigned char sha1[20];
  10         unsigned long pack_size = p->pack_size;
  11         void *pack_base;
  12         struct pack_header *hdr;
  13         int nr_objects;
  14
  15         hdr = p->pack_base;
  16         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
  17                 return error("Packfile signature mismatch", p->pack_name);
  18         if (hdr->hdr_version != htonl(PACK_VERSION))
  19                 return error("Packfile version %d different from ours %d",
  20                              ntohl(hdr->hdr_version), PACK_VERSION);
  21         nr_objects = ntohl(hdr->hdr_entries);
  22         if (num_packed_objects(p) != nr_objects)
  23                 return error("Packfile claims to have %d objects, "
  24                              "while idx size expects %d", nr_objects,
  25                              num_packed_objects(p));
  26
  27         SHA1_Init(&ctx);
  28         pack_base = p->pack_base;
  29         SHA1_Update(&ctx, pack_base, pack_size - 20);
  30         SHA1_Final(sha1, &ctx);
  31         if (memcmp(sha1, index_base + index_size - 40, 20))
  32                 return error("Packfile %s SHA1 mismatch with idx",
  33                              p->pack_name);
  34         if (memcmp(sha1, pack_base + pack_size - 20, 20))
  35                 return error("Packfile %s SHA1 mismatch with itself",
  36                              p->pack_name);
  37         return 0;
  38 }
  39
  40
  41 int verify_pack(struct packed_git *p)
  42 {
  43         unsigned long index_size = p->index_size;
  44         void *index_base = p->index_base;
  45         SHA_CTX ctx;
  46         unsigned char sha1[20];
  47         int ret;
  48
  49         /* Verify SHA1 sum of the index file */
  50         SHA1_Init(&ctx);
  51         SHA1_Update(&ctx, index_base, index_size - 20);
  52         SHA1_Final(sha1, &ctx);
  53         if (memcmp(sha1, index_base + index_size - 20, 20))
  54                 return error("Packfile index for %s SHA1 mismatch",
  55                              p->pack_name);
  56
  57         /* Verify pack file */
  58         use_packed_git(p);
  59         ret = verify_packfile(p);
  60         unuse_packed_git(p);
  61         return ret;
  62 }