forked from lix-project/lix
41c4558afe
This caused "nix-store --import" to compute an incorrect hash on NARs that don't fit in an unsigned int. The import would succeed, but "nix-store --verify-path" or subsequent exports would detect an incorrect hash. A deeper issue is that the export/import format does not contain a hash, so we can't detect such issues early. Also, I learned that -Wall does not warn about this.
355 lines
7.9 KiB
C++
355 lines
7.9 KiB
C++
#include <iostream>
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#include <cstring>
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#include <openssl/md5.h>
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#include <openssl/sha.h>
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#include "hash.hh"
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#include "archive.hh"
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#include "util.hh"
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#include "istringstream_nocopy.hh"
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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namespace nix {
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Hash::Hash()
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{
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type = htUnknown;
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hashSize = 0;
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memset(hash, 0, maxHashSize);
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}
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Hash::Hash(HashType type)
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{
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this->type = type;
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if (type == htMD5) hashSize = md5HashSize;
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else if (type == htSHA1) hashSize = sha1HashSize;
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else if (type == htSHA256) hashSize = sha256HashSize;
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else if (type == htSHA512) hashSize = sha512HashSize;
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else abort();
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assert(hashSize <= maxHashSize);
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memset(hash, 0, maxHashSize);
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}
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bool Hash::operator == (const Hash & h2) const
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{
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if (hashSize != h2.hashSize) return false;
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for (unsigned int i = 0; i < hashSize; i++)
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if (hash[i] != h2.hash[i]) return false;
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return true;
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}
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bool Hash::operator != (const Hash & h2) const
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{
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return !(*this == h2);
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}
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bool Hash::operator < (const Hash & h) const
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{
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for (unsigned int i = 0; i < hashSize; i++) {
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if (hash[i] < h.hash[i]) return true;
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if (hash[i] > h.hash[i]) return false;
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}
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return false;
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}
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std::string Hash::to_string(bool base32) const
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{
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return printHashType(type) + ":" + (base32 ? printHash32(*this) : printHash(*this));
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}
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const string base16Chars = "0123456789abcdef";
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string printHash(const Hash & hash)
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{
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char buf[hash.hashSize * 2];
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for (unsigned int i = 0; i < hash.hashSize; i++) {
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buf[i * 2] = base16Chars[hash.hash[i] >> 4];
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buf[i * 2 + 1] = base16Chars[hash.hash[i] & 0x0f];
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}
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return string(buf, hash.hashSize * 2);
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}
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Hash parseHash(const string & s)
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{
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string::size_type colon = s.find(':');
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if (colon == string::npos)
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throw BadHash(format("invalid hash ‘%s’") % s);
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string hts = string(s, 0, colon);
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HashType ht = parseHashType(hts);
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if (ht == htUnknown)
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throw BadHash(format("unknown hash type ‘%s’") % hts);
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return parseHash16or32(ht, string(s, colon + 1));
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}
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Hash parseHash(HashType ht, const string & s)
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{
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Hash hash(ht);
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if (s.length() != hash.hashSize * 2)
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throw BadHash(format("invalid hash ‘%1%’") % s);
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for (unsigned int i = 0; i < hash.hashSize; i++) {
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string s2(s, i * 2, 2);
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if (!isxdigit(s2[0]) || !isxdigit(s2[1]))
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throw BadHash(format("invalid hash ‘%1%’") % s);
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istringstream_nocopy str(s2);
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int n;
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str >> std::hex >> n;
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hash.hash[i] = n;
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}
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return hash;
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}
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// omitted: E O U T
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const string base32Chars = "0123456789abcdfghijklmnpqrsvwxyz";
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string printHash32(const Hash & hash)
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{
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assert(hash.hashSize);
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size_t len = hash.base32Len();
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assert(len);
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string s;
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s.reserve(len);
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for (int n = len - 1; n >= 0; n--) {
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unsigned int b = n * 5;
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unsigned int i = b / 8;
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unsigned int j = b % 8;
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unsigned char c =
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(hash.hash[i] >> j)
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| (i >= hash.hashSize - 1 ? 0 : hash.hash[i + 1] << (8 - j));
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s.push_back(base32Chars[c & 0x1f]);
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}
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return s;
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}
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string printHash16or32(const Hash & hash)
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{
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return hash.type == htMD5 ? printHash(hash) : printHash32(hash);
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}
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Hash parseHash32(HashType ht, const string & s)
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{
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Hash hash(ht);
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size_t len = hash.base32Len();
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assert(s.size() == len);
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for (unsigned int n = 0; n < len; ++n) {
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char c = s[len - n - 1];
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unsigned char digit;
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for (digit = 0; digit < base32Chars.size(); ++digit) /* !!! slow */
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if (base32Chars[digit] == c) break;
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if (digit >= 32)
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throw BadHash(format("invalid base-32 hash ‘%1%’") % s);
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unsigned int b = n * 5;
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unsigned int i = b / 8;
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unsigned int j = b % 8;
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hash.hash[i] |= digit << j;
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if (i < hash.hashSize - 1) {
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hash.hash[i + 1] |= digit >> (8 - j);
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} else {
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if (digit >> (8 - j))
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throw BadHash(format("invalid base-32 hash ‘%1%’") % s);
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}
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}
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return hash;
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}
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Hash parseHash16or32(HashType ht, const string & s)
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{
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Hash hash(ht);
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if (s.size() == hash.hashSize * 2)
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/* hexadecimal representation */
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hash = parseHash(ht, s);
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else if (s.size() == hash.base32Len())
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/* base-32 representation */
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hash = parseHash32(ht, s);
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else
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throw BadHash(format("hash ‘%1%’ has wrong length for hash type ‘%2%’")
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% s % printHashType(ht));
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return hash;
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}
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bool isHash(const string & s)
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{
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if (s.length() != 32) return false;
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for (int i = 0; i < 32; i++) {
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char c = s[i];
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if (!((c >= '0' && c <= '9') ||
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(c >= 'a' && c <= 'f')))
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return false;
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}
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return true;
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}
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union Ctx
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{
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MD5_CTX md5;
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SHA_CTX sha1;
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SHA256_CTX sha256;
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SHA512_CTX sha512;
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};
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static void start(HashType ht, Ctx & ctx)
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{
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if (ht == htMD5) MD5_Init(&ctx.md5);
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else if (ht == htSHA1) SHA1_Init(&ctx.sha1);
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else if (ht == htSHA256) SHA256_Init(&ctx.sha256);
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else if (ht == htSHA512) SHA512_Init(&ctx.sha512);
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}
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static void update(HashType ht, Ctx & ctx,
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const unsigned char * bytes, size_t len)
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{
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if (ht == htMD5) MD5_Update(&ctx.md5, bytes, len);
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else if (ht == htSHA1) SHA1_Update(&ctx.sha1, bytes, len);
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else if (ht == htSHA256) SHA256_Update(&ctx.sha256, bytes, len);
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else if (ht == htSHA512) SHA512_Update(&ctx.sha512, bytes, len);
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}
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static void finish(HashType ht, Ctx & ctx, unsigned char * hash)
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{
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if (ht == htMD5) MD5_Final(hash, &ctx.md5);
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else if (ht == htSHA1) SHA1_Final(hash, &ctx.sha1);
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else if (ht == htSHA256) SHA256_Final(hash, &ctx.sha256);
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else if (ht == htSHA512) SHA512_Final(hash, &ctx.sha512);
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}
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Hash hashString(HashType ht, const string & s)
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{
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Ctx ctx;
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Hash hash(ht);
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start(ht, ctx);
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update(ht, ctx, (const unsigned char *) s.data(), s.length());
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finish(ht, ctx, hash.hash);
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return hash;
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}
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Hash hashFile(HashType ht, const Path & path)
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{
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Ctx ctx;
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Hash hash(ht);
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start(ht, ctx);
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AutoCloseFD fd = open(path.c_str(), O_RDONLY | O_CLOEXEC);
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if (!fd) throw SysError(format("opening file ‘%1%’") % path);
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unsigned char buf[8192];
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ssize_t n;
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while ((n = read(fd.get(), buf, sizeof(buf)))) {
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checkInterrupt();
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if (n == -1) throw SysError(format("reading file ‘%1%’") % path);
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update(ht, ctx, buf, n);
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}
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finish(ht, ctx, hash.hash);
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return hash;
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}
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HashSink::HashSink(HashType ht) : ht(ht)
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{
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ctx = new Ctx;
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bytes = 0;
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start(ht, *ctx);
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}
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HashSink::~HashSink()
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{
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bufPos = 0;
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delete ctx;
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}
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void HashSink::write(const unsigned char * data, size_t len)
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{
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bytes += len;
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update(ht, *ctx, data, len);
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}
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HashResult HashSink::finish()
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{
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flush();
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Hash hash(ht);
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nix::finish(ht, *ctx, hash.hash);
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return HashResult(hash, bytes);
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}
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HashResult HashSink::currentHash()
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{
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flush();
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Ctx ctx2 = *ctx;
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Hash hash(ht);
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nix::finish(ht, ctx2, hash.hash);
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return HashResult(hash, bytes);
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}
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HashResult hashPath(
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HashType ht, const Path & path, PathFilter & filter)
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{
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HashSink sink(ht);
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dumpPath(path, sink, filter);
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return sink.finish();
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}
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Hash compressHash(const Hash & hash, unsigned int newSize)
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{
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Hash h;
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h.hashSize = newSize;
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for (unsigned int i = 0; i < hash.hashSize; ++i)
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h.hash[i % newSize] ^= hash.hash[i];
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return h;
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}
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HashType parseHashType(const string & s)
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{
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if (s == "md5") return htMD5;
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else if (s == "sha1") return htSHA1;
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else if (s == "sha256") return htSHA256;
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else if (s == "sha512") return htSHA512;
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else return htUnknown;
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}
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string printHashType(HashType ht)
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{
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if (ht == htMD5) return "md5";
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else if (ht == htSHA1) return "sha1";
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else if (ht == htSHA256) return "sha256";
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else if (ht == htSHA512) return "sha512";
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else abort();
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}
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}
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