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Fix and clean up hash parser

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This commit is contained in:
John Ericson 2020-06-23 18:19:40 +00:00
parent 98e5d1af03
commit ec3a857307
1 changed files with 30 additions and 32 deletions
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62
src/libutil/hash.cc
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@ -133,68 +133,66 @@ std::string Hash::to_string(Base base, bool includeType) const
Hash::Hash(std::string_view s, HashType type) : Hash(s, std::optional { type }) { }
Hash::Hash(std::string_view s) : Hash(s, std::optional<HashType>{}) { }
Hash::Hash(std::string_view s, std::optional<HashType> optType)
Hash::Hash(std::string_view original, std::optional<HashType> optType)
{
auto rest = original;
size_t pos = 0;
bool isSRI = false;
// Find the : or - separater, and set `isSRI` to the correct value
auto sep = s.find(':');
if (sep == std::string_view::npos) {
sep = s.find('-');
if (sep != std::string_view::npos)
isSRI = true;
}
// Parse the has type before the separater, if there was one.
std::optional<HashType> optParsedType;
if (sep != std::string_view::npos) {
auto hts = s.substr(0, sep);
auto optParsedType = parseHashTypeOpt(hts);
if (!optParsedType)
throw BadHash("unknown hash type '%s'", hts);
pos = sep + 1;
{
auto sep = rest.find(':');
if (sep == std::string_view::npos) {
sep = rest.find('-');
if (sep != std::string_view::npos)
isSRI = true;
}
if (sep != std::string_view::npos) {
auto hashRaw = rest.substr(0, sep);
optParsedType = parseHashType(hashRaw);
rest = rest.substr(sep + 1);
}
}
// Either the string or user must provide the type, if they both do they
// must agree.
if (!optParsedType && !optType) {
throw BadHash("hash '%s' does not include a type, nor is the type otherwise known from context.", s);
throw BadHash("hash '%s' does not include a type, nor is the type otherwise known from context.", rest);
} else {
this->type = optParsedType ? *optParsedType : *optType;
if (optParsedType && optType && *optParsedType != *optType)
throw BadHash("hash '%s' should have type '%s'", s, printHashType(*optType));
throw BadHash("hash '%s' should have type '%s'", original, printHashType(*optType));
}
init();
size_t size = s.size() - pos;
if (!isSRI && size == base16Len()) {
if (!isSRI && rest.size() == base16Len()) {
auto parseHexDigit = [&](char c) {
if (c >= '0' && c <= '9') return c - '0';
if (c >= 'A' && c <= 'F') return c - 'A' + 10;
if (c >= 'a' && c <= 'f') return c - 'a' + 10;
throw BadHash("invalid base-16 hash '%s'", s);
throw BadHash("invalid base-16 hash '%s'", original);
};
for (unsigned int i = 0; i < hashSize; i++) {
hash[i] =
parseHexDigit(s[pos + i * 2]) << 4
| parseHexDigit(s[pos + i * 2 + 1]);
parseHexDigit(rest[pos + i * 2]) << 4
| parseHexDigit(rest[pos + i * 2 + 1]);
}
}
else if (!isSRI && size == base32Len()) {
else if (!isSRI && rest.size() == base32Len()) {
for (unsigned int n = 0; n < size; ++n) {
char c = s[pos + size - n - 1];
for (unsigned int n = 0; n < rest.size(); ++n) {
char c = rest[rest.size() - n - 1];
unsigned char digit;
for (digit = 0; digit < base32Chars.size(); ++digit) /* !!! slow */
if (base32Chars[digit] == c) break;
if (digit >= 32)
throw BadHash("invalid base-32 hash '%s'", s);
throw BadHash("invalid base-32 hash '%s'", original);
unsigned int b = n * 5;
unsigned int i = b / 8;
unsigned int j = b % 8;
@ -204,21 +202,21 @@ Hash::Hash(std::string_view s, std::optional<HashType> optType)
hash[i + 1] |= digit >> (8 - j);
} else {
if (digit >> (8 - j))
throw BadHash("invalid base-32 hash '%s'", s);
throw BadHash("invalid base-32 hash '%s'", original);
}
}
}
else if (isSRI || size == base64Len()) {
auto d = base64Decode(s.substr(pos));
else if (isSRI || rest.size() == base64Len()) {
auto d = base64Decode(rest);
if (d.size() != hashSize)
throw BadHash("invalid %s hash '%s'", isSRI ? "SRI" : "base-64", s);
throw BadHash("invalid %s hash '%s'", isSRI ? "SRI" : "base-64", original);
assert(hashSize);
memcpy(hash, d.data(), hashSize);
}
else
throw BadHash("hash '%s' has wrong length for hash type '%s'", s, printHashType(type));
throw BadHash("hash '%s' has wrong length for hash type '%s'", rest, printHashType(this->type));
}
Hash newHashAllowEmpty(std::string hashStr, std::optional<HashType> ht)