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Diffstat (limited to 'apt-pkg/contrib/hashes.cc')
| -rw-r--r-- | apt-pkg/contrib/hashes.cc | 453 |
1 files changed, 453 insertions, 0 deletions
diff --git a/apt-pkg/contrib/hashes.cc b/apt-pkg/contrib/hashes.cc new file mode 100644 index 0000000..267e267 --- /dev/null +++ b/apt-pkg/contrib/hashes.cc @@ -0,0 +1,453 @@ +// -*- mode: cpp; mode: fold -*- +// Description /*{{{*/ +/* ###################################################################### + + Hashes - Simple wrapper around the hash functions + + This is just used to make building the methods simpler, this is the + only interface required.. + + ##################################################################### */ + /*}}}*/ +// Include Files /*{{{*/ +#include <config.h> + +#include <apt-pkg/configuration.h> +#include <apt-pkg/fileutl.h> +#include <apt-pkg/hashes.h> +#include <apt-pkg/macros.h> +#include <apt-pkg/strutl.h> + +#include <algorithm> +#include <iostream> +#include <string> +#include <assert.h> +#include <stddef.h> +#include <stdlib.h> +#include <unistd.h> + +#include <gcrypt.h> + /*}}}*/ + +static const constexpr struct HashAlgo +{ + const char *name; + int gcryAlgo; + Hashes::SupportedHashes ourAlgo; +} Algorithms[] = { + {"MD5Sum", GCRY_MD_MD5, Hashes::MD5SUM}, + {"SHA1", GCRY_MD_SHA1, Hashes::SHA1SUM}, + {"SHA256", GCRY_MD_SHA256, Hashes::SHA256SUM}, + {"SHA512", GCRY_MD_SHA512, Hashes::SHA512SUM}, +}; + +const char * HashString::_SupportedHashes[] = +{ + "SHA512", "SHA256", "SHA1", "MD5Sum", "Checksum-FileSize", NULL +}; + +HashString::HashString() +{ +} + +HashString::HashString(std::string Type, std::string Hash) : Type(Type), Hash(Hash) +{ +} + +HashString::HashString(std::string StringedHash) /*{{{*/ +{ + if (StringedHash.find(":") == std::string::npos) + { + // legacy: md5sum without "MD5Sum:" prefix + if (StringedHash.size() == 32) + { + Type = "MD5Sum"; + Hash = StringedHash; + } + if(_config->FindB("Debug::Hashes",false) == true) + std::clog << "HashString(string): invalid StringedHash " << StringedHash << std::endl; + return; + } + std::string::size_type pos = StringedHash.find(":"); + Type = StringedHash.substr(0,pos); + Hash = StringedHash.substr(pos+1, StringedHash.size() - pos); + + if(_config->FindB("Debug::Hashes",false) == true) + std::clog << "HashString(string): " << Type << " : " << Hash << std::endl; +} + /*}}}*/ +bool HashString::VerifyFile(std::string filename) const /*{{{*/ +{ + std::string fileHash = GetHashForFile(filename); + + if(_config->FindB("Debug::Hashes",false) == true) + std::clog << "HashString::VerifyFile: got: " << fileHash << " expected: " << toStr() << std::endl; + + return (fileHash == Hash); +} + /*}}}*/ +bool HashString::FromFile(std::string filename) /*{{{*/ +{ + // pick the strongest hash + if (Type == "") + Type = _SupportedHashes[0]; + + Hash = GetHashForFile(filename); + return true; +} + /*}}}*/ +std::string HashString::GetHashForFile(std::string filename) const /*{{{*/ +{ + std::string fileHash; + + FileFd Fd(filename, FileFd::ReadOnly); + if(strcasecmp(Type.c_str(), "MD5Sum") == 0) + { + Hashes MD5(Hashes::MD5SUM); + MD5.AddFD(Fd); + fileHash = MD5.GetHashString(Hashes::MD5SUM).Hash; + } + else if (strcasecmp(Type.c_str(), "SHA1") == 0) + { + Hashes SHA1(Hashes::SHA1SUM); + SHA1.AddFD(Fd); + fileHash = SHA1.GetHashString(Hashes::SHA1SUM).Hash; + } + else if (strcasecmp(Type.c_str(), "SHA256") == 0) + { + Hashes SHA256(Hashes::SHA256SUM); + SHA256.AddFD(Fd); + fileHash = SHA256.GetHashString(Hashes::SHA256SUM).Hash; + } + else if (strcasecmp(Type.c_str(), "SHA512") == 0) + { + Hashes SHA512(Hashes::SHA512SUM); + SHA512.AddFD(Fd); + fileHash = SHA512.GetHashString(Hashes::SHA512SUM).Hash; + } + else if (strcasecmp(Type.c_str(), "Checksum-FileSize") == 0) + strprintf(fileHash, "%llu", Fd.FileSize()); + Fd.Close(); + + return fileHash; +} + /*}}}*/ +const char** HashString::SupportedHashes() /*{{{*/ +{ + return _SupportedHashes; +} + /*}}}*/ +APT_PURE bool HashString::empty() const /*{{{*/ +{ + return (Type.empty() || Hash.empty()); +} + /*}}}*/ + +APT_PURE static bool IsConfigured(const char *name, const char *what) +{ + std::string option; + strprintf(option, "APT::Hashes::%s::%s", name, what); + return _config->FindB(option, false); +} + +APT_PURE bool HashString::usable() const /*{{{*/ +{ + return ( + (Type != "Checksum-FileSize") && + (Type != "MD5Sum") && + (Type != "SHA1") && + !IsConfigured(Type.c_str(), "Untrusted") + ); +} + /*}}}*/ +std::string HashString::toStr() const /*{{{*/ +{ + return Type + ":" + Hash; +} + /*}}}*/ +APT_PURE bool HashString::operator==(HashString const &other) const /*{{{*/ +{ + return (strcasecmp(Type.c_str(), other.Type.c_str()) == 0 && Hash == other.Hash); +} +APT_PURE bool HashString::operator!=(HashString const &other) const +{ + return !(*this == other); +} + /*}}}*/ + +bool HashStringList::usable() const /*{{{*/ +{ + if (empty() == true) + return false; + std::string const forcedType = _config->Find("Acquire::ForceHash", ""); + if (forcedType.empty() == true) + { + // See if there is at least one usable hash + return std::any_of(list.begin(), list.end(), [](auto const &hs) { return hs.usable(); }); + } + return find(forcedType) != NULL; +} + /*}}}*/ +HashString const * HashStringList::find(char const * const type) const /*{{{*/ +{ + if (type == NULL || type[0] == '\0') + { + std::string const forcedType = _config->Find("Acquire::ForceHash", ""); + if (forcedType.empty() == false) + return find(forcedType.c_str()); + for (char const * const * t = HashString::SupportedHashes(); *t != NULL; ++t) + for (std::vector<HashString>::const_iterator hs = list.begin(); hs != list.end(); ++hs) + if (strcasecmp(hs->HashType().c_str(), *t) == 0) + return &*hs; + return NULL; + } + for (std::vector<HashString>::const_iterator hs = list.begin(); hs != list.end(); ++hs) + if (strcasecmp(hs->HashType().c_str(), type) == 0) + return &*hs; + return NULL; +} + /*}}}*/ +unsigned long long HashStringList::FileSize() const /*{{{*/ +{ + HashString const * const hsf = find("Checksum-FileSize"); + if (hsf == NULL) + return 0; + std::string const hv = hsf->HashValue(); + return strtoull(hv.c_str(), NULL, 10); +} + /*}}}*/ +bool HashStringList::FileSize(unsigned long long const Size) /*{{{*/ +{ + return push_back(HashString("Checksum-FileSize", std::to_string(Size))); +} + /*}}}*/ +bool HashStringList::supported(char const * const type) /*{{{*/ +{ + for (char const * const * t = HashString::SupportedHashes(); *t != NULL; ++t) + if (strcasecmp(*t, type) == 0) + return true; + return false; +} + /*}}}*/ +bool HashStringList::push_back(const HashString &hashString) /*{{{*/ +{ + if (hashString.HashType().empty() == true || + hashString.HashValue().empty() == true || + supported(hashString.HashType().c_str()) == false) + return false; + + // ensure that each type is added only once + HashString const * const hs = find(hashString.HashType().c_str()); + if (hs != NULL) + return *hs == hashString; + + list.push_back(hashString); + return true; +} + /*}}}*/ +bool HashStringList::VerifyFile(std::string filename) const /*{{{*/ +{ + if (usable() == false) + return false; + + Hashes hashes(*this); + FileFd file(filename, FileFd::ReadOnly); + HashString const * const hsf = find("Checksum-FileSize"); + if (hsf != NULL) + { + std::string fileSize; + strprintf(fileSize, "%llu", file.FileSize()); + if (hsf->HashValue() != fileSize) + return false; + } + hashes.AddFD(file); + HashStringList const hsl = hashes.GetHashStringList(); + return hsl == *this; +} + /*}}}*/ +bool HashStringList::operator==(HashStringList const &other) const /*{{{*/ +{ + std::string const forcedType = _config->Find("Acquire::ForceHash", ""); + if (forcedType.empty() == false) + { + HashString const * const hs = find(forcedType); + HashString const * const ohs = other.find(forcedType); + if (hs == NULL || ohs == NULL) + return false; + return *hs == *ohs; + } + short matches = 0; + for (const_iterator hs = begin(); hs != end(); ++hs) + { + HashString const * const ohs = other.find(hs->HashType()); + if (ohs == NULL) + continue; + if (*hs != *ohs) + return false; + ++matches; + } + if (matches == 0) + return false; + return true; +} +bool HashStringList::operator!=(HashStringList const &other) const +{ + return !(*this == other); +} + /*}}}*/ + +// PrivateHashes /*{{{*/ +class PrivateHashes { +public: + unsigned long long FileSize; + gcry_md_hd_t hd; + + void maybeInit() + { + + // Yikes, we got to initialize libgcrypt, or we get warnings. But we + // abstract away libgcrypt in Hashes from our users - they are not + // supposed to know what the hashing backend is, so we can't force + // them to init themselves as libgcrypt folks want us to. So this + // only leaves us with this option... + if (!gcry_control(GCRYCTL_INITIALIZATION_FINISHED_P)) + { + if (!gcry_check_version(nullptr)) + { + fprintf(stderr, "libgcrypt is too old (need %s, have %s)\n", + "nullptr", gcry_check_version(NULL)); + exit(2); + } + + gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0); + } + } + + explicit PrivateHashes(unsigned int const CalcHashes) : FileSize(0) + { + maybeInit(); + gcry_md_open(&hd, 0, 0); + for (auto & Algo : Algorithms) + { + if ((CalcHashes & Algo.ourAlgo) == Algo.ourAlgo) + gcry_md_enable(hd, Algo.gcryAlgo); + } + } + + explicit PrivateHashes(HashStringList const &Hashes) : FileSize(0) { + maybeInit(); + gcry_md_open(&hd, 0, 0); + for (auto & Algo : Algorithms) + { + if (not Hashes.usable() || Hashes.find(Algo.name) != NULL) + gcry_md_enable(hd, Algo.gcryAlgo); + } + } + ~PrivateHashes() + { + gcry_md_close(hd); + } +}; + /*}}}*/ +// Hashes::Add* - Add the contents of data or FD /*{{{*/ +bool Hashes::Add(const unsigned char * const Data, unsigned long long const Size) +{ + if (Size != 0) + { + gcry_md_write(d->hd, Data, Size); + d->FileSize += Size; + } + return true; +} +bool Hashes::AddFD(int const Fd,unsigned long long Size) +{ + unsigned char Buf[APT_BUFFER_SIZE]; + bool const ToEOF = (Size == UntilEOF); + while (Size != 0 || ToEOF) + { + decltype(Size) n = sizeof(Buf); + if (!ToEOF) n = std::min(Size, n); + ssize_t const Res = read(Fd,Buf,n); + if (Res < 0 || (!ToEOF && Res != (ssize_t) n)) // error, or short read + return false; + if (ToEOF && Res == 0) // EOF + break; + Size -= Res; + if (Add(Buf, Res) == false) + return false; + } + return true; +} +bool Hashes::AddFD(FileFd &Fd,unsigned long long Size) +{ + unsigned char Buf[APT_BUFFER_SIZE]; + bool const ToEOF = (Size == 0); + while (Size != 0 || ToEOF) + { + decltype(Size) n = sizeof(Buf); + if (!ToEOF) n = std::min(Size, n); + decltype(Size) a = 0; + if (Fd.Read(Buf, n, &a) == false) // error + return false; + if (ToEOF == false) + { + if (a != n) // short read + return false; + } + else if (a == 0) // EOF + break; + Size -= a; + if (Add(Buf, a) == false) + return false; + } + return true; +} + /*}}}*/ + +static APT_PURE std::string HexDigest(gcry_md_hd_t hd, int algo) +{ + char Conv[16] = + {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', + 'c', 'd', 'e', 'f'}; + + auto Size = gcry_md_get_algo_dlen(algo); + assert(Size <= 512/8); + char Result[((Size)*2) + 1]; + Result[(Size)*2] = 0; + + auto Sum = gcry_md_read(hd, algo); + + // Convert each char into two letters + size_t J = 0; + size_t I = 0; + for (; I != (Size)*2; J++, I += 2) + { + Result[I] = Conv[Sum[J] >> 4]; + Result[I + 1] = Conv[Sum[J] & 0xF]; + } + return std::string(Result); +}; + +HashStringList Hashes::GetHashStringList() +{ + HashStringList hashes; + for (auto & Algo : Algorithms) + if (gcry_md_is_enabled(d->hd, Algo.gcryAlgo)) + hashes.push_back(HashString(Algo.name, HexDigest(d->hd, Algo.gcryAlgo))); + hashes.FileSize(d->FileSize); + + return hashes; +} + +HashString Hashes::GetHashString(SupportedHashes hash) +{ + for (auto & Algo : Algorithms) + if (hash == Algo.ourAlgo) + return HashString(Algo.name, HexDigest(d->hd, Algo.gcryAlgo)); + + abort(); +} +Hashes::Hashes() : d(new PrivateHashes(~0)) { } +Hashes::Hashes(unsigned int const Hashes) : d(new PrivateHashes(Hashes)) {} +Hashes::Hashes(HashStringList const &Hashes) : d(new PrivateHashes(Hashes)) {} +Hashes::~Hashes() { delete d; } |