Martchus
/
arch-repo-manager
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Use `CRYPTO_memcmp` to compare password to prevent timing attacks

This commit is contained in:
Martchus 2024-02-21 20:43:38 +01:00
parent cc05267338
commit ac30fd2996
1 changed files with 22 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
librepomgr/authentication.cpp
View File

@ -7,6 +7,7 @@
#include <c++utilities/io/ansiescapecodes.h>
#include <openssl/sha.h>
#include <openssl/crypto.h>
namespace LibRepoMgr {
@ -39,16 +40,19 @@ template <> inline void convertValue(const std::multimap<std::string, std::strin
}
}
static constexpr char toUpper(const char c)
{
return (c >= 'a' && c <= 'z') ? (c - ('a' - 'A')) : c;
}
void ServiceSetup::Authentication::applyConfig(const std::string &userName, const std::multimap<std::string, std::string> &multimap)
{
auto &user = users[userName];
convertValue(multimap, "password_sha512", user.passwordSha512);
convertValue(multimap, "permissions", user.permissions);
}
static constexpr char toLower(const char c)
{
return (c >= 'A' && c <= 'Z') ? (c + ('a' - 'A')) : c;
for (auto &c : user.passwordSha512) {
c = toUpper(c);
}
}
UserAuth ServiceSetup::Authentication::authenticate(std::string_view authorizationHeader) const
@ -83,22 +87,26 @@ UserAuth ServiceSetup::Authentication::authenticate(std::string_view authorizati
if (user == users.cend()) {
return auth;
}
constexpr auto sha512HexSize = 128;
constexpr auto sha512HexSize = SHA512_DIGEST_LENGTH * 2;
if (user->second.passwordSha512.size() != sha512HexSize) {
return auth;
}
// hash password
unsigned char hash[SHA512_DIGEST_LENGTH];
SHA512(reinterpret_cast<const unsigned char *>(password.data()), password.size(), hash);
auto hash = std::array<unsigned char, SHA512_DIGEST_LENGTH>();
SHA512(reinterpret_cast<const unsigned char *>(password.data()), password.size(), hash.data());
// convert hash to string (hexadecimal)
auto hashHex = std::array<char, sha512HexSize>();
auto hashHexIter = hashHex.begin();
for (const auto hashNumber : hash) {
*(hashHexIter++) = static_cast<char>(CppUtilities::digitToChar((hashNumber / 16) % 16));
*(hashHexIter++) = static_cast<char>(CppUtilities::digitToChar(hashNumber % 16));
}
// check whether password hash matches
auto i = user->second.passwordSha512.cbegin();
for (unsigned char hashNumber : hash) {
const auto digits = CppUtilities::numberToString(hashNumber, 16);
if ((toLower(*(i++)) != toLower(digits.size() < 2 ? '0' : digits.front())) || (toLower(*(i++)) != toLower(digits.back()))) {
return auth;
}
if (CRYPTO_memcmp(user->second.passwordSha512.data(), hashHex.data(), sha512HexSize) != 0) {
return auth;
}
// return the user's permissions