ffi.cpp

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/*
* (C) 2015,2017 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
 
#include <botan/ffi.h>
 
#include <botan/base64.h>
#include <botan/hex.h>
#include <botan/mem_ops.h>
#include <botan/version.h>
#include <botan/internal/ct_utils.h>
#include <botan/internal/ffi_util.h>
#include <botan/internal/os_utils.h>
#include <cstdio>
#include <cstdlib>
 
namespace Botan_FFI {
 
// NOLINTNEXTLINE(*-avoid-non-const-global-variables)
thread_local std::string g_last_exception_what;
 
int ffi_error_exception_thrown(const char* func_name, const char* exn, int rc) {
   g_last_exception_what.assign(exn);
 
   std::string val;
   if(Botan::OS::read_env_variable(val, "BOTAN_FFI_PRINT_EXCEPTIONS") == true && !val.empty()) {
      static_cast<void>(std::fprintf(stderr, "in %s exception '%s' returning %d\n", func_name, exn, rc));
   }
   return rc;
}
 
int botan_view_str_bounce_fn(botan_view_ctx vctx, const char* str, size_t len) {
   return botan_view_bin_bounce_fn(vctx, reinterpret_cast<const uint8_t*>(str), len);
}
 
int botan_view_bin_bounce_fn(botan_view_ctx vctx, const uint8_t* buf, size_t len) {
   if(vctx == nullptr || buf == nullptr) {
      return BOTAN_FFI_ERROR_NULL_POINTER;
   }
 
   botan_view_bounce_struct* ctx = static_cast<botan_view_bounce_struct*>(vctx);
 
   const size_t avail = *ctx->out_len;
   *ctx->out_len = len;
 
   if(avail < len || ctx->out_ptr == nullptr) {
      if(ctx->out_ptr) {
         Botan::clear_mem(ctx->out_ptr, avail);
      }
      return BOTAN_FFI_ERROR_INSUFFICIENT_BUFFER_SPACE;
   } else {
      Botan::copy_mem(ctx->out_ptr, buf, len);
      return BOTAN_FFI_SUCCESS;
   }
}
 
namespace {
 
int ffi_map_error_type(Botan::ErrorType err) {
   switch(err) {
      case Botan::ErrorType::Unknown:
         return BOTAN_FFI_ERROR_UNKNOWN_ERROR;
 
      case Botan::ErrorType::SystemError:
      case Botan::ErrorType::IoError:
      case Botan::ErrorType::Pkcs11Error:
      case Botan::ErrorType::CommonCryptoError:
      case Botan::ErrorType::TPMError:
      case Botan::ErrorType::ZlibError:
      case Botan::ErrorType::Bzip2Error:
      case Botan::ErrorType::LzmaError:
      case Botan::ErrorType::DatabaseError:
         return BOTAN_FFI_ERROR_SYSTEM_ERROR;
 
      case Botan::ErrorType::NotImplemented:
         return BOTAN_FFI_ERROR_NOT_IMPLEMENTED;
      case Botan::ErrorType::OutOfMemory:
         return BOTAN_FFI_ERROR_OUT_OF_MEMORY;
      case Botan::ErrorType::InternalError:
         return BOTAN_FFI_ERROR_INTERNAL_ERROR;
      case Botan::ErrorType::InvalidObjectState:
         return BOTAN_FFI_ERROR_INVALID_OBJECT_STATE;
      case Botan::ErrorType::KeyNotSet:
         return BOTAN_FFI_ERROR_KEY_NOT_SET;
      case Botan::ErrorType::InvalidArgument:
      case Botan::ErrorType::InvalidNonceLength:
         return BOTAN_FFI_ERROR_BAD_PARAMETER;
 
      case Botan::ErrorType::EncodingFailure:
      case Botan::ErrorType::DecodingFailure:
         return BOTAN_FFI_ERROR_INVALID_INPUT;
 
      case Botan::ErrorType::InvalidTag:
         return BOTAN_FFI_ERROR_BAD_MAC;
 
      case Botan::ErrorType::InvalidKeyLength:
         return BOTAN_FFI_ERROR_INVALID_KEY_LENGTH;
      case Botan::ErrorType::LookupError:
         return BOTAN_FFI_ERROR_NOT_IMPLEMENTED;
 
      case Botan::ErrorType::HttpError:
         return BOTAN_FFI_ERROR_HTTP_ERROR;
      case Botan::ErrorType::TLSError:
         return BOTAN_FFI_ERROR_TLS_ERROR;
      case Botan::ErrorType::RoughtimeError:
         return BOTAN_FFI_ERROR_ROUGHTIME_ERROR;
   }
 
   return BOTAN_FFI_ERROR_UNKNOWN_ERROR;
}
 
}  // namespace
 
int ffi_guard_thunk(const char* func_name, const std::function<int()>& thunk) {
   g_last_exception_what.clear();
 
   try {
      return thunk();
   } catch(std::bad_alloc&) {
      return ffi_error_exception_thrown(func_name, "bad_alloc", BOTAN_FFI_ERROR_OUT_OF_MEMORY);
   } catch(Botan_FFI::FFI_Error& e) {
      return ffi_error_exception_thrown(func_name, e.what(), e.error_code());
   } catch(Botan::Exception& e) {
      return ffi_error_exception_thrown(func_name, e.what(), ffi_map_error_type(e.error_type()));
   } catch(std::exception& e) {
      return ffi_error_exception_thrown(func_name, e.what());
   } catch(...) {
      return ffi_error_exception_thrown(func_name, "unknown exception");
   }
 
   return BOTAN_FFI_ERROR_UNKNOWN_ERROR;
}
 
}  // namespace Botan_FFI
 
extern "C" {
 
using namespace Botan_FFI;
 
const char* botan_error_last_exception_message() {
   return g_last_exception_what.c_str();
}
 
const char* botan_error_description(int err) {
   switch(err) {
      case BOTAN_FFI_SUCCESS:
         return "OK";
 
      case BOTAN_FFI_INVALID_VERIFIER:
         return "Invalid verifier";
 
      case BOTAN_FFI_ERROR_INVALID_INPUT:
         return "Invalid input";
 
      case BOTAN_FFI_ERROR_BAD_MAC:
         return "Invalid authentication code";
 
      case BOTAN_FFI_ERROR_INSUFFICIENT_BUFFER_SPACE:
         return "Insufficient buffer space";
 
      case BOTAN_FFI_ERROR_STRING_CONVERSION_ERROR:
         return "String conversion error";
 
      case BOTAN_FFI_ERROR_EXCEPTION_THROWN:
         return "Exception thrown";
 
      case BOTAN_FFI_ERROR_OUT_OF_MEMORY:
         return "Out of memory";
 
      case BOTAN_FFI_ERROR_SYSTEM_ERROR:
         return "Error while calling system API";
 
      case BOTAN_FFI_ERROR_INTERNAL_ERROR:
         return "Internal error";
 
      case BOTAN_FFI_ERROR_BAD_FLAG:
         return "Bad flag";
 
      case BOTAN_FFI_ERROR_NULL_POINTER:
         return "Null pointer argument";
 
      case BOTAN_FFI_ERROR_BAD_PARAMETER:
         return "Bad parameter";
 
      case BOTAN_FFI_ERROR_KEY_NOT_SET:
         return "Key not set on object";
 
      case BOTAN_FFI_ERROR_INVALID_KEY_LENGTH:
         return "Invalid key length";
 
      case BOTAN_FFI_ERROR_INVALID_OBJECT_STATE:
         return "Invalid object state";
 
      case BOTAN_FFI_ERROR_NOT_IMPLEMENTED:
         return "Not implemented";
 
      case BOTAN_FFI_ERROR_INVALID_OBJECT:
         return "Invalid object handle";
 
      case BOTAN_FFI_ERROR_TLS_ERROR:
         return "TLS error";
 
      case BOTAN_FFI_ERROR_HTTP_ERROR:
         return "HTTP error";
 
      case BOTAN_FFI_ERROR_UNKNOWN_ERROR:
         return "Unknown error";
 
      default:
         return "Unknown error";
   }
}
 
/*
* Versioning
*/
uint32_t botan_ffi_api_version() {
   return BOTAN_HAS_FFI;
}
 
int botan_ffi_supports_api(uint32_t api_version) {
   // This is the API introduced in 3.4
   if(api_version == 20240408) {
      return BOTAN_FFI_SUCCESS;
   }
 
   // This is the API introduced in 3.2
   if(api_version == 20231009) {
      return BOTAN_FFI_SUCCESS;
   }
 
   // This is the API introduced in 3.1
   if(api_version == 20230711) {
      return BOTAN_FFI_SUCCESS;
   }
 
   // This is the API introduced in 3.0
   if(api_version == 20230403) {
      return BOTAN_FFI_SUCCESS;
   }
 
   // This is the API introduced in 2.18
   if(api_version == 20210220) {
      return BOTAN_FFI_SUCCESS;
   }
 
   // This is the API introduced in 2.13
   if(api_version == 20191214) {
      return BOTAN_FFI_SUCCESS;
   }
 
   // This is the API introduced in 2.8
   if(api_version == 20180713) {
      return BOTAN_FFI_SUCCESS;
   }
 
   // This is the API introduced in 2.3
   if(api_version == 20170815) {
      return BOTAN_FFI_SUCCESS;
   }
 
   // This is the API introduced in 2.1
   if(api_version == 20170327) {
      return BOTAN_FFI_SUCCESS;
   }
 
   // This is the API introduced in 2.0
   if(api_version == 20150515) {
      return BOTAN_FFI_SUCCESS;
   }
 
   // Something else:
   return -1;
}
 
const char* botan_version_string() {
   return Botan::version_cstr();
}
 
uint32_t botan_version_major() {
   return Botan::version_major();
}
 
uint32_t botan_version_minor() {
   return Botan::version_minor();
}
 
uint32_t botan_version_patch() {
   return Botan::version_patch();
}
 
uint32_t botan_version_datestamp() {
   return Botan::version_datestamp();
}
 
int botan_constant_time_compare(const uint8_t* x, const uint8_t* y, size_t len) {
   auto same = Botan::CT::is_equal(x, y, len);
   // Return 0 if same or -1 otherwise
   return static_cast<int>(same.select(1, 0)) - 1;
}
 
int botan_same_mem(const uint8_t* x, const uint8_t* y, size_t len) {
   return botan_constant_time_compare(x, y, len);
}
 
int botan_scrub_mem(void* mem, size_t bytes) {
   Botan::secure_scrub_memory(mem, bytes);
   return BOTAN_FFI_SUCCESS;
}
 
int botan_hex_encode(const uint8_t* in, size_t len, char* out, uint32_t flags) {
   return ffi_guard_thunk(__func__, [=]() -> int {
      const bool uppercase = (flags & BOTAN_FFI_HEX_LOWER_CASE) == 0;
      Botan::hex_encode(out, in, len, uppercase);
      return BOTAN_FFI_SUCCESS;
   });
}
 
int botan_hex_decode(const char* hex_str, size_t in_len, uint8_t* out, size_t* out_len) {
   return ffi_guard_thunk(__func__, [=]() -> int {
      const std::vector<uint8_t> bin = Botan::hex_decode(hex_str, in_len);
      return Botan_FFI::write_vec_output(out, out_len, bin);
   });
}
 
int botan_base64_encode(const uint8_t* in, size_t len, char* out, size_t* out_len) {
   return ffi_guard_thunk(__func__, [=]() -> int {
      const std::string base64 = Botan::base64_encode(in, len);
      return Botan_FFI::write_str_output(out, out_len, base64);
   });
}
 
int botan_base64_decode(const char* base64_str, size_t in_len, uint8_t* out, size_t* out_len) {
   return ffi_guard_thunk(__func__, [=]() -> int {
      if(*out_len < Botan::base64_decode_max_output(in_len)) {
         *out_len = Botan::base64_decode_max_output(in_len);
         return BOTAN_FFI_ERROR_INSUFFICIENT_BUFFER_SPACE;
      }
 
      *out_len = Botan::base64_decode(out, std::string(base64_str, in_len));
      return BOTAN_FFI_SUCCESS;
   });
}
}