Merge 0.3.2 in FROST

.cirrus.yml

@@ -176,7 +176,7 @@ task:
     CTIMETESTS: no
   matrix:
     - env: {}
-    - env: {EXPERIMENTAL: yes, ASM: arm}
+    - env: {EXPERIMENTAL: yes, ASM: arm32}
   << : *MERGE_BASE
   test_script:
     - ./ci/cirrus.sh
@@ -397,13 +397,13 @@ task:
     - PowerShell -NoLogo -Command if ($env:CIRRUS_PR -ne $null) { git fetch $env:CIRRUS_REPO_CLONE_URL pull/$env:CIRRUS_PR/merge; git reset --hard FETCH_HEAD; }
   configure_script:
     - '%x64_NATIVE_TOOLS%'
-    - cmake -G "Visual Studio 17 2022" -A x64 -S . -B build -DSECP256K1_ENABLE_MODULE_RECOVERY=ON -DSECP256K1_BUILD_EXAMPLES=ON
+    - cmake -E env CFLAGS="/WX" cmake -G "Visual Studio 17 2022" -A x64 -S . -B build -DSECP256K1_ENABLE_MODULE_RECOVERY=ON -DSECP256K1_BUILD_EXAMPLES=ON
   build_script:
     - '%x64_NATIVE_TOOLS%'
     - cmake --build build --config RelWithDebInfo -- -property:UseMultiToolTask=true;CL_MPcount=5
   check_script:
     - '%x64_NATIVE_TOOLS%'
-    - ctest --test-dir build -j 5
+    - ctest -C RelWithDebInfo --test-dir build -j 5
     - build\src\RelWithDebInfo\bench_ecmult.exe
     - build\src\RelWithDebInfo\bench_internal.exe
     - build\src\RelWithDebInfo\bench.exe

.gitignore

@@ -60,5 +60,7 @@ build-aux/compile
 build-aux/test-driver
 libsecp256k1.pc
 
+### CMake
+/CMakeUserPresets.json
 # Default CMake build directory.
 /build

CHANGELOG.md

@@ -5,7 +5,24 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## [0.3.2] - 2023-05-13
+We strongly recommend updating to 0.3.2 if you use or plan to use GCC >=13 to compile libsecp256k1. When in doubt, check the GCC version using `gcc -v`.
+
+#### Security
+ - Module `ecdh`: Fix "constant-timeness" issue with GCC 13.1 (and potentially future versions of GCC) that could leave applications using libsecp256k1's ECDH module vulnerable to a timing side-channel attack. The fix avoids secret-dependent control flow during ECDH computations when libsecp256k1 is compiled with GCC 13.1.
+
+#### Fixed
+ - Fixed an old bug that permitted compilers to potentially output bad assembly code on x86_64. In theory, it could lead to a crash or a read of unrelated memory, but this has never been observed on any compilers so far.
+
+#### Changed
+ - Various improvements and changes to CMake builds. CMake builds remain experimental.
+   - Made API versioning consistent with GNU Autotools builds.
+   - Switched to `BUILD_SHARED_LIBS` variable for controlling whether to build a static or a shared library.
+   - Added `SECP256K1_INSTALL` variable for the controlling whether to install the build artefacts.
+ - Renamed asm build option `arm` to `arm32`. Use `--with-asm=arm32` instead of `--with-asm=arm` (GNU Autotools), and `-DSECP256K1_ASM=arm32` instead of `-DSECP256K1_ASM=arm` (CMake).
+
+#### ABI Compatibility
+The ABI is compatible with versions 0.3.0 and 0.3.1.
 
 ## [0.3.1] - 2023-04-10
 We strongly recommend updating to 0.3.1 if you use or plan to use Clang >=14 to compile libsecp256k1, e.g., Xcode >=14 on macOS has Clang >=14. When in doubt, check the Clang version using `clang -v`.
@@ -68,7 +85,8 @@ This version was in fact never released.
 The number was given by the build system since the introduction of autotools in Jan 2014 (ea0fe5a5bf0c04f9cc955b2966b614f5f378c6f6).
 Therefore, this version number does not uniquely identify a set of source files.
 
-[unreleased]: https://github.com/bitcoin-core/secp256k1/compare/v0.3.1...HEAD
+[unreleased]: https://github.com/bitcoin-core/secp256k1/compare/v0.3.2...HEAD
+[0.3.2]: https://github.com/bitcoin-core/secp256k1/compare/v0.3.1...v0.3.2
 [0.3.1]: https://github.com/bitcoin-core/secp256k1/compare/v0.3.0...v0.3.1
 [0.3.0]: https://github.com/bitcoin-core/secp256k1/compare/v0.2.0...v0.3.0
 [0.2.0]: https://github.com/bitcoin-core/secp256k1/compare/423b6d19d373f1224fd671a982584d7e7900bc93..v0.2.0

CMakeLists.txt

@@ -1,16 +1,33 @@
 cmake_minimum_required(VERSION 3.13)
 
-if(CMAKE_VERSION VERSION_GREATER 3.14)
+if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.15)
   # MSVC runtime library flags are selected by the CMAKE_MSVC_RUNTIME_LIBRARY abstraction.
   cmake_policy(SET CMP0091 NEW)
   # MSVC warning flags are not in CMAKE_<LANG>_FLAGS by default.
   cmake_policy(SET CMP0092 NEW)
 endif()
 
-# The package (a.k.a. release) version is based on semantic versioning 2.0.0 of
-# the API. All changes in experimental modules are treated as
-# backwards-compatible and therefore at most increase the minor version.
-project(libsecp256k1 VERSION 0.3.2.1 LANGUAGES C) # FROST_SPECIFIC: the fourth number must be equal to the value of _PKG_VERSION_FROST_BUILD in configure.ac
+project(libsecp256k1
+  # The package (a.k.a. release) version is based on semantic versioning 2.0.0 of
+  # the API. All changes in experimental modules are treated as
+  # backwards-compatible and therefore at most increase the minor version.
+  VERSION 0.3.2.1 # FROST_SPECIFIC: the fourth number must be equal to the value of _PKG_VERSION_FROST_BUILD in configure.ac
+  DESCRIPTION "Optimized C library for ECDSA signatures and secret/public key operations on curve secp256k1."
+  HOMEPAGE_URL "https://github.com/bancaditalia/secp256k1-frost" # FROST_SPECIFIC: replaced URIs with those of Bank of Italy's fork.
+  LANGUAGES C
+)
+
+if(CMAKE_VERSION VERSION_LESS 3.21)
+  get_directory_property(parent_directory PARENT_DIRECTORY)
+  if(parent_directory)
+    set(PROJECT_IS_TOP_LEVEL OFF CACHE INTERNAL "Emulates CMake 3.21+ behavior.")
+    set(${PROJECT_NAME}_IS_TOP_LEVEL OFF CACHE INTERNAL "Emulates CMake 3.21+ behavior.")
+  else()
+    set(PROJECT_IS_TOP_LEVEL ON CACHE INTERNAL "Emulates CMake 3.21+ behavior.")
+    set(${PROJECT_NAME}_IS_TOP_LEVEL ON CACHE INTERNAL "Emulates CMake 3.21+ behavior.")
+  endif()
+  unset(parent_directory)
+endif()
 
 # The library version is based on libtool versioning of the ABI. The set of
 # rules for updating the version can be found here:
@@ -26,36 +43,37 @@ set(CMAKE_C_EXTENSIONS OFF)
 
 list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
 
-# We do not use CMake's BUILD_SHARED_LIBS option.
-option(SECP256K1_BUILD_SHARED "Build shared library." ON)
-option(SECP256K1_BUILD_STATIC "Build static library." ON)
-if(NOT SECP256K1_BUILD_SHARED AND NOT SECP256K1_BUILD_STATIC)
-  message(FATAL_ERROR "At least one of SECP256K1_BUILD_SHARED and SECP256K1_BUILD_STATIC must be enabled.")
+option(BUILD_SHARED_LIBS "Build shared libraries." ON)
+option(SECP256K1_DISABLE_SHARED "Disable shared library. Overrides BUILD_SHARED_LIBS." OFF)
+if(SECP256K1_DISABLE_SHARED)
+  set(BUILD_SHARED_LIBS OFF)
 endif()
 
+option(SECP256K1_INSTALL "Enable installation." ${PROJECT_IS_TOP_LEVEL})
+
 option(SECP256K1_ENABLE_MODULE_ECDH "Enable ECDH module." ON)
 if(SECP256K1_ENABLE_MODULE_ECDH)
-  add_definitions(-DENABLE_MODULE_ECDH=1)
+  add_compile_definitions(ENABLE_MODULE_ECDH=1)
 endif()
 
 option(SECP256K1_ENABLE_MODULE_RECOVERY "Enable ECDSA pubkey recovery module." OFF)
 if(SECP256K1_ENABLE_MODULE_RECOVERY)
-  add_definitions(-DENABLE_MODULE_RECOVERY=1)
+  add_compile_definitions(ENABLE_MODULE_RECOVERY=1)
 endif()
 
 option(SECP256K1_ENABLE_MODULE_EXTRAKEYS "Enable extrakeys module." ON)
 option(SECP256K1_ENABLE_MODULE_SCHNORRSIG "Enable schnorrsig module." ON)
 if(SECP256K1_ENABLE_MODULE_SCHNORRSIG)
   set(SECP256K1_ENABLE_MODULE_EXTRAKEYS ON)
-  add_definitions(-DENABLE_MODULE_SCHNORRSIG=1)
+  add_compile_definitions(ENABLE_MODULE_SCHNORRSIG=1)
 endif()
 if(SECP256K1_ENABLE_MODULE_EXTRAKEYS)
-  add_definitions(-DENABLE_MODULE_EXTRAKEYS=1)
+  add_compile_definitions(ENABLE_MODULE_EXTRAKEYS=1)
 endif()
 
 option(SECP256K1_USE_EXTERNAL_DEFAULT_CALLBACKS "Enable external default callback functions." OFF)
 if(SECP256K1_USE_EXTERNAL_DEFAULT_CALLBACKS)
-  add_definitions(-DUSE_EXTERNAL_DEFAULT_CALLBACKS=1)
+  add_compile_definitions(USE_EXTERNAL_DEFAULT_CALLBACKS=1)
 endif()
 
 set(SECP256K1_ECMULT_WINDOW_SIZE "AUTO" CACHE STRING "Window size for ecmult precomputation for verification, specified as integer in range [2..24]. \"AUTO\" is a reasonable setting for desktop machines (currently 15). [default=AUTO]")
@@ -65,37 +83,43 @@ check_string_option_value(SECP256K1_ECMULT_WINDOW_SIZE)
 if(SECP256K1_ECMULT_WINDOW_SIZE STREQUAL "AUTO")
   set(SECP256K1_ECMULT_WINDOW_SIZE 15)
 endif()
-add_definitions(-DECMULT_WINDOW_SIZE=${SECP256K1_ECMULT_WINDOW_SIZE})
+add_compile_definitions(ECMULT_WINDOW_SIZE=${SECP256K1_ECMULT_WINDOW_SIZE})
 
 set(SECP256K1_ECMULT_GEN_PREC_BITS "AUTO" CACHE STRING "Precision bits to tune the precomputed table size for signing, specified as integer 2, 4 or 8. \"AUTO\" is a reasonable setting for desktop machines (currently 4). [default=AUTO]")
 set_property(CACHE SECP256K1_ECMULT_GEN_PREC_BITS PROPERTY STRINGS "AUTO" 2 4 8)
 check_string_option_value(SECP256K1_ECMULT_GEN_PREC_BITS)
 if(SECP256K1_ECMULT_GEN_PREC_BITS STREQUAL "AUTO")
   set(SECP256K1_ECMULT_GEN_PREC_BITS 4)
 endif()
-add_definitions(-DECMULT_GEN_PREC_BITS=${SECP256K1_ECMULT_GEN_PREC_BITS})
+add_compile_definitions(ECMULT_GEN_PREC_BITS=${SECP256K1_ECMULT_GEN_PREC_BITS})
 
 set(SECP256K1_TEST_OVERRIDE_WIDE_MULTIPLY "OFF" CACHE STRING "Test-only override of the (autodetected by the C code) \"widemul\" setting. Legal values are: \"OFF\", \"int128_struct\", \"int128\" or \"int64\". [default=OFF]")
 set_property(CACHE SECP256K1_TEST_OVERRIDE_WIDE_MULTIPLY PROPERTY STRINGS "OFF" "int128_struct" "int128" "int64")
 check_string_option_value(SECP256K1_TEST_OVERRIDE_WIDE_MULTIPLY)
 if(SECP256K1_TEST_OVERRIDE_WIDE_MULTIPLY)
   string(TOUPPER "${SECP256K1_TEST_OVERRIDE_WIDE_MULTIPLY}" widemul_upper_value)
-  add_definitions(-DUSE_FORCE_WIDEMUL_${widemul_upper_value}=1)
+  add_compile_definitions(USE_FORCE_WIDEMUL_${widemul_upper_value}=1)
 endif()
 mark_as_advanced(FORCE SECP256K1_TEST_OVERRIDE_WIDE_MULTIPLY)
 
-set(SECP256K1_ASM "AUTO" CACHE STRING "Assembly optimizations to use: \"AUTO\", \"OFF\", \"x86_64\" or \"arm\" (experimental). [default=AUTO]")
-set_property(CACHE SECP256K1_ASM PROPERTY STRINGS "AUTO" "OFF" "x86_64" "arm")
+set(SECP256K1_ASM "AUTO" CACHE STRING "Assembly optimizations to use: \"AUTO\", \"OFF\", \"x86_64\" or \"arm32\" (experimental). [default=AUTO]")
+set_property(CACHE SECP256K1_ASM PROPERTY STRINGS "AUTO" "OFF" "x86_64" "arm32")
 check_string_option_value(SECP256K1_ASM)
-if(SECP256K1_ASM STREQUAL "arm")
+if(SECP256K1_ASM STREQUAL "arm32")
   enable_language(ASM)
-  add_definitions(-DUSE_EXTERNAL_ASM=1)
+  include(CheckArm32Assembly)
+  check_arm32_assembly()
+  if(HAVE_ARM32_ASM)
+    add_compile_definitions(USE_EXTERNAL_ASM=1)
+  else()
+    message(FATAL_ERROR "ARM32 assembly optimization requested but not available.")
+  endif()
 elseif(SECP256K1_ASM)
-  include(Check64bitAssembly)
-  check_64bit_assembly()
-  if(HAS_64BIT_ASM)
+  include(CheckX86_64Assembly)
+  check_x86_64_assembly()
+  if(HAVE_X86_64_ASM)
     set(SECP256K1_ASM "x86_64")
-    add_definitions(-DUSE_ASM_X86_64=1)
+    add_compile_definitions(USE_ASM_X86_64=1)
   elseif(SECP256K1_ASM STREQUAL "AUTO")
     set(SECP256K1_ASM "OFF")
   else()
@@ -105,8 +129,8 @@ endif()
 
 option(SECP256K1_EXPERIMENTAL "Allow experimental configuration options." OFF)
 if(NOT SECP256K1_EXPERIMENTAL)
-  if(SECP256K1_ASM STREQUAL "arm")
-    message(FATAL_ERROR "ARM assembly optimization is experimental. Use -DSECP256K1_EXPERIMENTAL=ON to allow.")
+  if(SECP256K1_ASM STREQUAL "arm32")
+    message(FATAL_ERROR "ARM32 assembly optimization is experimental. Use -DSECP256K1_EXPERIMENTAL=ON to allow.")
   endif()
 endif()
 
@@ -116,7 +140,7 @@ if(SECP256K1_ENABLE_MODULE_FROST)
   if(NOT SECP256K1_EXPERIMENTAL)
     message(FATAL_ERROR "FROST module is experimental. Use -DSECP256K1_EXPERIMENTAL=ON to allow.")
   else()
-    add_definitions(-DENABLE_MODULE_FROST=1)
+    add_compile_definitions(ENABLE_MODULE_FROST=1)
   endif()
 endif()
 # FROST_SPECIFIC - END
@@ -129,7 +153,7 @@ if(SECP256K1_VALGRIND)
   if(Valgrind_FOUND)
     set(SECP256K1_VALGRIND ON)
     include_directories(${Valgrind_INCLUDE_DIR})
-    add_definitions(-DVALGRIND)
+    add_compile_definitions(VALGRIND)
   elseif(SECP256K1_VALGRIND STREQUAL "AUTO")
     set(SECP256K1_VALGRIND OFF)
   else()
@@ -176,42 +200,47 @@ mark_as_advanced(
   CMAKE_SHARED_LINKER_FLAGS_COVERAGE
 )
 
-if(CMAKE_CONFIGURATION_TYPES)
-  set(CMAKE_CONFIGURATION_TYPES "RelWithDebInfo" "Release" "Debug" "MinSizeRel" "Coverage")
-endif()
-
-get_property(cached_cmake_build_type CACHE CMAKE_BUILD_TYPE PROPERTY TYPE)
-if(cached_cmake_build_type)
+get_property(is_multi_config GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
+set(default_build_type "RelWithDebInfo")
+if(is_multi_config)
+  set(CMAKE_CONFIGURATION_TYPES "${default_build_type}" "Release" "Debug" "MinSizeRel" "Coverage" CACHE STRING
+    "Supported configuration types."
+    FORCE
+  )
+else()
   set_property(CACHE CMAKE_BUILD_TYPE PROPERTY
-    STRINGS "RelWithDebInfo" "Release" "Debug" "MinSizeRel" "Coverage"
+    STRINGS "${default_build_type}" "Release" "Debug" "MinSizeRel" "Coverage"
   )
+  if(NOT CMAKE_BUILD_TYPE)
+    message(STATUS "Setting build type to \"${default_build_type}\" as none was specified")
+    set(CMAKE_BUILD_TYPE "${default_build_type}" CACHE STRING
+      "Choose the type of build."
+      FORCE
+    )
+  endif()
 endif()
 
-set(default_build_type "RelWithDebInfo")
-if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
-  message(STATUS "Setting build type to \"${default_build_type}\" as none was specified")
-  set(CMAKE_BUILD_TYPE "${default_build_type}" CACHE STRING "Choose the type of build." FORCE)
-endif()
-
-include(TryAddCompileOption)
+include(TryAppendCFlags)
 if(MSVC)
-  try_add_compile_option(/W2)
-  try_add_compile_option(/wd4146)
+  # Keep the following commands ordered lexicographically.
+  try_append_c_flags(/W2) # Moderate warning level.
+  try_append_c_flags(/wd4146) # Disable warning C4146 "unary minus operator applied to unsigned type, result still unsigned".
 else()
-  try_add_compile_option(-pedantic)
-  try_add_compile_option(-Wall)
-  try_add_compile_option(-Wcast-align)
-  try_add_compile_option(-Wcast-align=strict)
-  try_add_compile_option(-Wconditional-uninitialized)
-  try_add_compile_option(-Wextra)
-  try_add_compile_option(-Wnested-externs)
-  try_add_compile_option(-Wno-long-long)
-  try_add_compile_option(-Wno-overlength-strings)
-  try_add_compile_option(-Wno-unused-function)
-  try_add_compile_option(-Wreserved-identifier)
-  try_add_compile_option(-Wshadow)
-  try_add_compile_option(-Wstrict-prototypes)
-  try_add_compile_option(-Wundef)
+  # Keep the following commands ordered lexicographically.
+  try_append_c_flags(-pedantic)
+  try_append_c_flags(-Wall) # GCC >= 2.95 and probably many other compilers.
+  try_append_c_flags(-Wcast-align) # GCC >= 2.95.
+  try_append_c_flags(-Wcast-align=strict) # GCC >= 8.0.
+  try_append_c_flags(-Wconditional-uninitialized) # Clang >= 3.0 only.
+  try_append_c_flags(-Wextra) # GCC >= 3.4, this is the newer name of -W, which we don't use because older GCCs will warn about unused functions.
+  try_append_c_flags(-Wnested-externs)
+  try_append_c_flags(-Wno-long-long) # GCC >= 3.0, -Wlong-long is implied by -pedantic.
+  try_append_c_flags(-Wno-overlength-strings) # GCC >= 4.2, -Woverlength-strings is implied by -pedantic.
+  try_append_c_flags(-Wno-unused-function) # GCC >= 3.0, -Wunused-function is implied by -Wall.
+  try_append_c_flags(-Wreserved-identifier) # Clang >= 13.0 only.
+  try_append_c_flags(-Wshadow)
+  try_append_c_flags(-Wstrict-prototypes)
+  try_append_c_flags(-Wundef)
 endif()
 
 set(CMAKE_C_VISIBILITY_PRESET hidden)
@@ -236,8 +265,13 @@ message("\n")
 message("secp256k1 configure summary")
 message("===========================")
 message("Build artifacts:")
-message("  shared library ...................... ${SECP256K1_BUILD_SHARED}")
-message("  static library ...................... ${SECP256K1_BUILD_STATIC}")
+if(BUILD_SHARED_LIBS)
+  set(library_type "Shared")
+else()
+  set(library_type "Static")
+endif()
+
+message("  library type ........................ ${library_type}")
 message("Optional modules:")
 message("  ECDH ................................ ${SECP256K1_ENABLE_MODULE_ECDH}")
 message("  ECDSA pubkey recovery ............... ${SECP256K1_ENABLE_MODULE_RECOVERY}")
@@ -282,15 +316,15 @@ message("CFLAGS ................................ ${CMAKE_C_FLAGS}")
 get_directory_property(compile_options COMPILE_OPTIONS)
 string(REPLACE ";" " " compile_options "${compile_options}")
 message("Compile options ....................... " ${compile_options})
-if(DEFINED CMAKE_BUILD_TYPE)
+if(NOT is_multi_config)
   message("Build type:")
   message(" - CMAKE_BUILD_TYPE ................... ${CMAKE_BUILD_TYPE}")
   string(TOUPPER "${CMAKE_BUILD_TYPE}" build_type)
   message(" - CFLAGS ............................. ${CMAKE_C_FLAGS_${build_type}}")
   message(" - LDFLAGS for executables ............ ${CMAKE_EXE_LINKER_FLAGS_${build_type}}")
   message(" - LDFLAGS for shared libraries ....... ${CMAKE_SHARED_LINKER_FLAGS_${build_type}}")
 else()
-  message("Available configurations .............. ${CMAKE_CONFIGURATION_TYPES}")
+  message("Supported configurations .............. ${CMAKE_CONFIGURATION_TYPES}")
   message("RelWithDebInfo configuration:")
   message(" - CFLAGS ............................. ${CMAKE_C_FLAGS_RELWITHDEBINFO}")
   message(" - LDFLAGS for executables ............ ${CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO}")

CMakePresets.json

@@ -0,0 +1,19 @@
+{
+  "cmakeMinimumRequired": {"major": 3, "minor": 21, "patch": 0}, 
+  "version": 3,
+  "configurePresets": [
+    {
+      "name": "dev-mode",
+      "displayName": "Development mode (intended only for developers of the library)",
+      "cacheVariables": {
+        "SECP256K1_EXPERIMENTAL": "ON",
+        "SECP256K1_ENABLE_MODULE_RECOVERY": "ON",
+        "SECP256K1_BUILD_EXAMPLES": "ON"
+      },
+      "warnings": {
+        "dev": true,
+        "uninitialized": true
+      }
+    }
+  ]
+}