[scudo] Add a shared runtime

[cryptoad]

Summary

Up to now, the Scudo cmake target only provided a static library that had to be
linked to an executable to benefit from the hardened allocator.
This introduces a shared library as well, that can be LD_PRELOAD'ed.

[alekseyshl]

lib/scudo/CMakeLists.txt

38

Shouldn't this new block go under if(COMPILER_RT_HAS_SCUDO)?

[cryptoad]

Move SCUDO_DYNAMIC_LIBS under if(COMPILER_RT_HAS_SCUDO).

lib/scudo/CMakeLists.txt

 
 # Enable the AArch64 CRC32 feature for scudo_crc32.cpp, if available.
 # Note that it is enabled by default starting with armv8.1-a.
 if (COMPILER_RT_HAS_MCRC_FLAG)
   set_source_files_properties(scudo_crc32.cpp PROPERTIES COMPILE_FLAGS -mcrc)
 endif()
 
 if(COMPILER_RT_HAS_SCUDO)
+  set(SCUDO_DYNAMIC_LIBS ${SANITIZER_COMMON_LINK_LIBS})
+  append_list_if(COMPILER_RT_HAS_LIBDL dl SCUDO_DYNAMIC_LIBS)
+  append_list_if(COMPILER_RT_HAS_LIBRT rt SCUDO_DYNAMIC_LIBS)
+  append_list_if(COMPILER_RT_HAS_LIBPTHREAD pthread SCUDO_DYNAMIC_LIBS)
+  append_list_if(COMPILER_RT_HAS_LIBLOG log SCUDO_DYNAMIC_LIBS)
+
   foreach(arch ${SCUDO_SUPPORTED_ARCH})
     add_compiler_rt_runtime(clang_rt.scudo
       STATIC
       ARCHS ${arch}
       SOURCES ${SCUDO_SOURCES}
-              $<TARGET_OBJECTS:RTInterception.${arch}>
-              $<TARGET_OBJECTS:RTSanitizerCommonNoTermination.${arch}>
-              $<TARGET_OBJECTS:RTSanitizerCommonLibc.${arch}>
+      OBJECT_LIBS RTSanitizerCommonNoTermination
+                  RTSanitizerCommonLibc
+                  RTInterception
+      CFLAGS ${SCUDO_CFLAGS}
+      PARENT_TARGET scudo)
+
+    add_compiler_rt_runtime(clang_rt.scudo
+      SHARED
+      ARCHS ${arch}
+      SOURCES ${SCUDO_SOURCES}
+      OBJECT_LIBS RTSanitizerCommonNoTermination
+                  RTSanitizerCommonLibc
+                  RTInterception
       CFLAGS ${SCUDO_CFLAGS}
+      LINK_LIBS ${SCUDO_DYNAMIC_LIBS}
       PARENT_TARGET scudo)
   endforeach()
 endif()

test/scudo/lit.cfg

 # -*- Python -*-
 
 import os
 
 # Setup config name.
 config.name = 'Scudo' + config.name_suffix
 
 # Setup source root.
 config.test_source_root = os.path.dirname(__file__)
 
-# Path to the static library
-base_lib = os.path.join(config.compiler_rt_libdir,
-                        "libclang_rt.scudo-%s.a" % config.target_arch)
-whole_archive = "-Wl,-whole-archive %s -Wl,-no-whole-archive " % base_lib
+# Path to the shared & static libraries
+shared_libscudo = os.path.join(config.compiler_rt_libdir, "libclang_rt.scudo-%s.so" % config.target_arch)
+static_libscudo = os.path.join(config.compiler_rt_libdir, "libclang_rt.scudo-%s.a" % config.target_arch)
+whole_archive = "-Wl,-whole-archive %s -Wl,-no-whole-archive " % static_libscudo
 
 # Test suffixes.
 config.suffixes = ['.c', '.cc', '.cpp']
 
 # C flags.
 c_flags = ([config.target_cflags] +
            ["-std=c++11",
            "-pthread",
            "-fPIE",
            "-pie",
            "-O0",
            "-UNDEBUG",
            "-ldl",
            "-Wl,--gc-sections"])
 
 # Android doesn't want -lrt.
 if not config.android:
   c_flags += ["-lrt"]
 
 def build_invocation(compile_flags):                                            
   return " " + " ".join([config.compile_wrapper, config.clang] + compile_flags) + " "                   
 
 # Add clang substitutions.
-config.substitutions.append(("%clang_scudo ",
-                             build_invocation(c_flags) + whole_archive))
+config.substitutions.append(("%clang ", build_invocation(c_flags)))
+config.substitutions.append(("%clang_scudo ", build_invocation(c_flags) + whole_archive))
+config.substitutions.append(("%shared_libscudo", shared_libscudo))
 
 # Platform-specific default SCUDO_OPTIONS for lit tests.
 default_scudo_opts = ''
 if config.android:
   # Android defaults to abort_on_error=1, which doesn't work for us.
   default_scudo_opts = 'abort_on_error=0'
 
 if default_scudo_opts:
   config.environment['SCUDO_OPTIONS'] = default_scudo_opts
   default_scudo_opts += ':'
 config.substitutions.append(('%env_scudo_opts=',
                              'env SCUDO_OPTIONS=' + default_scudo_opts))
 
 # Hardened Allocator tests are currently supported on Linux only.
 if config.host_os not in ['Linux']:
    config.unsupported = True

test/scudo/preload.cpp

+// Test that the preloaded runtime works without linking the static library.
+
+// RUN: %clang %s -o %t
+// RUN: env LD_PRELOAD=%shared_libscudo not %run %t 2>&1 | FileCheck %s
+
+// This way of setting LD_PRELOAD does not work with Android test runner.
+// REQUIRES: !android
+
+#include <assert.h>
+#include <stdlib.h>
+
+int main(int argc, char *argv[]) {
+  void *p = malloc(sizeof(int));
+  assert(p);
+  free(p);
+  free(p);
+  return 0;
+}
+
+// CHECK: ERROR: invalid chunk state