Decouple EXIV2_BUILD_FUZZ_TESTS from EXIV2_TEAM_USE_SANITIZERS.

CMakeLists.txt

@@ -93,10 +93,6 @@ if( EXIV2_BUILD_UNIT_TESTS )
 endif()
 
 if( EXIV2_BUILD_FUZZ_TESTS )
-    if ((NOT COMPILER_IS_CLANG) OR (NOT EXIV2_TEAM_USE_SANITIZERS))
-        message(FATAL_ERROR "You need to build with Clang and sanitizers for the fuzzers to work. "
-                "Use Clang and -DEXIV2_TEAM_USE_SANITIZERS=ON")
-    endif()
     add_subdirectory ( fuzz )
 endif()
 

cmake/compilerFlags.cmake

@@ -70,6 +70,17 @@ if ( MINGW OR UNIX OR MSYS ) # MINGW, Linux, APPLE, CYGWIN
         # This seems to be causing issues in the Fedora_MinGW GitLab job
         #add_compile_options(-fasynchronous-unwind-tables)
 
+        if( EXIV2_BUILD_FUZZ_TESTS )
+            if (NOT COMPILER_IS_CLANG)
+                message(FATAL_ERROR "You need to build with Clang for the fuzzers to work. "
+                        "Use Clang")
+            endif()
+            set(FUZZER_FLAGS "-fsanitize=fuzzer-no-link")
+            set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${FUZZER_FLAGS}")
+            set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${FUZZER_FLAGS}")
+            set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${FUZZER_FLAGS}")
+            set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} ${FUZZER_FLAGS}")
+        endif()
 
         if ( EXIV2_TEAM_USE_SANITIZERS )
             # ASAN is available in gcc from 4.8 and UBSAN from 4.9
@@ -84,9 +95,7 @@ if ( MINGW OR UNIX OR MSYS ) # MINGW, Linux, APPLE, CYGWIN
                     set(SANITIZER_FLAGS "-fno-omit-frame-pointer -fsanitize=address")
                 endif()
             elseif( COMPILER_IS_CLANG )
-                if ( EXIV2_BUILD_FUZZ_TESTS )
-                    set(SANITIZER_FLAGS "-fsanitize=fuzzer-no-link,address,undefined")
-                elseif ( CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.9 )
+                if ( CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.9 )
                     set(SANITIZER_FLAGS "-fno-omit-frame-pointer -fsanitize=address,undefined -fno-sanitize-recover=all")
                 elseif ( CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 3.4 )
                     set(SANITIZER_FLAGS "-fno-omit-frame-pointer -fsanitize=address,undefined")

src/basicio.cpp

@@ -1357,7 +1357,9 @@ namespace Exiv2 {
     {
         long avail = std::max(p_->size_ - p_->idx_, 0L);
         long allow = std::min(rcount, avail);
-        std::memcpy(buf, &p_->data_[p_->idx_], allow);
+        if (allow > 0) {
+            std::memcpy(buf, &p_->data_[p_->idx_], allow);
+        }
         p_->idx_ += allow;
         if (rcount > avail) p_->eof_ = true;
         return allow;

src/jpgimage.cpp

@@ -948,8 +948,10 @@ namespace Exiv2 {
                        memcmp(buf.pData_ + 2, exifId_, 6) == 0) {
                 skipApp1Exif = count;
                 ++search;
-                rawExif.alloc(size - 8);
-                memcpy(rawExif.pData_, buf.pData_ + 8, size - 8);
+                if (size > 8) {
+                    rawExif.alloc(size - 8);
+                    memcpy(rawExif.pData_, buf.pData_ + 8, size - 8);
+                }
             } else if (skipApp1Xmp == notfound &&
                        marker == app1_ &&
                        size >= 31 && // prevent out-of-bounds read in memcmp on next line

src/pngimage.cpp

@@ -62,7 +62,11 @@ namespace
     inline bool compare(const char* str, const Exiv2::DataBuf& buf, size_t length)
     {
         assert(strlen(str) <= length);
-        return memcmp(str, buf.pData_, std::min(static_cast<long>(length), buf.size_)) == 0;
+        const long minlen = std::min(static_cast<long>(length), buf.size_);
+        if (minlen == 0) {
+            return true;
+        }
+        return memcmp(str, buf.pData_, minlen) == 0;
     }
 }  // namespace
 

src/tiffvisitor_int.cpp

@@ -744,8 +744,10 @@ namespace Exiv2 {
                       << " to offset area.\n";
 #endif
             memset(buf + 8, 0x0, 4);
-            memcpy(buf + 8, pTiffEntry->pData(), pTiffEntry->size());
-            memset(const_cast<byte*>(pTiffEntry->pData()), 0x0, pTiffEntry->size());
+            if (pTiffEntry->size() > 0) {
+                memcpy(buf + 8, pTiffEntry->pData(), pTiffEntry->size());
+                memset(const_cast<byte*>(pTiffEntry->pData()), 0x0, pTiffEntry->size());
+            }
         }
         return 12;
     }