zydis: Add more fuzzer targets (#6827)

Additionally, set `max_len` for all targets for improved performance.

projects/zydis/Dockerfile

@@ -1,4 +1,4 @@
-# Copyright 2020 Google Inc.
+# Copyright 2021 Google Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -16,8 +16,12 @@
 
 FROM gcr.io/oss-fuzz-base/base-builder
 
-ADD https://github.com/zyantific/zydis/raw/master/assets/ZydisFuzz_seed_corpus.zip \
-    $SRC/ZydisFuzz_seed_corpus.zip
+ADD https://zydis.re/fuzzing-corpora/ZydisFuzzDecoder_seed_corpus.zip \
+    $SRC/ZydisFuzzDecoder_seed_corpus.zip
+ADD https://zydis.re/fuzzing-corpora/ZydisFuzzEncoder_seed_corpus.zip \
+    $SRC/ZydisFuzzEncoder_seed_corpus.zip
+ADD https://zydis.re/fuzzing-corpora/ZydisFuzzReEncoding_seed_corpus.zip \
+    $SRC/ZydisFuzzReEncoding_seed_corpus.zip
 
 COPY build.sh $SRC/
 

projects/zydis/build.sh

@@ -1,5 +1,6 @@
 #!/bin/bash -eu
-# Copyright 2020 Google Inc.
+#
+# Copyright 2021 Google Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -15,33 +16,58 @@
 #
 ################################################################################
 
-mv $SRC/ZydisFuzz_seed_corpus.zip $OUT/ZydisFuzz_seed_corpus.zip
+set -eu
+
+#
+# Build Zydis library.
+#
 
 mkdir build && cd build
 
-cmake                                   \
-    -DZYAN_FORCE_ASSERTS=ON             \
-    -DZYDIS_BUILD_EXAMPLES=OFF          \
-    -DZYDIS_BUILD_TOOLS=OFF             \
-    -DCMAKE_BUILD_TYPE=RelWithDebInfo   \
-    -DCMAKE_C_COMPILER=$CC              \
-    -DCMAKE_CXX_COMPILER=$CXX           \
-    -DCMAKE_C_FLAGS="$CFLAGS"           \
-    -DCMAKE_CXX_FLAGS="$CXXFLAGS"       \
+cmake                                       \
+    -DZYAN_FORCE_ASSERTS=ON                 \
+    -DZYDIS_BUILD_EXAMPLES=OFF              \
+    -DZYDIS_BUILD_TOOLS=OFF                 \
+    -DCMAKE_BUILD_TYPE=RelWithDebInfo       \
+    "-DCMAKE_C_COMPILER=${CC}"              \
+    "-DCMAKE_CXX_COMPILER=${CXX}"           \
+    "-DCMAKE_C_FLAGS=${CFLAGS}"             \
+    "-DCMAKE_CXX_FLAGS=${CXXFLAGS}"         \
     ..
 
 make -j$(nproc) VERBOSE=1
 
-$CXX                                    \
-    $CXXFLAGS                           \
-    $LIB_FUZZING_ENGINE                 \
-    ../tools/ZydisFuzzDecoder.c         \
-    ../tools/ZydisFuzzShared.c          \
-    -DZYDIS_LIBFUZZER                   \
-    -o $OUT/ZydisFuzz                   \
-    -I .                                \
-    -I ./zycore                         \
-    -I ../include                       \
-    -I ../dependencies/zycore/include   \
-    ./libZydis.a
+#
+# Build fuzzing tools.
+#
 
+function build_fuzzer() {
+    source_file="${1}"
+    max_len="${2}"
+    executable="${source_file%.c}"
+
+    $CC                                     \
+        $CFLAGS                             \
+        "${LIB_FUZZING_ENGINE}"             \
+        "../tools/${source_file}"           \
+        ../tools/ZydisFuzzShared.c          \
+        -DZYDIS_LIBFUZZER                   \
+        -o "${OUT}/${executable}"           \
+        -I .                                \
+        -I ./zycore                         \
+        -I ../include                       \
+        -I ../dependencies/zycore/include   \
+        ./libZydis.a
+
+    echo -e "[libfuzzer]\nmax_len = ${max_len}" > "${OUT}/${executable}.options"
+}
+
+build_fuzzer "ZydisFuzzDecoder.c"    350
+build_fuzzer "ZydisFuzzEncoder.c"    450
+build_fuzzer "ZydisFuzzReEncoding.c" 100
+
+#
+# Place fuzzing corpora where they belong.
+#
+
+cp ${SRC}/Zydis*_seed_corpus.zip ${OUT}