From 20e92f7d40740bb2d55fd6f8177b6b6ceb3bc88a Mon Sep 17 00:00:00 2001
From: Vincent Rabaud <vrabaud@google.com>
Date: Thu, 6 Jun 2024 11:57:39 +0200
Subject: [PATCH] Limit the possible fuzz engines.

Change-Id: I8f2fd84bc7175e4e74c4fb418fcc4f5549018ac3
---
 tests/fuzzer/oss-fuzz/build.sh | 56 ++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 27 deletions(-)

diff --git a/tests/fuzzer/oss-fuzz/build.sh b/tests/fuzzer/oss-fuzz/build.sh
index e8c34eca..6f233ab2 100644
--- a/tests/fuzzer/oss-fuzz/build.sh
+++ b/tests/fuzzer/oss-fuzz/build.sh
@@ -34,10 +34,15 @@
 # And then run the fuzzer locally, for example:
 #     python3 infra/helper.py run_fuzzer libwebp \
 #     --sanitizer address \
-#     animencoder_fuzzer__AnimEncoder.AnimEncoderTest
+#     animencoder_fuzzer@AnimEncoder.AnimEncoderTest
 
 set -eu
 
+# Avoid fuzz engines that do not compile.
+if [[ "$FUZZING_ENGINE" != "libfuzzer" ]]; then
+  exit
+fi
+
 # limit allocation size to reduce spurious OOMs
 WEBP_CFLAGS="$CFLAGS -DWEBP_MAX_IMAGE_SIZE=838860800" # 800MiB
 
@@ -48,36 +53,33 @@ cd build && make -j$(nproc) && cd ..
 find $SRC/libwebp-test-data -type f -size -32k -iname "*.webp" \
   -exec zip -qju fuzz_seed_corpus.zip "{}" \;
 
-# Restrict fuzztest tests to the only compatible fuzz engine: libfuzzer.
-if [[ "$FUZZING_ENGINE" == "libfuzzer" ]]; then
-  # build fuzztests
-  # The following is taken from https://github.com/google/oss-fuzz/blob/31ac7244748ea7390015455fb034b1f4eda039d9/infra/base-images/base-builder/compile_fuzztests.sh#L59
-  # Iterate the fuzz binaries and list each fuzz entrypoint in the binary. For
-  # each entrypoint create a wrapper script that calls into the binaries the
-  # given entrypoint as argument.
-  # The scripts will be named:
-  # {binary_name}@{fuzztest_entrypoint}
-  FUZZ_TEST_BINARIES_OUT_PATHS=$(find ./build/tests/fuzzer/ -executable -type f)
-  echo "Fuzz binaries: $FUZZ_TEST_BINARIES_OUT_PATHS"
-  for fuzz_main_file in $FUZZ_TEST_BINARIES_OUT_PATHS; do
-    FUZZ_TESTS=$($fuzz_main_file --list_fuzz_tests | cut -d ' ' -f 4)
-    cp -f ${fuzz_main_file} $OUT/
-    fuzz_basename=$(basename $fuzz_main_file)
-    chmod -x $OUT/$fuzz_basename
-    for fuzz_entrypoint in $FUZZ_TESTS; do
-      TARGET_FUZZER="${fuzz_basename}@$fuzz_entrypoint"
-      # Write executer script
-      echo "#!/bin/sh
+# build fuzztests
+# The following is taken from https://github.com/google/oss-fuzz/blob/31ac7244748ea7390015455fb034b1f4eda039d9/infra/base-images/base-builder/compile_fuzztests.sh#L59
+# Iterate the fuzz binaries and list each fuzz entrypoint in the binary. For
+# each entrypoint create a wrapper script that calls into the binaries the
+# given entrypoint as argument.
+# The scripts will be named:
+# {binary_name}@{fuzztest_entrypoint}
+FUZZ_TEST_BINARIES_OUT_PATHS=$(find ./build/tests/fuzzer/ -executable -type f)
+echo "Fuzz binaries: $FUZZ_TEST_BINARIES_OUT_PATHS"
+for fuzz_main_file in $FUZZ_TEST_BINARIES_OUT_PATHS; do
+  FUZZ_TESTS=$($fuzz_main_file --list_fuzz_tests | cut -d ' ' -f 4)
+  cp -f ${fuzz_main_file} $OUT/
+  fuzz_basename=$(basename $fuzz_main_file)
+  chmod -x $OUT/$fuzz_basename
+  for fuzz_entrypoint in $FUZZ_TESTS; do
+    TARGET_FUZZER="${fuzz_basename}@$fuzz_entrypoint"
+    # Write executer script
+    echo "#!/bin/sh
 # LLVMFuzzerTestOneInput for fuzzer detection.
 this_dir=\$(dirname \"\$0\")
 export TEST_DATA_DIRS=\$this_dir/corpus
 chmod +x \$this_dir/$fuzz_basename
 \$this_dir/$fuzz_basename --fuzz=$fuzz_entrypoint -- \$@
 chmod -x \$this_dir/$fuzz_basename" > $OUT/$TARGET_FUZZER
-      chmod +x $OUT/$TARGET_FUZZER
-    done
-  # Copy data.
-  cp fuzz_seed_corpus.zip $OUT/${fuzz_basename}_seed_corpus.zip
-  cp tests/fuzzer/fuzz.dict $OUT/${fuzz_basename}.dict
+    chmod +x $OUT/$TARGET_FUZZER
   done
-fi
+# Copy data.
+cp fuzz_seed_corpus.zip $OUT/${fuzz_basename}_seed_corpus.zip
+cp tests/fuzzer/fuzz.dict $OUT/${fuzz_basename}.dict
+done