webp_enc_dec: Clamp slow parameters for big images (#1854)

* Add new fuzz target for encoding and misc

- Add fuzz_webp_enc_dec and adapt Dockerfile, build.sh
- Lint existing targets
- Add license headers
- Increase fuzz.dict

* webp_enc_dec: Convert input images to inline C arrays

Local files are not available on oss-fuzz servers.

* webp_enc_dec: Fix timeout by skipping crusher

The target fuzz_webp_enc_dec with msan crashes (timeout)
on a 128*128px image encoding with max compression (crusher).
Reduce crusher encoding to 16*16px and below.
Bug report 10423

* webp_enc_dec: Replace cruncher by lossy alpha encoding

The target fuzz_webp_enc_dec with msan crashes (timeout)
during encoding with max compression (cruncher).
Reduce alpha cruncher encoding to 16*16px and below.
Bug report 10634

* webp_enc_dec: Clamp slow parameters for big images

The target fuzz_webp_enc_dec with ubsan crashes (timeout)
during encoding with heavy compression. The cause can not
be easily removed without reducing performance.
Clamp compression parameters for images bigger than 16*16.
Bug report 10700

2 files changed, 13 insertions, 9 deletions

diff --git a/projects/libwebp/Dockerfile b/projects/libwebp/Dockerfile
index 9345e07ec..b00a937e0 100644
--- a/projects/libwebp/Dockerfile
+++ b/projects/libwebp/Dockerfile
@@ -15,7 +15,7 @@
 ################################################################################
 
 FROM gcr.io/oss-fuzz-base/base-builder
-MAINTAINER pdknsk@gmail.com
+MAINTAINER yguyon@google.com
 RUN apt-get update && apt-get install -y autoconf make libtool zip
 RUN git clone https://chromium.googlesource.com/webm/libwebp
 RUN git clone https://chromium.googlesource.com/webm/libwebp-test-data
diff --git a/projects/libwebp/fuzz_webp_enc_dec.cc b/projects/libwebp/fuzz_webp_enc_dec.cc
index 993c554f9..84726eac3 100644
--- a/projects/libwebp/fuzz_webp_enc_dec.cc
+++ b/projects/libwebp/fuzz_webp_enc_dec.cc
@@ -181,14 +181,18 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
     }
   }
 
-  // Skip the cruncher except on small images, it's likely to timeout.
-  if (config.lossless && config.quality == 100. && config.method == 6 &&
-      pic.width * pic.height >= 16 * 16) {
-    config.lossless = 0;
-  }
-  if (config.alpha_quality == 100 && config.method == 6 &&
-      pic.width * pic.height >= 16 * 16) {
-    config.alpha_quality = 99;
+  // Skip slow settings on big images, it's likely to timeout.
+  if (pic.width * pic.height > 16 * 16) {
+    if (config.lossless) {
+      if (config.quality >= 99.0f && config.method >= 5) {
+        config.quality = 99.0f;
+        config.method = 5;
+      }
+    } else {
+      if (config.quality >= 99.0f && config.method == 6) {
+        config.quality = 99.0f;
+      }
+    }
   }
 
   // Encode.