[FFmpeg-devel] [PATCH 1/3] tools/target_dec_fuzzer: Limit number off all pixels decoded

Michael Niedermayer michael at niedermayer.cc
Wed Jul 31 11:52:32 EEST 2019


This should reduces the number of uninteresting timeouts encountered

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 tools/target_dec_fuzzer.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tools/target_dec_fuzzer.c b/tools/target_dec_fuzzer.c
index 8ba25b4e8a..0c398da95b 100644
--- a/tools/target_dec_fuzzer.c
+++ b/tools/target_dec_fuzzer.c
@@ -128,6 +128,8 @@ static void FDBPrepare(FuzzDataBuffer *FDB, AVPacket *dst, const uint8_t *data,
 
 // Ensure we don't loop forever
 const uint32_t maxiteration = 8096;
+const uint64_t maxpixels_per_frame = 4096 * 4096;
+const uint64_t maxpixels           = maxpixels_per_frame * maxiteration / 8;
 
 static const uint64_t FUZZ_TAG = 0x4741542D5A5A5546ULL;
 
@@ -171,7 +173,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
     if (!ctx || !parser_avctx)
         error("Failed memory allocation");
 
-    ctx->max_pixels = 4096 * 4096; //To reduce false positive OOM and hangs
+    ctx->max_pixels = maxpixels_per_frame; //To reduce false positive OOM and hangs
 
     if (size > 1024) {
         GetByteContext gbc;
@@ -260,6 +262,8 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
             ec_pixels += ctx->width * ctx->height;
             if (it > 20 || ec_pixels > 4 * ctx->max_pixels)
                 ctx->error_concealment = 0;
+            if (ec_pixels > maxpixels)
+                goto maximums_reached;
 
             if (ret <= 0 || ret > avpkt.size)
                break;
@@ -270,6 +274,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
           }
         }
     }
+maximums_reached:
 
     av_init_packet(&avpkt);
     avpkt.data = NULL;
-- 
2.22.0



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