Merge pull request #617 from AFLplusplus/dev

push to stable

1 files changed, 16 insertions, 0 deletions

diff --git a/utils/argv_fuzzing/README.md b/utils/argv_fuzzing/README.md
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+# argvfuzz
+
+afl supports fuzzing file inputs or stdin. When source is available,
+`argv-fuzz-inl.h` can be used to change `main()` to build argv from stdin.
+
+`argvfuzz` tries to provide the same functionality for binaries. When loaded
+using `LD_PRELOAD`, it will hook the call to `__libc_start_main` and replace
+argv using the same logic of `argv-fuzz-inl.h`.
+
+A few conditions need to be fulfilled for this mechanism to work correctly:
+
+1. As it relies on hooking the loader, it cannot work on static binaries.
+2. If the target binary does not use the default libc's `_start` implementation
+   (crt1.o), the hook may not run.
+3. The hook will replace argv with pointers to `.data` of `argvfuzz.so`. If the
+   target binary expects argv to be living on the stack, things may go wrong.