From 5d5ee85928fe710127a6341622f706e691daea08 Mon Sep 17 00:00:00 2001 From: Andrea Fioraldi Date: Thu, 12 Sep 2019 19:56:12 +0200 Subject: qemu mode readme update --- qemu_mode/README.md | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/qemu_mode/README.md b/qemu_mode/README.md index afa2595a..3b714a6a 100644 --- a/qemu_mode/README.md +++ b/qemu_mode/README.md @@ -64,15 +64,16 @@ which can be a huge speed improvement. Note that the specified address must be an address of a basic block. QEMU mode support also persistent mode for x86 and x86_64 targets. -The environment variable to enable it is AFL_QEMU_PERSISTENT_ADDR=. +The environment variable to enable it is AFL_QEMU_PERSISTENT_ADDR=`start addr`. In this variable you must specify the address of the function that must be the body of the persistent loop. The return address on stack is patched like in WinAFL in order to repeat the execution of such function. Another modality to execute the persistent loop is to specify also the -AFL_QEMU_PERSISTENT_RET= env variable. +AFL_QEMU_PERSISTENT_RET=`end addr` env variable. With this variable assigned, instead of patching the return address, the -specified instruction is transformed to a jump towards . +specified instruction is transformed to a jump towards `start addr`. +Note that the format of the addresses in such variables is hex. Note that the base address of PIE binaries in QEMU user is 0x4000000000. -- cgit 1.4.1