From a1458ea6715e8801bf28fec0ac66f06b96eb1e66 Mon Sep 17 00:00:00 2001 From: WorksButNotTested <62701594+WorksButNotTested@users.noreply.github.com> Date: Thu, 20 May 2021 18:16:58 +0100 Subject: Changes to have persistent mode exit at the end of the loop (#928) Co-authored-by: Your Name --- frida_mode/src/persistent/persistent_x86.c | 40 ++++++------------------------ 1 file changed, 7 insertions(+), 33 deletions(-) (limited to 'frida_mode/src/persistent/persistent_x86.c') diff --git a/frida_mode/src/persistent/persistent_x86.c b/frida_mode/src/persistent/persistent_x86.c index bd7171b9..20a3dc42 100644 --- a/frida_mode/src/persistent/persistent_x86.c +++ b/frida_mode/src/persistent/persistent_x86.c @@ -39,7 +39,6 @@ struct x86_regs { typedef struct x86_regs arch_api_regs; static arch_api_regs saved_regs = {0}; -static void * saved_return = NULL; gboolean persistent_is_supported(void) { @@ -138,36 +137,12 @@ static void instrument_persitent_restore_regs(GumX86Writer * cw, } -static void instrument_save_ret(GumX86Writer *cw, void **saved_return_ptr) { +static void instrument_exit(GumX86Writer *cw) { - GumAddress saved_return_address = GUM_ADDRESS(saved_return_ptr); - - gum_x86_writer_put_push_reg(cw, GUM_REG_EAX); - gum_x86_writer_put_push_reg(cw, GUM_REG_EBX); - - gum_x86_writer_put_mov_reg_address(cw, GUM_REG_EAX, saved_return_address); - gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_EBX, GUM_REG_ESP, 0x8); - gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_EAX, 0, GUM_REG_EBX); - - gum_x86_writer_put_pop_reg(cw, GUM_REG_EBX); - gum_x86_writer_put_pop_reg(cw, GUM_REG_EAX); - -} - -static void instrument_jump_ret(GumX86Writer *cw, void **saved_return_ptr) { - - GumAddress saved_return_address = GUM_ADDRESS(saved_return_ptr); - - /* Place holder for ret */ - gum_x86_writer_put_push_reg(cw, GUM_REG_EAX); - gum_x86_writer_put_push_reg(cw, GUM_REG_EAX); - - gum_x86_writer_put_mov_reg_address(cw, GUM_REG_EAX, saved_return_address); - gum_x86_writer_put_mov_reg_reg_offset_ptr(cw, GUM_REG_EAX, GUM_REG_EAX, 0); - - gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_ESP, 0x4, GUM_REG_EAX); - gum_x86_writer_put_pop_reg(cw, GUM_REG_EAX); - gum_x86_writer_put_ret(cw); + gum_x86_writer_put_mov_reg_address(cw, GUM_REG_EAX, GUM_ADDRESS(_exit)); + gum_x86_writer_put_mov_reg_u32(cw, GUM_REG_EDI, 0); + gum_x86_writer_put_push_reg(cw, GUM_REG_EDI); + gum_x86_writer_put_call_reg(cw, GUM_REG_EAX); } @@ -238,8 +213,7 @@ void persistent_prologue(GumStalkerOutput *output) { /* Stack must be 16-byte aligned per ABI */ instrument_persitent_save_regs(cw, &saved_regs); - /* Stash and pop the return value */ - instrument_save_ret(cw, &saved_return); + /* Pop the return value */ gum_x86_writer_put_lea_reg_reg_offset(cw, GUM_REG_ESP, GUM_REG_ESP, (4)); /* loop: */ @@ -265,7 +239,7 @@ void persistent_prologue(GumStalkerOutput *output) { /* done: */ gum_x86_writer_put_label(cw, done); - instrument_jump_ret(cw, &saved_return); + instrument_exit(cw); /* original: */ gum_x86_writer_put_label(cw, original); -- cgit 1.4.1