fix read_reg

cpu.c

@@ -63,10 +63,6 @@ int libafl_qemu_write_reg(int reg, uint8_t* val)
         return 0;
     }
 
-    if (libafl_qemu_mem_buf == NULL) {
-        libafl_qemu_mem_buf = g_byte_array_sized_new(64);
-    }
-
     CPUClass *cc = CPU_GET_CLASS(cpu);
     if (reg < cc->gdb_num_core_regs) {
         return cc->gdb_write_register(cpu, val, reg);
@@ -81,6 +77,10 @@ int libafl_qemu_read_reg(int reg, uint8_t* val)
         return 0;
     }
 
+    if (libafl_qemu_mem_buf == NULL) {
+        libafl_qemu_mem_buf = g_byte_array_sized_new(64);
+    }
+
     CPUClass *cc = CPU_GET_CLASS(cpu);
     if (reg < cc->gdb_num_core_regs) {
         int len = cc->gdb_read_register(cpu, libafl_qemu_mem_buf, reg);

qemu_libafl_bridge/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "qemu_libafl_bridge"
-version = "0.2.1"
+version = "0.2.2"
 authors = ["Andrea Fioraldi <andreafioraldi@gmail.com>"]
 description = "QEMU and LibAFL bridge lib"
 repository = "https://github.com/AFLplusplus/qemu-libafl-bridge/"

qemu_libafl_bridge/src/amd64.rs

@@ -5,13 +5,13 @@ use num_enum::{IntoPrimitive, TryFromPrimitive};
 #[allow(clippy::pub_enum_variant_names)]
 pub enum Amd64Regs {
     Rax = 0,
-    Rcx = 1,
-    Rdx = 2,
-    Rbx = 3,
-    Rsp = 4,
-    Rbp = 5,
-    Rsi = 6,
-    Rdi = 7,
+    Rbx = 1,
+    Rcx = 2,
+    Rdx = 3,
+    Rsi = 4,
+    Rdi = 5,
+    Rbp = 6,
+    Rsp = 7,
     R8 = 8,
     R9 = 9,
     R10 = 10,

qemu_libafl_bridge/src/lib.rs

@@ -2,6 +2,7 @@ use core::{mem::transmute, ptr::copy_nonoverlapping};
 use num::Num;
 
 pub mod amd64;
+pub mod x86;
 
 /*
   int libafl_qemu_write_reg(int reg, uint8_t* val);

qemu_libafl_bridge/src/x86.rs

@@ -0,0 +1,15 @@
+use num_enum::{IntoPrimitive, TryFromPrimitive};
+
+#[derive(IntoPrimitive, TryFromPrimitive, Clone, Copy)]
+#[repr(i32)]
+#[allow(clippy::pub_enum_variant_names)]
+pub enum X86Regs {
+    Eax = 0,
+    Ebx = 1,
+    Ecx = 2,
+    Edx = 3,
+    Esi = 4,
+    Edi = 5,
+    Ebp = 6,
+    Esp = 7,
+}