app/bench: Fix strlen scenario

README.md

@@ -255,16 +255,12 @@ $ make run
 ```
 
 To test timer single-stepping functionality, try for example building and
-running the `strlen` attack from the paper for a benchmark enclave that
-processes the secret string 100 repeated times:
+running a benchmark enclave to single-step a slide of 100 successive `nop`
+instructions:
 
 ```bash
 $ cd app/bench
-$ NUM=100 STRLEN=1 make parse   # alternatively vary NUM and use BENCH=1 or ZIGZAG=1
-$ # (above command defaults to the Dell Inspiron 13 7359 evaluation laptop machine;
-$ # use DESKTOP=1 to build for a Dell Optiplex 7040 machine)
-$ # use SGX_SDK=/home/jo/sgxsdk/ for a local SDK installation
-$ # use M32=1 To produce a 32-bit executable
+$ NUM=100 make parse   # alternatively vary NUM and use STRLEN=1 or ZIGZAG=1
 ```
 
 The above command builds `libsgxstep`, the benchmark victim enclave, and the

app/bench/main.c

@@ -133,8 +133,8 @@ void attacker_config_runtime(void) {
 void attacker_config_page_table(void) {
     void *code_adrs;
 #if (ATTACK_SCENARIO == STRLEN)
-    void *str_adrs;
-    str_adrs = get_symbol_offset("secret_str");
+    void *str_adrs = get_enclave_base();
+    str_adrs += get_symbol_offset("secret_str");
     info("enclave string adrs at %p", str_adrs);
     ASSERT(pte_str_encl = remap_page_table_level(str_adrs, PTE));
     ASSERT(PRESENT(*pte_str_encl));