Add text layout randomization

Purdue-eCTF · Mar 4, 2024 · 25ff703 · 25ff703
1 parent 80ef547
commit 25ff703
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Showing 5 changed files with 37 additions and 36 deletions.
diff --git a/application_processor/build.rs b/application_processor/build.rs
@@ -177,8 +177,9 @@ fn main() {
 
         let stack_start = ram_origin + (ram_length/4) + gen_addr(0, max_spacing, &mut rng);
 
-        let stext = 0x1000e200;
-
+        let sentry = gen_addr(0, max_spacing, &mut rng);
+
+        let textoffset = gen_addr(0, max_spacing, &mut rng);
         let rodataoffset = gen_addr(0, max_spacing, &mut rng);
         let dataoffset = gen_addr(0, max_spacing, &mut rng);
         let bssoffset = gen_addr(0, max_spacing, &mut rng);
@@ -192,15 +193,17 @@ fn main() {
             }}
             
             /* Bootloader jumps to this address to start the ap */
-            _stext = {stext:#x};
-            
+            _sentry = {sentry:#x};
+
             rodataoffset = {rodataoffset:#x};
 
             _stack_start = {stack_start:#x};
             dataoffset = {dataoffset:#x};
             bssoffset = {bssoffset:#x};
+            textoffset = {textoffset:#x};
         ");
 
+
         File::create(out.join("memory.x"))
             .unwrap()
             .write_all(memory_x.as_bytes())

diff --git a/application_processor/link.x b/application_processor/link.x
@@ -87,13 +87,20 @@ SECTIONS
     KEEP(*(.vector_table.interrupts)); /* this is the `__INTERRUPTS` symbol */
   } > FLASH
 
-  PROVIDE(_stext = ADDR(.vector_table) + SIZEOF(.vector_table));
 
+  .entry _sentry:
+  {
+    .__sentry = .;
+    *(.Reset);
+    .__eentry = .;
+
+  } > FLASH
+
   /* ### .text */
-  .text _stext :
+  .text :
   {
+    . = . + textoffset;
     __stext = .;
-    *(.Reset);
 
     *(.text .text.*);
 
@@ -251,15 +258,6 @@ Possible solutions, from most likely to less likely:
 may be enabling it)
 - Supply the interrupt handlers yourself. Check the documentation for details.");
 
-/* ## .text */
-ASSERT(ADDR(.vector_table) + SIZEOF(.vector_table) <= _stext, "
-ERROR(cortex-m-rt): The .text section can't be placed inside the .vector_table section
-Set _stext to an address greater than the end of .vector_table (See output of `nm`)");
-
-ASSERT(_stext + SIZEOF(.text) < ORIGIN(FLASH) + LENGTH(FLASH), "
-ERROR(cortex-m-rt): The .text section must be placed inside the FLASH memory.
-Set _stext to an address smaller than 'ORIGIN(FLASH) + LENGTH(FLASH)'");
-
 /* # Other checks */
 ASSERT(SIZEOF(.got) == 0, "
 ERROR(cortex-m-rt): .got section detected in the input object files

diff --git a/component/build.rs b/component/build.rs
@@ -156,8 +156,9 @@ fn main() {
 
         let stack_start = ram_origin + (ram_length/4) + gen_addr(0, max_spacing, &mut rng);
 
-        let stext = 0x1000e200;
-
+        let sentry = gen_addr(0, max_spacing, &mut rng);
+
+        let textoffset = gen_addr(0, max_spacing, &mut rng);
         let rodataoffset = gen_addr(0, max_spacing, &mut rng);
         let dataoffset = gen_addr(0, max_spacing, &mut rng);
         let bssoffset = gen_addr(0, max_spacing, &mut rng);
@@ -171,13 +172,14 @@ fn main() {
             }}
             
             /* Bootloader jumps to this address to start the ap */
-            _stext = {stext:#x};
-            
+            _sentry = {sentry:#x};
+
             rodataoffset = {rodataoffset:#x};
 
             _stack_start = {stack_start:#x};
             dataoffset = {dataoffset:#x};
             bssoffset = {bssoffset:#x};
+            textoffset = {textoffset:#x};
         ");
 
 

diff --git a/component/inc/ectf_params.h b/component/inc/ectf_params.h
@@ -1,8 +1,8 @@
 #ifndef __ECTF_PARAMS__
 #define __ECTF_PARAMS__
-#define COMPONENT_ID 0x11111125
-#define COMPONENT_BOOT_MSG "component a"
-#define ATTESTATION_LOC "detroit"
+#define COMPONENT_ID 0x11111126
+#define COMPONENT_BOOT_MSG "component b"
+#define ATTESTATION_LOC "honolulu"
 #define ATTESTATION_DATE "1/1/2069"
-#define ATTESTATION_CUSTOMER "bobs warehouse"
+#define ATTESTATION_CUSTOMER "sea anenome"
 #endif
diff --git a/component/link.x b/component/link.x
@@ -87,13 +87,20 @@ SECTIONS
     KEEP(*(.vector_table.interrupts)); /* this is the `__INTERRUPTS` symbol */
   } > FLASH
 
-  PROVIDE(_stext = ADDR(.vector_table) + SIZEOF(.vector_table));
 
+  .entry _sentry:
+  {
+    .__sentry = .;
+    *(.Reset);
+    .__eentry = .;
+
+  } > FLASH
+
   /* ### .text */
-  .text _stext :
+  .text :
   {
+    . = . + textoffset;
     __stext = .;
-    *(.Reset);
 
     *(.text .text.*);
 
@@ -251,15 +258,6 @@ Possible solutions, from most likely to less likely:
 may be enabling it)
 - Supply the interrupt handlers yourself. Check the documentation for details.");
 
-/* ## .text */
-ASSERT(ADDR(.vector_table) + SIZEOF(.vector_table) <= _stext, "
-ERROR(cortex-m-rt): The .text section can't be placed inside the .vector_table section
-Set _stext to an address greater than the end of .vector_table (See output of `nm`)");
-
-ASSERT(_stext + SIZEOF(.text) < ORIGIN(FLASH) + LENGTH(FLASH), "
-ERROR(cortex-m-rt): The .text section must be placed inside the FLASH memory.
-Set _stext to an address smaller than 'ORIGIN(FLASH) + LENGTH(FLASH)'");
-
 /* # Other checks */
 ASSERT(SIZEOF(.got) == 0, "
 ERROR(cortex-m-rt): .got section detected in the input object files