random bit not in executable

src/Makefile.in

@@ -204,19 +204,10 @@ endif
 
 include $(CHIBIOS)/os/ports/GCC/ARM/rules.mk
 
-OBJS += random-data.o
 OUTFILES += random_bits
 
 random_bits:
 	dd if=/dev/random bs=1 of=random_bits count=1024
 
-random-data.o: random_bits
-	$(CP) -I binary $< -O elf32-littlearm -B arm \
-	      --rename-section \
-		.data=.gnuk_random,alloc,load,readonly,data,contents \
-		$@
-
-$(PROJECT).elf: random-data.o
-
 distclean: clean
 	-rm -f Makefile gnuk.ld config.h

src/flash.c

@@ -600,10 +600,11 @@ flash_check_blank (const uint8_t *page, int size)
 int
 flash_erase_binary (uint8_t file_id)
 {
-  const uint8_t *p = &ch_certificate_start;
+  const uint8_t *p;
 
   if (file_id == FILEID_CH_CERTIFICATE)
     {
+      p = &ch_certificate_start;
       if (flash_check_blank (p, FLASH_CH_CERTIFICATE_SIZE) == 0)
 	{
 	  flash_erase_page ((uint32_t)p);
@@ -612,6 +613,15 @@ flash_erase_binary (uint8_t file_id)
 #endif
 	}
 
+      return 0;
+    }
+  else if (file_id == FILEID_RANDOM)
+    {
+      p = &random_bits_start;
+
+      if (flash_check_blank (p, FLASH_PAGE_SIZE) == 0)
+	flash_erase_page ((uint32_t)p);
+
       return 0;
     }
   else
@@ -623,29 +633,39 @@ int
 flash_write_binary (uint8_t file_id, const uint8_t *data,
 		    uint16_t len, uint16_t offset)
 {
+  uint16_t maxsize;
+  const uint8_t *p;
+
   if (file_id == FILEID_CH_CERTIFICATE)
     {
-      if (offset + len > FLASH_CH_CERTIFICATE_SIZE || (offset&1) || (len&1))
-	return -1;
-      else
-	{
-	  const uint8_t *p = &ch_certificate_start;
-	  uint16_t hw;
-	  uint32_t addr;
-	  int i;
-
-	  addr = (uint32_t)p + offset;
-	  for (i = 0; i < len/2; i++)
-	    {
-	      hw = data[i*2] | (data[i*2+1]<<8);
-	      if (flash_program_halfword (addr, hw) != FLASH_COMPLETE)
-		flash_warning ("DO WRITE ERROR");
-	      addr += 2;
-	    }
-
-	  return 0;
-	}
+      maxsize = FLASH_CH_CERTIFICATE_SIZE;
+      p = &ch_certificate_start;
+    }
+  else if (file_id == FILEID_RANDOM)
+    {
+      maxsize = FLASH_PAGE_SIZE;
+      p = &random_bits_start;
     }
   else
     return -1;
+
+  if (offset + len > maxsize || (offset&1) || (len&1))
+    return -1;
+  else
+    {
+      uint16_t hw;
+      uint32_t addr;
+      int i;
+
+      addr = (uint32_t)p + offset;
+      for (i = 0; i < len/2; i++)
+	{
+	  hw = data[i*2] | (data[i*2+1]<<8);
+	  if (flash_program_halfword (addr, hw) != FLASH_COMPLETE)
+	    flash_warning ("DO WRITE ERROR");
+	  addr += 2;
+	}
+
+      return 0;
+    }
 }

src/gnuk.h

@@ -36,7 +36,7 @@ extern void *memmove(void *dest, const void *src, size_t n);
 extern int icc_data_size;
 #define cmd_APDU_size icc_data_size
 extern int res_APDU_size;
-extern uint8_t *res_APDU_pointer;
+extern const uint8_t *res_APDU_pointer;
 
 /* USB buffer size of LL (Low-level): size of single Bulk transaction */
 #define USB_LL_BUF_SIZE 64
@@ -123,6 +123,7 @@ extern int flash_write_binary (uint8_t file_id, const uint8_t *data, uint16_t le
 
 /* Linker set this symbol */
 extern uint8_t ch_certificate_start;
+extern uint8_t random_bits_start;
 
 #define KEY_MAGIC_LEN 8
 #define KEY_CONTENT_LEN 256	/* p and q */

src/gnuk.ld.in

@@ -117,7 +117,8 @@ SECTIONS
     .gnuk_random :
     {
         . = ALIGN (@FLASH_PAGE_SIZE@);
-	*(.gnuk_random)
+        random_bits_start = .;
+	. += 1;
         . = ALIGN (@FLASH_PAGE_SIZE@);
     } > flash =0xffffffff
 

src/random.c

@@ -25,24 +25,22 @@
 #include "ch.h"
 #include "gnuk.h"
 
-extern void *_binary_random_bits_start;
-
 const uint8_t *
 random_bytes_get (void)
 {
   uint32_t addr, addr0;
 
-  addr = (uint32_t)&_binary_random_bits_start + ((hardclock () << 5) & 0x3e0);
+  addr = (uint32_t)&random_bits_start + ((hardclock () << 5) & 0x3e0);
   addr0 = addr; 
 
   while (1)
     {
-      if (*(uint32_t *)addr != 0)
+      if (*(uint32_t *)addr != 0 && *(uint32_t *)addr != 0xffffffff)
 	break;
 
       addr += 32;
-      if (addr >= ((uint32_t)&_binary_random_bits_start) + 1024)
-	addr = ((uint32_t)&_binary_random_bits_start);
+      if (addr >= ((uint32_t)&random_bits_start) + 1024)
+	addr = ((uint32_t)&random_bits_start);
 
       if (addr == addr0)
 	fatal (FATAL_RANDOM);

src/usb-icc.c

@@ -386,7 +386,7 @@ icc_power_off (void)
 }
 
 int res_APDU_size;
-uint8_t *res_APDU_pointer;
+const uint8_t *res_APDU_pointer;
 
 static void
 icc_send_data_block (int len, uint8_t status, uint8_t chain)