overhaul SSP support to use a real canary

[musl] / src / env / __stack_chk_fail.c

diff --git a/src/env/__stack_chk_fail.c b/src/env/__stack_chk_fail.c
index bbba351..c6d0feb 100644 (file)
--- a/src/env/__stack_chk_fail.c
+++ b/src/env/__stack_chk_fail.c
@@ -1,11 +1,20 @@
+#include <string.h>
+#include <inttypes.h>
+#include <elf.h>
 #include "pthread_impl.h"
 #include "atomic.h"
 
-void __init_ssp(void)
+uintptr_t __stack_chk_guard;
+
+void __init_ssp(size_t *auxv)
 {
-#ifndef __PIC__
-       __pthread_self_init();
-#endif
+       size_t i;
+       pthread_t self = __pthread_self_init();
+       uintptr_t canary;
+       for (i=0; auxv[i] && auxv[i]!=AT_RANDOM; i+=2);
+       if (auxv[i]) memcpy(&canary, (void *)auxv[i+1], sizeof canary);
+       else canary = (uintptr_t)&canary * 1103515245;
+       __stack_chk_guard = self->canary = canary;
 }
 
 void __stack_chk_fail(void)