diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/dl-execstack.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/dl-execstack.c | 63 |
1 files changed, 17 insertions, 46 deletions
diff --git a/sysdeps/unix/sysv/linux/dl-execstack.c b/sysdeps/unix/sysv/linux/dl-execstack.c index 97ff5d0e62..6ef9679045 100644 --- a/sysdeps/unix/sysv/linux/dl-execstack.c +++ b/sysdeps/unix/sysv/linux/dl-execstack.c @@ -45,25 +45,24 @@ _dl_make_stack_executable (void **stack_endp) || __builtin_expect (*stack_endp != __libc_stack_end, 0)) return EPERM; -#if _STACK_GROWS_DOWN /* Newer Linux kernels support a flag to make our job easy. */ -# ifdef PROT_GROWSDOWN -# if __ASSUME_PROT_GROWSUPDOWN == 0 - static bool no_growsdown; - if (! no_growsdown) -# endif +#if defined PROT_GROWSDOWN || defined PROT_GROWSUP +# if __ASSUME_PROT_GROWSUPDOWN == 0 + static bool no_growsupdown; + if (! no_growsupdown) +# endif { if (__builtin_expect (__mprotect ((void *) page, GLRO(dl_pagesize), __stack_prot) == 0, 1)) goto return_success; -# if __ASSUME_PROT_GROWSUPDOWN == 0 +# if __ASSUME_PROT_GROWSUPDOWN == 0 if (errno == EINVAL) - no_growsdown = true; + no_growsupdown = true; else -# endif +# endif return errno; } -# endif +#endif /* There is always a hole in the address space below the bottom of the stack. So when we make an mprotect call that starts below the bottom @@ -72,8 +71,10 @@ _dl_make_stack_executable (void **stack_endp) We start with a random guess at how deep the stack might have gotten so as to have extended the GROWSDOWN mapping to lower pages. */ -# if __ASSUME_PROT_GROWSUPDOWN == 0 +#if __ASSUME_PROT_GROWSUPDOWN == 0 size_t size = GLRO(dl_pagesize) * 8; + +# if _STACK_GROWS_DOWN page = page + GLRO(dl_pagesize) - size; while (1) { @@ -97,41 +98,11 @@ _dl_make_stack_executable (void **stack_endp) page += size; } } -# endif -#elif _STACK_GROWS_UP - /* Newer Linux kernels support a flag to make our job easy. */ -# ifdef PROT_GROWSUP -# if __ASSUME_PROT_GROWSUPDOWN == 0 - static bool no_growsup; - if (! no_growsup) -# endif - { - if (__mprotect ((void *) page, GLRO(dl_pagesize), - PROT_READ|PROT_WRITE|PROT_EXEC|PROT_GROWSUP) == 0) - goto return_success; -# if __ASSUME_PROT_GROWSUPDOWN == 0 - if (errno == EINVAL) - no_growsup = true; - else -# endif - return errno; - } -# endif - - /* There is always a hole in the address space above the top of the - stack. So when we make an mprotect call that spans past the top - of the stack, it will include the hole and fail with ENOMEM. - - We start with a random guess at how deep the stack might have gotten - so as to have extended the GROWSUP mapping to higher pages. */ - -# if __ASSUME_PROT_GROWSUPDOWN == 0 - size_t size = GLRO(dl_pagesize) * 8; +# elif _STACK_GROWS_UP while (1) { - if (__mprotect ((void *) page, size, - PROT_READ|PROT_WRITE|PROT_EXEC) == 0) + if (__mprotect ((void *) page, size, __stack_prot & ~PROT_GROWSUP) == 0) /* We got this chunk changed; loop to do another chunk below. */ page += size; else @@ -149,10 +120,10 @@ _dl_make_stack_executable (void **stack_endp) size /= 2; } } -# endif -#else -# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP" +# else +# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP" +# endif #endif return_success: |