diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/dl-execstack.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/dl-execstack.c | 30 |
1 files changed, 24 insertions, 6 deletions
diff --git a/sysdeps/unix/sysv/linux/dl-execstack.c b/sysdeps/unix/sysv/linux/dl-execstack.c index 7ea3a714ac..aafa2df1b1 100644 --- a/sysdeps/unix/sysv/linux/dl-execstack.c +++ b/sysdeps/unix/sysv/linux/dl-execstack.c @@ -23,6 +23,9 @@ #include <stdbool.h> #include <stackinfo.h> +#include "kernel-features.h" + + extern void *__libc_stack_end; int @@ -35,15 +38,20 @@ _dl_make_stack_executable (void) /* 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 (__mprotect ((void *) page, GL(dl_pagesize), PROT_READ|PROT_WRITE|PROT_EXEC|PROT_GROWSDOWN) == 0) - return 0; - if (errno != EINVAL) + goto return_success; +# if __ASSUME_PROT_GROWSUPDOWN == 0 + if (errno == EINVAL) + no_growsdown = true; + else +# endif return errno; - no_growsdown = true; } # endif @@ -54,6 +62,7 @@ _dl_make_stack_executable (void) 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 size_t size = GL(dl_pagesize) * 8; page = page + GL(dl_pagesize) - size; while (1) @@ -78,6 +87,7 @@ _dl_make_stack_executable (void) page += size; } } +# endif #elif _STACK_GROWS_UP @@ -86,15 +96,20 @@ _dl_make_stack_executable (void) /* 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, GL(dl_pagesize), PROT_READ|PROT_WRITE|PROT_EXEC|PROT_GROWSUP) == 0) - return 0; - if (errno != EINVAL) + goto return_success; +# if __ASSUME_PROT_GROWSUPDOWN == 0 + if (errno == EINVAL) + no_growsup = true; + else +# endif return errno; - no_growsup = true; } # endif @@ -105,6 +120,7 @@ _dl_make_stack_executable (void) 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 = GL(dl_pagesize) * 8; while (1) { @@ -127,11 +143,13 @@ _dl_make_stack_executable (void) size /= 2; } } +# endif #else # error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP" #endif + return_success: /* Remember that we changed the permission. */ GL(dl_stack_flags) |= PF_X; |