From 12ef66c411efe5910f0a9a74c92480db7e12eae0 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Tue, 26 Sep 2017 16:30:46 +0000 Subject: [PATCH] Fix ia64 executable stack default (bug 22156). As per https://gcc.gnu.org/ml/gcc-patches/2017-09/msg01220.html ia64 defaults to non-executable stacks in the Linux kernel (furthermore, the use of function descriptors means that trampolines for nested function pointers never need an executable stack). glibc however defines DEFAULT_STACK_PERMS to include PF_X for that architecture, meaning (a) elf/check-execstack fails and (b) (from code inspection, not tested, but this is why I think this is a user-visible bug) thread stacks are unnecessarily mapped with execute permission. This patch fixes the DEFAULT_STACK_PERMS definition in question. Tested (compilation only) with build-many-glibcs.py for ia64. This fixes the check-execstack failure. [BZ #22156] * sysdeps/ia64/stackinfo.h (DEFAULT_STACK_PERMS): Likewise. --- ChangeLog | 5 +++++ sysdeps/ia64/stackinfo.h | 5 ++--- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/ChangeLog b/ChangeLog index 41d3ed48ee..f8435ad1fa 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2017-09-26 Joseph Myers + + [BZ #22156] + * sysdeps/ia64/stackinfo.h (DEFAULT_STACK_PERMS): Likewise. + 2017-09-26 Florian Weimer * resolv/Makefile (tests-internal): Fix typo in comment. diff --git a/sysdeps/ia64/stackinfo.h b/sysdeps/ia64/stackinfo.h index 87e144876f..a50e72749a 100644 --- a/sysdeps/ia64/stackinfo.h +++ b/sysdeps/ia64/stackinfo.h @@ -27,8 +27,7 @@ here. */ #define _STACK_GROWS_DOWN 1 -/* Default to an executable stack. PF_X can be overridden if PT_GNU_STACK is - * present, but it is presumed absent. */ -#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X) +/* Default to a non-executable stack. */ +#define DEFAULT_STACK_PERMS (PF_R|PF_W) #endif /* stackinfo.h */