From de6591238b478bc86b8cf5af01a484114e399213 Mon Sep 17 00:00:00 2001 From: Nick Alcock Date: Mon, 26 Dec 2016 10:08:41 +0100 Subject: Do not stack-protect ifunc resolvers [BZ #7065] When dynamically linking, ifunc resolvers are called before TLS is initialized, so they cannot be safely stack-protected. We avoid disabling stack-protection on large numbers of files by using __attribute__ ((__optimize__ ("-fno-stack-protector"))) to turn it off just for the resolvers themselves. (We provide the attribute even when statically linking, because we will later use it elsewhere too.) --- sysdeps/unix/make-syscalls.sh | 1 + sysdeps/unix/sysv/linux/x86_64/x32/getcpu.c | 1 + 2 files changed, 2 insertions(+) (limited to 'sysdeps/unix') diff --git a/sysdeps/unix/make-syscalls.sh b/sysdeps/unix/make-syscalls.sh index 58d165e..123553c 100644 --- a/sysdeps/unix/make-syscalls.sh +++ b/sysdeps/unix/make-syscalls.sh @@ -287,6 +287,7 @@ while read file srcfile caller syscall args strong weak; do (echo '#include '; \\ echo 'extern void *${strong}_ifunc (void) __asm ("${strong}");'; \\ echo 'void *'; \\ + echo 'inhibit_stack_protector'; \\ echo '${strong}_ifunc (void)'; \\ echo '{'; \\ echo ' PREPARE_VERSION_KNOWN (symver, ${vdso_symver});'; \\ diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/getcpu.c b/sysdeps/unix/sysv/linux/x86_64/x32/getcpu.c index cbac4b3..8436f9d 100644 --- a/sysdeps/unix/sysv/linux/x86_64/x32/getcpu.c +++ b/sysdeps/unix/sysv/linux/x86_64/x32/getcpu.c @@ -21,6 +21,7 @@ void *getcpu_ifunc (void) __asm__ ("__getcpu"); void * +inhibit_stack_protector getcpu_ifunc (void) { PREPARE_VERSION (linux26, "LINUX_2.6", 61765110); -- cgit v1.1