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authorNick Alcock <nick.alcock@oracle.com>2016-12-26 10:08:41 +0100
committerFlorian Weimer <fweimer@redhat.com>2016-12-26 10:08:41 +0100
commitde6591238b478bc86b8cf5af01a484114e399213 (patch)
tree2717c115fbc7518fcbe9348239ff536eb914d267 /sysdeps/unix
parent003a27e8195470f470f4d9384ca70d4e9fc8bd1b (diff)
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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.)
Diffstat (limited to 'sysdeps/unix')
-rw-r--r--sysdeps/unix/make-syscalls.sh1
-rw-r--r--sysdeps/unix/sysv/linux/x86_64/x32/getcpu.c1
2 files changed, 2 insertions, 0 deletions
diff --git a/sysdeps/unix/make-syscalls.sh b/sysdeps/unix/make-syscalls.sh
index 58d165e015..123553c1d9 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 <dl-vdso.h>'; \\
 	 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 cbac4b3273..8436f9db93 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);