From 2e6c45c59bcd40f1ae8466cbd32f4d263ff45619 Mon Sep 17 00:00:00 2001 From: Nick Alcock Date: Mon, 26 Dec 2016 10:09:06 +0100 Subject: [PATCH] Do not stack-protect sigreturn stubs [BZ #7065] These are called from the kernel with the stack at a carefully- chosen location so that the stack frame can be restored: they must not move the stack pointer lest garbage be restored into the registers. We explicitly inhibit protection for SPARC and for signal/sigreturn.c: other arches either define their sigreturn stubs in .S files, or (i386, x86_64, mips) use macros expanding to top-level asm blocks and explicit labels in the text section to mock up a "function" without telling the compiler that one is there at all. --- ChangeLog | 9 +++++++++ signal/Makefile | 2 ++ sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c | 8 ++++++-- sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c | 4 +++- 4 files changed, 20 insertions(+), 3 deletions(-) diff --git a/ChangeLog b/ChangeLog index 99749a5..edf8523 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,6 +1,15 @@ 2016-12-26 Nick Alcock [BZ #7065] + * signal/Makefile (CFLAGS-sigreturn.c): Use $(no-stack-protector). + * sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c: + (__rt_sigreturn_stub): Use inhibit_stack_protector. + * sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c + (__rt_sigreturn_stub, __sigreturn_stub): Likewise. + +2016-12-26 Nick Alcock + + [BZ #7065] * login/Makefile (pt_chown-cflags): Remove. * nscd/Makefile (CFLAGS-nscd): Likewise. * resolv/Makefile (CFLAGS-libresolv): Likewise. diff --git a/signal/Makefile b/signal/Makefile index 9d29ff4..ccd6f51 100644 --- a/signal/Makefile +++ b/signal/Makefile @@ -48,3 +48,5 @@ CFLAGS-sigsuspend.c = -fexceptions -fasynchronous-unwind-tables CFLAGS-sigtimedwait.c = -fexceptions -fasynchronous-unwind-tables CFLAGS-sigwait.c = -fexceptions -fasynchronous-unwind-tables CFLAGS-sigwaitinfo.c = -fexceptions -fasynchronous-unwind-tables + +CFLAGS-sigreturn.c = $(no-stack-protector) diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c b/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c index 5aa3c35..b75142f 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c @@ -65,7 +65,9 @@ libc_hidden_def (__libc_sigaction) #include -static void +static +inhibit_stack_protector +void __rt_sigreturn_stub (void) { __asm__ ("mov %0, %%g1\n\t" @@ -74,7 +76,9 @@ __rt_sigreturn_stub (void) : "i" (__NR_rt_sigreturn)); } -static void +static +inhibit_stack_protector +void __sigreturn_stub (void) { __asm__ ("mov %0, %%g1\n\t" diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c b/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c index 50c444c..058c011 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c @@ -66,7 +66,9 @@ libc_hidden_def (__libc_sigaction) #include -static void +static +inhibit_stack_protector +void __rt_sigreturn_stub (void) { __asm__ ("mov %0, %%g1\n\t" -- 2.7.4