From patchwork Mon Dec 19 11:15:25 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nix X-Patchwork-Id: 18569 Received: (qmail 128144 invoked by alias); 19 Dec 2016 11:26:34 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 128032 invoked by uid 89); 19 Dec 2016 11:26:32 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.6 required=5.0 tests=AWL, BAYES_00, KAM_LAZY_DOMAIN_SECURITY, RP_MATCHES_RCVD autolearn=ham version=3.3.2 spammy=telling, expanding X-HELO: mail.esperi.org.uk From: Nix To: libc-alpha@sourceware.org Cc: fweimer@redhat.com Subject: [PATCH 12/15] Do not stack-protect sigreturn stubs. Date: Mon, 19 Dec 2016 11:15:25 +0000 Message-Id: <20161219111528.14969-13-nix@esperi.org.uk> In-Reply-To: <20161219111528.14969-1-nix@esperi.org.uk> References: <20161219111528.14969-1-nix@esperi.org.uk> X-DCC--Metrics: spindle 1480; Body=2 Fuz1=2 Fuz2=2 From: Nick Alcock 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. v2: New. v3: Use $(no-stack-protector). v4: Use inhibit_stack_protector. v7: Add sigreturn.c. * 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): Likewise. (__sigreturn_stub): Likewise. --- signal/Makefile | 2 ++ sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c | 8 ++++++-- sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c | 4 +++- 3 files changed, 11 insertions(+), 3 deletions(-) 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"