From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shi Weihua Date: Mon, 18 Feb 2008 10:27:08 +0000 Subject: [PATCH 5/5] signal(ia64_ia32): add a signal stack overflow check Message-Id: <47B95D7C.1080005@cn.fujitsu.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: tony.luck@intel.com Cc: linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org The similar check has been added to x86_32(i386) in commit id 83bd01024b1fdfc41d9b758e5669e80fca72df66. So we add this check to ia64_ia32 and improve it a liitle bit in that we need to check for stack overflow only when the signal is on stack. Signed-off-by: Shi Weihua --- --- linux-2.6.25-rc2.orig/arch/ia64/ia32/ia32_signal.c 2008-02-16 04:57:20.000000000 +0800 +++ linux-2.6.25-rc2/arch/ia64/ia32/ia32_signal.c 2008-02-18 18:12:49.000000000 +0800 @@ -766,8 +766,19 @@ get_sigframe (struct k_sigaction *ka, st /* This is the X/Open sanctioned signal stack switching. */ if (ka->sa.sa_flags & SA_ONSTACK) { - if (!on_sig_stack(esp)) + int onstack = sas_ss_flags(esp); + + if (onstack = 0) esp = current->sas_ss_sp + current->sas_ss_size; + else if (onstack = SS_ONSTACK) { + /* + * If we are on the alternate signal stack and would + * overflow it, don't return an always-bogus address + * instead so we will die with SIGSEGV. + */ + if (!likely(on_sig_stack(esp - frame_size))) + return (void __user *) -1L; + } } /* Legacy stack switching not supported */