| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20070214175114.GB5801@ccure.user-mode-linux.org>
Date: Wed, 14 Feb 2007 12:51:14 -0500
From: Jeff Dike <jdike@...toit.com>
To: Jan Beulich <jbeulich@...ell.com>
Cc: Andi Kleen <ak@...e.de>, linux-kernel@...r.kernel.org,
patches@...-64.org
Subject: Re: [patches] [PATCH 2.6.21 review I] [4/25] x86: kernel-mode faults pollute current->thead
On Tue, Feb 13, 2007 at 07:52:54AM +0000, Jan Beulich wrote:
> Actually, after a second round of thinking I believe there's still more to do
> - your second patch missed fixing i386's do_trap() similarly to x86-64's
> and, vice versa, x86-64's do_general_protection() similarly to i386's.
Sigh, here's another go at it - the full patch instead of
incrementally fixing the old one:
Index: linux-2.6/arch/i386/kernel/traps.c
===================================================================
--- linux-2.6.orig/arch/i386/kernel/traps.c
+++ linux-2.6/arch/i386/kernel/traps.c
@@ -473,8 +473,6 @@ static void __kprobes do_trap(int trapnr
siginfo_t *info)
{
struct task_struct *tsk = current;
- tsk->thread.error_code = error_code;
- tsk->thread.trap_no = trapnr;
if (regs->eflags & VM_MASK) {
if (vm86)
@@ -486,6 +484,9 @@ static void __kprobes do_trap(int trapnr
goto kernel_trap;
trap_signal: {
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_no = trapnr;
+
if (info)
force_sig_info(signr, info, tsk);
else
@@ -494,8 +495,11 @@ static void __kprobes do_trap(int trapnr
}
kernel_trap: {
- if (!fixup_exception(regs))
+ if (!fixup_exception(regs)) {
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_no = trapnr;
die(str, regs, error_code);
+ }
return;
}
@@ -600,15 +604,21 @@ fastcall void __kprobes do_general_prote
}
put_cpu();
- current->thread.error_code = error_code;
- current->thread.trap_no = 13;
-
if (regs->eflags & VM_MASK)
goto gp_in_vm86;
if (!user_mode(regs))
goto gp_in_kernel;
+ /*
+ * We want error_code and trap_no set for userspace faults and
+ * kernelspace faults which result in die(), but not
+ * kernelspace faults which are fixed up. die() gives the
+ * process no chance to handle the signal and notice the
+ * kernel fault information, so that won't result in polluting
+ * the information about previously queued, but not yet
+ * delivered, fault.
+ */
current->thread.error_code = error_code;
current->thread.trap_no = 13;
force_sig(SIGSEGV, current);
@@ -621,6 +631,8 @@ gp_in_vm86:
gp_in_kernel:
if (!fixup_exception(regs)) {
+ current->thread.error_code = error_code;
+ current->thread.trap_no = 13;
if (notify_die(DIE_GPF, "general protection fault", regs,
error_code, 13, SIGSEGV) == NOTIFY_STOP)
return;
Index: linux-2.6/arch/x86_64/kernel/traps.c
===================================================================
--- linux-2.6.orig/arch/x86_64/kernel/traps.c
+++ linux-2.6/arch/x86_64/kernel/traps.c
@@ -581,10 +581,19 @@ static void __kprobes do_trap(int trapnr
{
struct task_struct *tsk = current;
- tsk->thread.error_code = error_code;
- tsk->thread.trap_no = trapnr;
-
if (user_mode(regs)) {
+ /*
+ * We want error_code and trap_no set for userspace faults
+ * and kernelspace faults which result in die(), but
+ * not kernelspace faults which are fixed up. die()
+ * gives the process no chance to handle the signal
+ * and notice the kernel fault information, so that
+ * won't result in polluting the information about
+ * previously queued, but not yet delivered, fault.
+ */
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_no = trapnr;
+
if (exception_trace && unhandled_signal(tsk, signr))
printk(KERN_INFO
"%s[%d] trap %s rip:%lx rsp:%lx error:%lx\n",
@@ -605,8 +614,11 @@ static void __kprobes do_trap(int trapnr
fixup = search_exception_tables(regs->rip);
if (fixup)
regs->rip = fixup->fixup;
- else
+ else {
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_no = trapnr;
die(str, regs, error_code);
+ }
return;
}
}
@@ -682,10 +694,10 @@ asmlinkage void __kprobes do_general_pro
conditional_sti(regs);
- tsk->thread.error_code = error_code;
- tsk->thread.trap_no = 13;
-
if (user_mode(regs)) {
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_no = 13;
+
if (exception_trace && unhandled_signal(tsk, SIGSEGV))
printk(KERN_INFO
"%s[%d] general protection rip:%lx rsp:%lx error:%lx\n",
@@ -704,6 +716,10 @@ asmlinkage void __kprobes do_general_pro
regs->rip = fixup->fixup;
return;
}
+
+
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_no = 13;
if (notify_die(DIE_GPF, "general protection fault", regs,
error_code, 13, SIGSEGV) == NOTIFY_STOP)
return;
--
Work email - jdike at linux dot intel dot com
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists