| Message ID | 20201105223106.22517-1-julien@xen.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | xen/arm: traps: Don't panic when receiving an unknown debug trap | expand |
On Thu, Nov 05, 2020 at 10:31:06PM +0000, Julien Grall wrote: > Even if debug trap are only meant for debugging purpose, it is quite > harsh to crash Xen if one of the trap sent by the guest is not handled. > > So switch from a panic() to a printk(). Might this qualify as security due to potential DoS?
On 05/11/2020 23:10, Elliott Mitchell wrote: > On Thu, Nov 05, 2020 at 10:31:06PM +0000, Julien Grall wrote: >> Even if debug trap are only meant for debugging purpose, it is quite >> harsh to crash Xen if one of the trap sent by the guest is not handled. >> >> So switch from a panic() to a printk(). > > Might this qualify as security due to potential DoS? This code path only exists with CONFIG_DEBUG=y which is not security supported. Cheers,
On Thu, 5 Nov 2020, Julien Grall wrote: > From: Julien Grall <jgrall@amazon.com> > > Even if debug trap are only meant for debugging purpose, it is quite > harsh to crash Xen if one of the trap sent by the guest is not handled. > > So switch from a panic() to a printk(). > > Signed-off-by: Julien Grall <jgrall@amazon.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> > --- > xen/arch/arm/traps.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c > index 8f40d0e0b6b1..a36f145e6739 100644 > --- a/xen/arch/arm/traps.c > +++ b/xen/arch/arm/traps.c > @@ -1410,7 +1410,7 @@ static void do_debug_trap(struct cpu_user_regs *regs, unsigned int code) > show_execution_state(regs); > break; > default: > - panic("DOM%d: Unhandled debug trap %#x\n", domid, code); > + printk("DOM%d: Unhandled debug trap %#x\n", domid, code); > break; > } > } > -- > 2.17.1 >
Hi Julien, > On 5 Nov 2020, at 22:31, Julien Grall <julien@xen.org> wrote: > > From: Julien Grall <jgrall@amazon.com> > > Even if debug trap are only meant for debugging purpose, it is quite > harsh to crash Xen if one of the trap sent by the guest is not handled. > > So switch from a panic() to a printk(). Very smart idea :-) > > Signed-off-by: Julien Grall <jgrall@amazon.com> Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com> Cheers Bertrand > --- > xen/arch/arm/traps.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c > index 8f40d0e0b6b1..a36f145e6739 100644 > --- a/xen/arch/arm/traps.c > +++ b/xen/arch/arm/traps.c > @@ -1410,7 +1410,7 @@ static void do_debug_trap(struct cpu_user_regs *regs, unsigned int code) > show_execution_state(regs); > break; > default: > - panic("DOM%d: Unhandled debug trap %#x\n", domid, code); > + printk("DOM%d: Unhandled debug trap %#x\n", domid, code); > break; > } > } > -- > 2.17.1 > >
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c index 8f40d0e0b6b1..a36f145e6739 100644 --- a/xen/arch/arm/traps.c +++ b/xen/arch/arm/traps.c @@ -1410,7 +1410,7 @@ static void do_debug_trap(struct cpu_user_regs *regs, unsigned int code) show_execution_state(regs); break; default: - panic("DOM%d: Unhandled debug trap %#x\n", domid, code); + printk("DOM%d: Unhandled debug trap %#x\n", domid, code); break; } }