Re: [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations

2014-07-29 Thread Will Deacon
On Tue, Jul 29, 2014 at 07:49:47AM +0100, AKASHI Takahiro wrote: > On 07/25/2014 08:03 PM, Will Deacon wrote: > > On Fri, Jul 25, 2014 at 11:36:49AM +0100, AKASHI Takahiro wrote: > >> On 07/25/2014 12:01 AM, Andy Lutomirski wrote: > > If so, then you risk (at least) introducing > > > >

Re: [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations

2014-07-28 Thread AKASHI Takahiro
On 07/25/2014 08:03 PM, Will Deacon wrote: On Fri, Jul 25, 2014 at 11:36:49AM +0100, AKASHI Takahiro wrote: On 07/25/2014 12:01 AM, Andy Lutomirski wrote: If so, then you risk (at least) introducing a nice user-triggerable OOPS if audit is enabled. Can you please elaborate this? Since I did

Re: [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations

2014-07-25 Thread Will Deacon
On Fri, Jul 25, 2014 at 11:36:49AM +0100, AKASHI Takahiro wrote: > On 07/25/2014 12:01 AM, Andy Lutomirski wrote: > >>> If so, then you risk (at least) introducing > >>> > >>> a nice user-triggerable OOPS if audit is enabled. > >> > >> > >> Can you please elaborate this? > >> Since I didn't find an

Re: [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations

2014-07-25 Thread AKASHI Takahiro
On 07/25/2014 12:01 AM, Andy Lutomirski wrote: On Jul 23, 2014 10:57 PM, "AKASHI Takahiro" wrote: On 07/24/2014 12:54 PM, Andy Lutomirski wrote: On 07/22/2014 02:14 AM, AKASHI Takahiro wrote: Arm64 holds a syscall number in w8(x8) register. Ptrace tracer may change its value either to:

Re: [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations

2014-07-24 Thread Andy Lutomirski
On Jul 23, 2014 10:57 PM, "AKASHI Takahiro" wrote: > > On 07/24/2014 12:54 PM, Andy Lutomirski wrote: >> >> On 07/22/2014 02:14 AM, AKASHI Takahiro wrote: >>> >>> Arm64 holds a syscall number in w8(x8) register. Ptrace tracer may change >>> its value either to: >>>* any valid syscall number to

Re: [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations

2014-07-23 Thread AKASHI Takahiro
On 07/24/2014 12:54 PM, Andy Lutomirski wrote: On 07/22/2014 02:14 AM, AKASHI Takahiro wrote: Arm64 holds a syscall number in w8(x8) register. Ptrace tracer may change its value either to: * any valid syscall number to alter a system call, or * -1 to skip a system call This patch implemen

Re: [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations

2014-07-23 Thread Andy Lutomirski
On 07/22/2014 02:14 AM, AKASHI Takahiro wrote: Arm64 holds a syscall number in w8(x8) register. Ptrace tracer may change its value either to: * any valid syscall number to alter a system call, or * -1 to skip a system call This patch implements this behavior by reloading that value into sy

Re: [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations

2014-07-23 Thread Kees Cook
On Wed, Jul 23, 2014 at 12:03 AM, AKASHI Takahiro wrote: > On 07/23/2014 05:15 AM, Kees Cook wrote: >> >> On Tue, Jul 22, 2014 at 2:14 AM, AKASHI Takahiro >> wrote: >>> >>> Arm64 holds a syscall number in w8(x8) register. Ptrace tracer may change >>> its value either to: >>>* any valid syscal

Re: [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations

2014-07-23 Thread AKASHI Takahiro
On 07/23/2014 05:25 PM, Will Deacon wrote: On Wed, Jul 23, 2014 at 08:03:47AM +0100, AKASHI Takahiro wrote: On 07/23/2014 05:15 AM, Kees Cook wrote: On Tue, Jul 22, 2014 at 2:14 AM, AKASHI Takahiro wrote: asmlinkage int syscall_trace_enter(struct pt_regs *regs) { + unsigned long s

Re: [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations

2014-07-23 Thread Will Deacon
On Wed, Jul 23, 2014 at 08:03:47AM +0100, AKASHI Takahiro wrote: > On 07/23/2014 05:15 AM, Kees Cook wrote: > > On Tue, Jul 22, 2014 at 2:14 AM, AKASHI Takahiro > > wrote: > >> asmlinkage int syscall_trace_enter(struct pt_regs *regs) > >> { > >> + unsigned long saved_x0, saved_x8; > >> +

Re: [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations

2014-07-23 Thread AKASHI Takahiro
On 07/23/2014 05:15 AM, Kees Cook wrote: On Tue, Jul 22, 2014 at 2:14 AM, AKASHI Takahiro wrote: Arm64 holds a syscall number in w8(x8) register. Ptrace tracer may change its value either to: * any valid syscall number to alter a system call, or * -1 to skip a system call This patch impl

Re: [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations

2014-07-22 Thread Kees Cook
On Tue, Jul 22, 2014 at 2:14 AM, AKASHI Takahiro wrote: > Arm64 holds a syscall number in w8(x8) register. Ptrace tracer may change > its value either to: > * any valid syscall number to alter a system call, or > * -1 to skip a system call > > This patch implements this behavior by reloading t