Messages in this thread | | | Date | Thu, 06 Mar 2014 11:34:46 +0900 | From | AKASHI Takahiro <> | Subject | Re: [PATCH v2 2/3] arm64: Add seccomp support |
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On 03/01/2014 02:20 AM, Will Deacon wrote: > On Tue, Feb 25, 2014 at 09:20:24AM +0000, AKASHI Takahiro wrote: >> secure_computing() should always be called first in syscall_trace(), and >> if it returns non-zero, we should stop further handling. Then that system >> call may eventually fail, be trapped or the process itself be killed >> depending on loaded rules. > > [...] > >> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c >> index d4ce70e..f2a74bc 100644 >> --- a/arch/arm64/kernel/ptrace.c >> +++ b/arch/arm64/kernel/ptrace.c >> @@ -20,12 +20,14 @@ >> */ >> >> #include <linux/audit.h> >> +#include <linux/errno.h> >> #include <linux/kernel.h> >> #include <linux/sched.h> >> #include <linux/mm.h> >> #include <linux/smp.h> >> #include <linux/ptrace.h> >> #include <linux/user.h> >> +#include <linux/seccomp.h> >> #include <linux/security.h> >> #include <linux/init.h> >> #include <linux/signal.h> >> @@ -1064,6 +1066,10 @@ asmlinkage int syscall_trace(int dir, struct pt_regs *regs) >> { >> unsigned long saved_reg; >> >> + if (!dir && secure_computing((int)regs->syscallno)) > > Why do you need this cast to (int)?
OK. I will remove it because gcc doesn't complain about it anyway.
> Also, it's probably better to check for > -1 explicitly here.
I wil fix it.
> I'm slightly surprised that we do the secure computing check first. Doesn't > this allow a debugger to change the syscall to something else after we've > decided that it's ok?
To be honest, I just followed other architectures' implementation. Can you elaborate any use case that you have in your mind?
-Takahiro AKASHI
> Will >
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