Messages in this thread Patch in this message | | | Date | Fri, 28 Feb 2014 17:20:06 +0000 | From | Will Deacon <> | Subject | Re: [PATCH v2 2/3] arm64: Add seccomp support |
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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.
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> 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)? Also, it's probably better to check for -1 explicitly here.
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?
Will
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