On Thu, 29 Mar 2012 15:01:58 -0500 Will Drewry <wad@xxxxxxxxxxxx> wrote: > This change adds support for a new ptrace option, PTRACE_O_TRACESECCOMP, > and a new return value for seccomp BPF programs, SECCOMP_RET_TRACE. > > When a tracer specifies the PTRACE_O_TRACESECCOMP ptrace option, the > tracer will be notified, via PTRACE_EVENT_SECCOMP, for any syscall that > results in a BPF program returning SECCOMP_RET_TRACE. The 16-bit > SECCOMP_RET_DATA mask of the BPF program return value will be passed as > the ptrace_message and may be retrieved using PTRACE_GETEVENTMSG. > > If the subordinate process is not using seccomp filter, then no > system call notifications will occur even if the option is specified. > > If there is no tracer with PTRACE_O_TRACESECCOMP when SECCOMP_RET_TRACE > is returned, the system call will not be executed and an -ENOSYS errno > will be returned to userspace. > > This change adds a dependency on the system call slow path. Any future > efforts to use the system call fast path for seccomp filter will need to > address this restriction. > > > ... > > @@ -410,6 +411,15 @@ int __secure_computing_int(int this_syscall) > /* Let the filter pass back 16 bits of data. */ > seccomp_send_sigsys(this_syscall, data); > goto skip; > + case SECCOMP_RET_TRACE: > + /* Skip these calls if there is no tracer. */ > + if (!ptrace_event_enabled(current, PTRACE_EVENT_SECCOMP)) > + goto skip; > + /* Allow the BPF to provide the event message */ > + ptrace_event(PTRACE_EVENT_SECCOMP, data); > + if (fatal_signal_pending(current)) > + break; I don't have all the patches applied here so the context is missing. Perhaps tht would help me understand what this fatal_signal_pending() test is doing here. But an explanatory comment wouldn't hurt. What *is* it here for, anyway? > + return 0; > case SECCOMP_RET_ALLOW: > return 0; > case SECCOMP_RET_KILL: -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
