Add CONFIG_AUDITSC and CONFIG_SECCOMP support for ppc32

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

diff --git a/arch/ppc/Kconfig b/arch/ppc/Kconfig
index 600f23d..cd752a3 100644 (file)
--- a/arch/ppc/Kconfig
+++ b/arch/ppc/Kconfig
@@ -1083,6 +1083,23 @@ source "drivers/zorro/Kconfig"
 
 source kernel/power/Kconfig
 
+config SECCOMP
+       bool "Enable seccomp to safely compute untrusted bytecode"
+       depends on PROC_FS
+       default y
+       help
+         This kernel feature is useful for number crunching applications
+         that may need to compute untrusted bytecode during their
+         execution. By using pipes or other transports made available to
+         the process as file descriptors supporting the read/write
+         syscalls, it's possible to isolate those applications in
+         their own address space using seccomp. Once seccomp is
+         enabled via /proc/<pid>/seccomp, it cannot be disabled
+         and the task is only allowed to execute a few safe syscalls
+         defined by each seccomp mode.
+
+         If unsure, say Y. Only embedded should say N here.
+
 endmenu
 
 config ISA_DMA_API

diff --git a/arch/ppc/kernel/entry.S b/arch/ppc/kernel/entry.S
index 5f075db..6615237 100644 (file)
--- a/arch/ppc/kernel/entry.S
+++ b/arch/ppc/kernel/entry.S
@@ -202,7 +202,7 @@ _GLOBAL(DoSyscall)
        rlwinm  r11,r11,0,~_TIFL_FORCE_NOERROR
        stw     r11,TI_LOCAL_FLAGS(r10)
        lwz     r11,TI_FLAGS(r10)
-       andi.   r11,r11,_TIF_SYSCALL_TRACE
+       andi.   r11,r11,_TIF_SYSCALL_T_OR_A
        bne-    syscall_dotrace
 syscall_dotrace_cont:
        cmplwi  0,r0,NR_syscalls
@@ -237,7 +237,7 @@ ret_from_syscall:
        SYNC
        MTMSRD(r10)
        lwz     r9,TI_FLAGS(r12)
-       andi.   r0,r9,(_TIF_SYSCALL_TRACE|_TIF_SIGPENDING|_TIF_NEED_RESCHED)
+       andi.   r0,r9,(_TIF_SYSCALL_T_OR_A|_TIF_SIGPENDING|_TIF_NEED_RESCHED)
        bne-    syscall_exit_work
 syscall_exit_cont:
 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
@@ -277,7 +277,8 @@ syscall_dotrace:
        SAVE_NVGPRS(r1)
        li      r0,0xc00
        stw     r0,TRAP(r1)
-       bl      do_syscall_trace
+       addi    r3,r1,STACK_FRAME_OVERHEAD
+       bl      do_syscall_trace_enter
        lwz     r0,GPR0(r1)     /* Restore original registers */
        lwz     r3,GPR3(r1)
        lwz     r4,GPR4(r1)
@@ -291,7 +292,7 @@ syscall_dotrace:
 syscall_exit_work:
        stw     r6,RESULT(r1)   /* Save result */
        stw     r3,GPR3(r1)     /* Update return value */
-       andi.   r0,r9,_TIF_SYSCALL_TRACE
+       andi.   r0,r9,_TIF_SYSCALL_T_OR_A
        beq     5f
        ori     r10,r10,MSR_EE
        SYNC
@@ -303,7 +304,8 @@ syscall_exit_work:
        li      r4,0xc00
        stw     r4,TRAP(r1)
 4:
-       bl      do_syscall_trace
+       addi    r3,r1,STACK_FRAME_OVERHEAD
+       bl      do_syscall_trace_leave
        REST_NVGPRS(r1)
 2:
        lwz     r3,GPR3(r1)
@@ -627,8 +629,8 @@ sigreturn_exit:
        subi    r1,r3,STACK_FRAME_OVERHEAD
        rlwinm  r12,r1,0,0,18   /* current_thread_info() */
        lwz     r9,TI_FLAGS(r12)
-       andi.   r0,r9,_TIF_SYSCALL_TRACE
-       bnel-   do_syscall_trace
+       andi.   r0,r9,_TIF_SYSCALL_T_OR_A
+       bnel-   do_syscall_trace_leave
        /* fall through */
 
        .globl  ret_from_except_full

diff --git a/arch/ppc/kernel/ppc_ksyms.c b/arch/ppc/kernel/ppc_ksyms.c
index 2ccb58f..d59ad07 100644 (file)
--- a/arch/ppc/kernel/ppc_ksyms.c
+++ b/arch/ppc/kernel/ppc_ksyms.c
@@ -55,7 +55,6 @@
 #define EXPORT_SYMTAB_STROPS
 
 extern void transfer_to_handler(void);
-extern void do_syscall_trace(void);
 extern void do_IRQ(struct pt_regs *regs);
 extern void MachineCheckException(struct pt_regs *regs);
 extern void AlignmentException(struct pt_regs *regs);
@@ -74,7 +73,6 @@ extern unsigned long mm_ptov (unsigned long paddr);
 EXPORT_SYMBOL(clear_pages);
 EXPORT_SYMBOL(clear_user_page);
 EXPORT_SYMBOL(do_signal);
-EXPORT_SYMBOL(do_syscall_trace);
 EXPORT_SYMBOL(transfer_to_handler);
 EXPORT_SYMBOL(do_IRQ);
 EXPORT_SYMBOL(MachineCheckException);

diff --git a/arch/ppc/kernel/ptrace.c b/arch/ppc/kernel/ptrace.c
index 59d59a8..e7aee41 100644 (file)
--- a/arch/ppc/kernel/ptrace.c
+++ b/arch/ppc/kernel/ptrace.c
@@ -27,6 +27,9 @@
 #include <linux/user.h>
 #include <linux/security.h>
 #include <linux/signal.h>
+#include <linux/seccomp.h>
+#include <linux/audit.h>
+#include <linux/module.h>
 
 #include <asm/uaccess.h>
 #include <asm/page.h>
@@ -455,11 +458,10 @@ out:
        return ret;
 }
 
-void do_syscall_trace(void)
+static void do_syscall_trace(void)
 {
-        if (!test_thread_flag(TIF_SYSCALL_TRACE)
-           || !(current->ptrace & PT_PTRACED))
-               return;
+       /* the 0x80 provides a way for the tracing parent to distinguish
+          between a syscall stop and SIGTRAP delivery */
        ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
                                 ? 0x80 : 0));
 
@@ -473,3 +475,33 @@ void do_syscall_trace(void)
                current->exit_code = 0;
        }
 }
+
+void do_syscall_trace_enter(struct pt_regs *regs)
+{
+       if (test_thread_flag(TIF_SYSCALL_TRACE)
+           && (current->ptrace & PT_PTRACED))
+               do_syscall_trace();
+
+       if (unlikely(current->audit_context))
+               audit_syscall_entry(current, AUDIT_ARCH_PPC,
+                                   regs->gpr[0],
+                                   regs->gpr[3], regs->gpr[4],
+                                   regs->gpr[5], regs->gpr[6]);
+}
+
+void do_syscall_trace_leave(struct pt_regs *regs)
+{
+       secure_computing(regs->gpr[0]);
+
+       if (unlikely(current->audit_context))
+               audit_syscall_exit(current,
+                                  (regs->ccr&0x1000)?AUDITSC_FAILURE:AUDITSC_SUCCESS,
+                                  regs->result);
+
+       if ((test_thread_flag(TIF_SYSCALL_TRACE))
+           && (current->ptrace & PT_PTRACED))
+               do_syscall_trace();
+}
+
+EXPORT_SYMBOL(do_syscall_trace_enter);
+EXPORT_SYMBOL(do_syscall_trace_leave);

diff --git a/include/asm-ppc/thread_info.h b/include/asm-ppc/thread_info.h
index f7f0152..e3b5284 100644 (file)
--- a/include/asm-ppc/thread_info.h
+++ b/include/asm-ppc/thread_info.h
@@ -77,12 +77,19 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_POLLING_NRFLAG     4       /* true if poll_idle() is polling
                                           TIF_NEED_RESCHED */
 #define TIF_MEMDIE             5
+#define TIF_SYSCALL_AUDIT       6       /* syscall auditing active */
+#define TIF_SECCOMP             7      /* secure computing */
+
 /* as above, but as bit values */
 #define _TIF_SYSCALL_TRACE     (1<<TIF_SYSCALL_TRACE)
 #define _TIF_NOTIFY_RESUME     (1<<TIF_NOTIFY_RESUME)
 #define _TIF_SIGPENDING                (1<<TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED      (1<<TIF_NEED_RESCHED)
 #define _TIF_POLLING_NRFLAG    (1<<TIF_POLLING_NRFLAG)
+#define _TIF_SYSCALL_AUDIT      (1<<TIF_SYSCALL_AUDIT)
+#define _TIF_SECCOMP            (1<<TIF_SECCOMP)
+
+#define _TIF_SYSCALL_T_OR_A     (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP)
 
 /*
  * Non racy (local) flags bit numbers

diff --git a/init/Kconfig b/init/Kconfig
index d920bae..7054976 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -173,7 +173,7 @@ config AUDIT
 
 config AUDITSYSCALL
        bool "Enable system-call auditing support"
-       depends on AUDIT && (X86 || PPC64 || ARCH_S390 || IA64 || UML)
+       depends on AUDIT && (X86 || PPC || PPC64 || ARCH_S390 || IA64 || UML)
        default y if SECURITY_SELINUX
        help
          Enable low-overhead system-call auditing infrastructure that