Commit 70c70d97 authored by Nicolas Pitre's avatar Nicolas Pitre
Browse files

ARM: SECCOMP support


Signed-off-by: default avatarNicolas Pitre <nicolas.pitre@linaro.org>
parent 087aaffc
......@@ -1463,6 +1463,20 @@ config UACCESS_WITH_MEMCPY
However, if the CPU data cache is using a write-allocate mode,
this option is unlikely to provide any performance gain.
config SECCOMP
bool
prompt "Enable seccomp to safely compute untrusted bytecode"
---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 prctl(PR_SET_SECCOMP), it cannot be disabled
and the task is only allowed to execute a few safe syscalls
defined by each seccomp mode.
config CC_STACKPROTECTOR
bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
help
......
#ifndef _ASM_ARM_SECCOMP_H
#define _ASM_ARM_SECCOMP_H
#include <linux/unistd.h>
#define __NR_seccomp_read __NR_read
#define __NR_seccomp_write __NR_write
#define __NR_seccomp_exit __NR_exit
#define __NR_seccomp_sigreturn __NR_rt_sigreturn
#endif /* _ASM_ARM_SECCOMP_H */
......@@ -144,6 +144,7 @@ extern void vfp_flush_hwstate(struct thread_info *);
#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
#define TIF_FREEZE 19
#define TIF_RESTORE_SIGMASK 20
#define TIF_SECCOMP 21
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
......@@ -153,6 +154,7 @@ extern void vfp_flush_hwstate(struct thread_info *);
#define _TIF_USING_IWMMXT (1 << TIF_USING_IWMMXT)
#define _TIF_FREEZE (1 << TIF_FREEZE)
#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
/*
* Change these and you break ASM code in entry-common.S
......
......@@ -295,7 +295,6 @@ ENTRY(vector_swi)
get_thread_info tsk
adr tbl, sys_call_table @ load syscall table pointer
ldr ip, [tsk, #TI_FLAGS] @ check for syscall tracing
#if defined(CONFIG_OABI_COMPAT)
/*
......@@ -312,8 +311,20 @@ ENTRY(vector_swi)
eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
#endif
ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
stmdb sp!, {r4, r5} @ push fifth and sixth args
tst ip, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
#ifdef CONFIG_SECCOMP
tst r10, #_TIF_SECCOMP
beq 1f
mov r0, scno
bl __secure_computing
add r0, sp, #S_R0 + S_OFF @ pointer to regs
ldmia r0, {r0 - r3} @ have to reload r0 - r3
1:
#endif
tst r10, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
bne __sys_trace
cmp scno, #NR_syscalls @ check upper syscall limit
......
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