kernel-ark/include/linux/seccomp.h
Will Drewry e4da89d02f seccomp: ignore secure_computing return values
This change is inspired by
  https://lkml.org/lkml/2012/4/16/14
which fixes the build warnings for arches that don't support
CONFIG_HAVE_ARCH_SECCOMP_FILTER.

In particular, there is no requirement for the return value of
secure_computing() to be checked unless the architecture supports
seccomp filter.  Instead of silencing the warnings with (void)
a new static inline is added to encode the expected behavior
in a compiler and human friendly way.

v2: - cleans things up with a static inline
    - removes sfr's signed-off-by since it is a different approach
v1: - matches sfr's original change

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Will Drewry <wad@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2012-04-18 12:24:50 +10:00

134 lines
3.6 KiB
C

#ifndef _LINUX_SECCOMP_H
#define _LINUX_SECCOMP_H
#include <linux/compiler.h>
#include <linux/types.h>
/* Valid values for seccomp.mode and prctl(PR_SET_SECCOMP, <mode>) */
#define SECCOMP_MODE_DISABLED 0 /* seccomp is not in use. */
#define SECCOMP_MODE_STRICT 1 /* uses hard-coded filter. */
#define SECCOMP_MODE_FILTER 2 /* uses user-supplied filter. */
/*
* All BPF programs must return a 32-bit value.
* The bottom 16-bits are for optional return data.
* The upper 16-bits are ordered from least permissive values to most.
*
* The ordering ensures that a min_t() over composed return values always
* selects the least permissive choice.
*/
#define SECCOMP_RET_KILL 0x00000000U /* kill the task immediately */
#define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */
#define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */
#define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */
#define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */
/* Masks for the return value sections. */
#define SECCOMP_RET_ACTION 0x7fff0000U
#define SECCOMP_RET_DATA 0x0000ffffU
/**
* struct seccomp_data - the format the BPF program executes over.
* @nr: the system call number
* @arch: indicates system call convention as an AUDIT_ARCH_* value
* as defined in <linux/audit.h>.
* @instruction_pointer: at the time of the system call.
* @args: up to 6 system call arguments always stored as 64-bit values
* regardless of the architecture.
*/
struct seccomp_data {
int nr;
__u32 arch;
__u64 instruction_pointer;
__u64 args[6];
};
#ifdef __KERNEL__
#ifdef CONFIG_SECCOMP
#include <linux/thread_info.h>
#include <asm/seccomp.h>
struct seccomp_filter;
/**
* struct seccomp - the state of a seccomp'ed process
*
* @mode: indicates one of the valid values above for controlled
* system calls available to a process.
* @filter: The metadata and ruleset for determining what system calls
* are allowed for a task.
*
* @filter must only be accessed from the context of current as there
* is no locking.
*/
struct seccomp {
int mode;
struct seccomp_filter *filter;
};
extern int __secure_computing(int);
static inline int secure_computing(int this_syscall)
{
if (unlikely(test_thread_flag(TIF_SECCOMP)))
return __secure_computing(this_syscall);
return 0;
}
/* A wrapper for architectures supporting only SECCOMP_MODE_STRICT. */
static inline void secure_computing_strict(int this_syscall)
{
BUG_ON(secure_computing(this_syscall) != 0);
}
extern long prctl_get_seccomp(void);
extern long prctl_set_seccomp(unsigned long, char __user *);
static inline int seccomp_mode(struct seccomp *s)
{
return s->mode;
}
#else /* CONFIG_SECCOMP */
#include <linux/errno.h>
struct seccomp { };
struct seccomp_filter { };
static inline int secure_computing(int this_syscall) { return 0; }
static inline void secure_computing_strict(int this_syscall) { return; }
static inline long prctl_get_seccomp(void)
{
return -EINVAL;
}
static inline long prctl_set_seccomp(unsigned long arg2, char __user *arg3)
{
return -EINVAL;
}
static inline int seccomp_mode(struct seccomp *s)
{
return 0;
}
#endif /* CONFIG_SECCOMP */
#ifdef CONFIG_SECCOMP_FILTER
extern void put_seccomp_filter(struct task_struct *tsk);
extern void get_seccomp_filter(struct task_struct *tsk);
extern u32 seccomp_bpf_load(int off);
#else /* CONFIG_SECCOMP_FILTER */
static inline void put_seccomp_filter(struct task_struct *tsk)
{
return;
}
static inline void get_seccomp_filter(struct task_struct *tsk)
{
return;
}
#endif /* CONFIG_SECCOMP_FILTER */
#endif /* __KERNEL__ */
#endif /* _LINUX_SECCOMP_H */