e4da89d02f
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>
133 lines
3.6 KiB
C
133 lines
3.6 KiB
C
#ifndef _LINUX_SECCOMP_H
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#define _LINUX_SECCOMP_H
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#include <linux/compiler.h>
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#include <linux/types.h>
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/* Valid values for seccomp.mode and prctl(PR_SET_SECCOMP, <mode>) */
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#define SECCOMP_MODE_DISABLED 0 /* seccomp is not in use. */
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#define SECCOMP_MODE_STRICT 1 /* uses hard-coded filter. */
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#define SECCOMP_MODE_FILTER 2 /* uses user-supplied filter. */
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/*
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* All BPF programs must return a 32-bit value.
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* The bottom 16-bits are for optional return data.
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* The upper 16-bits are ordered from least permissive values to most.
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*
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* The ordering ensures that a min_t() over composed return values always
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* selects the least permissive choice.
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*/
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#define SECCOMP_RET_KILL 0x00000000U /* kill the task immediately */
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#define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */
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#define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */
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#define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */
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#define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */
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/* Masks for the return value sections. */
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#define SECCOMP_RET_ACTION 0x7fff0000U
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#define SECCOMP_RET_DATA 0x0000ffffU
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/**
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* struct seccomp_data - the format the BPF program executes over.
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* @nr: the system call number
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* @arch: indicates system call convention as an AUDIT_ARCH_* value
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* as defined in <linux/audit.h>.
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* @instruction_pointer: at the time of the system call.
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* @args: up to 6 system call arguments always stored as 64-bit values
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* regardless of the architecture.
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*/
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struct seccomp_data {
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int nr;
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__u32 arch;
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__u64 instruction_pointer;
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__u64 args[6];
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};
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#ifdef __KERNEL__
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#ifdef CONFIG_SECCOMP
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#include <linux/thread_info.h>
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#include <asm/seccomp.h>
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struct seccomp_filter;
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/**
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* struct seccomp - the state of a seccomp'ed process
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*
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* @mode: indicates one of the valid values above for controlled
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* system calls available to a process.
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* @filter: The metadata and ruleset for determining what system calls
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* are allowed for a task.
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*
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* @filter must only be accessed from the context of current as there
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* is no locking.
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*/
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struct seccomp {
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int mode;
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struct seccomp_filter *filter;
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};
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extern int __secure_computing(int);
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static inline int secure_computing(int this_syscall)
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{
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if (unlikely(test_thread_flag(TIF_SECCOMP)))
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return __secure_computing(this_syscall);
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return 0;
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}
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/* A wrapper for architectures supporting only SECCOMP_MODE_STRICT. */
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static inline void secure_computing_strict(int this_syscall)
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{
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BUG_ON(secure_computing(this_syscall) != 0);
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}
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extern long prctl_get_seccomp(void);
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extern long prctl_set_seccomp(unsigned long, char __user *);
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static inline int seccomp_mode(struct seccomp *s)
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{
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return s->mode;
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}
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#else /* CONFIG_SECCOMP */
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#include <linux/errno.h>
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struct seccomp { };
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struct seccomp_filter { };
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static inline int secure_computing(int this_syscall) { return 0; }
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static inline void secure_computing_strict(int this_syscall) { return; }
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static inline long prctl_get_seccomp(void)
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{
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return -EINVAL;
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}
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static inline long prctl_set_seccomp(unsigned long arg2, char __user *arg3)
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{
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return -EINVAL;
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}
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static inline int seccomp_mode(struct seccomp *s)
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{
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return 0;
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}
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#endif /* CONFIG_SECCOMP */
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#ifdef CONFIG_SECCOMP_FILTER
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extern void put_seccomp_filter(struct task_struct *tsk);
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extern void get_seccomp_filter(struct task_struct *tsk);
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extern u32 seccomp_bpf_load(int off);
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#else /* CONFIG_SECCOMP_FILTER */
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static inline void put_seccomp_filter(struct task_struct *tsk)
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{
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return;
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}
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static inline void get_seccomp_filter(struct task_struct *tsk)
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{
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return;
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}
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#endif /* CONFIG_SECCOMP_FILTER */
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#endif /* __KERNEL__ */
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#endif /* _LINUX_SECCOMP_H */
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