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@xxxxxxxxxxxxxxxx> Signed-off-by: Will Drewry <wad@xxxxxxxxxxxx> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx> --- arch/microblaze/kernel/ptrace.c | 2 +- arch/mips/kernel/ptrace.c | 2 +- arch/powerpc/kernel/ptrace.c | 2 +- arch/s390/kernel/ptrace.c | 2 +- arch/sh/kernel/ptrace_32.c | 2 +- arch/sh/kernel/ptrace_64.c | 2 +- arch/sparc/kernel/ptrace_64.c | 2 +- include/linux/seccomp.h | 7 +++++++ 8 files changed, 14 insertions(+), 7 deletions(-) diff --git a/arch/microblaze/kernel/ptrace.c b/arch/microblaze/kernel/ptrace.c index 6eb2aa9..ab1b9db 100644 --- a/arch/microblaze/kernel/ptrace.c +++ b/arch/microblaze/kernel/ptrace.c @@ -136,7 +136,7 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) { long ret = 0; - secure_computing(regs->r12); + secure_computing_strict(regs->r12); if (test_thread_flag(TIF_SYSCALL_TRACE) && tracehook_report_syscall_entry(regs)) diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index 7c24c29..4812c6d 100644 --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -535,7 +535,7 @@ static inline int audit_arch(void) asmlinkage void syscall_trace_enter(struct pt_regs *regs) { /* do the secure computing check first */ - secure_computing(regs->regs[2]); + secure_computing_strict(regs->regs[2]); if (!(current->ptrace & PT_PTRACED)) goto out; diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c index 8d8e028..dd5e214 100644 --- a/arch/powerpc/kernel/ptrace.c +++ b/arch/powerpc/kernel/ptrace.c @@ -1710,7 +1710,7 @@ long do_syscall_trace_enter(struct pt_regs *regs) { long ret = 0; - secure_computing(regs->gpr[0]); + secure_computing_strict(regs->gpr[0]); if (test_thread_flag(TIF_SYSCALL_TRACE) && tracehook_report_syscall_entry(regs)) diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index 02f300f..4993e68 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -719,7 +719,7 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) long ret = 0; /* Do the secure computing check first. */ - secure_computing(regs->gprs[2]); + secure_computing_strict(regs->gprs[2]); /* * The sysc_tracesys code in entry.S stored the system diff --git a/arch/sh/kernel/ptrace_32.c b/arch/sh/kernel/ptrace_32.c index 9698671..81f999a 100644 --- a/arch/sh/kernel/ptrace_32.c +++ b/arch/sh/kernel/ptrace_32.c @@ -503,7 +503,7 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) { long ret = 0; - secure_computing(regs->regs[0]); + secure_computing_strict(regs->regs[0]); if (test_thread_flag(TIF_SYSCALL_TRACE) && tracehook_report_syscall_entry(regs)) diff --git a/arch/sh/kernel/ptrace_64.c b/arch/sh/kernel/ptrace_64.c index bc81e07..af90339 100644 --- a/arch/sh/kernel/ptrace_64.c +++ b/arch/sh/kernel/ptrace_64.c @@ -522,7 +522,7 @@ asmlinkage long long do_syscall_trace_enter(struct pt_regs *regs) { long long ret = 0; - secure_computing(regs->regs[9]); + secure_computing_strict(regs->regs[9]); if (test_thread_flag(TIF_SYSCALL_TRACE) && tracehook_report_syscall_entry(regs)) diff --git a/arch/sparc/kernel/ptrace_64.c b/arch/sparc/kernel/ptrace_64.c index 6f97c07..484daba 100644 --- a/arch/sparc/kernel/ptrace_64.c +++ b/arch/sparc/kernel/ptrace_64.c @@ -1062,7 +1062,7 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs) int ret = 0; /* do the secure computing check first */ - secure_computing(regs->u_regs[UREG_G1]); + secure_computing_strict(regs->u_regs[UREG_G1]); if (test_thread_flag(TIF_SYSCALL_TRACE)) ret = tracehook_report_syscall_entry(regs); diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index 60f2b35..84f6320d 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -75,6 +75,12 @@ static inline int secure_computing(int 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 *); @@ -91,6 +97,7 @@ 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) { -- 1.7.5.4
