From 6baaade15594b28195da369962208b1f658e7342 Mon Sep 17 00:00:00 2001 From: Michael Schmitz Date: Thu, 12 Jan 2023 16:55:28 +1300 Subject: m68k: Add kernel seccomp support Add secure_computing() call to syscall_trace_enter to actually filter system calls. Add necessary arch Kconfig options, define TIF_SECCOMP trace flag and provide basic seccomp filter support in asm/syscall.h syscall_get_nr currently uses the syscall nr stored in orig_d0 because we change d0 to a default return code before starting a syscall trace. This may be inconsistent with syscall_rollback copying orig_d0 to d0 (which we never check upon return from trace). We use d0 for the return code from syscall_trace_enter in entry.S currently, and could perhaps expand that to store a new syscall number returned by the seccomp filter before executing the syscall. This clearly needs some discussion. seccomp_bpf self test on ARAnyM passes 81 out of 94 tests. Signed-off-by: Michael Schmitz Reviewed-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/20230112035529.13521-3-schmitzmic@gmail.com Signed-off-by: Geert Uytterhoeven --- arch/m68k/kernel/entry.S | 3 +++ arch/m68k/kernel/ptrace.c | 6 +++++- 2 files changed, 8 insertions(+), 1 deletion(-) (limited to 'arch/m68k/kernel') diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S index 42879e6eb651..4dd2fd7acba9 100644 --- a/arch/m68k/kernel/entry.S +++ b/arch/m68k/kernel/entry.S @@ -214,6 +214,9 @@ ENTRY(system_call) | syscall trace? tstb %a1@(TINFO_FLAGS+2) jmi do_trace_entry + | seccomp filter active? + btst #5,%a1@(TINFO_FLAGS+2) + bnes do_trace_entry cmpl #NR_syscalls,%d0 jcc badsys syscall: diff --git a/arch/m68k/kernel/ptrace.c b/arch/m68k/kernel/ptrace.c index 0a4184a37461..cd0172d29430 100644 --- a/arch/m68k/kernel/ptrace.c +++ b/arch/m68k/kernel/ptrace.c @@ -21,7 +21,7 @@ #include #include #include - +#include #include #include #include @@ -278,6 +278,10 @@ asmlinkage int syscall_trace_enter(void) if (test_thread_flag(TIF_SYSCALL_TRACE)) ret = ptrace_report_syscall_entry(task_pt_regs(current)); + + if (secure_computing() == -1) + return -1; + return ret; } -- cgit v1.2.3