There is very little difference in the TIF_SECCOMP and TIF_SYSCALL_TRACE path in entry-common.S. In order to add support for CONFIG_HAVE_ARCH_SECCOMP_FILTER without mangling the assembly too badly, seccomp was moved into the syscall_trace_enter() handler.
Expanded ptrace_syscall_trace() into both callers to make code more readable, as requested by Al Viro. Additionally, the return value for secure_computing() is now checked and a -1 value will result in the system call being skipped. Signed-off-by: Kees Cook <[email protected]> --- arch/arm/kernel/entry-common.S | 9 ++------- arch/arm/kernel/ptrace.c | 39 +++++++++++++++++++++++++-------------- 2 files changed, 27 insertions(+), 21 deletions(-) diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 3471175..c781012 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -418,13 +418,8 @@ local_restart: stmdb sp!, {r4, r5} @ push fifth and sixth args #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: + tst r10, #_TIF_SECCOMP @ is seccomp enabled? + bne __sys_trace #endif tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls? diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c index 739db3a..6b0e14b 100644 --- a/arch/arm/kernel/ptrace.c +++ b/arch/arm/kernel/ptrace.c @@ -916,13 +916,15 @@ enum ptrace_syscall_dir { PTRACE_SYSCALL_EXIT, }; -static int ptrace_syscall_trace(struct pt_regs *regs, int scno, - enum ptrace_syscall_dir dir) +asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno) { unsigned long ip; current_thread_info()->syscall = scno; + if (secure_computing(scno) == -1) + return -1; + if (!test_thread_flag(TIF_SYSCALL_TRACE)) return scno; @@ -931,20 +933,13 @@ static int ptrace_syscall_trace(struct pt_regs *regs, int scno, * IP = 0 -> entry, =1 -> exit */ ip = regs->ARM_ip; - regs->ARM_ip = dir; - - if (dir == PTRACE_SYSCALL_EXIT) - tracehook_report_syscall_exit(regs, 0); - else if (tracehook_report_syscall_entry(regs)) + regs->ARM_ip = PTRACE_SYSCALL_ENTER; + if (tracehook_report_syscall_entry(regs)) current_thread_info()->syscall = -1; - regs->ARM_ip = ip; - return current_thread_info()->syscall; -} -asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno) -{ - scno = ptrace_syscall_trace(regs, scno, PTRACE_SYSCALL_ENTER); + scno = current_thread_info()->syscall; + if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) trace_sys_enter(regs, scno); audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0, regs->ARM_r1, @@ -954,7 +949,23 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno) asmlinkage int syscall_trace_exit(struct pt_regs *regs, int scno) { - scno = ptrace_syscall_trace(regs, scno, PTRACE_SYSCALL_EXIT); + unsigned long ip; + + current_thread_info()->syscall = scno; + + if (!test_thread_flag(TIF_SYSCALL_TRACE)) + return scno; + + /* + * IP is used to denote syscall entry/exit: + * IP = 0 -> entry, =1 -> exit + */ + ip = regs->ARM_ip; + regs->ARM_ip = PTRACE_SYSCALL_EXIT; + tracehook_report_syscall_exit(regs, 0); + regs->ARM_ip = ip; + + scno = current_thread_info()->syscall; if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) trace_sys_exit(regs, scno); audit_syscall_exit(regs); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
