From cd29fa798001075a554b978df3a64e6656c25794 Mon Sep 17 00:00:00 2001 From: Sven Schnelle Date: Fri, 6 Mar 2020 13:18:31 +0100 Subject: [PATCH] s390/ptrace: return -ENOSYS when invalid syscall is supplied The current code returns the syscall number which an invalid syscall number is supplied and tracing is enabled. This makes the strace testsuite fail. Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik --- arch/s390/kernel/ptrace.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index e319482..ceb8105 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -837,6 +837,7 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) { unsigned long mask = -1UL; + long ret = -1; if (is_compat_task()) mask = 0xffffffff; @@ -853,8 +854,7 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) * debugger stored an invalid system call number. Skip * the system call and the system call restart handling. */ - clear_pt_regs_flag(regs, PIF_SYSCALL); - return -1; + goto skip; } #ifdef CONFIG_SECCOMP @@ -870,7 +870,7 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) sd.arch = AUDIT_ARCH_S390X; } - sd.nr = regs->gprs[2] & 0xffff; + sd.nr = regs->int_code & 0xffff; sd.args[0] = regs->orig_gpr2 & mask; sd.args[1] = regs->gprs[3] & mask; sd.args[2] = regs->gprs[4] & mask; @@ -879,19 +879,26 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) sd.args[5] = regs->gprs[7] & mask; if (__secure_computing(&sd) == -1) - return -1; + goto skip; } #endif /* CONFIG_SECCOMP */ if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) - trace_sys_enter(regs, regs->gprs[2]); + trace_sys_enter(regs, regs->int_code & 0xffff); - audit_syscall_entry(regs->gprs[2], regs->orig_gpr2 & mask, + audit_syscall_entry(regs->int_code & 0xffff, regs->orig_gpr2 & mask, regs->gprs[3] &mask, regs->gprs[4] &mask, regs->gprs[5] &mask); + if ((signed long)regs->gprs[2] >= NR_syscalls) { + regs->gprs[2] = -ENOSYS; + ret = -ENOSYS; + } return regs->gprs[2]; +skip: + clear_pt_regs_flag(regs, PIF_SYSCALL); + return ret; } asmlinkage void do_syscall_trace_exit(struct pt_regs *regs) -- 2.7.4