This is a note to let you know that I've just added the patch titled s390/ptrace: return -ENOSYS when invalid syscall is supplied to the 5.7-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: s390-ptrace-return-enosys-when-invalid-syscall-is-su.patch and it can be found in the queue-5.7 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 5ce966679d209a2cb74f22cc898ad721e7bc9fe6 Author: Sven Schnelle <svens@xxxxxxxxxxxxx> Date: Fri Mar 6 13:18:31 2020 +0100 s390/ptrace: return -ENOSYS when invalid syscall is supplied [ Upstream commit cd29fa798001075a554b978df3a64e6656c25794 ] 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 <svens@xxxxxxxxxxxxx> Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index 9eee345568890..3f29646313e82 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -838,6 +838,7 @@ 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; @@ -854,8 +855,7 @@ 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 @@ -871,7 +871,7 @@ 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; @@ -880,19 +880,26 @@ 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)