| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.18 32/60] s390/syscalls: Fix out of bounds arguments access | Date | Tue, 25 Jul 2017 12:16:23 -0700 |
| |
3.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jiri Olsa <jolsa@kernel.org>
commit c46fc0424ced3fb71208e72bd597d91b9169a781 upstream.
Zorro reported following crash while having enabled syscall tracing (CONFIG_FTRACE_SYSCALLS):
Unable to handle kernel pointer dereference at virtual ... Oops: 0011 [#1] SMP DEBUG_PAGEALLOC
SNIP
Call Trace: ([<000000000024d79c>] ftrace_syscall_enter+0xec/0x1d8) [<00000000001099c6>] do_syscall_trace_enter+0x236/0x2f8 [<0000000000730f1c>] sysc_tracesys+0x1a/0x32 [<000003fffcf946a2>] 0x3fffcf946a2 INFO: lockdep is turned off. Last Breaking-Event-Address: [<000000000022dd44>] rb_event_data+0x34/0x40 ---[ end trace 8c795f86b1b3f7b9 ]---
The crash happens in syscall_get_arguments function for syscalls with zero arguments, that will try to access first argument (args[0]) in event entry, but it's not allocated.
Bail out of there are no arguments.
Reported-by: Zorro Lang <zlang@redhat.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/s390/include/asm/syscall.h | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/arch/s390/include/asm/syscall.h +++ b/arch/s390/include/asm/syscall.h @@ -64,6 +64,12 @@ static inline void syscall_get_arguments { unsigned long mask = -1UL; + /* + * No arguments for this syscall, there's nothing to do. + */ + if (!n) + return; + BUG_ON(i + n > 6); #ifdef CONFIG_COMPAT if (test_tsk_thread_flag(task, TIF_31BIT))
|