path: root/arch
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authorJiri Olsa <jolsa@kernel.org>2017-06-29 11:38:11 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-07-27 15:06:06 -0700
commita89b6e355dae9ccfbe924625f467162c30238aa7 (patch)
tree0bf0feeb619a9d9bfb77a3986906f3c09d19ba0e /arch
parent098333918b4f70a21bc2bc996ae20d2d523bd0b5 (diff)
s390/syscalls: Fix out of bounds arguments access
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>
Diffstat (limited to 'arch')
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/s390/include/asm/syscall.h b/arch/s390/include/asm/syscall.h
index 6ba0bf928909..6bc941be6921 100644
--- a/arch/s390/include/asm/syscall.h
+++ b/arch/s390/include/asm/syscall.h
@@ -64,6 +64,12 @@ static inline void syscall_get_arguments(struct task_struct *task,
unsigned long mask = -1UL;
+ /*
+ * No arguments for this syscall, there's nothing to do.
+ */
+ if (!n)
+ return;
BUG_ON(i + n > 6);
if (test_tsk_thread_flag(task, TIF_31BIT))