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authorJiri Olsa <jolsa@kernel.org>2017-06-29 11:38:11 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2017-07-05 07:35:30 +0200
commitc46fc0424ced3fb71208e72bd597d91b9169a781 (patch)
tree3a1afec55c72563a63af08431270c6814a9a9979 /arch/s390/include/asm/syscall.h
parentc14b7a85be8f9f2c3faba45ddf47e851feb1c27c (diff)
downloadlinux-sh-c46fc0424ced3fb71208e72bd597d91b9169a781.tar.gz
s390/syscalls: Fix out of bounds arguments access
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. Cc: stable@vger.kernel.org Reported-by: Zorro Lang <zlang@redhat.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/syscall.h')
-rw-r--r--arch/s390/include/asm/syscall.h6
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);
#ifdef CONFIG_COMPAT
if (test_tsk_thread_flag(task, TIF_31BIT))