From 50268a3d266ecfdd6c5873d62b2758d9732fc598 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 10 Apr 2018 21:20:08 +0900 Subject: [PATCH] tracing/uprobe_event: Fix strncpy corner case MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fix string fetch function to terminate with NUL. It is OK to drop the rest of string. Signed-off-by: Masami Hiramatsu Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Song Liu Cc: Thomas Gleixner Cc: security@kernel.org Cc: 范龙飞 Fixes: 5baaa59ef09e ("tracing/probes: Implement 'memory' fetch method for uprobes") Signed-off-by: Ingo Molnar --- kernel/trace/trace_uprobe.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 2014f4351ae0..0d450b40988e 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -151,6 +151,8 @@ static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs, return; ret = strncpy_from_user(dst, src, maxlen); + if (ret == maxlen) + dst[--ret] = '\0'; if (ret < 0) { /* Failed to fetch string */ ((u8 *)get_rloc_data(dest))[0] = '\0';