From d59dd69d5576d699d7d3f5da0b4738c3a36d0133 Mon Sep 17 00:00:00 2001
From: "Daniel T. Lee" <danieltimlee@gmail.com>
Date: Mon, 3 Dec 2018 19:39:30 +0900
Subject: [PATCH] samples: bpf: fix: seg fault with NULL pointer arg
When NULL pointer accidentally passed to write_kprobe_events,
due to strlen(NULL), segmentation fault happens.
Changed code returns -1 to deal with this situation.
Bug issued with Smatch, static analysis.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
samples/bpf/bpf_load.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index 434ea34a59549..eae7b635343d1 100644
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c
@@ -58,7 +58,9 @@ static int write_kprobe_events(const char *val)
{
int fd, ret, flags;
- if ((val != NULL) && (val[0] == '\0'))
+ if (val == NULL)
+ return -1;
+ else if (val[0] == '\0')
flags = O_WRONLY | O_TRUNC;
else
flags = O_WRONLY | O_APPEND;
--
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