From: Daniel T. Lee <danieltimlee@gmail.com>
Date: Mon, 3 Dec 2018 10:39:30 +0000 (+0900)
Subject: samples: bpf: fix: seg fault with NULL pointer arg
X-Git-Tag: v5.0-rc1~129^2~114^2~12
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d59dd69d5576d699d7d3f5da0b4738c3a36d0133;p=thirdparty%2Fkernel%2Flinux.git

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>
---

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;