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From: "Daniel T. Lee" <danieltimlee@gmail.com>
To: Daniel Borkmann <daniel@iogearbox.net>,
	Alexei Starovoitov <ast@kernel.org>
Cc: netdev@vger.kernel.org
Subject: [PATCH] samples: bpf: fix: seg fault with NULL pointer arg
Date: Sun,  2 Dec 2018 06:06:57 +0900	[thread overview]
Message-ID: <20181201210657.5350-1-danieltimlee@gmail.com> (raw)

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>
---
 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 434ea34a5954..c670bd2200d2 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 != NULL) && (val[0] == '\0'))
 		flags = O_WRONLY | O_TRUNC;
 	else
 		flags = O_WRONLY | O_APPEND;
-- 
2.17.1

             reply	other threads:[~2018-12-02  8:20 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-01 21:06 Daniel T. Lee [this message]
2018-12-03  7:52 ` [PATCH] samples: bpf: fix: seg fault with NULL pointer arg Song Liu

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