From f7c2d64bac1be2ff32f8e4f500c6e5429c1003e0 Mon Sep 17 00:00:00 2001
From: Chang-Hsien Tsai <luke.tw@gmail.com>
Date: Sun, 19 May 2019 09:05:44 +0000
Subject: [PATCH] samples, bpf: fix to change the buffer size for read()
Git-commit: f7c2d64bac1be2ff32f8e4f500c6e5429c1003e0
Patch-mainline: v5.2-rc6
References: bsc#1051510
If the trace for read is larger than 4096, the return
value sz will be 4096. This results in off-by-one error
on buf:
static char buf[4096];
ssize_t sz;
sz = read(trace_fd, buf, sizeof(buf));
if (sz > 0) {
buf[sz] = 0;
puts(buf);
}
Signed-off-by: Chang-Hsien Tsai <luke.tw@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
samples/bpf/bpf_load.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index eae7b635343d..6e87cc831e84 100644
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c
@@ -678,7 +678,7 @@ void read_trace_pipe(void)
static char buf[4096];
ssize_t sz;
- sz = read(trace_fd, buf, sizeof(buf));
+ sz = read(trace_fd, buf, sizeof(buf) - 1);
if (sz > 0) {
buf[sz] = 0;
puts(buf);
--
2.16.4