From efcd764e52e35fc81ac8efefa9ecabece8b12eab Mon Sep 17 00:00:00 2001 From: Chang-Hsien Tsai Date: Sun, 19 May 2019 09:05:44 +0000 Subject: [PATCH] samples, bpf: fix to change the buffer size for read() [ Upstream commit f7c2d64bac1be2ff32f8e4f500c6e5429c1003e0 ] 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 Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin --- 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 2325d7ad76df..e8e8b756dc52 100644 --- a/samples/bpf/bpf_load.c +++ b/samples/bpf/bpf_load.c @@ -613,7 +613,7 @@ 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); -- 2.20.1