[ 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 luke.tw@gmail.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Sasha Levin sashal@kernel.org --- 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 da86a8e0a95a..e836b5ff2060 100644 --- a/samples/bpf/bpf_load.c +++ b/samples/bpf/bpf_load.c @@ -336,7 +336,7 @@ 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);