Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.14 02/35] samples, bpf: fix to change the buffer size for read() | Date | Wed, 26 Jun 2019 20:38:50 -0400 |
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From: Chang-Hsien Tsai <luke.tw@gmail.com>
[ 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 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
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