From d77be68955475fc2321e73fe006240248f2f8fef Mon Sep 17 00:00:00 2001 From: Quentin Monnet Date: Tue, 16 Jan 2018 15:51:48 -0800 Subject: libbpf: fix string comparison for guessing eBPF program type libbpf is able to deduce the type of a program from the name of the ELF section in which it is located. However, the comparison is made on the first n characters, n being determined with sizeof() applied to the reference string (e.g. "xdp"). When such section names are supposed to receive a suffix separated with a slash (e.g. "kprobe/"), using sizeof() takes the final NUL character of the reference string into account, which implies that both strings must be equal. Instead, the desired behaviour would consist in taking the length of the string, *without* accounting for the ending NUL character, and to make sure the reference string is a prefix to the ELF section name. Subtract 1 to the total size of the string for obtaining the length for the comparison. Fixes: 583c90097f72 ("libbpf: add ability to guess program type based on section name") Signed-off-by: Quentin Monnet Acked-by: Jakub Kicinski Signed-off-by: Daniel Borkmann --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib/bpf') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index e9c4b7cabcf2..30c776375118 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1803,7 +1803,7 @@ BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT); BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP); BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT); -#define BPF_PROG_SEC(string, type) { string, sizeof(string), type } +#define BPF_PROG_SEC(string, type) { string, sizeof(string) - 1, type } static const struct { const char *sec; size_t len; -- cgit v1.2.3