bpf: Fixes a snprintf truncation warning
gcc v9.3.1 reports:
bpf.c: In function ‘bpf_get_work_dir’:
bpf.c:784:49: warning: ‘snprintf’ output may be truncated before the last format character [-Wformat-truncation=]
784 | snprintf(bpf_wrk_dir, sizeof(bpf_wrk_dir), "%s/", mnt);
| ^
bpf.c:784:2: note: ‘snprintf’ output between 2 and 4097 bytes into a destination of size 4096
784 | snprintf(bpf_wrk_dir, sizeof(bpf_wrk_dir), "%s/", mnt);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fix this simply checking snprintf return code and properly handling the error.
Fixes: e42256699cac ("bpf: make tc's bpf loader generic and move into lib")
Signed-off-by: Andrea Claudi <aclaudi@redhat.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
diff --git a/lib/bpf.c b/lib/bpf.c
index 23cb0d9..c7d4507 100644
--- a/lib/bpf.c
+++ b/lib/bpf.c
@@ -781,7 +781,11 @@
}
}
- snprintf(bpf_wrk_dir, sizeof(bpf_wrk_dir), "%s/", mnt);
+ ret = snprintf(bpf_wrk_dir, sizeof(bpf_wrk_dir), "%s/", mnt);
+ if (ret < 0 || ret >= sizeof(bpf_wrk_dir)) {
+ mnt = NULL;
+ goto out;
+ }
ret = bpf_gen_hierarchy(bpf_wrk_dir);
if (ret) {
