netdev - [PATCH iproute2-next] bpf: fix snprintf truncation warning

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Date:   Wed,  4 Sep 2019 17:50:24 +0200
From:   Andrea Claudi <aclaudi@...hat.com>
To:     netdev@...r.kernel.org
Cc:     stephen@...workplumber.org, dsahern@...nel.org
Subject: [PATCH iproute2-next] bpf: fix snprintf truncation warning

gcc v9.2.1 produces the following warning compiling iproute2:

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 it extending bpf_wrk_dir size by 1 byte for the extra "/" char.

Signed-off-by: Andrea Claudi <aclaudi@...hat.com>
---
 lib/bpf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/bpf.c b/lib/bpf.c
index 7d2a322ffbaec..95de7894a93ce 100644
--- a/lib/bpf.c
+++ b/lib/bpf.c
@@ -742,7 +742,7 @@ static int bpf_gen_hierarchy(const char *base)
 static const char *bpf_get_work_dir(enum bpf_prog_type type)
 {
 	static char bpf_tmp[PATH_MAX] = BPF_DIR_MNT;
-	static char bpf_wrk_dir[PATH_MAX];
+	static char bpf_wrk_dir[PATH_MAX + 1];
 	static const char *mnt;
 	static bool bpf_mnt_cached;
 	const char *mnt_env = getenv(BPF_ENV_MNT);
-- 
2.21.0