netdev - [PATCH] net: sunrpc: Fix 'snprintf' return value check in 'do_xprt

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Message-ID: <20201015135341.GA16343@laptop>
Date:   Thu, 15 Oct 2020 16:59:08 +0300
From:   Fedor Tokarev <ftokarev@...il.com>
To:     bfields@...ldses.org, chuck.lever@...cle.com,
        anna.schumaker@...app.com, trond.myklebust@...merspace.com,
        davem@...emloft.net, kuba@...nel.org
Cc:     linux-nfs@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        ftokarev@...il.com
Subject: [PATCH] net: sunrpc: Fix 'snprintf' return value check in
 'do_xprt_debugfs'

'snprintf' returns the number of characters which would have been written
if enough space had been available, excluding the terminating null byte.
Thus, the return value of 'sizeof(buf)' means that the last character
has been dropped.

Signed-off-by: Fedor Tokarev <ftokarev@...il.com>
---
 net/sunrpc/debugfs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sunrpc/debugfs.c b/net/sunrpc/debugfs.c
index fd9bca2..56029e3 100644
--- a/net/sunrpc/debugfs.c
+++ b/net/sunrpc/debugfs.c
@@ -128,13 +128,13 @@ static int do_xprt_debugfs(struct rpc_clnt *clnt, struct rpc_xprt *xprt, void *n
 		return 0;
 	len = snprintf(name, sizeof(name), "../../rpc_xprt/%s",
 		       xprt->debugfs->d_name.name);
-	if (len > sizeof(name))
+	if (len >= sizeof(name))
 		return -1;
 	if (*nump == 0)
 		strcpy(link, "xprt");
 	else {
 		len = snprintf(link, sizeof(link), "xprt%d", *nump);
-		if (len > sizeof(link))
+		if (len >= sizeof(link))
 			return -1;
 	}
 	debugfs_create_symlink(link, clnt->cl_debugfs, name);
-- 
2.7.4