linux-kernel - [PATCH][next] NFS: Add missing null check for failed allocation

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Message-Id: <20200106131734.51759-1-colin.king@canonical.com>
Date:   Mon,  6 Jan 2020 13:17:34 +0000
From:   Colin King <colin.king@...onical.com>
To:     Trond Myklebust <trond.myklebust@...merspace.com>,
        Anna Schumaker <Anna.Schumaker@...app.com>,
        Scott Mayhew <smayhew@...hat.com>,
        David Howells <dhowells@...hat.com>,
        Al Viro <viro@...iv.linux.org.uk>, linux-nfs@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][next] NFS: Add missing null check for failed allocation

From: Colin Ian King <colin.king@...onical.com>

Currently the allocation of buf is not being null checked and
a null pointer dereference can occur when the memory allocation fails.
Fix this by adding a check and returning -ENOMEM.

Addresses-Coverity: ("Dereference null return")
Fixes: 6d972518b821 ("NFS: Add fs_context support.")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 fs/nfs/nfs4namespace.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 10e9e1887841..de6875a9b391 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -137,6 +137,9 @@ static int nfs4_validate_fspath(struct dentry *dentry,
 	int n;
 
 	buf = kmalloc(4096, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
 	path = nfs4_path(dentry, buf, 4096);
 	if (IS_ERR(path)) {
 		kfree(buf);
-- 
2.24.0