From d9060742fbf630fe31951dfc10b798deb2813f01 Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Fri, 28 Mar 2014 13:33:38 -0700 Subject: [PATCH] ocfs2: check if cluster name exists before deref Commit c74a3bdd9b52 ("ocfs2: add clustername to cluster connection") is trying to strlcpy a string which was explicitly passed as NULL in the very same patch, triggering a NULL ptr deref. BUG: unable to handle kernel NULL pointer dereference at (null) IP: strlcpy (lib/string.c:388 lib/string.c:151) CPU: 19 PID: 19426 Comm: trinity-c19 Tainted: G W 3.14.0-rc7-next-20140325-sasha-00014-g9476368-dirty #274 RIP: strlcpy (lib/string.c:388 lib/string.c:151) Call Trace: ocfs2_cluster_connect (fs/ocfs2/stackglue.c:350) ocfs2_cluster_connect_agnostic (fs/ocfs2/stackglue.c:396) user_dlm_register (fs/ocfs2/dlmfs/userdlm.c:679) dlmfs_mkdir (fs/ocfs2/dlmfs/dlmfs.c:503) vfs_mkdir (fs/namei.c:3467) SyS_mkdirat (fs/namei.c:3488 fs/namei.c:3472) tracesys (arch/x86/kernel/entry_64.S:749) akpm: this patch probably disables the feature. A temporary thing to avoid triviel oopses. Signed-off-by: Sasha Levin Cc: Goldwyn Rodrigues Cc: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/stackglue.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c index 1324e6600e57..ca5ce14cbddc 100644 --- a/fs/ocfs2/stackglue.c +++ b/fs/ocfs2/stackglue.c @@ -346,7 +346,9 @@ int ocfs2_cluster_connect(const char *stack_name, strlcpy(new_conn->cc_name, group, GROUP_NAME_MAX + 1); new_conn->cc_namelen = grouplen; - strlcpy(new_conn->cc_cluster_name, cluster_name, CLUSTER_NAME_MAX + 1); + if (cluster_name_len) + strlcpy(new_conn->cc_cluster_name, cluster_name, + CLUSTER_NAME_MAX + 1); new_conn->cc_cluster_name_len = cluster_name_len; new_conn->cc_recovery_handler = recovery_handler; new_conn->cc_recovery_data = recovery_data; -- 2.39.2