| From | Herton Ronaldo Krzesinski <> | Subject | [PATCH 106/222] NFS: avoid NULL dereference in nfs_destroy_server | Date | Wed, 16 Jan 2013 13:55:06 -0200 |
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3.5.7.3 -stable review patch. If anyone has any objections, please let me know.
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From: NeilBrown <neilb@suse.de>
commit f259613a1e4b44a0cf85a5dafd931be96ee7c9e5 upstream.
In rare circumstances, nfs_clone_server() of a v2 or v3 server can get an error between setting server->destory (to nfs_destroy_server), and calling nfs_start_lockd (which will set server->nlm_host).
If this happens, nfs_clone_server will call nfs_free_server which will call nfs_destroy_server and thence nlmclnt_done(NULL). This causes the NULL to be dereferenced.
So add a guard to only call nlmclnt_done() if ->nlm_host is not NULL.
The other guards there are irrelevant as nlm_host can only be non-NULL if one of these flags are set - so remove those tests. (Thanks to Trond for this suggestion).
This is suitable for any stable kernel since 2.6.25.
Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> --- fs/nfs/client.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/fs/nfs/client.c b/fs/nfs/client.c index f005b5b..ede78be 100644 --- a/fs/nfs/client.c +++ b/fs/nfs/client.c @@ -689,8 +689,7 @@ static int nfs_create_rpc_client(struct nfs_client *clp, */ static void nfs_destroy_server(struct nfs_server *server) { - if (!(server->flags & NFS_MOUNT_LOCAL_FLOCK) || - !(server->flags & NFS_MOUNT_LOCAL_FCNTL)) + if (server->nlm_host) nlmclnt_done(server->nlm_host); } -- 1.7.9.5
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