nfsd: enforce upper limit for namelen in __cld_pipe_inprogress_downcall()

This patch is intended to go on top of "nfsd: return -EINVAL when
namelen is 0" from Li Lingfeng.  Li's patch checks for 0, but we should
be enforcing an upper bound as well.

Note that if nfsdcld somehow gets an id > NFS4_OPAQUE_LIMIT in its
database, it'll truncate it to NFS4_OPAQUE_LIMIT when it does the
downcall anyway.

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 530686f32e9ecd9e00202e928d44bd08d0324793..b7d61eb8afe9e10d94b614ae50c2790fe6816732 100644 (file)
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -809,8 +809,8 @@ __cld_pipe_inprogress_downcall(const struct cld_msg_v2 __user *cmsg,
                        ci = &cmsg->cm_u.cm_clntinfo;
                        if (get_user(namelen, &ci->cc_name.cn_len))
                                return -EFAULT;
-                       if (!namelen) {
-                               dprintk("%s: namelen should not be zero", __func__);
+                       if (namelen == 0 || namelen > NFS4_OPAQUE_LIMIT) {
+                               dprintk("%s: invalid namelen (%u)", __func__, namelen);
                                return -EINVAL;
                        }
                        name.data = memdup_user(&ci->cc_name.cn_id, namelen);
@@ -835,8 +835,8 @@ __cld_pipe_inprogress_downcall(const struct cld_msg_v2 __user *cmsg,
                        cnm = &cmsg->cm_u.cm_name;
                        if (get_user(namelen, &cnm->cn_len))
                                return -EFAULT;
-                       if (!namelen) {
-                               dprintk("%s: namelen should not be zero", __func__);
+                       if (namelen == 0 || namelen > NFS4_OPAQUE_LIMIT) {
+                               dprintk("%s: invalid namelen (%u)", __func__, namelen);
                                return -EINVAL;
                        }
                        name.data = memdup_user(&cnm->cn_id, namelen);