NFSv4: Clean up owner/group attribute decode

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index ec0d767..3268a23 100644 (file)
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -3875,45 +3875,50 @@ out_overflow:
        return -EIO;
 }
 
+static ssize_t decode_nfs4_string(struct xdr_stream *xdr,
+               struct nfs4_string *name, gfp_t gfp_flags)
+{
+       ssize_t ret;
+
+       ret = xdr_stream_decode_string_dup(xdr, &name->data,
+                       XDR_MAX_NETOBJ, gfp_flags);
+       name->len = 0;
+       if (ret > 0)
+               name->len = ret;
+       return ret;
+}
+
 static int decode_attr_owner(struct xdr_stream *xdr, uint32_t *bitmap,
                const struct nfs_server *server, kuid_t *uid,
                struct nfs4_string *owner_name)
 {
-       uint32_t len;
-       __be32 *p;
-       int ret = 0;
+       ssize_t len;
+       char *p;
 
        *uid = make_kuid(&init_user_ns, -2);
        if (unlikely(bitmap[1] & (FATTR4_WORD1_OWNER - 1U)))
                return -EIO;
-       if (likely(bitmap[1] & FATTR4_WORD1_OWNER)) {
-               p = xdr_inline_decode(xdr, 4);
-               if (unlikely(!p))
-                       goto out_overflow;
-               len = be32_to_cpup(p);
-               p = xdr_inline_decode(xdr, len);
-               if (unlikely(!p))
-                       goto out_overflow;
-               if (owner_name != NULL) {
-                       owner_name->data = kmemdup(p, len, GFP_NOWAIT);
-                       if (owner_name->data != NULL) {
-                               owner_name->len = len;
-                               ret = NFS_ATTR_FATTR_OWNER_NAME;
-                       }
-               } else if (len < XDR_MAX_NETOBJ) {
-                       if (nfs_map_name_to_uid(server, (char *)p, len, uid) == 0)
-                               ret = NFS_ATTR_FATTR_OWNER;
-                       else
-                               dprintk("%s: nfs_map_name_to_uid failed!\n",
-                                               __func__);
-               } else
-                       dprintk("%s: name too long (%u)!\n",
-                                       __func__, len);
-               bitmap[1] &= ~FATTR4_WORD1_OWNER;
+       if (!(bitmap[1] & FATTR4_WORD1_OWNER))
+               return 0;
+       bitmap[1] &= ~FATTR4_WORD1_OWNER;
+
+       if (owner_name != NULL) {
+               len = decode_nfs4_string(xdr, owner_name, GFP_NOWAIT);
+               if (len <= 0)
+                       goto out;
+               dprintk("%s: name=%s\n", __func__, owner_name->data);
+               return NFS_ATTR_FATTR_OWNER_NAME;
+       } else {
+               len = xdr_stream_decode_opaque_inline(xdr, (void **)&p,
+                               XDR_MAX_NETOBJ);
+               if (len <= 0 || nfs_map_name_to_uid(server, p, len, uid) != 0)
+                       goto out;
+               dprintk("%s: uid=%d\n", __func__, (int)from_kuid(&init_user_ns, *uid));
+               return NFS_ATTR_FATTR_OWNER;
        }
-       dprintk("%s: uid=%d\n", __func__, (int)from_kuid(&init_user_ns, *uid));
-       return ret;
-out_overflow:
+out:
+       if (len != -EBADMSG)
+               return 0;
        print_overflow_msg(__func__, xdr);
        return -EIO;
 }
@@ -3922,41 +3927,33 @@ static int decode_attr_group(struct xdr_stream *xdr, uint32_t *bitmap,
                const struct nfs_server *server, kgid_t *gid,
                struct nfs4_string *group_name)
 {
-       uint32_t len;
-       __be32 *p;
-       int ret = 0;
+       ssize_t len;
+       char *p;
 
        *gid = make_kgid(&init_user_ns, -2);
        if (unlikely(bitmap[1] & (FATTR4_WORD1_OWNER_GROUP - 1U)))
                return -EIO;
-       if (likely(bitmap[1] & FATTR4_WORD1_OWNER_GROUP)) {
-               p = xdr_inline_decode(xdr, 4);
-               if (unlikely(!p))
-                       goto out_overflow;
-               len = be32_to_cpup(p);
-               p = xdr_inline_decode(xdr, len);
-               if (unlikely(!p))
-                       goto out_overflow;
-               if (group_name != NULL) {
-                       group_name->data = kmemdup(p, len, GFP_NOWAIT);
-                       if (group_name->data != NULL) {
-                               group_name->len = len;
-                               ret = NFS_ATTR_FATTR_GROUP_NAME;
-                       }
-               } else if (len < XDR_MAX_NETOBJ) {
-                       if (nfs_map_group_to_gid(server, (char *)p, len, gid) == 0)
-                               ret = NFS_ATTR_FATTR_GROUP;
-                       else
-                               dprintk("%s: nfs_map_group_to_gid failed!\n",
-                                               __func__);
-               } else
-                       dprintk("%s: name too long (%u)!\n",
-                                       __func__, len);
-               bitmap[1] &= ~FATTR4_WORD1_OWNER_GROUP;
+       if (!(bitmap[1] & FATTR4_WORD1_OWNER_GROUP))
+               return 0;
+       bitmap[1] &= ~FATTR4_WORD1_OWNER_GROUP;
+
+       if (group_name != NULL) {
+               len = decode_nfs4_string(xdr, group_name, GFP_NOWAIT);
+               if (len <= 0)
+                       goto out;
+               dprintk("%s: name=%s\n", __func__, group_name->data);
+               return NFS_ATTR_FATTR_OWNER_NAME;
+       } else {
+               len = xdr_stream_decode_opaque_inline(xdr, (void **)&p,
+                               XDR_MAX_NETOBJ);
+               if (len <= 0 || nfs_map_group_to_gid(server, p, len, gid) != 0)
+                       goto out;
+               dprintk("%s: gid=%d\n", __func__, (int)from_kgid(&init_user_ns, *gid));
+               return NFS_ATTR_FATTR_GROUP;
        }
-       dprintk("%s: gid=%d\n", __func__, (int)from_kgid(&init_user_ns, *gid));
-       return ret;
-out_overflow:
+out:
+       if (len != -EBADMSG)
+               return 0;
        print_overflow_msg(__func__, xdr);
        return -EIO;
 }