NFSD: fix LISTXATTRS returning more bytes than maxcount

The maxcount is the maximum number of bytes for the LISTXATTRS4resok
result. This includes the cookie and the count for the name array,
thus subtract 12 bytes from the maxcount: 8 (cookie) + 4 (array count)
when filling up the name array.

Fixes: 23e50fe3a5e6 ("nfsd: implement the xattr functions and en/decode logic")
Signed-off-by: Jorge Mora <mora@netapp.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 840ecd7eaf0713a674c3b877a84b7f71506e4de6..e3f761cd5ee78d2847efd8bc50d2feab5ee9f9f2 100644 (file)
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -5423,7 +5423,7 @@ nfsd4_encode_listxattrs(struct nfsd4_compoundres *resp, __be32 nfserr,
         */
        cookie_offset = xdr->buf->len;
        count_offset = cookie_offset + 8;
-       p = xdr_reserve_space(xdr, 12);
+       p = xdr_reserve_space(xdr, XDR_UNIT * 3);
        if (!p) {
                status = nfserr_resource;
                goto out;
@@ -5434,7 +5434,8 @@ nfsd4_encode_listxattrs(struct nfsd4_compoundres *resp, __be32 nfserr,
        sp = listxattrs->lsxa_buf;
        nuser = 0;
 
-       xdrleft = listxattrs->lsxa_maxcount;
+       /* Bytes left is maxcount - 8 (cookie) - 4 (array count) */
+       xdrleft = listxattrs->lsxa_maxcount - XDR_UNIT * 3;
 
        while (left > 0 && xdrleft > 0) {
                slen = strlen(sp);