gss_krb5: Introduce encryption type framework

Make the client and server code consistent regarding the extra buffer
space made available for the auth code when wrapping data.

Add some comments/documentation about the available buffer space
in the xdr_buf head and tail when gss_wrap is called.

Add a compile-time check to make sure we are not exceeding the available
buffer space.

Add a central function to shift head data.

Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c b/net/sunrpc/auth_gss/gss_krb5_wrap.c
index a6e905637e03..496281fabb91 100644
--- a/net/sunrpc/auth_gss/gss_krb5_wrap.c
+++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c
@@ -155,11 +155,9 @@ gss_wrap_kerberos(struct gss_ctx *ctx, int offset,
 
         ptr = buf->head[0].iov_base + offset;
         /* shift data to make room for header. */
+        xdr_extend_head(buf, offset, headlen);
+
         /* XXX Would be cleverer to encrypt while copying. */
-        /* XXX bounds checking, slack, etc. */
-        memmove(ptr + headlen, ptr, buf->head[0].iov_len - offset);
-        buf->head[0].iov_len += headlen;
-        buf->len += headlen;
         BUG_ON((buf->len - offset - headlen) % blocksize);
 
         g_make_token_header(&kctx->mech_used,