sunrpc: make token header values less confusing

g_make_token_header() and g_token_size() add two too many, and
therefore their callers pass in "(logical_value - 2)" rather
than "logical_value" as hard-coded values which causes confusion.

This dates back to the original g_make_token_header which took an
optional token type (token_id) value and added it to the token.
This was removed, but the routine always adds room for the token_id
rather than not.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

net/sunrpc/auth_gss/gss_generic_token.c

@@ -148,7 +148,7 @@ int
 g_token_size(struct xdr_netobj *mech, unsigned int body_size)
 {
 	/* set body_size to sequence contents size */
-	body_size += 4 + (int) mech->len;         /* NEED overflow check */
+	body_size += 2 + (int) mech->len;         /* NEED overflow check */
 	return(1 + der_length_size(body_size) + body_size);
 }
 
@@ -161,7 +161,7 @@ void
 g_make_token_header(struct xdr_netobj *mech, int body_size, unsigned char **buf)
 {
 	*(*buf)++ = 0x60;
-	der_write_length(buf, 4 + mech->len + body_size);
+	der_write_length(buf, 2 + mech->len + body_size);
 	*(*buf)++ = 0x06;
 	*(*buf)++ = (unsigned char) mech->len;
 	TWRITE_STR(*buf, mech->data, ((int) mech->len));

net/sunrpc/auth_gss/gss_krb5_seal.c

@@ -87,10 +87,10 @@ gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text,
 
 	now = get_seconds();
 
-	token->len = g_token_size(&ctx->mech_used, 22);
+	token->len = g_token_size(&ctx->mech_used, 24);
 
 	ptr = token->data;
-	g_make_token_header(&ctx->mech_used, 22, &ptr);
+	g_make_token_header(&ctx->mech_used, 24, &ptr);
 
 	*ptr++ = (unsigned char) ((KG_TOK_MIC_MSG>>8)&0xff);
 	*ptr++ = (unsigned char) (KG_TOK_MIC_MSG&0xff);

net/sunrpc/auth_gss/gss_krb5_wrap.c

@@ -137,7 +137,7 @@ gss_wrap_kerberos(struct gss_ctx *ctx, int offset,
 	BUG_ON((buf->len - offset) % blocksize);
 	plainlen = blocksize + buf->len - offset;
 
-	headlen = g_token_size(&kctx->mech_used, 22 + plainlen) -
+	headlen = g_token_size(&kctx->mech_used, 24 + plainlen) -
 						(buf->len - offset);
 
 	ptr = buf->head[0].iov_base + offset;
@@ -149,7 +149,7 @@ gss_wrap_kerberos(struct gss_ctx *ctx, int offset,
 	buf->len += headlen;
 	BUG_ON((buf->len - offset - headlen) % blocksize);
 
-	g_make_token_header(&kctx->mech_used, 22 + plainlen, &ptr);
+	g_make_token_header(&kctx->mech_used, 24 + plainlen, &ptr);
 
 
 	*ptr++ = (unsigned char) ((KG_TOK_WRAP_MSG>>8)&0xff);

net/sunrpc/auth_gss/gss_spkm3_seal.c

@@ -107,10 +107,10 @@ spkm3_make_token(struct spkm3_ctx *ctx,
 		tokenlen = 10 + ctxelen + 1 + md5elen + 1;
 
 		/* Create token header using generic routines */
-		token->len = g_token_size(&ctx->mech_used, tokenlen);
+		token->len = g_token_size(&ctx->mech_used, tokenlen + 2);
 
 		ptr = token->data;
-		g_make_token_header(&ctx->mech_used, tokenlen, &ptr);
+		g_make_token_header(&ctx->mech_used, tokenlen + 2, &ptr);
 
 		spkm3_make_mic_token(&ptr, tokenlen, &mic_hdr, &md5cksum, md5elen, md5zbit);
 	} else if (toktype == SPKM_WRAP_TOK) { /* Not Supported */