netlink_delinerize: incorrect byteorder in mark statement listing

commit 6696599e104098b61e45f99d161275883885b199 upstream.

When using ip dscp in combination with bitwise operation:

 # nft --debug=netlink add rule ip x y 'ct mark set ip dscp | 0x4'
 ip x y
   [ payload load 1b @ network header + 1 => reg 1 ]
   [ bitwise reg 1 = ( reg 1 & 0x000000fc ) ^ 0x00000000 ]
   [ bitwise reg 1 = ( reg 1 >> 0x00000002 ) ]
   [ bitwise reg 1 = ( reg 1 & 0xfffffffb ) ^ 0x00000004 ]
   [ ct set mark with reg 1 ]

the listing is showing in the incorrect byteorder:

 # nft list ruleset
 table ip x {
        chain y {
		ct mark set ip dscp | 0x4000000
	}
 }

handle and and or operations in host byteorder.

The following command:

 # nft --debug=netlink add rule ip6 x y 'ct mark set ip6 dscp | 0x4'
 ip6 x y
   [ payload load 2b @ network header + 0 => reg 1 ]
   [ bitwise reg 1 = ( reg 1 & 0x0000c00f ) ^ 0x00000000 ]
   [ bitwise reg 1 = ( reg 1 >> 0x00000006 ) ]
   [ byteorder reg 1 = ntoh(reg 1, 2, 1) ]
   [ bitwise reg 1 = ( reg 1 & 0xfffffffb ) ^ 0x00000004 ]
   [ ct set mark with reg 1 ]

works fine (without requiring this patch) because there is an explicit
byteorder expression.

However, ip dscp takes only 1-byte, so it does not require the byteorder
expression. Use host byteorder if the rhs of bitwise AND OR is larger
than lhs payload expression and such expression is equal or less than
1-byte.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index a132020c92d7056836659e855129957f7b57e675..623347bc1c4d01557e2e83f39cc2c64a9146a516 100644 (file)
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -2633,8 +2633,13 @@ static void expr_postprocess(struct rule_pp_ctx *ctx, struct expr **exprp)
                                      BYTEORDER_HOST_ENDIAN);
                        break;
                case OP_AND:
-                       expr_set_type(expr->right, expr->left->dtype,
-                                     expr->left->byteorder);
+                       if (expr->right->len > expr->left->len) {
+                               expr_set_type(expr->right, expr->left->dtype,
+                                             BYTEORDER_HOST_ENDIAN);
+                       } else {
+                               expr_set_type(expr->right, expr->left->dtype,
+                                             expr->left->byteorder);
+                       }
 
                        /* Do not process OP_AND in ordinary rule context.
                         *
@@ -2654,8 +2659,13 @@ static void expr_postprocess(struct rule_pp_ctx *ctx, struct expr **exprp)
                        }
                        break;
                default:
-                       expr_set_type(expr->right, expr->left->dtype,
-                                     expr->left->byteorder);
+                       if (expr->right->len > expr->left->len) {
+                               expr_set_type(expr->right, expr->left->dtype,
+                                             BYTEORDER_HOST_ENDIAN);
+                       } else {
+                               expr_set_type(expr->right, expr->left->dtype,
+                                             expr->left->byteorder);
+                       }
                }
                expr_postprocess(ctx, &expr->right);