netlink_delinearize: skip flags / mask notation for singleton bitmask

Do not transform 'tcp flags & flag == flag' to 'flag / flag'.
The parser does not accept this notation yet.

Fixes: c3d57114f119 ("parser_bison: add shortcut syntax for matching flags without binary operations")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index c7dae26684cd164e0ee62ce525f8a52179170428..49870eeadd576436187c769b5736222e869a1b1a 100644 (file)
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -2285,6 +2285,14 @@ static void relational_binop_postprocess(struct rule_pp_ctx *ctx,
                                        BUG("unknown operation type %d\n", expr->op);
                                }
                                expr_free(binop);
+                       } else if (binop->right->etype == EXPR_VALUE &&
+                                  value->etype == EXPR_VALUE &&
+                                  expr->op == OP_EQ &&
+                                  !mpz_cmp(value->value, binop->right->value)) {
+                               /* Skip flag / flag representation for:
+                                * data & flag == flag
+                                */
+                               ;
                        } else {
                                *exprp = flagcmp_expr_alloc(&expr->location, expr->op,
                                                            expr_get(binop->left),

diff --git a/tests/py/inet/tcp.t b/tests/py/inet/tcp.t
index 5e2830b679a84e0d9784cbf10af35de280cd2aa2..17e0d9b6df9f98289710bdc5027288867a80cce7 100644 (file)
--- a/tests/py/inet/tcp.t
+++ b/tests/py/inet/tcp.t
@@ -70,6 +70,8 @@ tcp flags == syn;ok
 tcp flags fin,syn / fin,syn;ok
 tcp flags != syn / fin,syn;ok
 tcp flags & syn != 0;ok;tcp flags syn
+# it should be possible to transform this to: tcp flags syn
+tcp flags & syn == syn;ok
 tcp flags & (fin | syn | rst | ack) syn;ok;tcp flags syn / fin,syn,rst,ack
 tcp flags & (fin | syn | rst | ack) != syn;ok;tcp flags != syn / fin,syn,rst,ack
 tcp flags & (fin | syn | rst | psh | ack | urg | ecn | cwr) == fin | syn | rst | psh | ack | urg | ecn | cwr;ok;tcp flags == 0xff

diff --git a/tests/py/inet/tcp.t.json b/tests/py/inet/tcp.t.json
index 6155c81f615085e087630d8b3401b38aeb3ffe8f..c1e4fb35a87cde023eb0dc93c6353fd3b92f001b 100644 (file)
--- a/tests/py/inet/tcp.t.json
+++ b/tests/py/inet/tcp.t.json
@@ -1537,6 +1537,27 @@
     }
 ]
 
+# tcp flags & syn == syn
+[
+    {
+        "match": {
+            "left": {
+                "&": [
+                    {
+                        "payload": {
+                            "field": "flags",
+                            "protocol": "tcp"
+                        }
+                    },
+                    "syn"
+                ]
+            },
+            "op": "==",
+            "right": "syn"
+        }
+    }
+]
+
 # tcp flags & (fin | syn | rst | ack) syn
 [
     {

diff --git a/tests/py/inet/tcp.t.payload b/tests/py/inet/tcp.t.payload
index 6b8b4ecdb4ac24862754155c50e97594baa13968..77b301883a15e40680ee0d645b3f9d70eea1c042 100644 (file)
--- a/tests/py/inet/tcp.t.payload
+++ b/tests/py/inet/tcp.t.payload
@@ -378,6 +378,14 @@ inet test-inet input
   [ bitwise reg 1 = ( reg 1 & 0x00000002 ) ^ 0x00000000 ]
   [ cmp neq reg 1 0x00000000 ]
 
+# tcp flags & syn == syn
+inet test-inet input
+  [ meta load l4proto => reg 1 ]
+  [ cmp eq reg 1 0x00000006 ]
+  [ payload load 1b @ transport header + 13 => reg 1 ]
+  [ bitwise reg 1 = ( reg 1 & 0x00000002 ) ^ 0x00000000 ]
+  [ cmp eq reg 1 0x00000002 ]
+
 # tcp flags & (fin | syn | rst | ack) syn
 inet test-inet input
   [ meta load l4proto => reg 1 ]