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authorPablo Neira Ayuso <pablo@netfilter.org>2021-07-27 22:26:52 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2021-07-28 00:31:32 +0200
commit347a4aa16e64b8708d61eeb074736bea02258d1d (patch)
tree054b49b7e70a6db2fd6ca711c2453c2de8d7c946
parent2acc8776e8b436566fc7d73161ef08e6b77b0c45 (diff)
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>
-rw-r--r--src/netlink_delinearize.c8
-rw-r--r--tests/py/inet/tcp.t2
-rw-r--r--tests/py/inet/tcp.t.json21
-rw-r--r--tests/py/inet/tcp.t.payload8
4 files changed, 39 insertions, 0 deletions
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index c7dae266..49870eea 100644
--- 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 5e2830b6..17e0d9b6 100644
--- 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 6155c81f..c1e4fb35 100644
--- 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 6b8b4ecd..77b30188 100644
--- 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 ]