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From: Jeremy Sowden <jeremy@azazel.net>
To: Netfilter Devel <netfilter-devel@vger.kernel.org>
Subject: [PATCH nftables] evaluate: remove expr_set_context call.
Date: Tue, 24 Dec 2019 23:12:11 +0000	[thread overview]
Message-ID: <20191224231211.1972101-1-jeremy@azazel.net> (raw)
In-Reply-To: <20191220190215.1743199-1-jeremy@azazel.net>

expr_evaluate_binop calls expr_set_context for shift expressions to set
the context data-type to `integer`.  This doesn't seem to serve a
purpose, and its only effect is to clobber the byte-order of the
context, resulting in unexpected conversions to NBO.  For example:

  $ sudo nft flush ruleset
  $ sudo nft add table t
  $ sudo nft add chain t c '{ type filter hook output priority mangle; }'
  $ sudo nft add rule t c oif lo tcp dport ssh ct mark set '0x10 | 0xe'
  $ sudo nft add rule t c oif lo tcp dport ssh ct mark set '0xf << 1'
  $ sudo nft list table t
  table ip t {
          chain c {
                  type filter hook output priority mangle; policy accept;
                  oif "lo" tcp dport 22 ct mark set 0x0000001e
                  oif "lo" tcp dport 22 ct mark set 0x1e000000
          }
  }

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
---
 src/evaluate.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/evaluate.c b/src/evaluate.c
index a865902c0fc7..0feb7d484405 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -1144,8 +1144,6 @@ static int expr_evaluate_binop(struct eval_ctx *ctx, struct expr **expr)
 		return -1;
 	left = op->left;
 
-	if (op->op == OP_LSHIFT || op->op == OP_RSHIFT)
-		expr_set_context(&ctx->ectx, &integer_type, ctx->ectx.len);
 	if (expr_evaluate(ctx, &op->right) < 0)
 		return -1;
 	right = op->right;
-- 
2.24.0


  reply	other threads:[~2019-12-24 23:12 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-20 19:02 [PATCH nftables] evaluate: remove expr_set_context call Jeremy Sowden
2019-12-24 23:12 ` Jeremy Sowden [this message]
2019-12-24 23:16   ` Jeremy Sowden
2019-12-24 23:14 ` [PATCH nft v2] evaluate: fix expr_set_context call for shift binops Jeremy Sowden
2020-01-06  9:28   ` Pablo Neira Ayuso
2020-01-06  9:31     ` Jeremy Sowden
2020-01-06 22:35     ` [PATCH nft v3] " Jeremy Sowden
2020-01-08 22:35       ` Pablo Neira Ayuso

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