| Message ID | 1453902155-3077-1-git-send-email-fw@strlen.de |
|---|---|
| State | Accepted |
| Delegated to: | Pablo Neira |
| Headers | show |
On Wed, Jan 27, 2016 at 02:42:35PM +0100, Florian Westphal wrote: > Check for OP_EQ before removing a dependency, else we may zap wrong one, > changing the meaning of the rule. > > Listing without patch: > ip protocol udp udp dport ssh > ip protocol udp udp dport ssh > counter packets 1 bytes 308 ip protocol udp udp dport ssh > > With patch: > ip protocol != tcp udp dport ssh > ip protocol != udp udp dport ssh > ip protocol != tcp counter packets 1 bytes 308 udp dport ssh Acked-by: Pablo Neira Ayuso <pablo@netfilter.org> > Signed-off-by: Florian Westphal <fw@strlen.de> > --- > NB: ip protocol != udp udp dport ... is nonsensical, not sure > if its worth the hassle to try to reject stuff like this. I agree this is not worth. We'll have more advanced tools to perform transformations and more in-depth semantic evaluation of the ruleset at some point, but not now ;-) -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c index 76d598c..2732c96 100644 --- a/src/netlink_delinearize.c +++ b/src/netlink_delinearize.c @@ -1042,6 +1042,7 @@ static void payload_match_expand(struct rule_pp_ctx *ctx, * payload expression. */ if (ctx->pbase == PROTO_BASE_INVALID && + expr->op == OP_EQ && left->flags & EXPR_F_PROTOCOL) { unsigned int proto = mpz_get_be16(tmp->value); const struct proto_desc *desc, *next; diff --git a/tests/py/ip/tcp.t b/tests/py/ip/tcp.t new file mode 100644 index 0000000..4dcfcb6 --- /dev/null +++ b/tests/py/ip/tcp.t @@ -0,0 +1,6 @@ +:input;type filter hook input priority 0 + +*ip;test-ip;input + +ip protocol tcp tcp dport ssh accept;ok;tcp dport 22 accept +ip protocol ne tcp udp dport ssh accept;ok;ip protocol != 6 udp dport 22 accept diff --git a/tests/py/ip/tcp.t.payload b/tests/py/ip/tcp.t.payload new file mode 100644 index 0000000..ed0dcc8 --- /dev/null +++ b/tests/py/ip/tcp.t.payload @@ -0,0 +1,18 @@ +# ip protocol tcp tcp dport ssh accept +ip test-ip input + [ payload load 1b @ network header + 9 => reg 1 ] + [ cmp eq reg 1 0x00000006 ] + [ payload load 2b @ transport header + 2 => reg 1 ] + [ cmp eq reg 1 0x00001600 ] + [ immediate reg 0 accept ] + +# ip protocol ne tcp udp dport ssh accept +ip test-ip input + [ payload load 1b @ network header + 9 => reg 1 ] + [ cmp neq reg 1 0x00000006 ] + [ payload load 1b @ network header + 9 => reg 1 ] + [ cmp eq reg 1 0x00000011 ] + [ payload load 2b @ transport header + 2 => reg 1 ] + [ cmp eq reg 1 0x00001600 ] + [ immediate reg 0 accept ] +
Check for OP_EQ before removing a dependency, else we may zap wrong one, changing the meaning of the rule. Listing without patch: ip protocol udp udp dport ssh ip protocol udp udp dport ssh counter packets 1 bytes 308 ip protocol udp udp dport ssh With patch: ip protocol != tcp udp dport ssh ip protocol != udp udp dport ssh ip protocol != tcp counter packets 1 bytes 308 udp dport ssh Signed-off-by: Florian Westphal <fw@strlen.de> --- NB: ip protocol != udp udp dport ... is nonsensical, not sure if its worth the hassle to try to reject stuff like this. src/netlink_delinearize.c | 1 + tests/py/ip/tcp.t | 6 ++++++ tests/py/ip/tcp.t.payload | 18 ++++++++++++++++++ 3 files changed, 25 insertions(+) create mode 100644 tests/py/ip/tcp.t create mode 100644 tests/py/ip/tcp.t.payload