SNAT, DNAT and REDIRECT extensions tried to prevent
NF_NAT_RANGE_PROTO_RANDOM flag from being set if no port or address was
also given.
With SNAT and DNAT, this is not possible as the respective
--to-destination or --to-source parameters are mandatory anyway.
Looking at the kernel code, doing so with REDIRECT seems harmless.
Moreover, nftables supports 'redirect random' without specifying a
port-range.
Signed-off-by: Phil Sutter <phil@xxxxxx>
---
extensions/libip6t_SNAT.c | 20 +++++---------------
extensions/libipt_SNAT.c | 16 ++++++----------
extensions/libxt_DNAT.c | 28 ++++------------------------
extensions/libxt_REDIRECT.t | 1 +
extensions/libxt_REDIRECT.txlate | 3 +++
5 files changed, 19 insertions(+), 49 deletions(-)
diff --git a/extensions/libip6t_SNAT.c b/extensions/libip6t_SNAT.c
index 4fe272b262a3d..8bf7b035f84b6 100644
--- a/extensions/libip6t_SNAT.c
+++ b/extensions/libip6t_SNAT.c
@@ -20,9 +20,6 @@ enum {
O_RANDOM,
O_RANDOM_FULLY,
O_PERSISTENT,
- F_TO_SRC = 1 << O_TO_SRC,
- F_RANDOM = 1 << O_RANDOM,
- F_RANDOM_FULLY = 1 << O_RANDOM_FULLY,
};
static void SNAT_help(void)
@@ -166,19 +163,13 @@ static void SNAT_parse(struct xt_option_call *cb)
case O_PERSISTENT:
range->flags |= NF_NAT_RANGE_PERSISTENT;
break;
- }
-}
-
-static void SNAT_fcheck(struct xt_fcheck_call *cb)
-{
- static const unsigned int f = F_TO_SRC | F_RANDOM;
- static const unsigned int r = F_TO_SRC | F_RANDOM_FULLY;
- struct nf_nat_range *range = cb->data;
-
- if ((cb->xflags & f) == f)
+ case O_RANDOM:
range->flags |= NF_NAT_RANGE_PROTO_RANDOM;
- if ((cb->xflags & r) == r)
+ break;
+ case O_RANDOM_FULLY:
range->flags |= NF_NAT_RANGE_PROTO_RANDOM_FULLY;
+ break;
+ }
}
static void print_range(const struct nf_nat_range *range)
@@ -295,7 +286,6 @@ static struct xtables_target snat_tg_reg = {
.userspacesize = XT_ALIGN(sizeof(struct nf_nat_range)),
.help = SNAT_help,
.x6_parse = SNAT_parse,
- .x6_fcheck = SNAT_fcheck,
.print = SNAT_print,
.save = SNAT_save,
.x6_options = SNAT_opts,
diff --git a/extensions/libipt_SNAT.c b/extensions/libipt_SNAT.c
index 211a20bc45bfe..9c8cdb46a1585 100644
--- a/extensions/libipt_SNAT.c
+++ b/extensions/libipt_SNAT.c
@@ -13,9 +13,6 @@ enum {
O_RANDOM,
O_RANDOM_FULLY,
O_PERSISTENT,
- F_TO_SRC = 1 << O_TO_SRC,
- F_RANDOM = 1 << O_RANDOM,
- F_RANDOM_FULLY = 1 << O_RANDOM_FULLY,
};
static void SNAT_help(void)
@@ -141,20 +138,19 @@ static void SNAT_parse(struct xt_option_call *cb)
case O_PERSISTENT:
mr->range->flags |= NF_NAT_RANGE_PERSISTENT;
break;
+ case O_RANDOM:
+ mr->range->flags |= NF_NAT_RANGE_PROTO_RANDOM;
+ break;
+ case O_RANDOM_FULLY:
+ mr->range->flags |= NF_NAT_RANGE_PROTO_RANDOM_FULLY;
+ break;
}
}
static void SNAT_fcheck(struct xt_fcheck_call *cb)
{
- static const unsigned int f = F_TO_SRC | F_RANDOM;
- static const unsigned int r = F_TO_SRC | F_RANDOM_FULLY;
struct nf_nat_ipv4_multi_range_compat *mr = cb->data;
- if ((cb->xflags & f) == f)
- mr->range->flags |= NF_NAT_RANGE_PROTO_RANDOM;
- if ((cb->xflags & r) == r)
- mr->range->flags |= NF_NAT_RANGE_PROTO_RANDOM_FULLY;
-
mr->rangesize = 1;
}
diff --git a/extensions/libxt_DNAT.c b/extensions/libxt_DNAT.c
index 7bfefc7961fac..af44518798aef 100644
--- a/extensions/libxt_DNAT.c
+++ b/extensions/libxt_DNAT.c
@@ -31,9 +31,6 @@ enum {
O_TO_PORTS,
O_RANDOM,
O_PERSISTENT,
- F_TO_DEST = 1 << O_TO_DEST,
- F_TO_PORTS = 1 << O_TO_PORTS,
- F_RANDOM = 1 << O_RANDOM,
};
static void DNAT_help(void)
@@ -229,6 +226,9 @@ static void __DNAT_parse(struct xt_option_call *cb, __u16 proto,
case O_PERSISTENT:
range->flags |= NF_NAT_RANGE_PERSISTENT;
break;
+ case O_RANDOM:
+ range->flags |= NF_NAT_RANGE_PROTO_RANDOM;
+ break;
}
}
@@ -250,21 +250,12 @@ static void DNAT_parse(struct xt_option_call *cb)
mr->range->max = range.max_proto;
/* fall through */
case O_PERSISTENT:
+ case O_RANDOM:
mr->range->flags |= range.flags;
break;
}
}
-static void __DNAT_fcheck(struct xt_fcheck_call *cb, unsigned int *flags)
-{
- static const unsigned int redir_f = F_TO_PORTS | F_RANDOM;
- static const unsigned int dnat_f = F_TO_DEST | F_RANDOM;
-
- if ((cb->xflags & redir_f) == redir_f ||
- (cb->xflags & dnat_f) == dnat_f)
- *flags |= NF_NAT_RANGE_PROTO_RANDOM;
-}
-
static void DNAT_fcheck(struct xt_fcheck_call *cb)
{
struct nf_nat_ipv4_multi_range_compat *mr = cb->data;
@@ -274,8 +265,6 @@ static void DNAT_fcheck(struct xt_fcheck_call *cb)
if (mr->range[0].flags & NF_NAT_RANGE_PROTO_OFFSET)
xtables_error(PARAMETER_PROBLEM,
"Shifted portmap ranges not supported with this kernel");
-
- __DNAT_fcheck(cb, &mr->range[0].flags);
}
static char *sprint_range(const struct nf_nat_range2 *r, int family)
@@ -388,11 +377,6 @@ static void DNAT_parse_v2(struct xt_option_call *cb)
__DNAT_parse(cb, entry->ip.proto, cb->data, AF_INET);
}
-static void DNAT_fcheck_v2(struct xt_fcheck_call *cb)
-{
- __DNAT_fcheck(cb, &((struct nf_nat_range2 *)cb->data)->flags);
-}
-
static void DNAT_print_v2(const void *ip, const struct xt_entry_target *target,
int numeric)
{
@@ -428,8 +412,6 @@ static void DNAT_fcheck6(struct xt_fcheck_call *cb)
if (range->flags & NF_NAT_RANGE_PROTO_OFFSET)
xtables_error(PARAMETER_PROBLEM,
"Shifted portmap ranges not supported with this kernel");
-
- __DNAT_fcheck(cb, &range->flags);
}
static void DNAT_print6(const void *ip, const struct xt_entry_target *target,
@@ -619,7 +601,6 @@ static struct xtables_target dnat_tg_reg[] = {
.print = DNAT_print_v2,
.save = DNAT_save_v2,
.x6_parse = DNAT_parse_v2,
- .x6_fcheck = DNAT_fcheck_v2,
.x6_options = DNAT_opts,
.xlate = DNAT_xlate_v2,
},
@@ -634,7 +615,6 @@ static struct xtables_target dnat_tg_reg[] = {
.print = DNAT_print6_v2,
.save = DNAT_save6_v2,
.x6_parse = DNAT_parse6_v2,
- .x6_fcheck = DNAT_fcheck_v2,
.x6_options = DNAT_opts,
.xlate = DNAT_xlate6_v2,
},
diff --git a/extensions/libxt_REDIRECT.t b/extensions/libxt_REDIRECT.t
index f607dd0a12c51..362efa8428ed4 100644
--- a/extensions/libxt_REDIRECT.t
+++ b/extensions/libxt_REDIRECT.t
@@ -14,3 +14,4 @@
-p tcp -j REDIRECT --to-ports ftp-ssh;;FAIL
-p tcp -j REDIRECT --to-ports 10-ssh;;FAIL
-j REDIRECT --to-ports 42;;FAIL
+-j REDIRECT --random;=;OK
diff --git a/extensions/libxt_REDIRECT.txlate b/extensions/libxt_REDIRECT.txlate
index 2c536495b35a2..36419a46bb366 100644
--- a/extensions/libxt_REDIRECT.txlate
+++ b/extensions/libxt_REDIRECT.txlate
@@ -16,6 +16,9 @@ nft add rule ip nat prerouting tcp dport 80 counter redirect to :10-22
iptables-translate -t nat -A prerouting -p tcp --dport 80 -j REDIRECT --to-ports 8080 --random
nft add rule ip nat prerouting tcp dport 80 counter redirect to :8080 random
+iptables-translate -t nat -A prerouting -j REDIRECT --random
+nft add rule ip nat prerouting counter redirect random
+
ip6tables-translate -t nat -A prerouting -p tcp --dport 80 -j REDIRECT
nft add rule ip6 nat prerouting tcp dport 80 counter redirect
--
2.38.0
