From 3cefc136d13f426fd68808ddfd39ada0c90f23db Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Sun, 22 Dec 2013 04:15:38 +0100 Subject: iptables: snat: add randomize-full support This patch provides the userspace part for snat in order to make randomize-full support available in {ip,nf}tables. It allows for enabling full port randomization that was motivated in [1] and introduced to the kernel in [2]. Joint work between Hannes Frederic Sowa and Daniel Borkmann. [1] https://sites.google.com/site/hayashulman/files/NIC-derandomisation.pdf [2] http://patchwork.ozlabs.org/patch/304306/ Signed-off-by: Hannes Frederic Sowa Signed-off-by: Daniel Borkmann Signed-off-by: Pablo Neira Ayuso --- extensions/libip6t_SNAT.c | 18 ++++++++++++++---- extensions/libipt_SNAT.c | 18 ++++++++++++++---- extensions/libxt_SNAT.man | 7 ++++++- 3 files changed, 34 insertions(+), 9 deletions(-) (limited to 'extensions') diff --git a/extensions/libip6t_SNAT.c b/extensions/libip6t_SNAT.c index 7382ad06..8eb50b8d 100644 --- a/extensions/libip6t_SNAT.c +++ b/extensions/libip6t_SNAT.c @@ -18,11 +18,13 @@ enum { O_TO_SRC = 0, O_RANDOM, + O_RANDOM_FULLY, O_PERSISTENT, O_X_TO_SRC, - F_TO_SRC = 1 << O_TO_SRC, - F_RANDOM = 1 << O_RANDOM, - F_X_TO_SRC = 1 << O_X_TO_SRC, + F_TO_SRC = 1 << O_TO_SRC, + F_RANDOM = 1 << O_RANDOM, + F_RANDOM_FULLY = 1 << O_RANDOM_FULLY, + F_X_TO_SRC = 1 << O_X_TO_SRC, }; static void SNAT_help(void) @@ -31,13 +33,14 @@ static void SNAT_help(void) "SNAT target options:\n" " --to-source [[-]][:port[-port]]\n" " Address to map source to.\n" -"[--random] [--persistent]\n"); +"[--random] [--random-fully] [--persistent]\n"); } static const struct xt_option_entry SNAT_opts[] = { {.name = "to-source", .id = O_TO_SRC, .type = XTTYPE_STRING, .flags = XTOPT_MAND | XTOPT_MULTI}, {.name = "random", .id = O_RANDOM, .type = XTTYPE_NONE}, + {.name = "random-fully", .id = O_RANDOM_FULLY, .type = XTTYPE_NONE}, {.name = "persistent", .id = O_PERSISTENT, .type = XTTYPE_NONE}, XTOPT_TABLEEND, }; @@ -180,10 +183,13 @@ static void SNAT_parse(struct xt_option_call *cb) 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) range->flags |= NF_NAT_RANGE_PROTO_RANDOM; + if ((cb->xflags & r) == r) + range->flags |= NF_NAT_RANGE_PROTO_RANDOM_FULLY; } static void print_range(const struct nf_nat_range *range) @@ -215,6 +221,8 @@ static void SNAT_print(const void *ip, const struct xt_entry_target *target, print_range(range); if (range->flags & NF_NAT_RANGE_PROTO_RANDOM) printf(" random"); + if (range->flags & NF_NAT_RANGE_PROTO_RANDOM_FULLY) + printf(" random-fully"); if (range->flags & NF_NAT_RANGE_PERSISTENT) printf(" persistent"); } @@ -227,6 +235,8 @@ static void SNAT_save(const void *ip, const struct xt_entry_target *target) print_range(range); if (range->flags & NF_NAT_RANGE_PROTO_RANDOM) printf(" --random"); + if (range->flags & NF_NAT_RANGE_PROTO_RANDOM_FULLY) + printf(" --random-fully"); if (range->flags & NF_NAT_RANGE_PERSISTENT) printf(" --persistent"); } diff --git a/extensions/libipt_SNAT.c b/extensions/libipt_SNAT.c index 1a24f3d8..78d2c2b1 100644 --- a/extensions/libipt_SNAT.c +++ b/extensions/libipt_SNAT.c @@ -11,11 +11,13 @@ enum { O_TO_SRC = 0, O_RANDOM, + O_RANDOM_FULLY, O_PERSISTENT, O_X_TO_SRC, - F_TO_SRC = 1 << O_TO_SRC, - F_RANDOM = 1 << O_RANDOM, - F_X_TO_SRC = 1 << O_X_TO_SRC, + F_TO_SRC = 1 << O_TO_SRC, + F_RANDOM = 1 << O_RANDOM, + F_RANDOM_FULLY = 1 << O_RANDOM_FULLY, + F_X_TO_SRC = 1 << O_X_TO_SRC, }; /* Source NAT data consists of a multi-range, indicating where to map @@ -32,13 +34,14 @@ static void SNAT_help(void) "SNAT target options:\n" " --to-source [[-]][:port[-port]]\n" " Address to map source to.\n" -"[--random] [--persistent]\n"); +"[--random] [--random-fully] [--persistent]\n"); } static const struct xt_option_entry SNAT_opts[] = { {.name = "to-source", .id = O_TO_SRC, .type = XTTYPE_STRING, .flags = XTOPT_MAND | XTOPT_MULTI}, {.name = "random", .id = O_RANDOM, .type = XTTYPE_NONE}, + {.name = "random-fully", .id = O_RANDOM_FULLY, .type = XTTYPE_NONE}, {.name = "persistent", .id = O_PERSISTENT, .type = XTTYPE_NONE}, XTOPT_TABLEEND, }; @@ -185,10 +188,13 @@ static void SNAT_parse(struct xt_option_call *cb) 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[0].flags |= NF_NAT_RANGE_PROTO_RANDOM; + if ((cb->xflags & r) == r) + mr->range[0].flags |= NF_NAT_RANGE_PROTO_RANDOM_FULLY; } static void print_range(const struct nf_nat_ipv4_range *r) @@ -222,6 +228,8 @@ static void SNAT_print(const void *ip, const struct xt_entry_target *target, print_range(&info->mr.range[i]); if (info->mr.range[i].flags & NF_NAT_RANGE_PROTO_RANDOM) printf(" random"); + if (info->mr.range[i].flags & NF_NAT_RANGE_PROTO_RANDOM_FULLY) + printf(" random-fully"); if (info->mr.range[i].flags & NF_NAT_RANGE_PERSISTENT) printf(" persistent"); } @@ -237,6 +245,8 @@ static void SNAT_save(const void *ip, const struct xt_entry_target *target) print_range(&info->mr.range[i]); if (info->mr.range[i].flags & NF_NAT_RANGE_PROTO_RANDOM) printf(" --random"); + if (info->mr.range[i].flags & NF_NAT_RANGE_PROTO_RANDOM_FULLY) + printf(" --random-fully"); if (info->mr.range[i].flags & NF_NAT_RANGE_PERSISTENT) printf(" --persistent"); } diff --git a/extensions/libxt_SNAT.man b/extensions/libxt_SNAT.man index f0620a21..8cd0b80e 100644 --- a/extensions/libxt_SNAT.man +++ b/extensions/libxt_SNAT.man @@ -29,7 +29,12 @@ anymore. \fB\-\-random\fP If option \fB\-\-random\fP -is used then port mapping will be randomized (kernel >= 2.6.21). +is used then port mapping will be randomized through a hash-based algorithm (kernel >= 2.6.21). +.TP +\fB\-\-random-fully\fP +If option +\fB\-\-random-fully\fP +is used then port mapping will be fully randomized through a PRNG (kernel >= 3.14). .TP \fB\-\-persistent\fP Gives a client the same source-/destination-address for each connection. -- cgit v1.2.3