From 89a26cd4b501e9511d3cd3d22327fc76a75a38b3 Mon Sep 17 00:00:00 2001 From: Juliana Rodrigueiro Date: Fri, 16 Aug 2019 17:02:22 +0200 Subject: [PATCH] netfilter: xt_nfacct: Fix alignment mismatch in xt_nfacct_match_info When running a 64-bit kernel with a 32-bit iptables binary, the size of the xt_nfacct_match_info struct diverges. kernel: sizeof(struct xt_nfacct_match_info) : 40 iptables: sizeof(struct xt_nfacct_match_info)) : 36 Trying to append nfacct related rules results in an unhelpful message. Although it is suggested to look for more information in dmesg, nothing can be found there. # iptables -A -m nfacct --nfacct-name iptables: Invalid argument. Run `dmesg' for more information. This patch fixes the memory misalignment by enforcing 8-byte alignment within the struct's first revision. This solution is often used in many other uapi netfilter headers. Signed-off-by: Juliana Rodrigueiro Acked-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/uapi/linux/netfilter/xt_nfacct.h | 5 ++++ net/netfilter/xt_nfacct.c | 36 ++++++++++++++++-------- 2 files changed, 30 insertions(+), 11 deletions(-) diff --git a/include/uapi/linux/netfilter/xt_nfacct.h b/include/uapi/linux/netfilter/xt_nfacct.h index 5c8a4d760ee3..b5123ab8d54a 100644 --- a/include/uapi/linux/netfilter/xt_nfacct.h +++ b/include/uapi/linux/netfilter/xt_nfacct.h @@ -11,4 +11,9 @@ struct xt_nfacct_match_info { struct nf_acct *nfacct; }; +struct xt_nfacct_match_info_v1 { + char name[NFACCT_NAME_MAX]; + struct nf_acct *nfacct __attribute__((aligned(8))); +}; + #endif /* _XT_NFACCT_MATCH_H */ diff --git a/net/netfilter/xt_nfacct.c b/net/netfilter/xt_nfacct.c index d0ab1adf5bff..5aab6df74e0f 100644 --- a/net/netfilter/xt_nfacct.c +++ b/net/netfilter/xt_nfacct.c @@ -54,25 +54,39 @@ nfacct_mt_destroy(const struct xt_mtdtor_param *par) nfnl_acct_put(info->nfacct); } -static struct xt_match nfacct_mt_reg __read_mostly = { - .name = "nfacct", - .family = NFPROTO_UNSPEC, - .checkentry = nfacct_mt_checkentry, - .match = nfacct_mt, - .destroy = nfacct_mt_destroy, - .matchsize = sizeof(struct xt_nfacct_match_info), - .usersize = offsetof(struct xt_nfacct_match_info, nfacct), - .me = THIS_MODULE, +static struct xt_match nfacct_mt_reg[] __read_mostly = { + { + .name = "nfacct", + .revision = 0, + .family = NFPROTO_UNSPEC, + .checkentry = nfacct_mt_checkentry, + .match = nfacct_mt, + .destroy = nfacct_mt_destroy, + .matchsize = sizeof(struct xt_nfacct_match_info), + .usersize = offsetof(struct xt_nfacct_match_info, nfacct), + .me = THIS_MODULE, + }, + { + .name = "nfacct", + .revision = 1, + .family = NFPROTO_UNSPEC, + .checkentry = nfacct_mt_checkentry, + .match = nfacct_mt, + .destroy = nfacct_mt_destroy, + .matchsize = sizeof(struct xt_nfacct_match_info_v1), + .usersize = offsetof(struct xt_nfacct_match_info_v1, nfacct), + .me = THIS_MODULE, + }, }; static int __init nfacct_mt_init(void) { - return xt_register_match(&nfacct_mt_reg); + return xt_register_matches(nfacct_mt_reg, ARRAY_SIZE(nfacct_mt_reg)); } static void __exit nfacct_mt_exit(void) { - xt_unregister_match(&nfacct_mt_reg); + xt_unregister_matches(nfacct_mt_reg, ARRAY_SIZE(nfacct_mt_reg)); } module_init(nfacct_mt_init);