From dcf67740f22d31be685d7172f05b289c8243ea12 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Sun, 16 Apr 2017 01:29:15 +0200 Subject: [PATCH] netfilter: helper: add build-time asserts for helper data size add a 32 byte scratch area in the helper struct instead of relying on variable sized helpers plus compile-time asserts to let us know if 32 bytes aren't enough anymore. Not having variable sized helpers will later allow to add BUILD_BUG_ON for the total size of conntrack extensions -- the helper extension is the only one that doesn't have a fixed size. The (useless!) NF_CT_HELPER_BUILD_BUG_ON(0); are added so that in case someone adds a new helper and copy-pastes from one that doesn't store private data at least some indication that this macro should be used somehow is there... Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_conntrack_helper.h | 5 ++++- net/netfilter/nf_conntrack_amanda.c | 2 ++ net/netfilter/nf_conntrack_ftp.c | 2 ++ net/netfilter/nf_conntrack_h323_main.c | 2 ++ net/netfilter/nf_conntrack_netbios_ns.c | 2 ++ net/netfilter/nf_conntrack_pptp.c | 2 ++ net/netfilter/nf_conntrack_sane.c | 2 ++ net/netfilter/nf_conntrack_sip.c | 2 ++ net/netfilter/nf_conntrack_tftp.c | 2 ++ 9 files changed, 20 insertions(+), 1 deletion(-) diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h index 15d746558665..29539ed1008f 100644 --- a/include/net/netfilter/nf_conntrack_helper.h +++ b/include/net/netfilter/nf_conntrack_helper.h @@ -66,9 +66,12 @@ struct nf_conn_help { u8 expecting[NF_CT_MAX_EXPECT_CLASSES]; /* private helper information. */ - char data[]; + char data[32] __aligned(8); }; +#define NF_CT_HELPER_BUILD_BUG_ON(structsize) \ + BUILD_BUG_ON((structsize) > FIELD_SIZEOF(struct nf_conn_help, data)) + struct nf_conntrack_helper *__nf_conntrack_helper_find(const char *name, u16 l3num, u8 protonum); diff --git a/net/netfilter/nf_conntrack_amanda.c b/net/netfilter/nf_conntrack_amanda.c index 57a26cc90c9f..03d2ccffa9fa 100644 --- a/net/netfilter/nf_conntrack_amanda.c +++ b/net/netfilter/nf_conntrack_amanda.c @@ -207,6 +207,8 @@ static int __init nf_conntrack_amanda_init(void) { int ret, i; + NF_CT_HELPER_BUILD_BUG_ON(0); + for (i = 0; i < ARRAY_SIZE(search); i++) { search[i].ts = textsearch_prepare(ts_algo, search[i].string, search[i].len, diff --git a/net/netfilter/nf_conntrack_ftp.c b/net/netfilter/nf_conntrack_ftp.c index 4aecef4a89fb..58e1256cd05d 100644 --- a/net/netfilter/nf_conntrack_ftp.c +++ b/net/netfilter/nf_conntrack_ftp.c @@ -577,6 +577,8 @@ static int __init nf_conntrack_ftp_init(void) { int i, ret = 0; + NF_CT_HELPER_BUILD_BUG_ON(sizeof(struct nf_ct_ftp_master)); + ftp_buffer = kmalloc(65536, GFP_KERNEL); if (!ftp_buffer) return -ENOMEM; diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c index f65d93639d12..e98204349efe 100644 --- a/net/netfilter/nf_conntrack_h323_main.c +++ b/net/netfilter/nf_conntrack_h323_main.c @@ -1836,6 +1836,8 @@ static int __init nf_conntrack_h323_init(void) { int ret; + NF_CT_HELPER_BUILD_BUG_ON(sizeof(struct nf_ct_h323_master)); + h323_buffer = kmalloc(65536, GFP_KERNEL); if (!h323_buffer) return -ENOMEM; diff --git a/net/netfilter/nf_conntrack_netbios_ns.c b/net/netfilter/nf_conntrack_netbios_ns.c index 4c8f30a3d6d2..496ce173f0c1 100644 --- a/net/netfilter/nf_conntrack_netbios_ns.c +++ b/net/netfilter/nf_conntrack_netbios_ns.c @@ -58,6 +58,8 @@ static struct nf_conntrack_helper helper __read_mostly = { static int __init nf_conntrack_netbios_ns_init(void) { + NF_CT_HELPER_BUILD_BUG_ON(0); + exp_policy.timeout = timeout; return nf_conntrack_helper_register(&helper); } diff --git a/net/netfilter/nf_conntrack_pptp.c b/net/netfilter/nf_conntrack_pptp.c index f60a4755d71e..34fac4c52c4c 100644 --- a/net/netfilter/nf_conntrack_pptp.c +++ b/net/netfilter/nf_conntrack_pptp.c @@ -607,6 +607,8 @@ static struct nf_conntrack_helper pptp __read_mostly = { static int __init nf_conntrack_pptp_init(void) { + NF_CT_HELPER_BUILD_BUG_ON(sizeof(struct nf_ct_pptp_master)); + return nf_conntrack_helper_register(&pptp); } diff --git a/net/netfilter/nf_conntrack_sane.c b/net/netfilter/nf_conntrack_sane.c index 9dcb9ee9b97d..1121db08d048 100644 --- a/net/netfilter/nf_conntrack_sane.c +++ b/net/netfilter/nf_conntrack_sane.c @@ -184,6 +184,8 @@ static int __init nf_conntrack_sane_init(void) { int i, ret = 0; + NF_CT_HELPER_BUILD_BUG_ON(sizeof(struct nf_ct_sane_master)); + sane_buffer = kmalloc(65536, GFP_KERNEL); if (!sane_buffer) return -ENOMEM; diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index 91a9c97b7e9a..79bbcc4d52ee 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -1622,6 +1622,8 @@ static int __init nf_conntrack_sip_init(void) { int i, ret; + NF_CT_HELPER_BUILD_BUG_ON(sizeof(struct nf_ct_sip_master)); + if (ports_c == 0) ports[ports_c++] = SIP_PORT; diff --git a/net/netfilter/nf_conntrack_tftp.c b/net/netfilter/nf_conntrack_tftp.c index b1227dc6f75e..27e2f6f904dc 100644 --- a/net/netfilter/nf_conntrack_tftp.c +++ b/net/netfilter/nf_conntrack_tftp.c @@ -113,6 +113,8 @@ static int __init nf_conntrack_tftp_init(void) { int i, ret; + NF_CT_HELPER_BUILD_BUG_ON(0); + if (ports_c == 0) ports[ports_c++] = TFTP_PORT;