From 0cafa3926f0d8d72a2a814843f4db8cfef66d4ce Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Fri, 1 Jun 2018 19:12:28 +0900 Subject: netfilter: nft_reject_bridge: fix skb allocation size in nft_reject_br_send_v6_unreach In order to allocate icmpv6 skb, sizeof(struct ipv6hdr) should be used. Signed-off-by: Taehee Yoo Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/nft_reject_bridge.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/bridge/netfilter') diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c index eaf05de37f75..6de981270566 100644 --- a/net/bridge/netfilter/nft_reject_bridge.c +++ b/net/bridge/netfilter/nft_reject_bridge.c @@ -261,7 +261,7 @@ static void nft_reject_br_send_v6_unreach(struct net *net, if (!reject6_br_csum_ok(oldskb, hook)) return; - nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmp6hdr) + + nskb = alloc_skb(sizeof(struct ipv6hdr) + sizeof(struct icmp6hdr) + LL_MAX_HEADER + len, GFP_ATOMIC); if (!nskb) return; -- cgit v1.2.1 From 9e8c8dabb78e886ace989729e763d28c76f5169e Mon Sep 17 00:00:00 2001 From: Alin Nastac Date: Wed, 30 May 2018 15:19:36 +0200 Subject: netfilter: ebtables: fix compat entry padding On arm64, ebt_entry_{match,watcher,target} structs are 40 bytes long while on 32-bit arm these structs have a size of 36 bytes. COMPAT_XT_ALIGN() macro cannot be used here to determine the necessary padding for the CONFIG_COMPAT because it imposes an 8-byte boundary alignment, condition that is not found in 32-bit ebtables application. Signed-off-by: Alin Nastac Acked-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/ebtables.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'net/bridge/netfilter') diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 6ba639f6c51d..5f459c8b7937 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -1610,16 +1610,16 @@ struct compat_ebt_entry_mwt { compat_uptr_t ptr; } u; compat_uint_t match_size; - compat_uint_t data[0]; + compat_uint_t data[0] __attribute__ ((aligned (__alignof__(struct compat_ebt_replace)))); }; /* account for possible padding between match_size and ->data */ static int ebt_compat_entry_padsize(void) { - BUILD_BUG_ON(XT_ALIGN(sizeof(struct ebt_entry_match)) < - COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt))); - return (int) XT_ALIGN(sizeof(struct ebt_entry_match)) - - COMPAT_XT_ALIGN(sizeof(struct compat_ebt_entry_mwt)); + BUILD_BUG_ON(sizeof(struct ebt_entry_match) < + sizeof(struct compat_ebt_entry_mwt)); + return (int) sizeof(struct ebt_entry_match) - + sizeof(struct compat_ebt_entry_mwt); } static int ebt_compat_match_offset(const struct xt_match *match, -- cgit v1.2.1 From 11ff7288beb2b7da889a014aff0a7b80bf8efcf3 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Wed, 6 Jun 2018 12:14:56 +0200 Subject: netfilter: ebtables: reject non-bridge targets the ebtables evaluation loop expects targets to return positive values (jumps), or negative values (absolute verdicts). This is completely different from what xtables does. In xtables, targets are expected to return the standard netfilter verdicts, i.e. NF_DROP, NF_ACCEPT, etc. ebtables will consider these as jumps. Therefore reject any target found due to unspec fallback. v2: also reject watchers. ebtables ignores their return value, so a target that assumes skb ownership (and returns NF_STOLEN) causes use-after-free. The only watchers in the 'ebtables' front-end are log and nflog; both have AF_BRIDGE specific wrappers on kernel side. Reported-by: syzbot+2b43f681169a2a0d306a@syzkaller.appspotmail.com Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/ebtables.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'net/bridge/netfilter') diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 5f459c8b7937..08a65e4a77d0 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -396,6 +396,12 @@ ebt_check_watcher(struct ebt_entry_watcher *w, struct xt_tgchk_param *par, watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0); if (IS_ERR(watcher)) return PTR_ERR(watcher); + + if (watcher->family != NFPROTO_BRIDGE) { + module_put(watcher->me); + return -ENOENT; + } + w->u.watcher = watcher; par->target = watcher; @@ -715,6 +721,13 @@ ebt_check_entry(struct ebt_entry *e, struct net *net, goto cleanup_watchers; } + /* Reject UNSPEC, xtables verdicts/return values are incompatible */ + if (target->family != NFPROTO_BRIDGE) { + module_put(target->me); + ret = -ENOENT; + goto cleanup_watchers; + } + t->u.target = target; if (t->u.target == &ebt_standard_target) { if (gap < sizeof(struct ebt_standard_target)) { -- cgit v1.2.1 From c568503ef02030f169c9e19204def610a3510918 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 7 Jun 2018 21:34:43 +0200 Subject: netfilter: x_tables: initialise match/target check parameter struct syzbot reports following splat: BUG: KMSAN: uninit-value in ebt_stp_mt_check+0x24b/0x450 net/bridge/netfilter/ebt_stp.c:162 ebt_stp_mt_check+0x24b/0x450 net/bridge/netfilter/ebt_stp.c:162 xt_check_match+0x1438/0x1650 net/netfilter/x_tables.c:506 ebt_check_match net/bridge/netfilter/ebtables.c:372 [inline] ebt_check_entry net/bridge/netfilter/ebtables.c:702 [inline] The uninitialised access is xt_mtchk_param->nft_compat ... which should be set to 0. Fix it by zeroing the struct beforehand, same for tgchk. ip(6)tables targetinfo uses c99-style initialiser, so no change needed there. Reported-by: syzbot+da4494182233c23a5fcf@syzkaller.appspotmail.com Fixes: 55917a21d0cc0 ("netfilter: x_tables: add context to know if extension runs from nft_compat") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/ebtables.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/bridge/netfilter') diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 08a65e4a77d0..ead123dab05e 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -700,6 +700,8 @@ ebt_check_entry(struct ebt_entry *e, struct net *net, } i = 0; + memset(&mtpar, 0, sizeof(mtpar)); + memset(&tgpar, 0, sizeof(tgpar)); mtpar.net = tgpar.net = net; mtpar.table = tgpar.table = name; mtpar.entryinfo = tgpar.entryinfo = e; -- cgit v1.2.1