From c9b3b8207bc487de02cbca968927ba2c2cb46aaf Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 10 Dec 2019 21:24:28 +0100 Subject: [PATCH 1/4] netfilter: nf_flow_table: fix big-endian integer overflow In some configurations, gcc reports an integer overflow: net/netfilter/nf_flow_table_offload.c: In function 'nf_flow_rule_match': net/netfilter/nf_flow_table_offload.c:80:21: error: unsigned conversion from 'int' to '__be16' {aka 'short unsigned int'} changes value from '327680' to '0' [-Werror=overflow] mask->tcp.flags = TCP_FLAG_RST | TCP_FLAG_FIN; ^~~~~~~~~~~~ From what I can tell, we want the upper 16 bits of these constants, so they need to be shifted in cpu-endian mode. Fixes: c29f74e0df7a ("netfilter: nf_flow_table: hardware offload support") Signed-off-by: Arnd Bergmann Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_flow_table_offload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c index de7a0d1e15c8..0d72e5ccb47b 100644 --- a/net/netfilter/nf_flow_table_offload.c +++ b/net/netfilter/nf_flow_table_offload.c @@ -88,7 +88,7 @@ static int nf_flow_rule_match(struct nf_flow_match *match, switch (tuple->l4proto) { case IPPROTO_TCP: key->tcp.flags = 0; - mask->tcp.flags = TCP_FLAG_RST | TCP_FLAG_FIN; + mask->tcp.flags = cpu_to_be16(be32_to_cpu(TCP_FLAG_RST | TCP_FLAG_FIN) >> 16); match->dissector.used_keys |= BIT(FLOW_DISSECTOR_KEY_TCP); break; case IPPROTO_UDP: From d05d5db815d56a0ce203ed297153d9794dfdcb68 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 13 Dec 2019 01:19:58 +0100 Subject: [PATCH 2/4] selftests: netfilter: extend flowtable test script with dnat rule NAT test currently covers snat (masquerade) only. Also add a dnat rule and then check that a connecting to the to-be-dnated address will work. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- .../selftests/netfilter/nft_flowtable.sh | 39 ++++++++++++++++--- 1 file changed, 34 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/netfilter/nft_flowtable.sh b/tools/testing/selftests/netfilter/nft_flowtable.sh index 16571ac1dab4..d3e0809ab368 100755 --- a/tools/testing/selftests/netfilter/nft_flowtable.sh +++ b/tools/testing/selftests/netfilter/nft_flowtable.sh @@ -226,17 +226,19 @@ check_transfer() return 0 } -test_tcp_forwarding() +test_tcp_forwarding_ip() { local nsa=$1 local nsb=$2 + local dstip=$3 + local dstport=$4 local lret=0 ip netns exec $nsb nc -w 5 -l -p 12345 < "$ns2in" > "$ns2out" & lpid=$! sleep 1 - ip netns exec $nsa nc -w 4 10.0.2.99 12345 < "$ns1in" > "$ns1out" & + ip netns exec $nsa nc -w 4 "$dstip" "$dstport" < "$ns1in" > "$ns1out" & cpid=$! sleep 3 @@ -258,6 +260,28 @@ test_tcp_forwarding() return $lret } +test_tcp_forwarding() +{ + test_tcp_forwarding_ip "$1" "$2" 10.0.2.99 12345 + + return $? +} + +test_tcp_forwarding_nat() +{ + local lret + + test_tcp_forwarding_ip "$1" "$2" 10.0.2.99 12345 + lret=$? + + if [ $lret -eq 0 ] ; then + test_tcp_forwarding_ip "$1" "$2" 10.6.6.6 1666 + lret=$? + fi + + return $lret +} + make_file "$ns1in" "ns1" make_file "$ns2in" "ns2" @@ -283,14 +307,19 @@ ip -net ns2 route add 192.168.10.1 via 10.0.2.1 # Same, but with NAT enabled. ip netns exec nsr1 nft -f - < /dev/null ip netns exec ns2 sysctl net.ipv4.ip_no_pmtu_disc=0 > /dev/null -test_tcp_forwarding ns1 ns2 +test_tcp_forwarding_nat ns1 ns2 if [ $? -eq 0 ] ;then echo "PASS: flow offloaded for ns1/ns2 with NAT and pmtu discovery" else From e608f631f0ba5f1fc5ee2e260a3a35d13107cbfe Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Sun, 15 Dec 2019 03:49:25 +0100 Subject: [PATCH 3/4] netfilter: ebtables: compat: reject all padding in matches/watchers syzbot reported following splat: BUG: KASAN: vmalloc-out-of-bounds in size_entry_mwt net/bridge/netfilter/ebtables.c:2063 [inline] BUG: KASAN: vmalloc-out-of-bounds in compat_copy_entries+0x128b/0x1380 net/bridge/netfilter/ebtables.c:2155 Read of size 4 at addr ffffc900004461f4 by task syz-executor267/7937 CPU: 1 PID: 7937 Comm: syz-executor267 Not tainted 5.5.0-rc1-syzkaller #0 size_entry_mwt net/bridge/netfilter/ebtables.c:2063 [inline] compat_copy_entries+0x128b/0x1380 net/bridge/netfilter/ebtables.c:2155 compat_do_replace+0x344/0x720 net/bridge/netfilter/ebtables.c:2249 compat_do_ebt_set_ctl+0x22f/0x27e net/bridge/netfilter/ebtables.c:2333 [..] Because padding isn't considered during computation of ->buf_user_offset, "total" is decremented by fewer bytes than it should. Therefore, the first part of if (*total < sizeof(*entry) || entry->next_offset < sizeof(*entry)) will pass, -- it should not have. This causes oob access: entry->next_offset is past the vmalloced size. Reject padding and check that computed user offset (sum of ebt_entry structure plus all individual matches/watchers/targets) is same value that userspace gave us as the offset of the next entry. Reported-by: syzbot+f68108fed972453a0ad4@syzkaller.appspotmail.com Fixes: 81e675c227ec ("netfilter: ebtables: add CONFIG_COMPAT support") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/ebtables.c | 35 ++++++++++++++++----------------- 1 file changed, 17 insertions(+), 18 deletions(-) diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 4096d8a74a2b..e1256e03a9a8 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -1867,7 +1867,7 @@ static int ebt_buf_count(struct ebt_entries_buf_state *state, unsigned int sz) } static int ebt_buf_add(struct ebt_entries_buf_state *state, - void *data, unsigned int sz) + const void *data, unsigned int sz) { if (state->buf_kern_start == NULL) goto count_only; @@ -1901,7 +1901,7 @@ enum compat_mwt { EBT_COMPAT_TARGET, }; -static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt, +static int compat_mtw_from_user(const struct compat_ebt_entry_mwt *mwt, enum compat_mwt compat_mwt, struct ebt_entries_buf_state *state, const unsigned char *base) @@ -1979,22 +1979,23 @@ static int compat_mtw_from_user(struct compat_ebt_entry_mwt *mwt, /* return size of all matches, watchers or target, including necessary * alignment and padding. */ -static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32, +static int ebt_size_mwt(const struct compat_ebt_entry_mwt *match32, unsigned int size_left, enum compat_mwt type, struct ebt_entries_buf_state *state, const void *base) { + const char *buf = (const char *)match32; int growth = 0; - char *buf; if (size_left == 0) return 0; - buf = (char *) match32; - - while (size_left >= sizeof(*match32)) { + do { struct ebt_entry_match *match_kern; int ret; + if (size_left < sizeof(*match32)) + return -EINVAL; + match_kern = (struct ebt_entry_match *) state->buf_kern_start; if (match_kern) { char *tmp; @@ -2031,22 +2032,18 @@ static int ebt_size_mwt(struct compat_ebt_entry_mwt *match32, if (match_kern) match_kern->match_size = ret; - /* rule should have no remaining data after target */ - if (type == EBT_COMPAT_TARGET && size_left) - return -EINVAL; - match32 = (struct compat_ebt_entry_mwt *) buf; - } + } while (size_left); return growth; } /* called for all ebt_entry structures. */ -static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base, +static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *base, unsigned int *total, struct ebt_entries_buf_state *state) { - unsigned int i, j, startoff, new_offset = 0; + unsigned int i, j, startoff, next_expected_off, new_offset = 0; /* stores match/watchers/targets & offset of next struct ebt_entry: */ unsigned int offsets[4]; unsigned int *offsets_update = NULL; @@ -2132,11 +2129,13 @@ static int size_entry_mwt(struct ebt_entry *entry, const unsigned char *base, return ret; } - startoff = state->buf_user_offset - startoff; - - if (WARN_ON(*total < startoff)) + next_expected_off = state->buf_user_offset - startoff; + if (next_expected_off != entry->next_offset) return -EINVAL; - *total -= startoff; + + if (*total < entry->next_offset) + return -EINVAL; + *total -= entry->next_offset; return 0; } From 8cb4ec44de42b99b92399b4d1daf3dc430ed0186 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Wed, 18 Dec 2019 00:59:29 +0100 Subject: [PATCH 4/4] netfilter: nft_tproxy: Fix port selector on Big Endian MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On Big Endian architectures, u16 port value was extracted from the wrong parts of u32 sreg_port, just like commit 10596608c4d62 ("netfilter: nf_tables: fix mismatch in big-endian system") describes. Fixes: 4ed8eb6570a49 ("netfilter: nf_tables: Add native tproxy support") Signed-off-by: Phil Sutter Acked-by: Florian Westphal Acked-by: Máté Eckl Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_tproxy.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nft_tproxy.c b/net/netfilter/nft_tproxy.c index f92a82c73880..95980154ef02 100644 --- a/net/netfilter/nft_tproxy.c +++ b/net/netfilter/nft_tproxy.c @@ -50,7 +50,7 @@ static void nft_tproxy_eval_v4(const struct nft_expr *expr, taddr = nf_tproxy_laddr4(skb, taddr, iph->daddr); if (priv->sreg_port) - tport = regs->data[priv->sreg_port]; + tport = nft_reg_load16(®s->data[priv->sreg_port]); if (!tport) tport = hp->dest; @@ -117,7 +117,7 @@ static void nft_tproxy_eval_v6(const struct nft_expr *expr, taddr = *nf_tproxy_laddr6(skb, &taddr, &iph->daddr); if (priv->sreg_port) - tport = regs->data[priv->sreg_port]; + tport = nft_reg_load16(®s->data[priv->sreg_port]); if (!tport) tport = hp->dest;