linux.git/net/netfilter, branch vm-bind

ip: Fix data-races around sysctl_ip_default_ttl.

2022-07-15T10:49:55+00:00

While reading sysctl_ip_default_ttl, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller

netfilter: nf_tables: replace BUG_ON by element length check

2022-07-09T14:25:09+00:00

BUG_ON can be triggered from userspace with an element with a large userdata area. Replace it by length check and return EINVAL instead. Over time extensions have been growing in size. Pick a sufficiently old Fixes: tag to propagate this fix. Fixes: 7d7402642eaf ("netfilter: nf_tables: variable sized set element keys / data") Signed-off-by: Pablo Neira Ayuso

netfilter: nf_log: incorrect offset to network header

2022-07-09T07:55:43+00:00

NFPROTO_ARP is expecting to find the ARP header at the network offset. In the particular case of ARP, HTYPE= field shows the initial bytes of the ethernet header destination MAC address. netdev out: IN= OUT=bridge0 MACSRC=c2:76:e5:71:e1:de MACDST=36:b0:4a:e2:72:ea MACPROTO=0806 ARP HTYPE=14000 PTYPE=0x4ae2 OPCODE=49782 NFPROTO_NETDEV egress hook is also expecting to find the IP headers at the network offset. Fixes: 35b9395104d5 ("netfilter: add generic ARP packet logger") Reported-by: Tom Yan Signed-off-by: Pablo Neira Ayuso

netfilter: conntrack: fix crash due to confirmed bit load reordering

2022-07-07T18:55:18+00:00

Kajetan Puchalski reports crash on ARM, with backtrace of: __nf_ct_delete_from_lists nf_ct_delete early_drop __nf_conntrack_alloc Unlike atomic_inc_not_zero, refcount_inc_not_zero is not a full barrier. conntrack uses SLAB_TYPESAFE_BY_RCU, i.e. it is possible that a 'newly' allocated object is still in use on another CPU: CPU1 CPU2 encounter 'ct' during hlist walk delete_from_lists refcount drops to 0 kmem_cache_free(ct); __nf_conntrack_alloc() // returns same object refcount_inc_not_zero(ct); /* might fail */ /* If set, ct is public/in the hash table */ test_bit(IPS_CONFIRMED_BIT, &ct->status); In case CPU1 already set refcount back to 1, refcount_inc_not_zero() will succeed. The expected possibilities for a CPU that obtained the object 'ct' (but no reference so far) are: 1. refcount_inc_not_zero() fails. CPU2 ignores the object and moves to the next entry in the list. This happens for objects that are about to be free'd, that have been free'd, or that have been reallocated by __nf_conntrack_alloc(), but where the refcount has not been increased back to 1 yet. 2. refcount_inc_not_zero() succeeds. CPU2 checks the CONFIRMED bit in ct->status. If set, the object is public/in the table. If not, the object must be skipped; CPU2 calls nf_ct_put() to un-do the refcount increment and moves to the next object. Parallel deletion from the hlists is prevented by a 'test_and_set_bit(IPS_DYING_BIT, &ct->status);' check, i.e. only one cpu will do the unlink, the other one will only drop its reference count. Because refcount_inc_not_zero is not a full barrier, CPU2 may try to delete an object that is not on any list: 1. refcount_inc_not_zero() successful (refcount inited to 1 on other CPU) 2. CONFIRMED test also successful (load was reordered or zeroing of ct->status not yet visible) 3. delete_from_lists unlinks entry not on the hlist, because IPS_DYING_BIT is 0 (already cleared). 2) is already wrong: CPU2 will handle a partially initited object that is supposed to be private to CPU1. Add needed barriers when refcount_inc_not_zero() is successful. It also inserts a smp_wmb() before the refcount is set to 1 during allocation. Because other CPU might still see the object, refcount_set(1) "resurrects" it, so we need to make sure that other CPUs will also observe the right content. In particular, the CONFIRMED bit test must only pass once the object is fully initialised and either in the hash or about to be inserted (with locks held to delay possible unlink from early_drop or gc worker). I did not change flow_offload_alloc(), as far as I can see it should call refcount_inc(), not refcount_inc_not_zero(): the ct object is attached to the skb so its refcount should be >= 1 in all cases. v2: prefer smp_acquire__after_ctrl_dep to smp_rmb (Will Deacon). v3: keep smp_acquire__after_ctrl_dep close to refcount_inc_not_zero call add comment in nf_conntrack_netlink, no control dependency there due to locks. Cc: Peter Zijlstra Link: https://lore.kernel.org/all/Yr7WTfd6AVTQkLjI@e126311.manchester.arm.com/ Reported-by: Kajetan Puchalski Diagnosed-by: Will Deacon Fixes: 719774377622 ("netfilter: conntrack: convert to refcount_t api") Signed-off-by: Florian Westphal Acked-by: Will Deacon

netfilter: nft_set_pipapo: release elements in clone from abort path

2022-07-02T19:04:19+00:00

New elements that reside in the clone are not released in case that the transaction is aborted. [16302.231754] ------------[ cut here ]------------ [16302.231756] WARNING: CPU: 0 PID: 100509 at net/netfilter/nf_tables_api.c:1864 nf_tables_chain_destroy+0x26/0x127 [nf_tables] [...] [16302.231882] CPU: 0 PID: 100509 Comm: nft Tainted: G W 5.19.0-rc3+ #155 [...] [16302.231887] RIP: 0010:nf_tables_chain_destroy+0x26/0x127 [nf_tables] [16302.231899] Code: f3 fe ff ff 41 55 41 54 55 53 48 8b 6f 10 48 89 fb 48 c7 c7 82 96 d9 a0 8b 55 50 48 8b 75 58 e8 de f5 92 e0 83 7d 50 00 74 09 <0f> 0b 5b 5d 41 5c 41 5d c3 4c 8b 65 00 48 8b 7d 08 49 39 fc 74 05 [...] [16302.231917] Call Trace: [16302.231919] [16302.231921] __nf_tables_abort.cold+0x23/0x28 [nf_tables] [16302.231934] nf_tables_abort+0x30/0x50 [nf_tables] [16302.231946] nfnetlink_rcv_batch+0x41a/0x840 [nfnetlink] [16302.231952] ? __nla_validate_parse+0x48/0x190 [16302.231959] nfnetlink_rcv+0x110/0x129 [nfnetlink] [16302.231963] netlink_unicast+0x211/0x340 [16302.231969] netlink_sendmsg+0x21e/0x460 Add nft_set_pipapo_match_destroy() helper function to release the elements in the lookup tables. Stefano Brivio says: "We additionally look for elements pointers in the cloned matching data if priv->dirty is set, because that means that cloned data might point to additional elements we did not commit to the working copy yet (such as the abort path case, but perhaps not limited to it)." Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges") Reviewed-by: Stefano Brivio Signed-off-by: Pablo Neira Ayuso

netfilter: nf_tables: stricter validation of element data

2022-07-02T19:04:10+00:00

Make sure element data type and length do not mismatch the one specified by the set declaration. Fixes: 7d7402642eaf ("netfilter: nf_tables: variable sized set element keys / data") Reported-by: Hugues ANGUELKOV Signed-off-by: Pablo Neira Ayuso

netfilter: nf_tables: avoid skb access on nf_stolen

2022-06-27T17:22:54+00:00

When verdict is NF_STOLEN, the skb might have been freed. When tracing is enabled, this can result in a use-after-free: 1. access to skb->nf_trace 2. access to skb->mark 3. computation of trace id 4. dump of packet payload To avoid 1, keep a cached copy of skb->nf_trace in the trace state struct. Refresh this copy whenever verdict is != STOLEN. Avoid 2 by skipping skb->mark access if verdict is STOLEN. 3 is avoided by precomputing the trace id. Only dump the packet when verdict is not "STOLEN". Reported-by: Pablo Neira Ayuso Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso

netfilter: nft_dynset: restore set element counter when failing to update

2022-06-27T17:03:37+00:00

This patch fixes a race condition. nft_rhash_update() might fail for two reasons: - Element already exists in the hashtable. - Another packet won race to insert an entry in the hashtable. In both cases, new() has already bumped the counter via atomic_add_unless(), therefore, decrement the set element counter. Fixes: 22fe54d5fefc ("netfilter: nf_tables: add support for dynamic set updates") Signed-off-by: Pablo Neira Ayuso

netfilter: nf_dup_netdev: add and use recursion counter

2022-06-21T08:50:41+00:00

Now that the egress function can be called from egress hook, we need to avoid recursive calls into the nf_tables traverser, else crash. Fixes: f87b9464d152 ("netfilter: nft_fwd_netdev: Support egress hook") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso

netfilter: nf_dup_netdev: do not push mac header a second time

2022-06-21T08:50:40+00:00

Eric reports skb_under_panic when using dup/fwd via bond+egress hook. Before pushing mac header, we should make sure that we're called from ingress to put back what was pulled earlier. In egress case, the MAC header is already there; we should leave skb alone. While at it be more careful here: skb might have been altered and headroom reduced, so add a skb_cow() before so that headroom is increased if necessary. nf_do_netdev_egress() assumes skb ownership (it normally ends with a call to dev_queue_xmit), so we must free the packet on error. Fixes: f87b9464d152 ("netfilter: nft_fwd_netdev: Support egress hook") Reported-by: Eric Garver Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso