From 7997eff82828304b780dc0a39707e1946d6f1ebf Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Sat, 20 Aug 2022 17:38:37 +0200 Subject: netfilter: ebtables: reject blobs that don't provide all entry points Harshit Mogalapalli says: In ebt_do_table() function dereferencing 'private->hook_entry[hook]' can lead to NULL pointer dereference. [..] Kernel panic: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] [..] RIP: 0010:ebt_do_table+0x1dc/0x1ce0 Code: 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 5c 16 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 6c df 08 48 8d 7d 2c 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 88 [..] Call Trace: nf_hook_slow+0xb1/0x170 __br_forward+0x289/0x730 maybe_deliver+0x24b/0x380 br_flood+0xc6/0x390 br_dev_xmit+0xa2e/0x12c0 For some reason ebtables rejects blobs that provide entry points that are not supported by the table, but what it should instead reject is the opposite: blobs that DO NOT provide an entry point supported by the table. t->valid_hooks is the bitmask of hooks (input, forward ...) that will see packets. Providing an entry point that is not support is harmless (never called/used), but the inverse isn't: it results in a crash because the ebtables traverser doesn't expect a NULL blob for a location its receiving packets for. Instead of fixing all the individual checks, do what iptables is doing and reject all blobs that differ from the expected hooks. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Harshit Mogalapalli Reported-by: syzkaller Signed-off-by: Florian Westphal --- include/linux/netfilter_bridge/ebtables.h | 4 ---- 1 file changed, 4 deletions(-) (limited to 'include') diff --git a/include/linux/netfilter_bridge/ebtables.h b/include/linux/netfilter_bridge/ebtables.h index a13296d6c7ce..fd533552a062 100644 --- a/include/linux/netfilter_bridge/ebtables.h +++ b/include/linux/netfilter_bridge/ebtables.h @@ -94,10 +94,6 @@ struct ebt_table { struct ebt_replace_kernel *table; unsigned int valid_hooks; rwlock_t lock; - /* e.g. could be the table explicitly only allows certain - * matches, targets, ... 0 == let it in */ - int (*check)(const struct ebt_table_info *info, - unsigned int valid_hooks); /* the data used by the kernel */ struct ebt_table_info *private; struct nf_hook_ops *ops; -- cgit v1.2.3 From ab482c6b66a4a8c0a8c0b0f577a785cf9ff1c2e2 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Sun, 21 Aug 2022 10:52:48 +0200 Subject: netfilter: nf_tables: make table handle allocation per-netns friendly mutex is per-netns, move table_netns to the pernet area. *read-write* to 0xffffffff883a01e8 of 8 bytes by task 6542 on cpu 0: nf_tables_newtable+0x6dc/0xc00 net/netfilter/nf_tables_api.c:1221 nfnetlink_rcv_batch net/netfilter/nfnetlink.c:513 [inline] nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:634 [inline] nfnetlink_rcv+0xa6a/0x13a0 net/netfilter/nfnetlink.c:652 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x652/0x730 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x643/0x740 net/netlink/af_netlink.c:1921 Fixes: f102d66b335a ("netfilter: nf_tables: use dedicated mutex to guard transactions") Reported-by: Abhishek Shah Reviewed-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_tables.h | 1 + net/netfilter/nf_tables_api.c | 3 +-- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index 99aae36c04b9..cdb7db9b0e25 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -1652,6 +1652,7 @@ struct nftables_pernet { struct list_head module_list; struct list_head notify_list; struct mutex commit_mutex; + u64 table_handle; unsigned int base_seq; u8 validate_state; }; diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index dff2b5851bbb..0951f31caabe 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -32,7 +32,6 @@ static LIST_HEAD(nf_tables_objects); static LIST_HEAD(nf_tables_flowtables); static LIST_HEAD(nf_tables_destroy_list); static DEFINE_SPINLOCK(nf_tables_destroy_list_lock); -static u64 table_handle; enum { NFT_VALIDATE_SKIP = 0, @@ -1235,7 +1234,7 @@ static int nf_tables_newtable(struct sk_buff *skb, const struct nfnl_info *info, INIT_LIST_HEAD(&table->flowtables); table->family = family; table->flags = flags; - table->handle = ++table_handle; + table->handle = ++nft_net->table_handle; if (table->flags & NFT_TABLE_F_OWNER) table->nlpid = NETLINK_CB(skb).portid; -- cgit v1.2.3 From 759eebbcfafcefa23b59e912396306543764bd3c Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Mon, 22 Aug 2022 23:13:00 +0200 Subject: netfilter: flowtable: add function to invoke garbage collection immediately Expose nf_flow_table_gc_run() to force a garbage collector run from the offload infrastructure. Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_flow_table.h | 1 + net/netfilter/nf_flow_table_core.c | 12 +++++++++--- 2 files changed, 10 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/net/netfilter/nf_flow_table.h b/include/net/netfilter/nf_flow_table.h index d5326c44b453..476cc4423a90 100644 --- a/include/net/netfilter/nf_flow_table.h +++ b/include/net/netfilter/nf_flow_table.h @@ -270,6 +270,7 @@ void flow_offload_refresh(struct nf_flowtable *flow_table, struct flow_offload_tuple_rhash *flow_offload_lookup(struct nf_flowtable *flow_table, struct flow_offload_tuple *tuple); +void nf_flow_table_gc_run(struct nf_flowtable *flow_table); void nf_flow_table_gc_cleanup(struct nf_flowtable *flowtable, struct net_device *dev); void nf_flow_table_cleanup(struct net_device *dev); diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c index 765ac779bfc8..60fc1e1b7182 100644 --- a/net/netfilter/nf_flow_table_core.c +++ b/net/netfilter/nf_flow_table_core.c @@ -437,12 +437,17 @@ static void nf_flow_offload_gc_step(struct nf_flowtable *flow_table, } } +void nf_flow_table_gc_run(struct nf_flowtable *flow_table) +{ + nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL); +} + static void nf_flow_offload_work_gc(struct work_struct *work) { struct nf_flowtable *flow_table; flow_table = container_of(work, struct nf_flowtable, gc_work.work); - nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL); + nf_flow_table_gc_run(flow_table); queue_delayed_work(system_power_efficient_wq, &flow_table->gc_work, HZ); } @@ -601,10 +606,11 @@ void nf_flow_table_free(struct nf_flowtable *flow_table) cancel_delayed_work_sync(&flow_table->gc_work); nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL); - nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL); + nf_flow_table_gc_run(flow_table); nf_flow_table_offload_flush(flow_table); if (nf_flowtable_hw_offload(flow_table)) - nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL); + nf_flow_table_gc_run(flow_table); + rhashtable_destroy(&flow_table->rhashtable); } EXPORT_SYMBOL_GPL(nf_flow_table_free); -- cgit v1.2.3 From 9afb4b27349a499483ae0134282cefd0c90f480f Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Thu, 18 Nov 2021 22:24:15 +0100 Subject: netfilter: flowtable: fix stuck flows on cleanup due to pending work To clear the flow table on flow table free, the following sequence normally happens in order: 1) gc_step work is stopped to disable any further stats/del requests. 2) All flow table entries are set to teardown state. 3) Run gc_step which will queue HW del work for each flow table entry. 4) Waiting for the above del work to finish (flush). 5) Run gc_step again, deleting all entries from the flow table. 6) Flow table is freed. But if a flow table entry already has pending HW stats or HW add work step 3 will not queue HW del work (it will be skipped), step 4 will wait for the pending add/stats to finish, and step 5 will queue HW del work which might execute after freeing of the flow table. To fix the above, this patch flushes the pending work, then it sets the teardown flag to all flows in the flowtable and it forces a garbage collector run to queue work to remove the flows from hardware, then it flushes this new pending work and (finally) it forces another garbage collector run to remove the entry from the software flowtable. Stack trace: [47773.882335] BUG: KASAN: use-after-free in down_read+0x99/0x460 [47773.883634] Write of size 8 at addr ffff888103b45aa8 by task kworker/u20:6/543704 [47773.885634] CPU: 3 PID: 543704 Comm: kworker/u20:6 Not tainted 5.12.0-rc7+ #2 [47773.886745] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009) [47773.888438] Workqueue: nf_ft_offload_del flow_offload_work_handler [nf_flow_table] [47773.889727] Call Trace: [47773.890214] dump_stack+0xbb/0x107 [47773.890818] print_address_description.constprop.0+0x18/0x140 [47773.892990] kasan_report.cold+0x7c/0xd8 [47773.894459] kasan_check_range+0x145/0x1a0 [47773.895174] down_read+0x99/0x460 [47773.899706] nf_flow_offload_tuple+0x24f/0x3c0 [nf_flow_table] [47773.907137] flow_offload_work_handler+0x72d/0xbe0 [nf_flow_table] [47773.913372] process_one_work+0x8ac/0x14e0 [47773.921325] [47773.921325] Allocated by task 592159: [47773.922031] kasan_save_stack+0x1b/0x40 [47773.922730] __kasan_kmalloc+0x7a/0x90 [47773.923411] tcf_ct_flow_table_get+0x3cb/0x1230 [act_ct] [47773.924363] tcf_ct_init+0x71c/0x1156 [act_ct] [47773.925207] tcf_action_init_1+0x45b/0x700 [47773.925987] tcf_action_init+0x453/0x6b0 [47773.926692] tcf_exts_validate+0x3d0/0x600 [47773.927419] fl_change+0x757/0x4a51 [cls_flower] [47773.928227] tc_new_tfilter+0x89a/0x2070 [47773.936652] [47773.936652] Freed by task 543704: [47773.937303] kasan_save_stack+0x1b/0x40 [47773.938039] kasan_set_track+0x1c/0x30 [47773.938731] kasan_set_free_info+0x20/0x30 [47773.939467] __kasan_slab_free+0xe7/0x120 [47773.940194] slab_free_freelist_hook+0x86/0x190 [47773.941038] kfree+0xce/0x3a0 [47773.941644] tcf_ct_flow_table_cleanup_work Original patch description and stack trace by Paul Blakey. Fixes: c29f74e0df7a ("netfilter: nf_flow_table: hardware offload support") Reported-by: Paul Blakey Tested-by: Paul Blakey Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_flow_table.h | 2 ++ net/netfilter/nf_flow_table_core.c | 7 +++---- net/netfilter/nf_flow_table_offload.c | 8 ++++++++ 3 files changed, 13 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/net/netfilter/nf_flow_table.h b/include/net/netfilter/nf_flow_table.h index 476cc4423a90..cd982f4a0f50 100644 --- a/include/net/netfilter/nf_flow_table.h +++ b/include/net/netfilter/nf_flow_table.h @@ -307,6 +307,8 @@ void nf_flow_offload_stats(struct nf_flowtable *flowtable, struct flow_offload *flow); void nf_flow_table_offload_flush(struct nf_flowtable *flowtable); +void nf_flow_table_offload_flush_cleanup(struct nf_flowtable *flowtable); + int nf_flow_table_offload_setup(struct nf_flowtable *flowtable, struct net_device *dev, enum flow_block_command cmd); diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c index 60fc1e1b7182..81c26a96c30b 100644 --- a/net/netfilter/nf_flow_table_core.c +++ b/net/netfilter/nf_flow_table_core.c @@ -605,12 +605,11 @@ void nf_flow_table_free(struct nf_flowtable *flow_table) mutex_unlock(&flowtable_lock); cancel_delayed_work_sync(&flow_table->gc_work); + nf_flow_table_offload_flush(flow_table); + /* ... no more pending work after this stage ... */ nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL); nf_flow_table_gc_run(flow_table); - nf_flow_table_offload_flush(flow_table); - if (nf_flowtable_hw_offload(flow_table)) - nf_flow_table_gc_run(flow_table); - + nf_flow_table_offload_flush_cleanup(flow_table); rhashtable_destroy(&flow_table->rhashtable); } EXPORT_SYMBOL_GPL(nf_flow_table_free); diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c index 103b6cbf257f..b04645ced89b 100644 --- a/net/netfilter/nf_flow_table_offload.c +++ b/net/netfilter/nf_flow_table_offload.c @@ -1074,6 +1074,14 @@ void nf_flow_offload_stats(struct nf_flowtable *flowtable, flow_offload_queue_work(offload); } +void nf_flow_table_offload_flush_cleanup(struct nf_flowtable *flowtable) +{ + if (nf_flowtable_hw_offload(flowtable)) { + flush_workqueue(nf_flow_offload_del_wq); + nf_flow_table_gc_run(flowtable); + } +} + void nf_flow_table_offload_flush(struct nf_flowtable *flowtable) { if (nf_flowtable_hw_offload(flowtable)) { -- cgit v1.2.3