The table list iteration holds rcu read lock side, but recent audit code
dereferences table object out of the rcu read lock side:
[ 4137.407349] BUG: unable to handle page fault for address: 00000000001f3c50
[ 4137.407357] #PF: supervisor read access in kernel mode
[ 4137.407359] #PF: error_code(0x0000) - not-present page
[ 4137.407360] PGD 0 P4D 0
[ 4137.407363] Oops: 0000 [#1] PREEMPT SMP PTI
[ 4137.407365] CPU: 4 PID: 500177 Comm: nft Not tainted 6.5.0+ #277
[ 4137.407369] RIP: 0010:string+0x49/0xd0
[ 4137.407374] Code: ff 77 36 45 89 d1 31 f6 49 01 f9 66 45 85 d2 75 19 eb 1e 49 39 f8 76 02 88 07 48 83 c7 01 83 c6 01 48 83 c2 01 4c 39 cf 74 07 <0f> b6 02 84 c0 75 e2 4c 89 c2 e9 58 e5 ff ff 48 c7 c0 0e b2 ff 81
[ 4137.407377] RSP: 0018:ffff8881179737f0 EFLAGS: 00010286
[ 4137.407379] RAX: 00000000001f2c50 RBX: ffff888117973848 RCX: ffff0a00ffffff04
[ 4137.407380] RDX: 00000000001f3c50 RSI: 0000000000000000 RDI: 0000000000000000
[ 4137.407381] RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000ffffffff
[ 4137.407383] R10: ffffffffffffffff R11: ffff88813584d200 R12: 0000000000000000
[ 4137.407384] R13: ffffffffa15cf709 R14: 0000000000000000 R15: ffffffffa15cf709
[ 4137.407385] FS: 00007fcfc18bb580(0000) GS:ffff88840e700000(0000) knlGS:0000000000000000
[ 4137.407387] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4137.407388] CR2: 00000000001f3c50 CR3: 00000001055b2001 CR4: 00000000001706e0
[ 4137.407390] Call Trace:
[ 4137.407392] <TASK>
[ 4137.407393] ? __die+0x1b/0x60
[ 4137.407397] ? page_fault_oops+0x6b/0xa0
[ 4137.407399] ? exc_page_fault+0x60/0x120
[ 4137.407403] ? asm_exc_page_fault+0x22/0x30
[ 4137.407408] ? string+0x49/0xd0
[ 4137.407410] vsnprintf+0x257/0x4f0
[ 4137.407414] kvasprintf+0x3e/0xb0
[ 4137.407417] kasprintf+0x3e/0x50
[ 4137.407419] nf_tables_dump_rules+0x1c0/0x360 [nf_tables]
[ 4137.407439] ? __alloc_skb+0xc3/0x170
[ 4137.407442] netlink_dump+0x170/0x330
[ 4137.407447] __netlink_dump_start+0x227/0x300
[ 4137.407449] nf_tables_getrule+0x205/0x390 [nf_tables]
Fixes: ea078ae9108e ("netfilter: nf_tables: Audit log rule reset")
Fixes: 7e9be1124dbe ("netfilter: nf_tables: Audit log setelem reset")
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nf_tables_api.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 2c81cee858d6..68aa8e4ea2e2 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3538,11 +3538,12 @@ static int nf_tables_dump_rules(struct sk_buff *skb,
break;
}
done:
- rcu_read_unlock();
if (reset && idx > cb->args[0])
audit_log_rule_reset(table, cb->seq, idx - cb->args[0]);
+ rcu_read_unlock();
+
cb->args[0] = idx;
return skb->len;
}
@@ -5760,8 +5761,6 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb)
if (!args.iter.err && args.iter.count == cb->args[0])
args.iter.err = nft_set_catchall_dump(net, skb, set,
reset, cb->seq);
- rcu_read_unlock();
-
nla_nest_end(skb, nest);
nlmsg_end(skb, nlh);
@@ -5769,6 +5768,8 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb)
audit_log_nft_set_reset(table, cb->seq,
args.iter.count - args.iter.skip);
+ rcu_read_unlock();
+
if (args.iter.err && args.iter.err != -EMSGSIZE)
return args.iter.err;
if (args.iter.count == cb->args[0])
--
2.30.2
