Jumping between chains doesn't mix well with flush ruleset. Rules
from a different chain and set element may still refer to us.
[ 353.373791] ------------[ cut here ]------------
[ 353.373845] kernel BUG at net/netfilter/nf_tables_api.c:1159!
[ 353.373896] invalid opcode: 0000 [#1] SMP
[ 353.373942] Modules linked in: intel_powerclamp uas iwldvm iwlwifi
[ 353.374017] CPU: 0 PID: 6445 Comm: 31c3.nft Not tainted 3.18.0 #98
[ 353.374069] Hardware name: LENOVO 5129CTO/5129CTO, BIOS 6QET47WW (1.17 ) 07/14/2010
[...]
[ 353.375018] Call Trace:
[ 353.375046] [<ffffffff81964c31>] ? nf_tables_commit+0x381/0x540
[ 353.375101] [<ffffffff81949118>] nfnetlink_rcv+0x3d8/0x4b0
[ 353.375150] [<ffffffff81943fc5>] netlink_unicast+0x105/0x1a0
[ 353.375200] [<ffffffff8194438e>] netlink_sendmsg+0x32e/0x790
[ 353.375253] [<ffffffff818f398e>] sock_sendmsg+0x8e/0xc0
[ 353.375300] [<ffffffff818f36b9>] ? move_addr_to_kernel.part.20+0x19/0x70
[ 353.375357] [<ffffffff818f44f9>] ? move_addr_to_kernel+0x19/0x30
[ 353.375410] [<ffffffff819016d2>] ? verify_iovec+0x42/0xd0
[ 353.375459] [<ffffffff818f3e10>] ___sys_sendmsg+0x3f0/0x400
[ 353.375510] [<ffffffff810615fa>] ? native_sched_clock+0x2a/0x90
[ 353.375563] [<ffffffff81176697>] ? acct_account_cputime+0x17/0x20
[ 353.375616] [<ffffffff8110dc78>] ? account_user_time+0x88/0xa0
[ 353.375667] [<ffffffff818f4bbd>] __sys_sendmsg+0x3d/0x80
[ 353.375719] [<ffffffff81b184f4>] ? int_check_syscall_exit_work+0x34/0x3d
[ 353.375776] [<ffffffff818f4c0d>] SyS_sendmsg+0xd/0x20
[ 353.375823] [<ffffffff81b1826d>] system_call_fastpath+0x16/0x1b
Release object in this order: rules -> sets -> chains -> tables, to
make sure no references to chains are held anymore.
Reported-by: Asbjoern Sloth Toennesen <asbjorn@xxxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nf_tables_api.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 129a8da..3b3ddb4 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -713,16 +713,12 @@ static int nft_flush_table(struct nft_ctx *ctx)
struct nft_chain *chain, *nc;
struct nft_set *set, *ns;
- list_for_each_entry_safe(chain, nc, &ctx->table->chains, list) {
+ list_for_each_entry(chain, &ctx->table->chains, list) {
ctx->chain = chain;
err = nft_delrule_by_chain(ctx);
if (err < 0)
goto out;
-
- err = nft_delchain(ctx);
- if (err < 0)
- goto out;
}
list_for_each_entry_safe(set, ns, &ctx->table->sets, list) {
@@ -735,6 +731,14 @@ static int nft_flush_table(struct nft_ctx *ctx)
goto out;
}
+ list_for_each_entry_safe(chain, nc, &ctx->table->chains, list) {
+ ctx->chain = chain;
+
+ err = nft_delchain(ctx);
+ if (err < 0)
+ goto out;
+ }
+
err = nft_deltable(ctx);
out:
return err;
--
1.7.10.4
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