On Tue, Jul 13, 2021 at 11:42 AM Dongliang Mu <mudongliangabcd@xxxxxxxxx> wrote:
>
> In nf_tables_commit, if nf_tables_commit_audit_alloc fails, it does not
> free the adp variable.
>
> Fix this by freeing the linked list with head adl.
>
> backtrace:
> kmalloc include/linux/slab.h:591 [inline]
> kzalloc include/linux/slab.h:721 [inline]
> nf_tables_commit_audit_alloc net/netfilter/nf_tables_api.c:8439 [inline]
> nf_tables_commit+0x16e/0x1760 net/netfilter/nf_tables_api.c:8508
> nfnetlink_rcv_batch+0x512/0xa80 net/netfilter/nfnetlink.c:562
> nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:634 [inline]
> nfnetlink_rcv+0x1fa/0x220 net/netfilter/nfnetlink.c:652
> netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
> netlink_unicast+0x2c7/0x3e0 net/netlink/af_netlink.c:1340
> netlink_sendmsg+0x36b/0x6b0 net/netlink/af_netlink.c:1929
> sock_sendmsg_nosec net/socket.c:702 [inline]
> sock_sendmsg+0x56/0x80 net/socket.c:722
>
> Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
As far as I see, the more default way is to reference to syzbot by:
Reported-by: syzbot+[[20-letter hex reference]]@syzkaller.appspotmail.com
as in for example:
Reported-by: syzbot+fee64147a25aecd48055@xxxxxxxxxxxxxxxxxxxxxxxxx
A rough count says that format above is used 1300 times, whereas
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
is only used about 330 times.
Lukas
> Fixes: c520292f29b8 ("audit: log nftables configuration change events once per table")
> Signed-off-by: Dongliang Mu <mudongliangabcd@xxxxxxxxx>
> ---
> net/netfilter/nf_tables_api.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
> index 390d4466567f..7f45b291be13 100644
> --- a/net/netfilter/nf_tables_api.c
> +++ b/net/netfilter/nf_tables_api.c
> @@ -8444,6 +8444,16 @@ static int nf_tables_commit_audit_alloc(struct list_head *adl,
> return 0;
> }
>
> +static void nf_tables_commit_free(struct list_head *adl)
> +{
> + struct nft_audit_data *adp, *adn;
> +
> + list_for_each_entry_safe(adp, adn, adl, list) {
> + list_del(&adp->list);
> + kfree(adp);
> + }
> +}
> +
> static void nf_tables_commit_audit_collect(struct list_head *adl,
> struct nft_table *table, u32 op)
> {
> @@ -8508,6 +8518,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
> ret = nf_tables_commit_audit_alloc(&adl, trans->ctx.table);
> if (ret) {
> nf_tables_commit_chain_prepare_cancel(net);
> + nf_tables_commit_free(adl);
> return ret;
> }
> if (trans->msg_type == NFT_MSG_NEWRULE ||
> @@ -8517,6 +8528,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
> ret = nf_tables_commit_chain_prepare(net, chain);
> if (ret < 0) {
> nf_tables_commit_chain_prepare_cancel(net);
> + nf_tables_commit_free(adl);
> return ret;
> }
> }
> --
> 2.25.1
>
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