4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Taehee Yoo <ap420073@xxxxxxxxx> [ Upstream commit d71efb599ad42ef1e564c652d8084252bdc85edf ] When chain name is changed, nft_chain_commit_update is called. In the nft_chain_commit_update, trans->ctx.chain->name has old chain name and nft_trans_chain_name(trans) has new chain name. If new chain name is longer than old chain name, KASAN warns slab-out-of-bounds. [ 175.015012] BUG: KASAN: slab-out-of-bounds in strcpy+0x9e/0xb0 [ 175.022735] Write of size 1 at addr ffff880114e022da by task iptables-compat/1458 [ 175.031353] CPU: 0 PID: 1458 Comm: iptables-compat Not tainted 4.16.0-rc7+ #146 [ 175.031353] Hardware name: To be filled by O.E.M. To be filled by O.E.M./Aptio CRB, BIOS 5.6.5 07/08/2015 [ 175.031353] Call Trace: [ 175.031353] dump_stack+0x68/0xa0 [ 175.031353] print_address_description+0xd0/0x260 [ 175.031353] ? strcpy+0x9e/0xb0 [ 175.031353] kasan_report+0x234/0x350 [ 175.031353] __asan_report_store1_noabort+0x1c/0x20 [ 175.031353] strcpy+0x9e/0xb0 [ 175.031353] nf_tables_commit+0x1ccc/0x2990 [ 175.031353] nfnetlink_rcv+0x141e/0x16c0 [ 175.031353] ? nfnetlink_net_init+0x150/0x150 [ 175.031353] ? lock_acquire+0x370/0x370 [ 175.031353] ? lock_acquire+0x370/0x370 [ 175.031353] netlink_unicast+0x444/0x640 [ 175.031353] ? netlink_attachskb+0x700/0x700 [ 175.031353] ? _copy_from_iter_full+0x180/0x740 [ 175.031353] ? kasan_check_write+0x14/0x20 [ 175.031353] ? _copy_from_user+0x9b/0xd0 [ 175.031353] netlink_sendmsg+0x845/0xc70 [ ... ] Steps to reproduce: iptables-compat -N 1 iptables-compat -E 1 aaaaaaaaa Signed-off-by: Taehee Yoo <ap420073@xxxxxxxxx> Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/netfilter/nf_tables_api.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -5741,7 +5741,7 @@ static void nft_chain_commit_update(stru struct nft_base_chain *basechain; if (nft_trans_chain_name(trans)) - strcpy(trans->ctx.chain->name, nft_trans_chain_name(trans)); + swap(trans->ctx.chain->name, nft_trans_chain_name(trans)); if (!nft_is_base_chain(trans->ctx.chain)) return;
