Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:  netfilter: nft_ct: fix use-after-free in timeout object destroy  nft_ct_timeout_obj_destroy() frees the timeout object with kfree() immediately after nf_ct_untimeout(), without waiting for an RCU grace period. Concurrent packet processing on other CPUs may still hold RCU-protected references to the timeout object obtained via rcu_dereference() in nf_ct_timeout_data().  Add an rcu_head to struct nf_ct_timeout and use kfree_rcu() to defer freeing until after an RCU grace period, matching the approach already used in nfnetlink_cttimeout.c.  KASAN report:  BUG: KASAN: slab-use-after-free in nf_conntrack_tcp_packet+0x1381/0x29d0  Read of size 4 at addr ffff8881035fe19c by task exploit/80   Call Trace:   nf_conntrack_tcp_packet+0x1381/0x29d0   nf_conntrack_in+0x612/0x8b0   nf_hook_slow+0x70/0x100   __ip_local_out+0x1b2/0x210   tcp_sendmsg_locked+0x722/0x1580   __sys_sendto+0x2d8/0x320   Allocated by task 75:   nft_ct_timeout_obj_init+0xf6/0x290   nft_obj_init+0x107/0x1b0   nf_tables_newobj+0x680/0x9c0   nfnetlink_rcv_batch+0xc29/0xe00   Freed by task 26:   nft_obj_destroy+0x3f/0xa0   nf_tables_trans_destroy_work+0x51c/0x5c0   process_one_work+0x2c4/0x5a0