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57f015f5ec
syzkaller found a race condition fanout_demux_rollover() while removing a packet socket from a fanout group. po->rollover is read and operated on during packet_rcv_fanout(), via fanout_demux_rollover(), but the pointer is currently cleared before the synchronization in packet_release(). It is safer to delay the cleanup until after synchronize_net() has been called, ensuring all calls to packet_rcv_fanout() for this socket have finished. To further simplify synchronization around the rollover structure, set po->rollover in fanout_add() only if there are no errors. This removes the need for rcu in the struct and in the call to packet_getsockopt(..., PACKET_ROLLOVER_STATS, ...). Crashing stack trace: fanout_demux_rollover+0xb6/0x4d0 net/packet/af_packet.c:1392 packet_rcv_fanout+0x649/0x7c8 net/packet/af_packet.c:1487 dev_queue_xmit_nit+0x835/0xc10 net/core/dev.c:1953 xmit_one net/core/dev.c:2975 [inline] dev_hard_start_xmit+0x16b/0xac0 net/core/dev.c:2995 __dev_queue_xmit+0x17a4/0x2050 net/core/dev.c:3476 dev_queue_xmit+0x17/0x20 net/core/dev.c:3509 neigh_connected_output+0x489/0x720 net/core/neighbour.c:1379 neigh_output include/net/neighbour.h:482 [inline] ip6_finish_output2+0xad1/0x22a0 net/ipv6/ip6_output.c:120 ip6_finish_output+0x2f9/0x920 net/ipv6/ip6_output.c:146 NF_HOOK_COND include/linux/netfilter.h:239 [inline] ip6_output+0x1f4/0x850 net/ipv6/ip6_output.c:163 dst_output include/net/dst.h:459 [inline] NF_HOOK.constprop.35+0xff/0x630 include/linux/netfilter.h:250 mld_sendpack+0x6a8/0xcc0 net/ipv6/mcast.c:1660 mld_send_initial_cr.part.24+0x103/0x150 net/ipv6/mcast.c:2072 mld_send_initial_cr net/ipv6/mcast.c:2056 [inline] ipv6_mc_dad_complete+0x99/0x130 net/ipv6/mcast.c:2079 addrconf_dad_completed+0x595/0x970 net/ipv6/addrconf.c:4039 addrconf_dad_work+0xac9/0x1160 net/ipv6/addrconf.c:3971 process_one_work+0xbf0/0x1bc0 kernel/workqueue.c:2113 worker_thread+0x223/0x1990 kernel/workqueue.c:2247 kthread+0x35e/0x430 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:432 Fixes:0648ab70af
("packet: rollover prepare: per-socket state") Fixes:509c7a1ecc
("packet: avoid panic in packet_getsockopt()") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Mike Maloney <maloney@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
142 lines
3.1 KiB
C
142 lines
3.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __PACKET_INTERNAL_H__
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#define __PACKET_INTERNAL_H__
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#include <linux/refcount.h>
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struct packet_mclist {
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struct packet_mclist *next;
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int ifindex;
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int count;
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unsigned short type;
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unsigned short alen;
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unsigned char addr[MAX_ADDR_LEN];
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};
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/* kbdq - kernel block descriptor queue */
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struct tpacket_kbdq_core {
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struct pgv *pkbdq;
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unsigned int feature_req_word;
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unsigned int hdrlen;
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unsigned char reset_pending_on_curr_blk;
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unsigned char delete_blk_timer;
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unsigned short kactive_blk_num;
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unsigned short blk_sizeof_priv;
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/* last_kactive_blk_num:
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* trick to see if user-space has caught up
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* in order to avoid refreshing timer when every single pkt arrives.
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*/
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unsigned short last_kactive_blk_num;
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char *pkblk_start;
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char *pkblk_end;
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int kblk_size;
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unsigned int max_frame_len;
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unsigned int knum_blocks;
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uint64_t knxt_seq_num;
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char *prev;
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char *nxt_offset;
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struct sk_buff *skb;
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atomic_t blk_fill_in_prog;
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/* Default is set to 8ms */
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#define DEFAULT_PRB_RETIRE_TOV (8)
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unsigned short retire_blk_tov;
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unsigned short version;
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unsigned long tov_in_jiffies;
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/* timer to retire an outstanding block */
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struct timer_list retire_blk_timer;
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};
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struct pgv {
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char *buffer;
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};
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struct packet_ring_buffer {
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struct pgv *pg_vec;
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unsigned int head;
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unsigned int frames_per_block;
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unsigned int frame_size;
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unsigned int frame_max;
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unsigned int pg_vec_order;
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unsigned int pg_vec_pages;
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unsigned int pg_vec_len;
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unsigned int __percpu *pending_refcnt;
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struct tpacket_kbdq_core prb_bdqc;
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};
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extern struct mutex fanout_mutex;
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#define PACKET_FANOUT_MAX 256
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struct packet_fanout {
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possible_net_t net;
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unsigned int num_members;
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u16 id;
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u8 type;
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u8 flags;
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union {
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atomic_t rr_cur;
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struct bpf_prog __rcu *bpf_prog;
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};
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struct list_head list;
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struct sock *arr[PACKET_FANOUT_MAX];
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spinlock_t lock;
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refcount_t sk_ref;
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struct packet_type prot_hook ____cacheline_aligned_in_smp;
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};
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struct packet_rollover {
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int sock;
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atomic_long_t num;
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atomic_long_t num_huge;
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atomic_long_t num_failed;
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#define ROLLOVER_HLEN (L1_CACHE_BYTES / sizeof(u32))
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u32 history[ROLLOVER_HLEN] ____cacheline_aligned;
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} ____cacheline_aligned_in_smp;
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struct packet_sock {
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/* struct sock has to be the first member of packet_sock */
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struct sock sk;
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struct packet_fanout *fanout;
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union tpacket_stats_u stats;
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struct packet_ring_buffer rx_ring;
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struct packet_ring_buffer tx_ring;
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int copy_thresh;
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spinlock_t bind_lock;
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struct mutex pg_vec_lock;
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unsigned int running:1, /* prot_hook is attached*/
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auxdata:1,
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origdev:1,
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has_vnet_hdr:1;
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int pressure;
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int ifindex; /* bound device */
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__be16 num;
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struct packet_rollover *rollover;
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struct packet_mclist *mclist;
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atomic_t mapped;
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enum tpacket_versions tp_version;
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unsigned int tp_hdrlen;
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unsigned int tp_reserve;
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unsigned int tp_loss:1;
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unsigned int tp_tx_has_off:1;
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unsigned int tp_tstamp;
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struct net_device __rcu *cached_dev;
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int (*xmit)(struct sk_buff *skb);
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struct packet_type prot_hook ____cacheline_aligned_in_smp;
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};
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static struct packet_sock *pkt_sk(struct sock *sk)
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{
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return (struct packet_sock *)sk;
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}
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#endif
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