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In some potential instances the reference count on struct packet_sock could be saturated and cause overflows which gets the kernel a bit confused. To prevent this, move to a 64-bit atomic reference count on 64-bit architectures to prevent the possibility of this type to overflow. Because we can not handle saturation, using refcount_t is not possible in this place. Maybe someday in the future if it changes it could be used. Also, instead of using plain atomic64_t, use atomic_long_t instead. 32-bit machines tend to be memory-limited (i.e. anything that increases a reference uses so much memory that you can't actually get to 2**32 references). 32-bit architectures also tend to have serious problems with 64-bit atomics. Hence, atomic_long_t is the more natural solution. Reported-by: "The UK's National Cyber Security Centre (NCSC)" <security@ncsc.gov.uk> Co-developed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: stable@kernel.org Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20231201131021.19999-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
165 lines
3.7 KiB
C
165 lines
3.7 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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rwlock_t blk_fill_in_prog_lock;
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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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union {
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unsigned long *rx_owner_map;
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struct tpacket_kbdq_core prb_bdqc;
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};
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};
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extern struct mutex fanout_mutex;
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#define PACKET_FANOUT_MAX (1 << 16)
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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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u32 max_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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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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struct sock __rcu *arr[] __counted_by(max_num_members);
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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 long flags;
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int ifindex; /* bound device */
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u8 vnet_hdr_sz;
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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_long_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_tstamp;
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struct completion skb_completion;
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struct net_device __rcu *cached_dev;
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struct packet_type prot_hook ____cacheline_aligned_in_smp;
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atomic_t tp_drops ____cacheline_aligned_in_smp;
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};
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#define pkt_sk(ptr) container_of_const(ptr, struct packet_sock, sk)
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enum packet_sock_flags {
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PACKET_SOCK_ORIGDEV,
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PACKET_SOCK_AUXDATA,
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PACKET_SOCK_TX_HAS_OFF,
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PACKET_SOCK_TP_LOSS,
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PACKET_SOCK_RUNNING,
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PACKET_SOCK_PRESSURE,
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PACKET_SOCK_QDISC_BYPASS,
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};
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static inline void packet_sock_flag_set(struct packet_sock *po,
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enum packet_sock_flags flag,
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bool val)
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{
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if (val)
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set_bit(flag, &po->flags);
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else
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clear_bit(flag, &po->flags);
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}
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static inline bool packet_sock_flag(const struct packet_sock *po,
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enum packet_sock_flags flag)
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{
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return test_bit(flag, &po->flags);
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}
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#endif
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