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linux/net/packet/internal.h
Daniel Borkmann db3fadacaf packet: Move reference count in packet_sock to atomic_long_t
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>
2023-12-04 14:45:04 -08:00

165 lines
3.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __PACKET_INTERNAL_H__
#define __PACKET_INTERNAL_H__
#include <linux/refcount.h>
struct packet_mclist {
struct packet_mclist *next;
int ifindex;
int count;
unsigned short type;
unsigned short alen;
unsigned char addr[MAX_ADDR_LEN];
};
/* kbdq - kernel block descriptor queue */
struct tpacket_kbdq_core {
struct pgv *pkbdq;
unsigned int feature_req_word;
unsigned int hdrlen;
unsigned char reset_pending_on_curr_blk;
unsigned char delete_blk_timer;
unsigned short kactive_blk_num;
unsigned short blk_sizeof_priv;
/* last_kactive_blk_num:
* trick to see if user-space has caught up
* in order to avoid refreshing timer when every single pkt arrives.
*/
unsigned short last_kactive_blk_num;
char *pkblk_start;
char *pkblk_end;
int kblk_size;
unsigned int max_frame_len;
unsigned int knum_blocks;
uint64_t knxt_seq_num;
char *prev;
char *nxt_offset;
struct sk_buff *skb;
rwlock_t blk_fill_in_prog_lock;
/* Default is set to 8ms */
#define DEFAULT_PRB_RETIRE_TOV (8)
unsigned short retire_blk_tov;
unsigned short version;
unsigned long tov_in_jiffies;
/* timer to retire an outstanding block */
struct timer_list retire_blk_timer;
};
struct pgv {
char *buffer;
};
struct packet_ring_buffer {
struct pgv *pg_vec;
unsigned int head;
unsigned int frames_per_block;
unsigned int frame_size;
unsigned int frame_max;
unsigned int pg_vec_order;
unsigned int pg_vec_pages;
unsigned int pg_vec_len;
unsigned int __percpu *pending_refcnt;
union {
unsigned long *rx_owner_map;
struct tpacket_kbdq_core prb_bdqc;
};
};
extern struct mutex fanout_mutex;
#define PACKET_FANOUT_MAX (1 << 16)
struct packet_fanout {
possible_net_t net;
unsigned int num_members;
u32 max_num_members;
u16 id;
u8 type;
u8 flags;
union {
atomic_t rr_cur;
struct bpf_prog __rcu *bpf_prog;
};
struct list_head list;
spinlock_t lock;
refcount_t sk_ref;
struct packet_type prot_hook ____cacheline_aligned_in_smp;
struct sock __rcu *arr[] __counted_by(max_num_members);
};
struct packet_rollover {
int sock;
atomic_long_t num;
atomic_long_t num_huge;
atomic_long_t num_failed;
#define ROLLOVER_HLEN (L1_CACHE_BYTES / sizeof(u32))
u32 history[ROLLOVER_HLEN] ____cacheline_aligned;
} ____cacheline_aligned_in_smp;
struct packet_sock {
/* struct sock has to be the first member of packet_sock */
struct sock sk;
struct packet_fanout *fanout;
union tpacket_stats_u stats;
struct packet_ring_buffer rx_ring;
struct packet_ring_buffer tx_ring;
int copy_thresh;
spinlock_t bind_lock;
struct mutex pg_vec_lock;
unsigned long flags;
int ifindex; /* bound device */
u8 vnet_hdr_sz;
__be16 num;
struct packet_rollover *rollover;
struct packet_mclist *mclist;
atomic_long_t mapped;
enum tpacket_versions tp_version;
unsigned int tp_hdrlen;
unsigned int tp_reserve;
unsigned int tp_tstamp;
struct completion skb_completion;
struct net_device __rcu *cached_dev;
struct packet_type prot_hook ____cacheline_aligned_in_smp;
atomic_t tp_drops ____cacheline_aligned_in_smp;
};
#define pkt_sk(ptr) container_of_const(ptr, struct packet_sock, sk)
enum packet_sock_flags {
PACKET_SOCK_ORIGDEV,
PACKET_SOCK_AUXDATA,
PACKET_SOCK_TX_HAS_OFF,
PACKET_SOCK_TP_LOSS,
PACKET_SOCK_RUNNING,
PACKET_SOCK_PRESSURE,
PACKET_SOCK_QDISC_BYPASS,
};
static inline void packet_sock_flag_set(struct packet_sock *po,
enum packet_sock_flags flag,
bool val)
{
if (val)
set_bit(flag, &po->flags);
else
clear_bit(flag, &po->flags);
}
static inline bool packet_sock_flag(const struct packet_sock *po,
enum packet_sock_flags flag)
{
return test_bit(flag, &po->flags);
}
#endif