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kernel/include/net/ax25.h
Murad Masimov 2f6efbabce ax25: Remove broken autobind 
Binding AX25 socket by using the autobind feature leads to memory leaks
in ax25_connect() and also refcount leaks in ax25_release(). Memory
leak was detected with kmemleak:

================================================================
unreferenced object 0xffff8880253cd680 (size 96):
backtrace:
__kmalloc_node_track_caller_noprof (./include/linux/kmemleak.h:43)
kmemdup_noprof (mm/util.c:136)
ax25_rt_autobind (net/ax25/ax25_route.c:428)
ax25_connect (net/ax25/af_ax25.c:1282)
__sys_connect_file (net/socket.c:2045)
__sys_connect (net/socket.c:2064)
__x64_sys_connect (net/socket.c:2067)
do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
================================================================

When socket is bound, refcounts must be incremented the way it is done
in ax25_bind() and ax25_setsockopt() (SO_BINDTODEVICE). In case of
autobind, the refcounts are not incremented.

This bug leads to the following issue reported by Syzkaller:

================================================================
ax25_connect(): syz-executor318 uses autobind, please contact jreuter@yaina.de
------------[ cut here ]------------
refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 0 PID: 5317 at lib/refcount.c:31 refcount_warn_saturate+0xfa/0x1d0 lib/refcount.c:31
Modules linked in:
CPU: 0 UID: 0 PID: 5317 Comm: syz-executor318 Not tainted 6.14.0-rc4-syzkaller-00278-gece144f151ac #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:refcount_warn_saturate+0xfa/0x1d0 lib/refcount.c:31
...
Call Trace:
 <TASK>
 __refcount_dec include/linux/refcount.h:336 [inline]
 refcount_dec include/linux/refcount.h:351 [inline]
 ref_tracker_free+0x6af/0x7e0 lib/ref_tracker.c:236
 netdev_tracker_free include/linux/netdevice.h:4302 [inline]
 netdev_put include/linux/netdevice.h:4319 [inline]
 ax25_release+0x368/0x960 net/ax25/af_ax25.c:1080
 __sock_release net/socket.c:647 [inline]
 sock_close+0xbc/0x240 net/socket.c:1398
 __fput+0x3e9/0x9f0 fs/file_table.c:464
 __do_sys_close fs/open.c:1580 [inline]
 __se_sys_close fs/open.c:1565 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1565
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
 ...
 </TASK>
================================================================

Considering the issues above and the comments left in the code that say:
"check if we can remove this feature. It is broken."; "autobinding in this
may or may not work"; - it is better to completely remove this feature than
to fix it because it is broken and leads to various kinds of memory bugs.

Now calling connect() without first binding socket will result in an
error (-EINVAL). Userspace software that relies on the autobind feature
might get broken. However, this feature does not seem widely used with
this specific driver as it was not reliable at any point of time, and it
is already broken anyway. E.g. ax25-tools and ax25-apps packages for
popular distributions do not use the autobind feature for AF_AX25.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: syzbot+33841dc6aa3e1d86b78a@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=33841dc6aa3e1d86b78a
Signed-off-by: Murad Masimov <m.masimov@mt-integration.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-24 10:26:53 +00:00

486 lines
15 KiB
C
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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Declarations of AX.25 type objects.
*
* Alan Cox (GW4PTS) 10/11/93
*/
#ifndef _AX25_H
#define _AX25_H
#include <linux/ax25.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/refcount.h>
#include <net/neighbour.h>
#include <net/sock.h>
#include <linux/seq_file.h>
#define AX25_T1CLAMPLO 1
#define AX25_T1CLAMPHI (30 * HZ)
#define AX25_BPQ_HEADER_LEN 16
#define AX25_KISS_HEADER_LEN 1
#define AX25_HEADER_LEN 17
#define AX25_ADDR_LEN 7
#define AX25_DIGI_HEADER_LEN (AX25_MAX_DIGIS * AX25_ADDR_LEN)
#define AX25_MAX_HEADER_LEN (AX25_HEADER_LEN + AX25_DIGI_HEADER_LEN)
/* AX.25 Protocol IDs */
#define AX25_P_ROSE 0x01
#define AX25_P_VJCOMP 0x06 /* Compressed TCP/IP packet */
/* Van Jacobsen (RFC 1144) */
#define AX25_P_VJUNCOMP 0x07 /* Uncompressed TCP/IP packet */
/* Van Jacobsen (RFC 1144) */
#define AX25_P_SEGMENT 0x08 /* Segmentation fragment */
#define AX25_P_TEXNET 0xc3 /* TEXTNET datagram protocol */
#define AX25_P_LQ 0xc4 /* Link Quality Protocol */
#define AX25_P_ATALK 0xca /* Appletalk */
#define AX25_P_ATALK_ARP 0xcb /* Appletalk ARP */
#define AX25_P_IP 0xcc /* ARPA Internet Protocol */
#define AX25_P_ARP 0xcd /* ARPA Address Resolution */
#define AX25_P_FLEXNET 0xce /* FlexNet */
#define AX25_P_NETROM 0xcf /* NET/ROM */
#define AX25_P_TEXT 0xF0 /* No layer 3 protocol impl. */
/* AX.25 Segment control values */
#define AX25_SEG_REM 0x7F
#define AX25_SEG_FIRST 0x80
#define AX25_CBIT 0x80 /* Command/Response bit */
#define AX25_EBIT 0x01 /* HDLC Address Extension bit */
#define AX25_HBIT 0x80 /* Has been repeated bit */
#define AX25_SSSID_SPARE 0x60 /* Unused bits in SSID for standard AX.25 */
#define AX25_ESSID_SPARE 0x20 /* Unused bits in SSID for extended AX.25 */
#define AX25_DAMA_FLAG 0x20 /* Well, it is *NOT* unused! (dl1bke 951121 */
#define AX25_COND_ACK_PENDING 0x01
#define AX25_COND_REJECT 0x02
#define AX25_COND_PEER_RX_BUSY 0x04
#define AX25_COND_OWN_RX_BUSY 0x08
#define AX25_COND_DAMA_MODE 0x10
#ifndef _LINUX_NETDEVICE_H
#include <linux/netdevice.h>
#endif
/* Upper sub-layer (LAPB) definitions */
/* Control field templates */
#define AX25_I 0x00 /* Information frames */
#define AX25_S 0x01 /* Supervisory frames */
#define AX25_RR 0x01 /* Receiver ready */
#define AX25_RNR 0x05 /* Receiver not ready */
#define AX25_REJ 0x09 /* Reject */
#define AX25_U 0x03 /* Unnumbered frames */
#define AX25_SABM 0x2f /* Set Asynchronous Balanced Mode */
#define AX25_SABME 0x6f /* Set Asynchronous Balanced Mode Extended */
#define AX25_DISC 0x43 /* Disconnect */
#define AX25_DM 0x0f /* Disconnected mode */
#define AX25_UA 0x63 /* Unnumbered acknowledge */
#define AX25_FRMR 0x87 /* Frame reject */
#define AX25_UI 0x03 /* Unnumbered information */
#define AX25_XID 0xaf /* Exchange information */
#define AX25_TEST 0xe3 /* Test */
#define AX25_PF 0x10 /* Poll/final bit for standard AX.25 */
#define AX25_EPF 0x01 /* Poll/final bit for extended AX.25 */
#define AX25_ILLEGAL 0x100 /* Impossible to be a real frame type */
#define AX25_POLLOFF 0
#define AX25_POLLON 1
/* AX25 L2 C-bit */
#define AX25_COMMAND 1
#define AX25_RESPONSE 2
/* Define Link State constants. */
enum {
AX25_STATE_0, /* Listening */
AX25_STATE_1, /* SABM sent */
AX25_STATE_2, /* DISC sent */
AX25_STATE_3, /* Established */
AX25_STATE_4 /* Recovery */
};
#define AX25_MODULUS 8 /* Standard AX.25 modulus */
#define AX25_EMODULUS 128 /* Extended AX.25 modulus */
enum {
AX25_PROTO_STD_SIMPLEX,
AX25_PROTO_STD_DUPLEX,
#ifdef CONFIG_AX25_DAMA_SLAVE
AX25_PROTO_DAMA_SLAVE,
#ifdef CONFIG_AX25_DAMA_MASTER
AX25_PROTO_DAMA_MASTER,
#define AX25_PROTO_MAX AX25_PROTO_DAMA_MASTER
#endif
#endif
__AX25_PROTO_MAX,
AX25_PROTO_MAX = __AX25_PROTO_MAX -1
};
enum {
AX25_VALUES_IPDEFMODE, /* 0=DG 1=VC */
AX25_VALUES_AXDEFMODE, /* 0=Normal 1=Extended Seq Nos */
AX25_VALUES_BACKOFF, /* 0=None 1=Linear 2=Exponential */
AX25_VALUES_CONMODE, /* Allow connected modes - 0=No 1=no "PID text" 2=all PIDs */
AX25_VALUES_WINDOW, /* Default window size for standard AX.25 */
AX25_VALUES_EWINDOW, /* Default window size for extended AX.25 */
AX25_VALUES_T1, /* Default T1 timeout value */
AX25_VALUES_T2, /* Default T2 timeout value */
AX25_VALUES_T3, /* Default T3 timeout value */
AX25_VALUES_IDLE, /* Connected mode idle timer */
AX25_VALUES_N2, /* Default N2 value */
AX25_VALUES_PACLEN, /* AX.25 MTU */
AX25_VALUES_PROTOCOL, /* Std AX.25, DAMA Slave, DAMA Master */
#ifdef CONFIG_AX25_DAMA_SLAVE
AX25_VALUES_DS_TIMEOUT, /* DAMA Slave timeout */
#endif
AX25_MAX_VALUES /* THIS MUST REMAIN THE LAST ENTRY OF THIS LIST */
};
#define AX25_DEF_IPDEFMODE 0 /* Datagram */
#define AX25_DEF_AXDEFMODE 0 /* Normal */
#define AX25_DEF_BACKOFF 1 /* Linear backoff */
#define AX25_DEF_CONMODE 2 /* Connected mode allowed */
#define AX25_DEF_WINDOW 2 /* Window=2 */
#define AX25_DEF_EWINDOW 32 /* Module-128 Window=32 */
#define AX25_DEF_T1 10000 /* T1=10s */
#define AX25_DEF_T2 3000 /* T2=3s */
#define AX25_DEF_T3 300000 /* T3=300s */
#define AX25_DEF_N2 10 /* N2=10 */
#define AX25_DEF_IDLE 0 /* Idle=None */
#define AX25_DEF_PACLEN 256 /* Paclen=256 */
#define AX25_DEF_PROTOCOL AX25_PROTO_STD_SIMPLEX /* Standard AX.25 */
#define AX25_DEF_DS_TIMEOUT 180000 /* DAMA timeout 3 minutes */
typedef struct ax25_uid_assoc {
struct hlist_node uid_node;
refcount_t refcount;
kuid_t uid;
ax25_address call;
} ax25_uid_assoc;
#define ax25_uid_for_each(__ax25, list) \
hlist_for_each_entry(__ax25, list, uid_node)
#define ax25_uid_hold(ax25) \
refcount_inc(&((ax25)->refcount))
static inline void ax25_uid_put(ax25_uid_assoc *assoc)
{
if (refcount_dec_and_test(&assoc->refcount)) {
kfree(assoc);
}
}
typedef struct {
ax25_address calls[AX25_MAX_DIGIS];
unsigned char repeated[AX25_MAX_DIGIS];
unsigned char ndigi;
signed char lastrepeat;
} ax25_digi;
typedef struct ax25_route {
struct ax25_route *next;
ax25_address callsign;
struct net_device *dev;
ax25_digi *digipeat;
char ip_mode;
} ax25_route;
void __ax25_put_route(ax25_route *ax25_rt);
extern rwlock_t ax25_route_lock;
static inline void ax25_route_lock_use(void)
{
read_lock(&ax25_route_lock);
}
static inline void ax25_route_lock_unuse(void)
{
read_unlock(&ax25_route_lock);
}
typedef struct {
char slave; /* slave_mode? */
struct timer_list slave_timer; /* timeout timer */
unsigned short slave_timeout; /* when? */
} ax25_dama_info;
struct ctl_table;
typedef struct ax25_dev {
struct list_head list;
struct net_device *dev;
netdevice_tracker dev_tracker;
struct net_device *forward;
struct ctl_table_header *sysheader;
int values[AX25_MAX_VALUES];
#if defined(CONFIG_AX25_DAMA_SLAVE) || defined(CONFIG_AX25_DAMA_MASTER)
ax25_dama_info dama;
#endif
refcount_t refcount;
bool device_up;
struct rcu_head rcu;
} ax25_dev;
typedef struct ax25_cb {
struct hlist_node ax25_node;
ax25_address source_addr, dest_addr;
ax25_digi *digipeat;
ax25_dev *ax25_dev;
netdevice_tracker dev_tracker;
unsigned char iamdigi;
unsigned char state, modulus, pidincl;
unsigned short vs, vr, va;
unsigned char condition, backoff;
unsigned char n2, n2count;
struct timer_list t1timer, t2timer, t3timer, idletimer;
unsigned long t1, t2, t3, idle, rtt;
unsigned short paclen, fragno, fraglen;
struct sk_buff_head write_queue;
struct sk_buff_head reseq_queue;
struct sk_buff_head ack_queue;
struct sk_buff_head frag_queue;
unsigned char window;
struct timer_list timer, dtimer;
struct sock *sk; /* Backlink to socket */
refcount_t refcount;
} ax25_cb;
struct ax25_sock {
struct sock sk;
struct ax25_cb *cb;
};
#define ax25_sk(ptr) container_of_const(ptr, struct ax25_sock, sk)
static inline struct ax25_cb *sk_to_ax25(const struct sock *sk)
{
return ax25_sk(sk)->cb;
}
#define ax25_for_each(__ax25, list) \
hlist_for_each_entry(__ax25, list, ax25_node)
#define ax25_cb_hold(__ax25) \
refcount_inc(&((__ax25)->refcount))
static __inline__ void ax25_cb_put(ax25_cb *ax25)
{
if (refcount_dec_and_test(&ax25->refcount)) {
kfree(ax25->digipeat);
kfree(ax25);
}
}
static inline void ax25_dev_hold(ax25_dev *ax25_dev)
{
refcount_inc(&ax25_dev->refcount);
}
static inline void ax25_dev_put(ax25_dev *ax25_dev)
{
if (refcount_dec_and_test(&ax25_dev->refcount))
kfree_rcu(ax25_dev, rcu);
}
static inline __be16 ax25_type_trans(struct sk_buff *skb, struct net_device *dev)
{
skb->dev = dev;
skb_reset_mac_header(skb);
skb->pkt_type = PACKET_HOST;
return htons(ETH_P_AX25);
}
/* af_ax25.c */
extern struct hlist_head ax25_list;
extern spinlock_t ax25_list_lock;
void ax25_cb_add(ax25_cb *);
struct sock *ax25_find_listener(ax25_address *, int, struct net_device *, int);
struct sock *ax25_get_socket(ax25_address *, ax25_address *, int);
ax25_cb *ax25_find_cb(const ax25_address *, ax25_address *, ax25_digi *,
struct net_device *);
void ax25_send_to_raw(ax25_address *, struct sk_buff *, int);
void ax25_destroy_socket(ax25_cb *);
ax25_cb * __must_check ax25_create_cb(void);
void ax25_fillin_cb(ax25_cb *, ax25_dev *);
struct sock *ax25_make_new(struct sock *, struct ax25_dev *);
/* ax25_addr.c */
extern const ax25_address ax25_bcast;
extern const ax25_address ax25_defaddr;
extern const ax25_address null_ax25_address;
char *ax2asc(char *buf, const ax25_address *);
void asc2ax(ax25_address *addr, const char *callsign);
int ax25cmp(const ax25_address *, const ax25_address *);
int ax25digicmp(const ax25_digi *, const ax25_digi *);
const unsigned char *ax25_addr_parse(const unsigned char *, int,
ax25_address *, ax25_address *, ax25_digi *, int *, int *);
int ax25_addr_build(unsigned char *, const ax25_address *,
const ax25_address *, const ax25_digi *, int, int);
int ax25_addr_size(const ax25_digi *);
void ax25_digi_invert(const ax25_digi *, ax25_digi *);
/* ax25_dev.c */
extern spinlock_t ax25_dev_lock;
#if IS_ENABLED(CONFIG_AX25)
static inline ax25_dev *ax25_dev_ax25dev(const struct net_device *dev)
{
return rcu_dereference_rtnl(dev->ax25_ptr);
}
#endif
ax25_dev *ax25_addr_ax25dev(ax25_address *);
void ax25_dev_device_up(struct net_device *);
void ax25_dev_device_down(struct net_device *);
int ax25_fwd_ioctl(unsigned int, struct ax25_fwd_struct *);
struct net_device *ax25_fwd_dev(struct net_device *);
void ax25_dev_free(void);
/* ax25_ds_in.c */
int ax25_ds_frame_in(ax25_cb *, struct sk_buff *, int);
/* ax25_ds_subr.c */
void ax25_ds_nr_error_recovery(ax25_cb *);
void ax25_ds_enquiry_response(ax25_cb *);
void ax25_ds_establish_data_link(ax25_cb *);
void ax25_dev_dama_off(ax25_dev *);
void ax25_dama_on(ax25_cb *);
void ax25_dama_off(ax25_cb *);
/* ax25_ds_timer.c */
void ax25_ds_setup_timer(ax25_dev *);
void ax25_ds_set_timer(ax25_dev *);
void ax25_ds_del_timer(ax25_dev *);
void ax25_ds_timer(ax25_cb *);
void ax25_ds_t1_timeout(ax25_cb *);
void ax25_ds_heartbeat_expiry(ax25_cb *);
void ax25_ds_t3timer_expiry(ax25_cb *);
void ax25_ds_idletimer_expiry(ax25_cb *);
/* ax25_iface.c */
struct ax25_protocol {
struct ax25_protocol *next;
unsigned int pid;
int (*func)(struct sk_buff *, ax25_cb *);
};
void ax25_register_pid(struct ax25_protocol *ap);
void ax25_protocol_release(unsigned int);
struct ax25_linkfail {
struct hlist_node lf_node;
void (*func)(ax25_cb *, int);
};
void ax25_linkfail_register(struct ax25_linkfail *lf);
void ax25_linkfail_release(struct ax25_linkfail *lf);
int __must_check ax25_listen_register(const ax25_address *,
struct net_device *);
void ax25_listen_release(const ax25_address *, struct net_device *);
int(*ax25_protocol_function(unsigned int))(struct sk_buff *, ax25_cb *);
int ax25_listen_mine(const ax25_address *, struct net_device *);
void ax25_link_failed(ax25_cb *, int);
int ax25_protocol_is_registered(unsigned int);
/* ax25_in.c */
int ax25_rx_iframe(ax25_cb *, struct sk_buff *);
int ax25_kiss_rcv(struct sk_buff *, struct net_device *, struct packet_type *,
struct net_device *);
/* ax25_ip.c */
netdev_tx_t ax25_ip_xmit(struct sk_buff *skb);
extern const struct header_ops ax25_header_ops;
/* ax25_out.c */
ax25_cb *ax25_send_frame(struct sk_buff *, int, const ax25_address *,
ax25_address *, ax25_digi *, struct net_device *);
void ax25_output(ax25_cb *, int, struct sk_buff *);
void ax25_kick(ax25_cb *);
void ax25_transmit_buffer(ax25_cb *, struct sk_buff *, int);
void ax25_queue_xmit(struct sk_buff *skb, struct net_device *dev);
int ax25_check_iframes_acked(ax25_cb *, unsigned short);
/* ax25_route.c */
void ax25_rt_device_down(struct net_device *);
int ax25_rt_ioctl(unsigned int, void __user *);
extern const struct seq_operations ax25_rt_seqops;
ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev);
struct sk_buff *ax25_rt_build_path(struct sk_buff *, ax25_address *,
ax25_address *, ax25_digi *);
void ax25_rt_free(void);
/* ax25_std_in.c */
int ax25_std_frame_in(ax25_cb *, struct sk_buff *, int);
/* ax25_std_subr.c */
void ax25_std_nr_error_recovery(ax25_cb *);
void ax25_std_establish_data_link(ax25_cb *);
void ax25_std_transmit_enquiry(ax25_cb *);
void ax25_std_enquiry_response(ax25_cb *);
void ax25_std_timeout_response(ax25_cb *);
/* ax25_std_timer.c */
void ax25_std_heartbeat_expiry(ax25_cb *);
void ax25_std_t1timer_expiry(ax25_cb *);
void ax25_std_t2timer_expiry(ax25_cb *);
void ax25_std_t3timer_expiry(ax25_cb *);
void ax25_std_idletimer_expiry(ax25_cb *);
/* ax25_subr.c */
void ax25_clear_queues(ax25_cb *);
void ax25_frames_acked(ax25_cb *, unsigned short);
void ax25_requeue_frames(ax25_cb *);
int ax25_validate_nr(ax25_cb *, unsigned short);
int ax25_decode(ax25_cb *, struct sk_buff *, int *, int *, int *);
void ax25_send_control(ax25_cb *, int, int, int);
void ax25_return_dm(struct net_device *, ax25_address *, ax25_address *,
ax25_digi *);
void ax25_calculate_t1(ax25_cb *);
void ax25_calculate_rtt(ax25_cb *);
void ax25_disconnect(ax25_cb *, int);
/* ax25_timer.c */
void ax25_setup_timers(ax25_cb *);
void ax25_start_heartbeat(ax25_cb *);
void ax25_start_t1timer(ax25_cb *);
void ax25_start_t2timer(ax25_cb *);
void ax25_start_t3timer(ax25_cb *);
void ax25_start_idletimer(ax25_cb *);
void ax25_stop_heartbeat(ax25_cb *);
void ax25_stop_t1timer(ax25_cb *);
void ax25_stop_t2timer(ax25_cb *);
void ax25_stop_t3timer(ax25_cb *);
void ax25_stop_idletimer(ax25_cb *);
int ax25_t1timer_running(ax25_cb *);
unsigned long ax25_display_timer(struct timer_list *);
/* ax25_uid.c */
extern int ax25_uid_policy;
ax25_uid_assoc *ax25_findbyuid(kuid_t);
int __must_check ax25_uid_ioctl(int, struct sockaddr_ax25 *);
extern const struct seq_operations ax25_uid_seqops;
void ax25_uid_free(void);
/* sysctl_net_ax25.c */
#ifdef CONFIG_SYSCTL
int ax25_register_dev_sysctl(ax25_dev *ax25_dev);
void ax25_unregister_dev_sysctl(ax25_dev *ax25_dev);
#else
static inline int ax25_register_dev_sysctl(ax25_dev *ax25_dev) { return 0; }
static inline void ax25_unregister_dev_sysctl(ax25_dev *ax25_dev) {}
#endif /* CONFIG_SYSCTL */
#endif
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