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linux/include/net/llc.h
Eric Dumazet 8ac9dfd58b llc: fix out-of-bound array index in llc_sk_dev_hash() 
Both ifindex and LLC_SK_DEV_HASH_ENTRIES are signed.

This means that (ifindex % LLC_SK_DEV_HASH_ENTRIES) is negative
if @ifindex is negative.

We could simply make LLC_SK_DEV_HASH_ENTRIES unsigned.

In this patch I chose to use hash_32() to get more entropy
from @ifindex, like llc_sk_laddr_hashfn().

UBSAN: array-index-out-of-bounds in ./include/net/llc.h:75:26
index -43 is out of range for type 'hlist_head [64]'
CPU: 1 PID: 20999 Comm: syz-executor.3 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 ubsan_epilogue+0xb/0x5a lib/ubsan.c:151
 __ubsan_handle_out_of_bounds.cold+0x62/0x6c lib/ubsan.c:291
 llc_sk_dev_hash include/net/llc.h:75 [inline]
 llc_sap_add_socket+0x49c/0x520 net/llc/llc_conn.c:697
 llc_ui_bind+0x680/0xd70 net/llc/af_llc.c:404
 __sys_bind+0x1e9/0x250 net/socket.c:1693
 __do_sys_bind net/socket.c:1704 [inline]
 __se_sys_bind net/socket.c:1702 [inline]
 __x64_sys_bind+0x6f/0xb0 net/socket.c:1702
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fa503407ae9

Fixes: 6d2e3ea284 ("llc: use a device based hash table to speed up multicast delivery")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-07 19:25:29 +00:00

166 lines
4.4 KiB
C
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#ifndef LLC_H
#define LLC_H
/*
* Copyright (c) 1997 by Procom Technology, Inc.
* 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* This program can be redistributed or modified under the terms of the
* GNU General Public License as published by the Free Software Foundation.
* This program is distributed without any warranty or implied warranty
* of merchantability or fitness for a particular purpose.
*
* See the GNU General Public License for more details.
*/
#include <linux/if.h>
#include <linux/if_ether.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/rculist_nulls.h>
#include <linux/hash.h>
#include <linux/jhash.h>
#include <linux/atomic.h>
struct net_device;
struct packet_type;
struct sk_buff;
struct llc_addr {
unsigned char lsap;
unsigned char mac[IFHWADDRLEN];
};
#define LLC_SAP_STATE_INACTIVE 1
#define LLC_SAP_STATE_ACTIVE 2
#define LLC_SK_DEV_HASH_BITS 6
#define LLC_SK_DEV_HASH_ENTRIES (1<<LLC_SK_DEV_HASH_BITS)
#define LLC_SK_LADDR_HASH_BITS 6
#define LLC_SK_LADDR_HASH_ENTRIES (1<<LLC_SK_LADDR_HASH_BITS)
/**
* struct llc_sap - Defines the SAP component
*
* @station - station this sap belongs to
* @state - sap state
* @p_bit - only lowest-order bit used
* @f_bit - only lowest-order bit used
* @laddr - SAP value in this 'lsap'
* @node - entry in station sap_list
* @sk_list - LLC sockets this one manages
*/
struct llc_sap {
unsigned char state;
unsigned char p_bit;
unsigned char f_bit;
refcount_t refcnt;
int (*rcv_func)(struct sk_buff *skb,
struct net_device *dev,
struct packet_type *pt,
struct net_device *orig_dev);
struct llc_addr laddr;
struct list_head node;
spinlock_t sk_lock;
int sk_count;
struct hlist_nulls_head sk_laddr_hash[LLC_SK_LADDR_HASH_ENTRIES];
struct hlist_head sk_dev_hash[LLC_SK_DEV_HASH_ENTRIES];
struct rcu_head rcu;
};
static inline
struct hlist_head *llc_sk_dev_hash(struct llc_sap *sap, int ifindex)
{
u32 bucket = hash_32(ifindex, LLC_SK_DEV_HASH_BITS);
return &sap->sk_dev_hash[bucket];
}
static inline
u32 llc_sk_laddr_hashfn(struct llc_sap *sap, const struct llc_addr *laddr)
{
return hash_32(jhash(laddr->mac, sizeof(laddr->mac), 0),
LLC_SK_LADDR_HASH_BITS);
}
static inline
struct hlist_nulls_head *llc_sk_laddr_hash(struct llc_sap *sap,
const struct llc_addr *laddr)
{
return &sap->sk_laddr_hash[llc_sk_laddr_hashfn(sap, laddr)];
}
#define LLC_DEST_INVALID 0 /* Invalid LLC PDU type */
#define LLC_DEST_SAP 1 /* Type 1 goes here */
#define LLC_DEST_CONN 2 /* Type 2 goes here */
extern struct list_head llc_sap_list;
int llc_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
struct net_device *orig_dev);
int llc_mac_hdr_init(struct sk_buff *skb, const unsigned char *sa,
const unsigned char *da);
void llc_add_pack(int type,
void (*handler)(struct llc_sap *sap, struct sk_buff *skb));
void llc_remove_pack(int type);
void llc_set_station_handler(void (*handler)(struct sk_buff *skb));
struct llc_sap *llc_sap_open(unsigned char lsap,
int (*rcv)(struct sk_buff *skb,
struct net_device *dev,
struct packet_type *pt,
struct net_device *orig_dev));
static inline void llc_sap_hold(struct llc_sap *sap)
{
refcount_inc(&sap->refcnt);
}
static inline bool llc_sap_hold_safe(struct llc_sap *sap)
{
return refcount_inc_not_zero(&sap->refcnt);
}
void llc_sap_close(struct llc_sap *sap);
static inline void llc_sap_put(struct llc_sap *sap)
{
if (refcount_dec_and_test(&sap->refcnt))
llc_sap_close(sap);
}
struct llc_sap *llc_sap_find(unsigned char sap_value);
int llc_build_and_send_ui_pkt(struct llc_sap *sap, struct sk_buff *skb,
const unsigned char *dmac, unsigned char dsap);
void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb);
void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb);
void llc_station_init(void);
void llc_station_exit(void);
#ifdef CONFIG_PROC_FS
int llc_proc_init(void);
void llc_proc_exit(void);
#else
#define llc_proc_init() (0)
#define llc_proc_exit() do { } while(0)
#endif /* CONFIG_PROC_FS */
#ifdef CONFIG_SYSCTL
int llc_sysctl_init(void);
void llc_sysctl_exit(void);
extern int sysctl_llc2_ack_timeout;
extern int sysctl_llc2_busy_timeout;
extern int sysctl_llc2_p_timeout;
extern int sysctl_llc2_rej_timeout;
#else
#define llc_sysctl_init() (0)
#define llc_sysctl_exit() do { } while(0)
#endif /* CONFIG_SYSCTL */
#endif /* LLC_H */
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