linux/include/net/netns/xfrm.h
Eric Dumazet 3e4bc23926 xfrm: fix a data-race in xfrm_gen_index()
xfrm_gen_index() mutual exclusion uses net->xfrm.xfrm_policy_lock.

This means we must use a per-netns idx_generator variable,
instead of a static one.
Alternative would be to use an atomic variable.

syzbot reported:

BUG: KCSAN: data-race in xfrm_sk_policy_insert / xfrm_sk_policy_insert

write to 0xffffffff87005938 of 4 bytes by task 29466 on cpu 0:
xfrm_gen_index net/xfrm/xfrm_policy.c:1385 [inline]
xfrm_sk_policy_insert+0x262/0x640 net/xfrm/xfrm_policy.c:2347
xfrm_user_policy+0x413/0x540 net/xfrm/xfrm_state.c:2639
do_ipv6_setsockopt+0x1317/0x2ce0 net/ipv6/ipv6_sockglue.c:943
ipv6_setsockopt+0x57/0x130 net/ipv6/ipv6_sockglue.c:1012
rawv6_setsockopt+0x21e/0x410 net/ipv6/raw.c:1054
sock_common_setsockopt+0x61/0x70 net/core/sock.c:3697
__sys_setsockopt+0x1c9/0x230 net/socket.c:2263
__do_sys_setsockopt net/socket.c:2274 [inline]
__se_sys_setsockopt net/socket.c:2271 [inline]
__x64_sys_setsockopt+0x66/0x80 net/socket.c:2271
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffffff87005938 of 4 bytes by task 29460 on cpu 1:
xfrm_sk_policy_insert+0x13e/0x640
xfrm_user_policy+0x413/0x540 net/xfrm/xfrm_state.c:2639
do_ipv6_setsockopt+0x1317/0x2ce0 net/ipv6/ipv6_sockglue.c:943
ipv6_setsockopt+0x57/0x130 net/ipv6/ipv6_sockglue.c:1012
rawv6_setsockopt+0x21e/0x410 net/ipv6/raw.c:1054
sock_common_setsockopt+0x61/0x70 net/core/sock.c:3697
__sys_setsockopt+0x1c9/0x230 net/socket.c:2263
__do_sys_setsockopt net/socket.c:2274 [inline]
__se_sys_setsockopt net/socket.c:2271 [inline]
__x64_sys_setsockopt+0x66/0x80 net/socket.c:2271
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00006ad8 -> 0x00006b18

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 29460 Comm: syz-executor.1 Not tainted 6.5.0-rc5-syzkaller-00243-g9106536c1aa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023

Fixes: 1121994c80 ("netns xfrm: policy insertion in netns")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2023-09-13 09:20:28 +02:00

89 lines
2.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __NETNS_XFRM_H
#define __NETNS_XFRM_H
#include <linux/list.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/rhashtable-types.h>
#include <linux/xfrm.h>
#include <net/dst_ops.h>
struct ctl_table_header;
struct xfrm_policy_hash {
struct hlist_head __rcu *table;
unsigned int hmask;
u8 dbits4;
u8 sbits4;
u8 dbits6;
u8 sbits6;
};
struct xfrm_policy_hthresh {
struct work_struct work;
seqlock_t lock;
u8 lbits4;
u8 rbits4;
u8 lbits6;
u8 rbits6;
};
struct netns_xfrm {
struct list_head state_all;
/*
* Hash table to find appropriate SA towards given target (endpoint of
* tunnel or destination of transport mode) allowed by selector.
*
* Main use is finding SA after policy selected tunnel or transport
* mode. Also, it can be used by ah/esp icmp error handler to find
* offending SA.
*/
struct hlist_head __rcu *state_bydst;
struct hlist_head __rcu *state_bysrc;
struct hlist_head __rcu *state_byspi;
struct hlist_head __rcu *state_byseq;
unsigned int state_hmask;
unsigned int state_num;
struct work_struct state_hash_work;
struct list_head policy_all;
struct hlist_head *policy_byidx;
unsigned int policy_idx_hmask;
unsigned int idx_generator;
struct hlist_head policy_inexact[XFRM_POLICY_MAX];
struct xfrm_policy_hash policy_bydst[XFRM_POLICY_MAX];
unsigned int policy_count[XFRM_POLICY_MAX * 2];
struct work_struct policy_hash_work;
struct xfrm_policy_hthresh policy_hthresh;
struct list_head inexact_bins;
struct sock *nlsk;
struct sock *nlsk_stash;
u32 sysctl_aevent_etime;
u32 sysctl_aevent_rseqth;
int sysctl_larval_drop;
u32 sysctl_acq_expires;
u8 policy_default[XFRM_POLICY_MAX];
#ifdef CONFIG_SYSCTL
struct ctl_table_header *sysctl_hdr;
#endif
struct dst_ops xfrm4_dst_ops;
#if IS_ENABLED(CONFIG_IPV6)
struct dst_ops xfrm6_dst_ops;
#endif
spinlock_t xfrm_state_lock;
seqcount_spinlock_t xfrm_state_hash_generation;
seqcount_spinlock_t xfrm_policy_hash_generation;
spinlock_t xfrm_policy_lock;
struct mutex xfrm_cfg_mutex;
};
#endif