Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f682cefa authored by Changli Gao's avatar Changli Gao Committed by David S. Miller
Browse files

netfilter: fix the race when initializing nf_ct_expect_hash_rnd 



Since nf_ct_expect_dst_hash() may be called without nf_conntrack_lock
locked, nf_ct_expect_hash_rnd should be initialized in the atomic way.

In this patch, we use nf_conntrack_hash_rnd instead of
nf_ct_expect_hash_rnd.

Signed-off-by: default avatarChangli Gao <xiaosuo@gmail.com>
Acked-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6623e3b2

include/net/netfilter/nf_conntrack.h

+2 −0
Original line number Diff line number Diff line
@@ -298,6 +298,8 @@ static inline int nf_ct_is_untracked(const struct nf_conn *ct) 
extern int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);

extern unsigned int nf_conntrack_htable_size;

extern unsigned int nf_conntrack_max;

extern unsigned int nf_conntrack_hash_rnd;

void init_nf_conntrack_hash_rnd(void);



#define NF_CT_STAT_INC(net, count)	\

	__this_cpu_inc((net)->ct.stat->count)

net/netfilter/nf_conntrack_core.c

+17 −13
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ EXPORT_SYMBOL_GPL(nf_conntrack_max); 
DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked);

EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked);



static unsigned int nf_conntrack_hash_rnd __read_mostly;

unsigned int nf_conntrack_hash_rnd __read_mostly;



static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone)

{
@@ -596,15 +596,8 @@ static noinline int early_drop(struct net *net, unsigned int hash) 
	return dropped;

}



static struct nf_conn *

__nf_conntrack_alloc(struct net *net, u16 zone,

		     const struct nf_conntrack_tuple *orig,

		     const struct nf_conntrack_tuple *repl,

		     gfp_t gfp, u32 hash)

void init_nf_conntrack_hash_rnd(void)

{

	struct nf_conn *ct;



	if (unlikely(!nf_conntrack_hash_rnd)) {

	unsigned int rand;



	/*
@@ -616,7 +609,18 @@ __nf_conntrack_alloc(struct net *net, u16 zone, 
		get_random_bytes(&rand, sizeof(rand));

	} while (!rand);

	cmpxchg(&nf_conntrack_hash_rnd, 0, rand);

}



static struct nf_conn *

__nf_conntrack_alloc(struct net *net, u16 zone,

		     const struct nf_conntrack_tuple *orig,

		     const struct nf_conntrack_tuple *repl,

		     gfp_t gfp, u32 hash)

{

	struct nf_conn *ct;



	if (unlikely(!nf_conntrack_hash_rnd)) {

		init_nf_conntrack_hash_rnd();

		/* recompute the hash as nf_conntrack_hash_rnd is initialized */

		hash = hash_conntrack_raw(orig, zone);

	}

net/netfilter/nf_conntrack_expect.c

+3 −7
Original line number Diff line number Diff line
@@ -32,9 +32,7 @@ 
unsigned int nf_ct_expect_hsize __read_mostly;

EXPORT_SYMBOL_GPL(nf_ct_expect_hsize);



static unsigned int nf_ct_expect_hash_rnd __read_mostly;

unsigned int nf_ct_expect_max __read_mostly;

static int nf_ct_expect_hash_rnd_initted __read_mostly;



static struct kmem_cache *nf_ct_expect_cachep __read_mostly;
@@ -77,15 +75,13 @@ static unsigned int nf_ct_expect_dst_hash(const struct nf_conntrack_tuple *tuple 
{

	unsigned int hash;



	if (unlikely(!nf_ct_expect_hash_rnd_initted)) {

		get_random_bytes(&nf_ct_expect_hash_rnd,

				 sizeof(nf_ct_expect_hash_rnd));

		nf_ct_expect_hash_rnd_initted = 1;

	if (unlikely(!nf_conntrack_hash_rnd)) {

		init_nf_conntrack_hash_rnd();

	}



	hash = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all),

		      (((tuple->dst.protonum ^ tuple->src.l3num) << 16) |

		       (__force __u16)tuple->dst.u.all) ^ nf_ct_expect_hash_rnd);

		       (__force __u16)tuple->dst.u.all) ^ nf_conntrack_hash_rnd);

	return ((u64)hash * nf_ct_expect_hsize) >> 32;

}