diff options
Diffstat (limited to 'net/netfilter/x_tables.c')
| -rw-r--r-- | net/netfilter/x_tables.c | 55 |
1 files changed, 38 insertions, 17 deletions
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index acce622582e3..6bd31a7a27fc 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -330,6 +330,7 @@ static int match_revfn(u8 af, const char *name, u8 revision, int *bestp) const struct xt_match *m; int have_rev = 0; + mutex_lock(&xt[af].mutex); list_for_each_entry(m, &xt[af].match, list) { if (strcmp(m->name, name) == 0) { if (m->revision > *bestp) @@ -338,6 +339,7 @@ static int match_revfn(u8 af, const char *name, u8 revision, int *bestp) have_rev = 1; } } + mutex_unlock(&xt[af].mutex); if (af != NFPROTO_UNSPEC && !have_rev) return match_revfn(NFPROTO_UNSPEC, name, revision, bestp); @@ -350,6 +352,7 @@ static int target_revfn(u8 af, const char *name, u8 revision, int *bestp) const struct xt_target *t; int have_rev = 0; + mutex_lock(&xt[af].mutex); list_for_each_entry(t, &xt[af].target, list) { if (strcmp(t->name, name) == 0) { if (t->revision > *bestp) @@ -358,6 +361,7 @@ static int target_revfn(u8 af, const char *name, u8 revision, int *bestp) have_rev = 1; } } + mutex_unlock(&xt[af].mutex); if (af != NFPROTO_UNSPEC && !have_rev) return target_revfn(NFPROTO_UNSPEC, name, revision, bestp); @@ -371,12 +375,10 @@ int xt_find_revision(u8 af, const char *name, u8 revision, int target, { int have_rev, best = -1; - mutex_lock(&xt[af].mutex); if (target == 1) have_rev = target_revfn(af, name, revision, &best); else have_rev = match_revfn(af, name, revision, &best); - mutex_unlock(&xt[af].mutex); /* Nothing at all? Return 0 to try loading module. */ if (best == -1) { @@ -1349,14 +1351,6 @@ struct xt_counters *xt_counters_alloc(unsigned int counters) } EXPORT_SYMBOL(xt_counters_alloc); -struct xt_table_info -*xt_table_get_private_protected(const struct xt_table *table) -{ - return rcu_dereference_protected(table->private, - mutex_is_locked(&xt[table->af].mutex)); -} -EXPORT_SYMBOL(xt_table_get_private_protected); - struct xt_table_info * xt_replace_table(struct xt_table *table, unsigned int num_counters, @@ -1364,6 +1358,7 @@ xt_replace_table(struct xt_table *table, int *error) { struct xt_table_info *private; + unsigned int cpu; int ret; ret = xt_jumpstack_alloc(newinfo); @@ -1373,20 +1368,47 @@ xt_replace_table(struct xt_table *table, } /* Do the substitution. */ - private = xt_table_get_private_protected(table); + local_bh_disable(); + private = table->private; /* Check inside lock: is the old number correct? */ if (num_counters != private->number) { pr_debug("num_counters != table->private->number (%u/%u)\n", num_counters, private->number); + local_bh_enable(); *error = -EAGAIN; return NULL; } newinfo->initial_entries = private->initial_entries; + /* + * Ensure contents of newinfo are visible before assigning to + * private. + */ + smp_wmb(); + table->private = newinfo; + + /* make sure all cpus see new ->private value */ + smp_mb(); + + /* + * Even though table entries have now been swapped, other CPU's + * may still be using the old entries... + */ + local_bh_enable(); - rcu_assign_pointer(table->private, newinfo); - synchronize_rcu(); + /* ... so wait for even xt_recseq on all cpus */ + for_each_possible_cpu(cpu) { + seqcount_t *s = &per_cpu(xt_recseq, cpu); + u32 seq = raw_read_seqcount(s); + + if (seq & 1) { + do { + cond_resched(); + cpu_relax(); + } while (seq == raw_read_seqcount(s)); + } + } audit_log_nfcfg(table->name, table->af, private->number, !private->number ? AUDIT_XT_OP_REGISTER : @@ -1422,12 +1444,12 @@ struct xt_table *xt_register_table(struct net *net, } /* Simplifies replace_table code. */ - rcu_assign_pointer(table->private, bootstrap); + table->private = bootstrap; if (!xt_replace_table(table, 0, newinfo, &ret)) goto unlock; - private = xt_table_get_private_protected(table); + private = table->private; pr_debug("table->private->number = %u\n", private->number); /* save number of initial entries */ @@ -1450,8 +1472,7 @@ void *xt_unregister_table(struct xt_table *table) struct xt_table_info *private; mutex_lock(&xt[table->af].mutex); - private = xt_table_get_private_protected(table); - RCU_INIT_POINTER(table->private, NULL); + private = table->private; list_del(&table->list); mutex_unlock(&xt[table->af].mutex); audit_log_nfcfg(table->name, table->af, private->number, |