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-rw-r--r--net/ipv4/netfilter/arp_tables.c201
1 files changed, 131 insertions, 70 deletions
diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index a7969286e6e7..3c2e9639bba6 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -347,58 +347,106 @@ unsigned int arpt_do_table(struct sk_buff **pskb,
return verdict;
}
-static inline void *find_inlist_lock_noload(struct list_head *head,
- const char *name,
- int *error,
- struct semaphore *mutex)
+/*
+ * These are weird, but module loading must not be done with mutex
+ * held (since they will register), and we have to have a single
+ * function to use try_then_request_module().
+ */
+
+/* Find table by name, grabs mutex & ref. Returns ERR_PTR() on error. */
+static inline struct arpt_table *find_table_lock(const char *name)
{
- void *ret;
+ struct arpt_table *t;
- *error = down_interruptible(mutex);
- if (*error != 0)
- return NULL;
+ if (down_interruptible(&arpt_mutex) != 0)
+ return ERR_PTR(-EINTR);
- ret = list_named_find(head, name);
- if (!ret) {
- *error = -ENOENT;
- up(mutex);
- }
- return ret;
+ list_for_each_entry(t, &arpt_tables, list)
+ if (strcmp(t->name, name) == 0 && try_module_get(t->me))
+ return t;
+ up(&arpt_mutex);
+ return NULL;
}
-#ifndef CONFIG_KMOD
-#define find_inlist_lock(h,n,p,e,m) find_inlist_lock_noload((h),(n),(e),(m))
-#else
-static void *
-find_inlist_lock(struct list_head *head,
- const char *name,
- const char *prefix,
- int *error,
- struct semaphore *mutex)
+
+/* Find target, grabs ref. Returns ERR_PTR() on error. */
+static inline struct arpt_target *find_target(const char *name, u8 revision)
{
- void *ret;
+ struct arpt_target *t;
+ int err = 0;
- ret = find_inlist_lock_noload(head, name, error, mutex);
- if (!ret) {
- duprintf("find_inlist: loading `%s%s'.\n", prefix, name);
- request_module("%s%s", prefix, name);
- ret = find_inlist_lock_noload(head, name, error, mutex);
+ if (down_interruptible(&arpt_mutex) != 0)
+ return ERR_PTR(-EINTR);
+
+ list_for_each_entry(t, &arpt_target, list) {
+ if (strcmp(t->name, name) == 0) {
+ if (t->revision == revision) {
+ if (try_module_get(t->me)) {
+ up(&arpt_mutex);
+ return t;
+ }
+ } else
+ err = -EPROTOTYPE; /* Found something. */
+ }
}
+ up(&arpt_mutex);
+ return ERR_PTR(err);
+}
- return ret;
+struct arpt_target *arpt_find_target(const char *name, u8 revision)
+{
+ struct arpt_target *target;
+
+ target = try_then_request_module(find_target(name, revision),
+ "arpt_%s", name);
+ if (IS_ERR(target) || !target)
+ return NULL;
+ return target;
}
-#endif
-static inline struct arpt_table *arpt_find_table_lock(const char *name, int *error, struct semaphore *mutex)
+static int target_revfn(const char *name, u8 revision, int *bestp)
{
- return find_inlist_lock(&arpt_tables, name, "arptable_", error, mutex);
+ struct arpt_target *t;
+ int have_rev = 0;
+
+ list_for_each_entry(t, &arpt_target, list) {
+ if (strcmp(t->name, name) == 0) {
+ if (t->revision > *bestp)
+ *bestp = t->revision;
+ if (t->revision == revision)
+ have_rev =1;
+ }
+ }
+ return have_rev;
}
-static struct arpt_target *arpt_find_target_lock(const char *name, int *error, struct semaphore *mutex)
+/* Returns true or false (if no such extension at all) */
+static inline int find_revision(const char *name, u8 revision,
+ int (*revfn)(const char *, u8, int *),
+ int *err)
{
- return find_inlist_lock(&arpt_target, name, "arpt_", error, mutex);
+ int have_rev, best = -1;
+
+ if (down_interruptible(&arpt_mutex) != 0) {
+ *err = -EINTR;
+ return 1;
+ }
+ have_rev = revfn(name, revision, &best);
+ up(&arpt_mutex);
+
+ /* Nothing at all? Return 0 to try loading module. */
+ if (best == -1) {
+ *err = -ENOENT;
+ return 0;
+ }
+
+ *err = best;
+ if (!have_rev)
+ *err = -EPROTONOSUPPORT;
+ return 1;
}
+
/* All zeroes == unconditional rule. */
static inline int unconditional(const struct arpt_arp *arp)
{
@@ -544,17 +592,15 @@ static inline int check_entry(struct arpt_entry *e, const char *name, unsigned i
}
t = arpt_get_target(e);
- target = arpt_find_target_lock(t->u.user.name, &ret, &arpt_mutex);
- if (!target) {
+ target = try_then_request_module(find_target(t->u.user.name,
+ t->u.user.revision),
+ "arpt_%s", t->u.user.name);
+ if (IS_ERR(target) || !target) {
duprintf("check_entry: `%s' not found\n", t->u.user.name);
+ ret = target ? PTR_ERR(target) : -ENOENT;
goto out;
}
- if (!try_module_get((target->me))) {
- ret = -ENOENT;
- goto out_unlock;
- }
t->u.kernel.target = target;
- up(&arpt_mutex);
if (t->u.kernel.target == &arpt_standard_target) {
if (!standard_check(t, size)) {
@@ -576,8 +622,6 @@ static inline int check_entry(struct arpt_entry *e, const char *name, unsigned i
(*i)++;
return 0;
-out_unlock:
- up(&arpt_mutex);
out:
return ret;
}
@@ -846,8 +890,8 @@ static int get_entries(const struct arpt_get_entries *entries,
int ret;
struct arpt_table *t;
- t = arpt_find_table_lock(entries->name, &ret, &arpt_mutex);
- if (t) {
+ t = find_table_lock(entries->name);
+ if (t || !IS_ERR(t)) {
duprintf("t->private->number = %u\n",
t->private->number);
if (entries->size == t->private->size)
@@ -859,10 +903,10 @@ static int get_entries(const struct arpt_get_entries *entries,
entries->size);
ret = -EINVAL;
}
+ module_put(t->me);
up(&arpt_mutex);
} else
- duprintf("get_entries: Can't find %s!\n",
- entries->name);
+ ret = t ? PTR_ERR(t) : -ENOENT;
return ret;
}
@@ -913,22 +957,19 @@ static int do_replace(void __user *user, unsigned int len)
duprintf("arp_tables: Translated table\n");
- t = arpt_find_table_lock(tmp.name, &ret, &arpt_mutex);
- if (!t)
+ t = try_then_request_module(find_table_lock(tmp.name),
+ "arptable_%s", tmp.name);
+ if (!t || IS_ERR(t)) {
+ ret = t ? PTR_ERR(t) : -ENOENT;
goto free_newinfo_counters_untrans;
+ }
/* You lied! */
if (tmp.valid_hooks != t->valid_hooks) {
duprintf("Valid hook crap: %08X vs %08X\n",
tmp.valid_hooks, t->valid_hooks);
ret = -EINVAL;
- goto free_newinfo_counters_untrans_unlock;
- }
-
- /* Get a reference in advance, we're not allowed fail later */
- if (!try_module_get(t->me)) {
- ret = -EBUSY;
- goto free_newinfo_counters_untrans_unlock;
+ goto put_module;
}
oldinfo = replace_table(t, tmp.num_counters, newinfo, &ret);
@@ -959,7 +1000,6 @@ static int do_replace(void __user *user, unsigned int len)
put_module:
module_put(t->me);
- free_newinfo_counters_untrans_unlock:
up(&arpt_mutex);
free_newinfo_counters_untrans:
ARPT_ENTRY_ITERATE(newinfo->entries, newinfo->size, cleanup_entry, NULL);
@@ -989,7 +1029,7 @@ static int do_add_counters(void __user *user, unsigned int len)
unsigned int i;
struct arpt_counters_info tmp, *paddc;
struct arpt_table *t;
- int ret;
+ int ret = 0;
if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
return -EFAULT;
@@ -1006,9 +1046,11 @@ static int do_add_counters(void __user *user, unsigned int len)
goto free;
}
- t = arpt_find_table_lock(tmp.name, &ret, &arpt_mutex);
- if (!t)
+ t = find_table_lock(tmp.name);
+ if (!t || IS_ERR(t)) {
+ ret = t ? PTR_ERR(t) : -ENOENT;
goto free;
+ }
write_lock_bh(&t->lock);
if (t->private->number != paddc->num_counters) {
@@ -1025,6 +1067,7 @@ static int do_add_counters(void __user *user, unsigned int len)
unlock_up_free:
write_unlock_bh(&t->lock);
up(&arpt_mutex);
+ module_put(t->me);
free:
vfree(paddc);
@@ -1079,8 +1122,10 @@ static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len
break;
}
name[ARPT_TABLE_MAXNAMELEN-1] = '\0';
- t = arpt_find_table_lock(name, &ret, &arpt_mutex);
- if (t) {
+
+ t = try_then_request_module(find_table_lock(name),
+ "arptable_%s", name);
+ if (t && !IS_ERR(t)) {
struct arpt_getinfo info;
info.valid_hooks = t->valid_hooks;
@@ -1096,9 +1141,10 @@ static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len
ret = -EFAULT;
else
ret = 0;
-
up(&arpt_mutex);
- }
+ module_put(t->me);
+ } else
+ ret = t ? PTR_ERR(t) : -ENOENT;
}
break;
@@ -1119,6 +1165,24 @@ static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len
break;
}
+ case ARPT_SO_GET_REVISION_TARGET: {
+ struct arpt_get_revision rev;
+
+ if (*len != sizeof(rev)) {
+ ret = -EINVAL;
+ break;
+ }
+ if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
+ ret = -EFAULT;
+ break;
+ }
+
+ try_then_request_module(find_revision(rev.name, rev.revision,
+ target_revfn, &ret),
+ "arpt_%s", rev.name);
+ break;
+ }
+
default:
duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
ret = -EINVAL;
@@ -1136,12 +1200,9 @@ int arpt_register_target(struct arpt_target *target)
if (ret != 0)
return ret;
- if (!list_named_insert(&arpt_target, target)) {
- duprintf("arpt_register_target: `%s' already in list!\n",
- target->name);
- ret = -EINVAL;
- }
+ list_add(&target->list, &arpt_target);
up(&arpt_mutex);
+
return ret;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-20 10:11:51 +0000