Merge tag 'nf-next-23-08-22' of https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next

Florian Westphal says:

====================
netfilter updates for net-next

First patch resolves a fortify warning by wrapping the to-be-copied
members via struct_group.

Second patch replaces array[0] with array[] in ebtables uapi.
Both changes from GONG Ruiqi.

The largest chunk is replacement of strncpy with strscpy_pad()
in netfilter, from Justin Stitt.

Last patch, from myself, aborts ruleset validation if a fatal
signal is pending, this speeds up process exit.

* tag 'nf-next-23-08-22' of https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next:
  netfilter: nf_tables: allow loop termination for pending fatal signal
  netfilter: xtables: refactor deprecated strncpy
  netfilter: x_tables: refactor deprecated strncpy
  netfilter: nft_meta: refactor deprecated strncpy
  netfilter: nft_osf: refactor deprecated strncpy
  netfilter: nf_tables: refactor deprecated strncpy
  netfilter: nf_tables: refactor deprecated strncpy
  netfilter: ipset: refactor deprecated strncpy
  netfilter: ebtables: replace zero-length array members
  netfilter: ebtables: fix fortify warnings in size_entry_mwt()
====================

Link: https://lore.kernel.org/r/20230822154336.12888-1-fw@strlen.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/uapi/linux/netfilter_bridge/ebtables.h

@@ -87,7 +87,7 @@ struct ebt_entries {
 	/* nr. of entries */
 	unsigned int nentries;
 	/* entry list */
-	char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
+	char data[] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 };
 
 /* used for the bitmask of struct ebt_entry */
@@ -129,7 +129,7 @@ struct ebt_entry_match {
 	} u;
 	/* size of data */
 	unsigned int match_size;
-	unsigned char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
+	unsigned char data[] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 };
 
 struct ebt_entry_watcher {
@@ -142,7 +142,7 @@ struct ebt_entry_watcher {
 	} u;
 	/* size of data */
 	unsigned int watcher_size;
-	unsigned char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
+	unsigned char data[] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 };
 
 struct ebt_entry_target {
@@ -182,13 +182,15 @@ struct ebt_entry {
 	unsigned char sourcemsk[ETH_ALEN];
 	unsigned char destmac[ETH_ALEN];
 	unsigned char destmsk[ETH_ALEN];
-	/* sizeof ebt_entry + matches */
-	unsigned int watchers_offset;
-	/* sizeof ebt_entry + matches + watchers */
-	unsigned int target_offset;
-	/* sizeof ebt_entry + matches + watchers + target */
-	unsigned int next_offset;
-	unsigned char elems[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
+	__struct_group(/* no tag */, offsets, /* no attrs */,
+		/* sizeof ebt_entry + matches */
+		unsigned int watchers_offset;
+		/* sizeof ebt_entry + matches + watchers */
+		unsigned int target_offset;
+		/* sizeof ebt_entry + matches + watchers + target */
+		unsigned int next_offset;
+	);
+	unsigned char elems[] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 };
 
 static __inline__ struct ebt_entry_target *

net/bridge/netfilter/ebtables.c

@@ -2115,8 +2115,7 @@ static int size_entry_mwt(const struct ebt_entry *entry, const unsigned char *ba
 		return ret;
 
 	offsets[0] = sizeof(struct ebt_entry); /* matches come first */
-	memcpy(&offsets[1], &entry->watchers_offset,
-			sizeof(offsets) - sizeof(offsets[0]));
+	memcpy(&offsets[1], &entry->offsets, sizeof(entry->offsets));
 
 	if (state->buf_kern_start) {
 		buf_start = state->buf_kern_start + state->buf_kern_offset;

net/netfilter/ipset/ip_set_core.c

@@ -872,7 +872,7 @@ ip_set_name_byindex(struct net *net, ip_set_id_t index, char *name)
 	BUG_ON(!set);
 
 	read_lock_bh(&ip_set_ref_lock);
-	strncpy(name, set->name, IPSET_MAXNAMELEN);
+	strscpy_pad(name, set->name, IPSET_MAXNAMELEN);
 	read_unlock_bh(&ip_set_ref_lock);
 }
 EXPORT_SYMBOL_GPL(ip_set_name_byindex);
@@ -1326,7 +1326,7 @@ static int ip_set_rename(struct sk_buff *skb, const struct nfnl_info *info,
 			goto out;
 		}
 	}
-	strncpy(set->name, name2, IPSET_MAXNAMELEN);
+	strscpy_pad(set->name, name2, IPSET_MAXNAMELEN);
 
 out:
 	write_unlock_bh(&ip_set_ref_lock);
@@ -1380,9 +1380,9 @@ static int ip_set_swap(struct sk_buff *skb, const struct nfnl_info *info,
 		return -EBUSY;
 	}
 
-	strncpy(from_name, from->name, IPSET_MAXNAMELEN);
-	strncpy(from->name, to->name, IPSET_MAXNAMELEN);
-	strncpy(to->name, from_name, IPSET_MAXNAMELEN);
+	strscpy_pad(from_name, from->name, IPSET_MAXNAMELEN);
+	strscpy_pad(from->name, to->name, IPSET_MAXNAMELEN);
+	strscpy_pad(to->name, from_name, IPSET_MAXNAMELEN);
 
 	swap(from->ref, to->ref);
 	ip_set(inst, from_id) = to;

net/netfilter/nf_tables_api.c

@@ -3675,6 +3675,9 @@ int nft_chain_validate(const struct nft_ctx *ctx, const struct nft_chain *chain)
 		return -EMLINK;
 
 	list_for_each_entry(rule, &chain->rules, list) {
+		if (fatal_signal_pending(current))
+			return -EINTR;
+
 		if (!nft_is_active_next(ctx->net, rule))
 			continue;
 
@@ -10479,6 +10482,9 @@ static int nf_tables_check_loops(const struct nft_ctx *ctx,
 	if (ctx->chain == chain)
 		return -ELOOP;
 
+	if (fatal_signal_pending(current))
+		return -EINTR;
+
 	list_for_each_entry(rule, &chain->rules, list) {
 		nft_rule_for_each_expr(expr, last, rule) {
 			struct nft_immediate_expr *priv;

net/netfilter/nft_ct.c

@@ -108,7 +108,7 @@ static void nft_ct_get_eval(const struct nft_expr *expr,
 		helper = rcu_dereference(help->helper);
 		if (helper == NULL)
 			goto err;
-		strncpy((char *)dest, helper->name, NF_CT_HELPER_NAME_LEN);
+		strscpy_pad((char *)dest, helper->name, NF_CT_HELPER_NAME_LEN);
 		return;
 #ifdef CONFIG_NF_CONNTRACK_LABELS
 	case NFT_CT_LABELS: {

net/netfilter/nft_fib.c

@@ -151,7 +151,7 @@ void nft_fib_store_result(void *reg, const struct nft_fib *priv,
 		if (priv->flags & NFTA_FIB_F_PRESENT)
 			*dreg = !!dev;
 		else
-			strncpy(reg, dev ? dev->name : "", IFNAMSIZ);
+			strscpy_pad(reg, dev ? dev->name : "", IFNAMSIZ);
 		break;
 	default:
 		WARN_ON_ONCE(1);

net/netfilter/nft_meta.c

@@ -185,12 +185,12 @@ static noinline bool nft_meta_get_eval_kind(enum nft_meta_keys key,
 	case NFT_META_IIFKIND:
 		if (!in || !in->rtnl_link_ops)
 			return false;
-		strncpy((char *)dest, in->rtnl_link_ops->kind, IFNAMSIZ);
+		strscpy_pad((char *)dest, in->rtnl_link_ops->kind, IFNAMSIZ);
 		break;
 	case NFT_META_OIFKIND:
 		if (!out || !out->rtnl_link_ops)
 			return false;
-		strncpy((char *)dest, out->rtnl_link_ops->kind, IFNAMSIZ);
+		strscpy_pad((char *)dest, out->rtnl_link_ops->kind, IFNAMSIZ);
 		break;
 	default:
 		return false;
@@ -206,7 +206,7 @@ static void nft_meta_store_ifindex(u32 *dest, const struct net_device *dev)
 
 static void nft_meta_store_ifname(u32 *dest, const struct net_device *dev)
 {
-	strncpy((char *)dest, dev ? dev->name : "", IFNAMSIZ);
+	strscpy_pad((char *)dest, dev ? dev->name : "", IFNAMSIZ);
 }
 
 static bool nft_meta_store_iftype(u32 *dest, const struct net_device *dev)

net/netfilter/nft_osf.c

@@ -23,7 +23,7 @@ static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
 	struct nft_osf *priv = nft_expr_priv(expr);
 	u32 *dest = &regs->data[priv->dreg];
 	struct sk_buff *skb = pkt->skb;
-	char os_match[NFT_OSF_MAXGENRELEN + 1];
+	char os_match[NFT_OSF_MAXGENRELEN];
 	const struct tcphdr *tcp;
 	struct nf_osf_data data;
 	struct tcphdr _tcph;
@@ -45,7 +45,7 @@ static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
 	}
 
 	if (!nf_osf_find(skb, nf_osf_fingers, priv->ttl, &data)) {
-		strncpy((char *)dest, "unknown", NFT_OSF_MAXGENRELEN);
+		strscpy_pad((char *)dest, "unknown", NFT_OSF_MAXGENRELEN);
 	} else {
 		if (priv->flags & NFT_OSF_F_VERSION)
 			snprintf(os_match, NFT_OSF_MAXGENRELEN, "%s:%s",
@@ -53,7 +53,7 @@ static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
 		else
 			strscpy(os_match, data.genre, NFT_OSF_MAXGENRELEN);
 
-		strncpy((char *)dest, os_match, NFT_OSF_MAXGENRELEN);
+		strscpy_pad((char *)dest, os_match, NFT_OSF_MAXGENRELEN);
 	}
 }
 

net/netfilter/x_tables.c

@@ -768,7 +768,7 @@ void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
 	m->u.user.match_size = msize;
 	strscpy(name, match->name, sizeof(name));
 	module_put(match->me);
-	strncpy(m->u.user.name, name, sizeof(m->u.user.name));
+	strscpy_pad(m->u.user.name, name, sizeof(m->u.user.name));
 
 	*size += off;
 	*dstptr += msize;
@@ -1148,7 +1148,7 @@ void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr,
 	t->u.user.target_size = tsize;
 	strscpy(name, target->name, sizeof(name));
 	module_put(target->me);
-	strncpy(t->u.user.name, name, sizeof(t->u.user.name));
+	strscpy_pad(t->u.user.name, name, sizeof(t->u.user.name));
 
 	*size += off;
 	*dstptr += tsize;
@@ -2014,4 +2014,3 @@ static void __exit xt_fini(void)
 
 module_init(xt_init);
 module_exit(xt_fini);
-

net/netfilter/xt_repldata.h

@@ -29,7 +29,7 @@
 	if (tbl == NULL) \
 		return NULL; \
 	term = (struct type##_error *)&(((char *)tbl)[term_offset]); \
-	strncpy(tbl->repl.name, info->name, sizeof(tbl->repl.name)); \
+	strscpy_pad(tbl->repl.name, info->name, sizeof(tbl->repl.name)); \
 	*term = (struct type##_error)typ2##_ERROR_INIT;  \
 	tbl->repl.valid_hooks = hook_mask; \
 	tbl->repl.num_entries = nhooks + 1; \