From 9cc4d9720d70f391dca52a07e72652f1693a6239 Mon Sep 17 00:00:00 2001 From: Ian Bridges Date: Fri, 26 Jun 2026 17:25:35 -0500 Subject: [PATCH] netfilter: x_tables: replace strlcat() with snprintf() In preparation for removing the deprecated strlcat() API[1], replace the strscpy()/strlcat() pairs in xt_proto_init() and xt_proto_fini() with snprintf(), which builds each /proc file name in a single call. Each name is "", where is the address-family string xt_prefix[af] and is one of the FORMAT_TABLES, FORMAT_MATCHES or FORMAT_TARGETS literals. Prepend %s to the FORMAT macros and switch to snprintf(). Link: https://github.com/KSPP/linux/issues/370 [1] Signed-off-by: Ian Bridges Signed-off-by: Florian Westphal --- net/netfilter/x_tables.c | 30 +++++++++++------------------- 1 file changed, 11 insertions(+), 19 deletions(-) diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index 4e6708c23922..e64116bf2637 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -1920,9 +1920,9 @@ static const struct seq_operations xt_target_seq_ops = { .show = xt_target_seq_show, }; -#define FORMAT_TABLES "_tables_names" -#define FORMAT_MATCHES "_tables_matches" -#define FORMAT_TARGETS "_tables_targets" +#define FORMAT_TABLES "%s_tables_names" +#define FORMAT_MATCHES "%s_tables_matches" +#define FORMAT_TARGETS "%s_tables_targets" #endif /* CONFIG_PROC_FS */ @@ -2033,8 +2033,7 @@ int xt_proto_init(struct net *net, u_int8_t af) root_uid = make_kuid(net->user_ns, 0); root_gid = make_kgid(net->user_ns, 0); - strscpy(buf, xt_prefix[af], sizeof(buf)); - strlcat(buf, FORMAT_TABLES, sizeof(buf)); + snprintf(buf, sizeof(buf), FORMAT_TABLES, xt_prefix[af]); proc = proc_create_net_data(buf, 0440, net->proc_net, &xt_table_seq_ops, sizeof(struct seq_net_private), (void *)(unsigned long)af); @@ -2043,8 +2042,7 @@ int xt_proto_init(struct net *net, u_int8_t af) if (uid_valid(root_uid) && gid_valid(root_gid)) proc_set_user(proc, root_uid, root_gid); - strscpy(buf, xt_prefix[af], sizeof(buf)); - strlcat(buf, FORMAT_MATCHES, sizeof(buf)); + snprintf(buf, sizeof(buf), FORMAT_MATCHES, xt_prefix[af]); proc = proc_create_seq_private(buf, 0440, net->proc_net, &xt_match_seq_ops, sizeof(struct nf_mttg_trav), (void *)(unsigned long)af); @@ -2053,8 +2051,7 @@ int xt_proto_init(struct net *net, u_int8_t af) if (uid_valid(root_uid) && gid_valid(root_gid)) proc_set_user(proc, root_uid, root_gid); - strscpy(buf, xt_prefix[af], sizeof(buf)); - strlcat(buf, FORMAT_TARGETS, sizeof(buf)); + snprintf(buf, sizeof(buf), FORMAT_TARGETS, xt_prefix[af]); proc = proc_create_seq_private(buf, 0440, net->proc_net, &xt_target_seq_ops, sizeof(struct nf_mttg_trav), (void *)(unsigned long)af); @@ -2068,13 +2065,11 @@ int xt_proto_init(struct net *net, u_int8_t af) #ifdef CONFIG_PROC_FS out_remove_matches: - strscpy(buf, xt_prefix[af], sizeof(buf)); - strlcat(buf, FORMAT_MATCHES, sizeof(buf)); + snprintf(buf, sizeof(buf), FORMAT_MATCHES, xt_prefix[af]); remove_proc_entry(buf, net->proc_net); out_remove_tables: - strscpy(buf, xt_prefix[af], sizeof(buf)); - strlcat(buf, FORMAT_TABLES, sizeof(buf)); + snprintf(buf, sizeof(buf), FORMAT_TABLES, xt_prefix[af]); remove_proc_entry(buf, net->proc_net); out: return -1; @@ -2087,16 +2082,13 @@ void xt_proto_fini(struct net *net, u_int8_t af) #ifdef CONFIG_PROC_FS char buf[XT_FUNCTION_MAXNAMELEN]; - strscpy(buf, xt_prefix[af], sizeof(buf)); - strlcat(buf, FORMAT_TABLES, sizeof(buf)); + snprintf(buf, sizeof(buf), FORMAT_TABLES, xt_prefix[af]); remove_proc_entry(buf, net->proc_net); - strscpy(buf, xt_prefix[af], sizeof(buf)); - strlcat(buf, FORMAT_TARGETS, sizeof(buf)); + snprintf(buf, sizeof(buf), FORMAT_TARGETS, xt_prefix[af]); remove_proc_entry(buf, net->proc_net); - strscpy(buf, xt_prefix[af], sizeof(buf)); - strlcat(buf, FORMAT_MATCHES, sizeof(buf)); + snprintf(buf, sizeof(buf), FORMAT_MATCHES, xt_prefix[af]); remove_proc_entry(buf, net->proc_net); #endif /*CONFIG_PROC_FS*/ }