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Mon, 28 Sep 2026 19:31:36 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 4RBiFn3AumpWOAAAD6G6ig:T4 (envelope-from ); Mon, 28 Sep 2026 19:31:36 +0000 From: Fernando Fernandez Mancera To: netdev@vger.kernel.org Cc: horms@kernel.org, kuba@kernel.org, pabeni@redhat.com, edumazet@kernel.org, davem@davemloft.net, Fernando Fernandez Mancera , Eric Dumazet , David Ahern , Ido Schimmel , Kuniyuki Iwashima , Kees Cook , Willem de Bruijn , Jiayuan Chen , Christian Brauner , Qi Tang , Jeff Layton , linux-kernel@vger.kernel.org Subject: [PATCH 03/16 net-next v2] net: inet: relocate ip_generic_getfrag and guard IPv4 socket logic Date: Mon, 28 Sep 2026 21:29:59 +0200 Message-ID: <20260928193046.6698-4-fmancera@suse.de> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260928193046.6698-1-fmancera@suse.de> References: <20260928193046.6698-1-fmancera@suse.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Level: X-Spam-Score: -2.80 X-Spam-Flag: NO X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCPT_COUNT_TWELVE(0.00)[18]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; RCVD_TLS_ALL(0.00)[]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[kernel.org,redhat.com,davemloft.net,suse.de,google.com,nvidia.com,linux.dev,gmail.com,vger.kernel.org]; RCVD_COUNT_TWO(0.00)[2]; RCVD_VIA_SMTP_AUTH(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:email,suse.de:mid,imap1.dmz-prg2.suse.org:helo]; FREEMAIL_ENVRCPT(0.00)[gmail.com] To enable compiling the INET subsystem without IPv4, shared generic utilities must be relocated and IPv4 socket logic must be guarded for CONFIG_IPV4. This patch moves the generic ip_generec_getfrag() from ip_output.c to af_inet.c. It also introduces CONFIG_IPV4 guards around af_inet.c to reject IPv4-specific ioctls, protocol registrations and bind requests. The same guard is added to reject IPv4-mapped IPv6. Signed-off-by: Fernando Fernandez Mancera --- net/ipv4/af_inet.c | 69 ++++++++++++++++++++++++++++++++++++++------ net/ipv4/ip_output.c | 18 ------------ net/ipv6/af_inet6.c | 5 ++++ net/ipv6/datagram.c | 4 +-- 4 files changed, 67 insertions(+), 29 deletions(-) diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index d9421ac38d78..cf00386933d6 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -129,6 +129,28 @@ int disable_ipv6_mod; EXPORT_SYMBOL(disable_ipv6_mod); +/* Keep the function here for now as it is generic, it should be moved + * to a common L3 place + */ +int +ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) +{ + struct msghdr *msg = from; + + if (skb->ip_summed == CHECKSUM_PARTIAL) { + if (!copy_from_iter_full(to, len, &msg->msg_iter)) + return -EFAULT; + } else { + __wsum csum = 0; + + if (!csum_and_copy_from_iter_full(to, len, &csum, &msg->msg_iter)) + return -EFAULT; + skb->csum = csum_block_add(skb->csum, csum, odd); + } + return 0; +} +EXPORT_SYMBOL(ip_generic_getfrag); + /* The inetsw table contains everything that inet_create needs to * build a new socket. */ @@ -426,7 +448,8 @@ int inet_release(struct socket *sock) BPF_CGROUP_RUN_PROG_INET_SOCK_RELEASE(sk); /* Applications forget to leave groups before exiting */ - ip_mc_drop_socket(sk); + if (IS_ENABLED(CONFIG_IPV4)) + ip_mc_drop_socket(sk); /* If linger is set, we don't return until the close * is complete. Otherwise we return immediately. The @@ -486,6 +509,9 @@ int __inet_bind(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len, u32 tb_id = RT_TABLE_LOCAL; int err; + if (!IS_ENABLED(CONFIG_IPV4)) + return -EAFNOSUPPORT; + if (addr->sin_family != AF_INET) { /* Compatibility games : accept AF_UNSPEC (mapped to AF_INET) * only if s_addr is INADDR_ANY. @@ -968,6 +994,9 @@ int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) struct ifreq ifr; struct rtentry rt; + if (!IS_ENABLED(CONFIG_IPV4)) + return -EOPNOTSUPP; + switch (cmd) { case SIOCADDRT: case SIOCDELRT: @@ -1023,6 +1052,9 @@ static int inet_compat_routing_ioctl(struct sock *sk, unsigned int cmd, compat_uptr_t rtdev; struct rtentry rt; + if (!IS_ENABLED(CONFIG_IPV4)) + return -EOPNOTSUPP; + if (copy_from_user(&rt.rt_dst, &ur->rt_dst, 3 * sizeof(struct sockaddr)) || get_user(rt.rt_flags, &ur->rt_flags) || @@ -1153,6 +1185,7 @@ static const struct net_proto_family inet_family_ops = { .owner = THIS_MODULE, }; +#if IS_ENABLED(CONFIG_IPV4) /* Upon startup we insert all the elements in inetsw_array[] into * the linked list inetsw. */ @@ -1193,6 +1226,7 @@ static struct inet_protosw inetsw_array[] = }; #define INETSW_ARRAY_LEN ARRAY_SIZE(inetsw_array) +#endif void inet_register_protosw(struct inet_protosw *p) { @@ -1267,6 +1301,9 @@ static int inet_sk_reselect_saddr(struct sock *sk) struct ip_options_rcu *inet_opt; int err; + if (!IS_ENABLED(CONFIG_IPV4)) + return -EAFNOSUPPORT; + inet_opt = rcu_dereference_protected(inet->inet_opt, lockdep_sock_is_held(sk)); if (inet_opt && inet_opt->opt.srr) @@ -1371,6 +1408,9 @@ struct sk_buff *inet_gso_segment(struct sk_buff *skb, int ihl; int id; + if (!IS_ENABLED(CONFIG_IPV4)) + return ERR_PTR(-EPROTONOSUPPORT); + skb_reset_network_header(skb); nhoff = skb_network_header(skb) - skb_mac_header(skb); if (unlikely(!pskb_may_pull(skb, sizeof(*iph)))) @@ -1774,6 +1814,10 @@ static int __init init_ipv4_mibs(void) return register_pernet_subsys(&ipv4_mib_ops); } +#if IS_ENABLED(CONFIG_IPV4) +static int ipv4_proc_init(void); +#endif + static __net_init int inet_init_net(struct net *net) { /* @@ -1824,8 +1868,6 @@ static int __init init_inet_pernet_ops(void) return register_pernet_subsys(&af_inet_ops); } -static int ipv4_proc_init(void); - /* * IP protocol layer initialiser */ @@ -1870,20 +1912,25 @@ static int __init ipv4_offload_init(void) fs_initcall(ipv4_offload_init); +#if IS_ENABLED(CONFIG_IPV4) static struct packet_type ip_packet_type __read_mostly = { .type = cpu_to_be16(ETH_P_IP), .func = ip_rcv, .list_func = ip_list_rcv, }; +#endif static int __init inet_init(void) { +#if IS_ENABLED(CONFIG_IPV4) struct inet_protosw *q; struct list_head *r; int rc; +#endif sock_skb_cb_check_size(sizeof(struct inet_skb_parm)); +#if IS_ENABLED(CONFIG_IPV4) raw_hashinfo_init(&raw_v4_hashinfo); rc = proto_register(&tcp_prot, 1); @@ -1958,7 +2005,7 @@ static int __init inet_init(void) */ ip_init(); - +#endif /* CONFIG_IPV4 */ /* Initialise per-cpu ipv4 mibs */ if (init_ipv4_mibs()) panic("%s: Cannot init ipv4 mibs\n", __func__); @@ -1980,6 +2027,9 @@ static int __init inet_init(void) if (icmp_init() < 0) panic("Failed to create the ICMP control socket.\n"); + if (init_inet_pernet_ops()) + pr_crit("%s: Cannot init ipv4 inet pernet ops\n", __func__); +#if IS_ENABLED(CONFIG_IPV4) /* * Initialise the multicast router */ @@ -1987,19 +2037,17 @@ static int __init inet_init(void) if (ip_mr_init()) pr_crit("%s: Cannot init ipv4 mroute\n", __func__); #endif - - if (init_inet_pernet_ops()) - pr_crit("%s: Cannot init ipv4 inet pernet ops\n", __func__); - ipv4_proc_init(); ipfrag_init(); dev_add_pack(&ip_packet_type); +#endif /* CONFIG_IPV4 */ ip_tunnel_core_init(); - rc = 0; + return 0; +#if IS_ENABLED(CONFIG_IPV4) out: return rc; out_unregister_raw_proto: @@ -2009,12 +2057,14 @@ static int __init inet_init(void) out_unregister_tcp_proto: proto_unregister(&tcp_prot); goto out; +#endif } fs_initcall(inet_init); /* ------------------------------------------------------------------------ */ +#if IS_ENABLED(CONFIG_IPV4) #ifdef CONFIG_PROC_FS static int __init ipv4_proc_init(void) { @@ -2051,3 +2101,4 @@ static int __init ipv4_proc_init(void) return 0; } #endif /* CONFIG_PROC_FS */ +#endif diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index a24cc8ee11d3..4c6b34e70990 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -932,24 +932,6 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, } EXPORT_SYMBOL(ip_do_fragment); -int -ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) -{ - struct msghdr *msg = from; - - if (skb->ip_summed == CHECKSUM_PARTIAL) { - if (!copy_from_iter_full(to, len, &msg->msg_iter)) - return -EFAULT; - } else { - __wsum csum = 0; - if (!csum_and_copy_from_iter_full(to, len, &csum, &msg->msg_iter)) - return -EFAULT; - skb->csum = csum_block_add(skb->csum, csum, odd); - } - return 0; -} -EXPORT_SYMBOL(ip_generic_getfrag); - static int __ip_append_data(struct sock *sk, struct flowi4 *fl4, struct sk_buff_head *queue, diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index f0efdc13baf4..f220eaab085b 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -302,6 +302,11 @@ int __inet6_bind(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len, struct net_device *dev = NULL; int chk_addr_ret; + if (!IS_ENABLED(CONFIG_IPV4)) { + err = -EADDRNOTAVAIL; + goto out; + } + /* Binding to v4-mapped address on a v6-only socket * makes no sense */ diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c index 191c9733ff9f..079d1951405b 100644 --- a/net/ipv6/datagram.c +++ b/net/ipv6/datagram.c @@ -153,7 +153,7 @@ int __ip6_datagram_connect(struct sock *sk, struct sockaddr_unsized *uaddr, int err; if (usin->sin6_family == AF_INET) { - if (ipv6_only_sock(sk)) + if (!IS_ENABLED(CONFIG_IPV4) || ipv6_only_sock(sk)) return -EAFNOSUPPORT; err = __ip4_datagram_connect(sk, uaddr, addr_len); goto ipv4_connected; @@ -186,7 +186,7 @@ int __ip6_datagram_connect(struct sock *sk, struct sockaddr_unsized *uaddr, if (addr_type & IPV6_ADDR_MAPPED) { struct sockaddr_in sin; - if (ipv6_only_sock(sk)) { + if (!IS_ENABLED(CONFIG_IPV4) || ipv6_only_sock(sk)) { err = -ENETUNREACH; goto out; } -- 2.55.0