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Mon, 28 Sep 2026 13:30:21 +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 xjXhCO1rumqiPQAAD6G6ig (envelope-from ); Mon, 28 Sep 2026 13:30:21 +0000 Message-ID: <77efdf03-8960-484a-a804-83c3253f6145@suse.de> Date: Mon, 28 Sep 2026 15:29:23 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 03/13 net-next] net: inet: relocate ip_generic_getfrag and guard IPv4 socket logic To: Stanislav Fomichev Cc: netdev@vger.kernel.org, horms@kernel.org, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com, davem@davemloft.net, David Ahern , Ido Schimmel , Willem de Bruijn , Kees Cook , Kuniyuki Iwashima , Richard Gobert , Marc Kleine-Budde , Jeff Layton , Qi Tang , linux-kernel@vger.kernel.org References: <20260910144914.8025-1-fmancera@suse.de> <20260910144914.8025-4-fmancera@suse.de> Content-Language: en-US From: Fernando Fernandez Mancera In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; TAGGED_RCPT(0.00)[]; RCVD_TLS_ALL(0.00)[]; MIME_TRACE(0.00)[0:+]; RCPT_COUNT_TWELVE(0.00)[17]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; FREEMAIL_TO(0.00)[gmail.com]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; TO_DN_SOME(0.00)[]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[vger.kernel.org,kernel.org,redhat.com,google.com,davemloft.net,nvidia.com,gmail.com,pengutronix.de]; MID_RHS_MATCH_FROM(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:email,suse.de:mid,imap1.dmz-prg2.suse.org:helo] On 9/10/26 11:19 PM, Stanislav Fomichev wrote: > On 09/10, Fernando Fernandez Mancera wrote: >> 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 | 96 +++++++++++++++++++++++++++++++++++++------- >> net/ipv4/ip_output.c | 18 --------- >> net/ipv6/af_inet6.c | 5 +++ >> net/ipv6/datagram.c | 12 ++++++ >> 4 files changed, 99 insertions(+), 32 deletions(-) >> >> diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c >> index d9421ac38d78..b0c48ba544bf 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. >> */ >> @@ -425,8 +447,10 @@ int inet_release(struct socket *sock) >> if (!sk->sk_kern_sock) >> BPF_CGROUP_RUN_PROG_INET_SOCK_RELEASE(sk); >> >> +#if IS_ENABLED(CONFIG_IPV4) >> /* Applications forget to leave groups before exiting */ >> ip_mc_drop_socket(sk); >> +#endif >> >> /* If linger is set, we don't return until the close >> * is complete. Otherwise we return immediately. The >> @@ -478,6 +502,7 @@ EXPORT_SYMBOL(inet_bind); >> int __inet_bind(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len, >> u32 flags) >> { >> +#if IS_ENABLED(CONFIG_IPV4) >> struct sockaddr_in *addr = (struct sockaddr_in *)uaddr; >> struct inet_sock *inet = inet_sk(sk); >> struct net *net = sock_net(sk); >> @@ -570,6 +595,9 @@ int __inet_bind(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len, >> release_sock(sk); >> out: >> return err; >> +#else >> + return -EAFNOSUPPORT; >> +#endif >> } >> >> int inet_dgram_connect(struct socket *sock, struct sockaddr_unsized *uaddr, >> @@ -962,18 +990,24 @@ EXPORT_SYMBOL(inet_shutdown); >> int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) >> { >> struct sock *sk = sock->sk; >> - int err = 0; >> - struct net *net = sock_net(sk); >> +#if IS_ENABLED(CONFIG_IPV4) >> void __user *p = (void __user *)arg; >> - struct ifreq ifr; >> + struct net *net = sock_net(sk); >> struct rtentry rt; >> + struct ifreq ifr; >> +#endif >> + int err = 0; >> >> switch (cmd) { >> case SIOCADDRT: >> case SIOCDELRT: >> +#if IS_ENABLED(CONFIG_IPV4) >> if (copy_from_user(&rt, p, sizeof(struct rtentry))) >> return -EFAULT; >> err = ip_rt_ioctl(net, cmd, &rt); >> +#else >> + err = -EOPNOTSUPP; >> +#endif >> break; >> case SIOCRTMSG: >> err = -EINVAL; >> @@ -981,18 +1015,26 @@ int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) >> case SIOCDARP: >> case SIOCGARP: >> case SIOCSARP: >> +#if IS_ENABLED(CONFIG_IPV4) >> err = arp_ioctl(net, cmd, (void __user *)arg); >> +#else >> + err = -EOPNOTSUPP; >> +#endif >> break; >> case SIOCGIFADDR: >> case SIOCGIFBRDADDR: >> case SIOCGIFNETMASK: >> case SIOCGIFDSTADDR: >> case SIOCGIFPFLAGS: >> +#if IS_ENABLED(CONFIG_IPV4) >> if (get_user_ifreq(&ifr, NULL, p)) >> return -EFAULT; >> err = devinet_ioctl(net, cmd, &ifr); >> if (!err && put_user_ifreq(&ifr, p)) >> err = -EFAULT; >> +#else >> + err = -EOPNOTSUPP; >> +#endif >> break; >> >> case SIOCSIFADDR: >> @@ -1001,9 +1043,13 @@ int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) >> case SIOCSIFDSTADDR: >> case SIOCSIFPFLAGS: >> case SIOCSIFFLAGS: >> +#if IS_ENABLED(CONFIG_IPV4) >> if (get_user_ifreq(&ifr, NULL, p)) >> return -EFAULT; >> err = devinet_ioctl(net, cmd, &ifr); >> +#else >> + err = -EOPNOTSUPP; >> +#endif > > (passing by comment) > > Don't we have a coding style rule to avoid ifdef conditional in C code? > Should we add some new devinet4_ioctl/etc wrappers that we can conditionally > compile out in the headers? I agree here.. and went on a different direction for the upcoming v2. I decided to rely on DCE (Dead Code Elimination) to avoid using ifdef conditional. I think the v2 looks much better (to be sent in some minutes). Thanks!