Convert the SOL_IP switch and ip_mroute_getsockopt(), its last leaf on
a sockptr_t pair. The IP_MSFILTER and MCAST_MSFILTER bridges go away.

ip_getsockopt() builds the sockopt_t with sockopt_init_user() and
writes optlen back unconditionally, because IP_OPTIONS and others
report a length then fail; ip_mc_msfget() therefore stores its length
last. IP_PKTOPTIONS takes its buffer off iter_out. The argument is
sopt, since IP_OPTIONS already has an ip_options local named opt.

Validating optlen now precedes the level check and the MRT_* dispatch,
so a negative optlen wins over -EOPNOTSUPP there.

Signed-off-by: Breno Leitao <[email protected]>
---
 include/linux/mroute.h |  4 +--
 include/net/ip.h       |  3 +-
 net/core/filter.c      | 18 ++++++++---
 net/ipv4/igmp.c        |  3 +-
 net/ipv4/ip_sockglue.c | 87 +++++++++++++++++++-------------------------------
 net/ipv4/ipmr.c        | 11 +++----
 6 files changed, 56 insertions(+), 70 deletions(-)

diff --git a/include/linux/mroute.h b/include/linux/mroute.h
index 4c5003afee6c51..c1c21e61c81c37 100644
--- a/include/linux/mroute.h
+++ b/include/linux/mroute.h
@@ -17,7 +17,7 @@ static inline int ip_mroute_opt(int opt)
 }
 
 int ip_mroute_setsockopt(struct sock *, int, sockptr_t, unsigned int);
-int ip_mroute_getsockopt(struct sock *, int, sockptr_t, sockptr_t);
+int ip_mroute_getsockopt(struct sock *sk, int optname, sockopt_t *opt);
 int ipmr_ioctl(struct sock *sk, int cmd, void *arg);
 int ipmr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
 int ip_mr_init(void);
@@ -31,7 +31,7 @@ static inline int ip_mroute_setsockopt(struct sock *sock, int 
optname,
 }
 
 static inline int ip_mroute_getsockopt(struct sock *sk, int optname,
-                                      sockptr_t optval, sockptr_t optlen)
+                                      sockopt_t *opt)
 {
        return -ENOPROTOOPT;
 }
diff --git a/include/net/ip.h b/include/net/ip.h
index 6f602df72ee621..81aef4b98430bf 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -823,8 +823,7 @@ int do_ip_setsockopt(struct sock *sk, int level, int 
optname, sockptr_t optval,
                     unsigned int optlen);
 int ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
                  unsigned int optlen);
-int do_ip_getsockopt(struct sock *sk, int level, int optname,
-                    sockptr_t optval, sockptr_t optlen);
+int do_ip_getsockopt(struct sock *sk, int level, int optname, sockopt_t *sopt);
 int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
                  int __user *optlen);
 int ip_ra_control(struct sock *sk, unsigned char on,
diff --git a/net/core/filter.c b/net/core/filter.c
index 70dc621672f2e9..9a706ec1f7f122 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5737,10 +5737,20 @@ static int sol_ip_sockopt(struct sock *sk, int optname,
                return -EINVAL;
        }
 
-       if (getopt)
-               return do_ip_getsockopt(sk, SOL_IP, optname,
-                                       KERNEL_SOCKPTR(optval),
-                                       KERNEL_SOCKPTR(optlen));
+       if (getopt) {
+               struct kvec kvec;
+               sockopt_t opt;
+               int err;
+
+               err = sockptr_to_sockopt(&opt, KERNEL_SOCKPTR(optval),
+                                        KERNEL_SOCKPTR(optlen), &kvec);
+               if (err)
+                       return err;
+
+               err = do_ip_getsockopt(sk, SOL_IP, optname, &opt);
+               *optlen = opt.optlen;
+               return err;
+       }
 
        return do_ip_setsockopt(sk, SOL_IP, optname,
                                KERNEL_SOCKPTR(optval), *optlen);
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index d573c5bf8f038b..bf00810cdd7a13 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -2763,12 +2763,13 @@ int ip_mc_msfget(struct sock *sk, struct ip_msfilter 
*msf, sockopt_t *opt)
        if (err)
                return err;
 
-       opt->optlen = msf_size;
        if (copy_to_iter(msf, IP_MSFILTER_SIZE(0), &opt->iter_out) !=
            IP_MSFILTER_SIZE(0))
                return -EFAULT;
        if (len && copy_to_iter(psl->sl_addr, len, &opt->iter_out) != len)
                return -EFAULT;
+
+       opt->optlen = msf_size;
        return 0;
 done:
        return err;
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 1f452b6ea86e9d..2e78b11d294a9f 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1509,8 +1509,7 @@ static int compat_ip_get_mcast_msfilter(struct sock *sk, 
sockopt_t *opt)
        return 0;
 }
 
-int do_ip_getsockopt(struct sock *sk, int level, int optname,
-                    sockptr_t optval, sockptr_t optlen)
+int do_ip_getsockopt(struct sock *sk, int level, int optname, sockopt_t *sopt)
 {
        struct inet_sock *inet = inet_sk(sk);
        bool needs_rtnl = getsockopt_needs_rtnl(optname);
@@ -1521,10 +1520,9 @@ int do_ip_getsockopt(struct sock *sk, int level, int 
optname,
                return -EOPNOTSUPP;
 
        if (ip_mroute_opt(optname))
-               return ip_mroute_getsockopt(sk, optname, optval, optlen);
+               return ip_mroute_getsockopt(sk, optname, sopt);
 
-       if (copy_from_sockptr(&len, optlen, sizeof(int)))
-               return -EFAULT;
+       len = sopt->optlen;
        if (len < 0)
                return -EINVAL;
 
@@ -1620,16 +1618,15 @@ int do_ip_getsockopt(struct sock *sk, int level, int 
optname,
                rcu_read_unlock();
 
                if (opt->optlen == 0) {
-                       len = 0;
-                       return copy_to_sockptr(optlen, &len, sizeof(int));
+                       sopt->optlen = 0;
+                       return 0;
                }
 
                ip_options_undo(opt);
 
                len = min_t(unsigned int, len, opt->optlen);
-               if (copy_to_sockptr(optlen, &len, sizeof(int)))
-                       return -EFAULT;
-               if (copy_to_sockptr(optval, opt->__data, len))
+               sopt->optlen = len;
+               if (copy_to_iter(opt->__data, len, &sopt->iter_out) != len)
                        return -EFAULT;
                return 0;
        }
@@ -1653,12 +1650,12 @@ int do_ip_getsockopt(struct sock *sk, int level, int 
optname,
                if (sk->sk_type != SOCK_STREAM)
                        return -ENOPROTOOPT;
 
-               if (optval.is_kernel) {
+               if (iov_iter_is_kvec(&sopt->iter_out)) {
                        msg.msg_control_is_user = false;
-                       msg.msg_control = optval.kernel;
+                       msg.msg_control = sopt->iter_out.kvec->iov_base;
                } else {
                        msg.msg_control_is_user = true;
-                       msg.msg_control_user = optval.user;
+                       msg.msg_control_user = sopt->iter_out.ubuf;
                }
                msg.msg_controllen = len;
                msg.msg_flags = in_compat_syscall() ? MSG_CMSG_COMPAT : 0;
@@ -1680,8 +1677,8 @@ int do_ip_getsockopt(struct sock *sk, int level, int 
optname,
                        int tos = READ_ONCE(inet->rcv_tos);
                        put_cmsg(&msg, SOL_IP, IP_TOS, sizeof(tos), &tos);
                }
-               len -= msg.msg_controllen;
-               return copy_to_sockptr(optlen, &len, sizeof(int));
+               sopt->optlen = len - msg.msg_controllen;
+               return 0;
        }
        case IP_UNICAST_IF:
                val = (__force int)htonl((__u32) READ_ONCE(inet->uc_index));
@@ -1692,9 +1689,8 @@ int do_ip_getsockopt(struct sock *sk, int level, int 
optname,
                len = min_t(unsigned int, len, sizeof(struct in_addr));
                addr.s_addr = READ_ONCE(inet->mc_addr);
 
-               if (copy_to_sockptr(optlen, &len, sizeof(int)))
-                       return -EFAULT;
-               if (copy_to_sockptr(optval, &addr, len))
+               sopt->optlen = len;
+               if (copy_to_iter(&addr, len, &sopt->iter_out) != len)
                        return -EFAULT;
                return 0;
        }
@@ -1711,43 +1707,25 @@ int do_ip_getsockopt(struct sock *sk, int level, int 
optname,
        case IP_MSFILTER:
        {
                struct ip_msfilter msf;
-               struct kvec kvec;
-               sockopt_t opt;
 
                if (len < IP_MSFILTER_SIZE(0)) {
                        err = -EINVAL;
                        goto out;
                }
-               if (copy_from_sockptr(&msf, optval, IP_MSFILTER_SIZE(0))) {
+               if (copy_from_iter(&msf, IP_MSFILTER_SIZE(0), &sopt->iter_in) !=
+                   IP_MSFILTER_SIZE(0)) {
                        err = -EFAULT;
                        goto out;
                }
-               err = sockptr_to_sockopt(&opt, optval, optlen, &kvec);
-               if (err)
-                       goto out;
-
-               err = ip_mc_msfget(sk, &msf, &opt);
-               if (!err && copy_to_sockptr(optlen, &opt.optlen, sizeof(int)))
-                       err = -EFAULT;
+               err = ip_mc_msfget(sk, &msf, sopt);
                goto out;
        }
        case MCAST_MSFILTER:
-       {
-               struct kvec kvec;
-               sockopt_t opt;
-
-               err = sockptr_to_sockopt(&opt, optval, optlen, &kvec);
-               if (err)
-                       goto out;
-
                if (in_compat_syscall())
-                       err = compat_ip_get_mcast_msfilter(sk, &opt);
+                       err = compat_ip_get_mcast_msfilter(sk, sopt);
                else
-                       err = ip_get_mcast_msfilter(sk, &opt);
-               if (!err && copy_to_sockptr(optlen, &opt.optlen, sizeof(int)))
-                       err = -EFAULT;
+                       err = ip_get_mcast_msfilter(sk, sopt);
                goto out;
-       }
        case IP_PROTOCOL:
                val = inet_sk(sk)->inet_num;
                break;
@@ -1759,16 +1737,14 @@ int do_ip_getsockopt(struct sock *sk, int level, int 
optname,
 copyval:
        if (len < sizeof(int) && len > 0 && val >= 0 && val <= 255) {
                unsigned char ucval = (unsigned char)val;
-               len = 1;
-               if (copy_to_sockptr(optlen, &len, sizeof(int)))
-                       return -EFAULT;
-               if (copy_to_sockptr(optval, &ucval, 1))
+
+               sopt->optlen = 1;
+               if (copy_to_iter(&ucval, 1, &sopt->iter_out) != 1)
                        return -EFAULT;
        } else {
                len = min_t(unsigned int, sizeof(int), len);
-               if (copy_to_sockptr(optlen, &len, sizeof(int)))
-                       return -EFAULT;
-               if (copy_to_sockptr(optval, &val, len))
+               sopt->optlen = len;
+               if (copy_to_iter(&val, len, &sopt->iter_out) != len)
                        return -EFAULT;
        }
        return 0;
@@ -1783,19 +1759,22 @@ int do_ip_getsockopt(struct sock *sk, int level, int 
optname,
 int ip_getsockopt(struct sock *sk, int level,
                  int optname, char __user *optval, int __user *optlen)
 {
+       sockopt_t opt;
        int err;
 
-       err = do_ip_getsockopt(sk, level, optname,
-                              USER_SOCKPTR(optval), USER_SOCKPTR(optlen));
+       err = sockopt_init_user(&opt, optval, optlen);
+       if (err)
+               return err;
+
+       err = do_ip_getsockopt(sk, level, optname, &opt);
+       if (put_user(opt.optlen, optlen))
+               return -EFAULT;
 
 #ifdef CONFIG_NETFILTER
        /* we need to exclude all possible ENOPROTOOPTs except default case */
        if (err == -ENOPROTOOPT && optname != IP_PKTOPTIONS &&
                        !ip_mroute_opt(optname)) {
-               int len;
-
-               if (get_user(len, optlen))
-                       return -EFAULT;
+               int len = opt.optlen;
 
                err = nf_getsockopt(sk, PF_INET, optname, optval, &len);
                if (err >= 0)
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index e4c51ca473019c..f249569b4bf8b9 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1638,8 +1638,7 @@ int ipmr_sk_ioctl(struct sock *sk, unsigned int cmd, void 
__user *arg)
 }
 
 /* Getsock opt support for the multicast routing system. */
-int ip_mroute_getsockopt(struct sock *sk, int optname, sockptr_t optval,
-                        sockptr_t optlen)
+int ip_mroute_getsockopt(struct sock *sk, int optname, sockopt_t *opt)
 {
        int olr;
        int val;
@@ -1670,16 +1669,14 @@ int ip_mroute_getsockopt(struct sock *sk, int optname, 
sockptr_t optval,
                return -ENOPROTOOPT;
        }
 
-       if (copy_from_sockptr(&olr, optlen, sizeof(int)))
-               return -EFAULT;
+       olr = opt->optlen;
        if (olr < 0)
                return -EINVAL;
 
        olr = min_t(unsigned int, olr, sizeof(int));
 
-       if (copy_to_sockptr(optlen, &olr, sizeof(int)))
-               return -EFAULT;
-       if (copy_to_sockptr(optval, &val, olr))
+       opt->optlen = olr;
+       if (copy_to_iter(&val, olr, &opt->iter_out) != olr)
                return -EFAULT;
        return 0;
 }

-- 
2.53.0-Meta


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