net: simplify cBPF setsockopt compat handling

Add a helper that copies either a native or compat bpf_fprog from
userspace after verifying the length, and remove the compat setsockopt
handlers that now aren't required.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 0b0144752d780aec77f01a8bac8f055752fe6a12..4d049c8e1fbeaa48bfc7133179c425bd84217cca 100644 (file)
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -502,13 +502,11 @@ static inline bool insn_is_zext(const struct bpf_insn *insn)
                offsetof(TYPE, MEMBER);                                         \
        })
 
-#ifdef CONFIG_COMPAT
 /* A struct sock_filter is architecture independent. */
 struct compat_sock_fprog {
        u16             len;
        compat_uptr_t   filter; /* struct sock_filter * */
 };
-#endif
 
 struct sock_fprog_kern {
        u16                     len;
@@ -1278,4 +1276,6 @@ struct bpf_sockopt_kern {
        s32             retval;
 };
 
+int copy_bpf_fprog_from_user(struct sock_fprog *dst, void __user *src, int len);
+
 #endif /* __LINUX_FILTER_H__ */

diff --git a/include/net/compat.h b/include/net/compat.h
index f241666117d88cea220276c9cc95ff5c85a3b3cc..745db0d605b62b237a7df3afe34d97fdfc024dfd 100644 (file)
--- a/include/net/compat.h
+++ b/include/net/compat.h
@@ -61,7 +61,6 @@ int __get_compat_msghdr(struct msghdr *kmsg, struct compat_msghdr __user *umsg,
                        compat_size_t *len);
 int get_compat_msghdr(struct msghdr *, struct compat_msghdr __user *,
                      struct sockaddr __user **, struct iovec **);
-struct sock_fprog __user *get_compat_bpf_fprog(char __user *optval);
 int put_cmsg_compat(struct msghdr*, int, int, int, void *);
 
 int cmsghdr_from_user_compat_to_kern(struct msghdr *, struct sock *,

diff --git a/net/compat.c b/net/compat.c
index 5e3041a2c37d4da62a007f77fe226a0a0f81ec66..3e6c2c5ff2609cc7a0a8f7a7ff5ed61d939be25d 100644 (file)
--- a/net/compat.c
+++ b/net/compat.c
@@ -335,49 +335,6 @@ void scm_detach_fds_compat(struct msghdr *kmsg, struct scm_cookie *scm)
        __scm_destroy(scm);
 }
 
-/* allocate a 64-bit sock_fprog on the user stack for duration of syscall. */
-struct sock_fprog __user *get_compat_bpf_fprog(char __user *optval)
-{
-       struct compat_sock_fprog __user *fprog32 = (struct compat_sock_fprog __user *)optval;
-       struct sock_fprog __user *kfprog = compat_alloc_user_space(sizeof(struct sock_fprog));
-       struct compat_sock_fprog f32;
-       struct sock_fprog f;
-
-       if (copy_from_user(&f32, fprog32, sizeof(*fprog32)))
-               return NULL;
-       memset(&f, 0, sizeof(f));
-       f.len = f32.len;
-       f.filter = compat_ptr(f32.filter);
-       if (copy_to_user(kfprog, &f, sizeof(struct sock_fprog)))
-               return NULL;
-
-       return kfprog;
-}
-EXPORT_SYMBOL_GPL(get_compat_bpf_fprog);
-
-static int do_set_attach_filter(struct socket *sock, int level, int optname,
-                               char __user *optval, unsigned int optlen)
-{
-       struct sock_fprog __user *kfprog;
-
-       kfprog = get_compat_bpf_fprog(optval);
-       if (!kfprog)
-               return -EFAULT;
-
-       return sock_setsockopt(sock, level, optname, (char __user *)kfprog,
-                             sizeof(struct sock_fprog));
-}
-
-static int compat_sock_setsockopt(struct socket *sock, int level, int optname,
-                               char __user *optval, unsigned int optlen)
-{
-       if (optname == SO_ATTACH_FILTER ||
-           optname == SO_ATTACH_REUSEPORT_CBPF)
-               return do_set_attach_filter(sock, level, optname,
-                                           optval, optlen);
-       return sock_setsockopt(sock, level, optname, optval, optlen);
-}
-
 static int __compat_sys_setsockopt(int fd, int level, int optname,
                                   char __user *optval, unsigned int optlen)
 {
@@ -396,7 +353,7 @@ static int __compat_sys_setsockopt(int fd, int level, int optname,
                }
 
                if (level == SOL_SOCKET)
-                       err = compat_sock_setsockopt(sock, level,
+                       err = sock_setsockopt(sock, level,
                                        optname, optval, optlen);
                else if (sock->ops->compat_setsockopt)
                        err = sock->ops->compat_setsockopt(sock, level,

diff --git a/net/core/filter.c b/net/core/filter.c
index bdd2382e655d850e6f136e0ebe5e8a336b87d9f5..2bf6624796d86f47e0d208e87612e032e36a8167 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -77,6 +77,29 @@
 #include <net/transp_v6.h>
 #include <linux/btf_ids.h>
 
+int copy_bpf_fprog_from_user(struct sock_fprog *dst, void __user *src, int len)
+{
+       if (in_compat_syscall()) {
+               struct compat_sock_fprog f32;
+
+               if (len != sizeof(f32))
+                       return -EINVAL;
+               if (copy_from_user(&f32, src, sizeof(f32)))
+                       return -EFAULT;
+               memset(dst, 0, sizeof(*dst));
+               dst->len = f32.len;
+               dst->filter = compat_ptr(f32.filter);
+       } else {
+               if (len != sizeof(*dst))
+                       return -EINVAL;
+               if (copy_from_user(dst, src, sizeof(*dst)))
+                       return -EFAULT;
+       }
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(copy_bpf_fprog_from_user);
+
 /**
  *     sk_filter_trim_cap - run a packet through a socket filter
  *     @sk: sock associated with &sk_buff

diff --git a/net/core/sock.c b/net/core/sock.c
index 11d6f77dd562077d46342fba6c75a6b6aba0797d..e085df79482520eb1ed18912418f0fecd1e3a38c 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1059,19 +1059,14 @@ set_sndbuf:
                ret = sock_set_timeout(&sk->sk_sndtimeo, optval, optlen, optname == SO_SNDTIMEO_OLD);
                break;
 
-       case SO_ATTACH_FILTER:
-               ret = -EINVAL;
-               if (optlen == sizeof(struct sock_fprog)) {
-                       struct sock_fprog fprog;
-
-                       ret = -EFAULT;
-                       if (copy_from_user(&fprog, optval, sizeof(fprog)))
-                               break;
+       case SO_ATTACH_FILTER: {
+               struct sock_fprog fprog;
 
+               ret = copy_bpf_fprog_from_user(&fprog, optval, optlen);
+               if (!ret)
                        ret = sk_attach_filter(&fprog, sk);
-               }
                break;
-
+       }
        case SO_ATTACH_BPF:
                ret = -EINVAL;
                if (optlen == sizeof(u32)) {
@@ -1085,19 +1080,14 @@ set_sndbuf:
                }
                break;
 
-       case SO_ATTACH_REUSEPORT_CBPF:
-               ret = -EINVAL;
-               if (optlen == sizeof(struct sock_fprog)) {
-                       struct sock_fprog fprog;
-
-                       ret = -EFAULT;
-                       if (copy_from_user(&fprog, optval, sizeof(fprog)))
-                               break;
+       case SO_ATTACH_REUSEPORT_CBPF: {
+               struct sock_fprog fprog;
 
+               ret = copy_bpf_fprog_from_user(&fprog, optval, optlen);
+               if (!ret)
                        ret = sk_reuseport_attach_filter(&fprog, sk);
-               }
                break;
-
+       }
        case SO_ATTACH_REUSEPORT_EBPF:
                ret = -EINVAL;
                if (optlen == sizeof(u32)) {

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 781fee93b7d5e33d4fcbf3efb7718795a82351e7..35aee9e980536d81155d002b4a0dd937d5c20586 100644 (file)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1545,10 +1545,10 @@ static int fanout_set_data_cbpf(struct packet_sock *po, char __user *data,
 
        if (sock_flag(&po->sk, SOCK_FILTER_LOCKED))
                return -EPERM;
-       if (len != sizeof(fprog))
-               return -EINVAL;
-       if (copy_from_user(&fprog, data, len))
-               return -EFAULT;
+
+       ret = copy_bpf_fprog_from_user(&fprog, data, len);
+       if (ret)
+               return ret;
 
        ret = bpf_prog_create_from_user(&new, &fprog, NULL, false);
        if (ret)
@@ -4040,28 +4040,6 @@ static int packet_getsockopt(struct socket *sock, int level, int optname,
        return 0;
 }
 
-
-#ifdef CONFIG_COMPAT
-static int compat_packet_setsockopt(struct socket *sock, int level, int optname,
-                                   char __user *optval, unsigned int optlen)
-{
-       struct packet_sock *po = pkt_sk(sock->sk);
-
-       if (level != SOL_PACKET)
-               return -ENOPROTOOPT;
-
-       if (optname == PACKET_FANOUT_DATA &&
-           po->fanout && po->fanout->type == PACKET_FANOUT_CBPF) {
-               optval = (char __user *)get_compat_bpf_fprog(optval);
-               if (!optval)
-                       return -EFAULT;
-               optlen = sizeof(struct sock_fprog);
-       }
-
-       return packet_setsockopt(sock, level, optname, optval, optlen);
-}
-#endif
-
 static int packet_notifier(struct notifier_block *this,
                           unsigned long msg, void *ptr)
 {
@@ -4549,9 +4527,6 @@ static const struct proto_ops packet_ops = {
        .shutdown =     sock_no_shutdown,
        .setsockopt =   packet_setsockopt,
        .getsockopt =   packet_getsockopt,
-#ifdef CONFIG_COMPAT
-       .compat_setsockopt = compat_packet_setsockopt,
-#endif
        .sendmsg =      packet_sendmsg,
        .recvmsg =      packet_recvmsg,
        .mmap =         packet_mmap,