bpf: net: Change sk_getsockopt() to take the sockptr_t argument

This patch changes sk_getsockopt() to take the sockptr_t argument
such that it can be used by bpf_getsockopt(SOL_SOCKET) in a
latter patch.

security_socket_getpeersec_stream() is not changed.  It stays
with the __user ptr (optval.user and optlen.user) to avoid changes
to other security hooks.  bpf_getsockopt(SOL_SOCKET) also does not
support SO_PEERSEC.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002802.2888419-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

include/linux/filter.h

@@ -900,8 +900,7 @@ int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk);
 void sk_reuseport_prog_free(struct bpf_prog *prog);
 int sk_detach_filter(struct sock *sk);
-int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
-		  unsigned int len);
+int sk_get_filter(struct sock *sk, sockptr_t optval, unsigned int len);
 
 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);

include/linux/sockptr.h

@@ -64,6 +64,11 @@ static inline int copy_to_sockptr_offset(sockptr_t dst, size_t offset,
 	return 0;
 }
 
+static inline int copy_to_sockptr(sockptr_t dst, const void *src, size_t size)
+{
+	return copy_to_sockptr_offset(dst, 0, src, size);
+}
+
 static inline void *memdup_sockptr(sockptr_t src, size_t len)
 {
 	void *p = kmalloc_track_caller(len, GFP_USER | __GFP_NOWARN);

net/core/filter.c

@@ -10716,8 +10716,7 @@ int sk_detach_filter(struct sock *sk)
 }
 EXPORT_SYMBOL_GPL(sk_detach_filter);
 
-int sk_get_filter(struct sock *sk, struct sock_filter __user *ubuf,
-		  unsigned int len)
+int sk_get_filter(struct sock *sk, sockptr_t optval, unsigned int len)
 {
 	struct sock_fprog_kern *fprog;
 	struct sk_filter *filter;
@@ -10748,7 +10747,7 @@ int sk_get_filter(struct sock *sk, struct sock_filter __user *ubuf,
 		goto out;
 
 	ret = -EFAULT;
-	if (copy_to_user(ubuf, fprog->filter, bpf_classic_proglen(fprog)))
+	if (copy_to_sockptr(optval, fprog->filter, bpf_classic_proglen(fprog)))
 		goto out;
 
 	/* Instead of bytes, the API requests to return the number

net/core/sock.c

@@ -712,8 +712,8 @@ out:
 	return ret;
 }
 
-static int sock_getbindtodevice(struct sock *sk, char __user *optval,
-				int __user *optlen, int len)
+static int sock_getbindtodevice(struct sock *sk, sockptr_t optval,
+				sockptr_t optlen, int len)
 {
 	int ret = -ENOPROTOOPT;
 #ifdef CONFIG_NETDEVICES
@@ -737,12 +737,12 @@ static int sock_getbindtodevice(struct sock *sk, char __user *optval,
 	len = strlen(devname) + 1;
 
 	ret = -EFAULT;
-	if (copy_to_user(optval, devname, len))
+	if (copy_to_sockptr(optval, devname, len))
 		goto out;
 
 zero:
 	ret = -EFAULT;
-	if (put_user(len, optlen))
+	if (copy_to_sockptr(optlen, &len, sizeof(int)))
 		goto out;
 
 	ret = 0;
@@ -1568,20 +1568,23 @@ static void cred_to_ucred(struct pid *pid, const struct cred *cred,
 	}
 }
 
-static int groups_to_user(gid_t __user *dst, const struct group_info *src)
+static int groups_to_user(sockptr_t dst, const struct group_info *src)
 {
 	struct user_namespace *user_ns = current_user_ns();
 	int i;
 
-	for (i = 0; i < src->ngroups; i++)
-		if (put_user(from_kgid_munged(user_ns, src->gid[i]), dst + i))
+	for (i = 0; i < src->ngroups; i++) {
+		gid_t gid = from_kgid_munged(user_ns, src->gid[i]);
+
+		if (copy_to_sockptr_offset(dst, i * sizeof(gid), &gid, sizeof(gid)))
 			return -EFAULT;
+	}
 
 	return 0;
 }
 
 static int sk_getsockopt(struct sock *sk, int level, int optname,
-			 char __user *optval, int __user *optlen)
+			 sockptr_t optval, sockptr_t optlen)
 {
 	struct socket *sock = sk->sk_socket;
 
@@ -1600,7 +1603,7 @@ static int sk_getsockopt(struct sock *sk, int level, int optname,
 	int lv = sizeof(int);
 	int len;
 
-	if (get_user(len, optlen))
+	if (copy_from_sockptr(&len, optlen, sizeof(int)))
 		return -EFAULT;
 	if (len < 0)
 		return -EINVAL;
@@ -1735,7 +1738,7 @@ static int sk_getsockopt(struct sock *sk, int level, int optname,
 		cred_to_ucred(sk->sk_peer_pid, sk->sk_peer_cred, &peercred);
 		spin_unlock(&sk->sk_peer_lock);
 
-		if (copy_to_user(optval, &peercred, len))
+		if (copy_to_sockptr(optval, &peercred, len))
 			return -EFAULT;
 		goto lenout;
 	}
@@ -1753,11 +1756,11 @@ static int sk_getsockopt(struct sock *sk, int level, int optname,
 		if (len < n * sizeof(gid_t)) {
 			len = n * sizeof(gid_t);
 			put_cred(cred);
-			return put_user(len, optlen) ? -EFAULT : -ERANGE;
+			return copy_to_sockptr(optlen, &len, sizeof(int)) ? -EFAULT : -ERANGE;
 		}
 		len = n * sizeof(gid_t);
 
-		ret = groups_to_user((gid_t __user *)optval, cred->group_info);
+		ret = groups_to_user(optval, cred->group_info);
 		put_cred(cred);
 		if (ret)
 			return ret;
@@ -1773,7 +1776,7 @@ static int sk_getsockopt(struct sock *sk, int level, int optname,
 			return -ENOTCONN;
 		if (lv < len)
 			return -EINVAL;
-		if (copy_to_user(optval, address, len))
+		if (copy_to_sockptr(optval, address, len))
 			return -EFAULT;
 		goto lenout;
 	}
@@ -1790,7 +1793,7 @@ static int sk_getsockopt(struct sock *sk, int level, int optname,
 		break;
 
 	case SO_PEERSEC:
-		return security_socket_getpeersec_stream(sock, optval, optlen, len);
+		return security_socket_getpeersec_stream(sock, optval.user, optlen.user, len);
 
 	case SO_MARK:
 		v.val = sk->sk_mark;
@@ -1822,7 +1825,7 @@ static int sk_getsockopt(struct sock *sk, int level, int optname,
 		return sock_getbindtodevice(sk, optval, optlen, len);
 
 	case SO_GET_FILTER:
-		len = sk_get_filter(sk, (struct sock_filter __user *)optval, len);
+		len = sk_get_filter(sk, optval, len);
 		if (len < 0)
 			return len;
 
@@ -1870,7 +1873,7 @@ static int sk_getsockopt(struct sock *sk, int level, int optname,
 		sk_get_meminfo(sk, meminfo);
 
 		len = min_t(unsigned int, len, sizeof(meminfo));
-		if (copy_to_user(optval, &meminfo, len))
+		if (copy_to_sockptr(optval, &meminfo, len))
 			return -EFAULT;
 
 		goto lenout;
@@ -1939,10 +1942,10 @@ static int sk_getsockopt(struct sock *sk, int level, int optname,
 
 	if (len > lv)
 		len = lv;
-	if (copy_to_user(optval, &v, len))
+	if (copy_to_sockptr(optval, &v, len))
 		return -EFAULT;
 lenout:
-	if (put_user(len, optlen))
+	if (copy_to_sockptr(optlen, &len, sizeof(int)))
 		return -EFAULT;
 	return 0;
 }
@@ -1950,7 +1953,9 @@ lenout:
 int sock_getsockopt(struct socket *sock, int level, int optname,
 		    char __user *optval, int __user *optlen)
 {
-	return sk_getsockopt(sock->sk, level, optname, optval, optlen);
+	return sk_getsockopt(sock->sk, level, optname,
+			     USER_SOCKPTR(optval),
+			     USER_SOCKPTR(optlen));
 }
 
 /*