net: switch importing msghdr from userland to {compat_,}import_iovec()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

include/net/compat.h

@@ -40,7 +40,7 @@ int compat_sock_get_timestampns(struct sock *, struct timespec __user *);
 #define compat_mmsghdr	mmsghdr
 #endif /* defined(CONFIG_COMPAT) */
 
-ssize_t get_compat_msghdr(struct msghdr *, struct compat_msghdr __user *,
+int get_compat_msghdr(struct msghdr *, struct compat_msghdr __user *,
 		      struct sockaddr __user **, struct iovec **);
 asmlinkage long compat_sys_sendmsg(int, struct compat_msghdr __user *,
 				   unsigned int);

net/compat.c

@@ -31,7 +31,7 @@
 #include <asm/uaccess.h>
 #include <net/compat.h>
 
-ssize_t get_compat_msghdr(struct msghdr *kmsg,
+int get_compat_msghdr(struct msghdr *kmsg,
 		      struct compat_msghdr __user *umsg,
 		      struct sockaddr __user **save_addr,
 		      struct iovec **iov)
@@ -81,13 +81,9 @@ ssize_t get_compat_msghdr(struct msghdr *kmsg,
 
 	kmsg->msg_iocb = NULL;
 
-	err = compat_rw_copy_check_uvector(save_addr ? READ : WRITE,
+	return compat_import_iovec(save_addr ? READ : WRITE,
 				   compat_ptr(uiov), nr_segs,
-					   UIO_FASTIOV, *iov, iov);
-	if (err >= 0)
-		iov_iter_init(&kmsg->msg_iter, save_addr ? READ : WRITE,
-			      *iov, nr_segs, err);
-	return err;
+				   UIO_FASTIOV, iov, &kmsg->msg_iter);
 }
 
 /* Bleech... */

net/socket.c

@@ -1841,7 +1841,7 @@ struct used_address {
 	unsigned int name_len;
 };
 
-static ssize_t copy_msghdr_from_user(struct msghdr *kmsg,
+static int copy_msghdr_from_user(struct msghdr *kmsg,
 				 struct user_msghdr __user *umsg,
 				 struct sockaddr __user **save_addr,
 				 struct iovec **iov)
@@ -1890,13 +1890,8 @@ static ssize_t copy_msghdr_from_user(struct msghdr *kmsg,
 
 	kmsg->msg_iocb = NULL;
 
-	err = rw_copy_check_uvector(save_addr ? READ : WRITE,
-				    uiov, nr_segs,
-				    UIO_FASTIOV, *iov, iov);
-	if (err >= 0)
-		iov_iter_init(&kmsg->msg_iter, save_addr ? READ : WRITE,
-			      *iov, nr_segs, err);
-	return err;
+	return import_iovec(save_addr ? READ : WRITE, uiov, nr_segs,
+			    UIO_FASTIOV, iov, &kmsg->msg_iter);
 }
 
 static int ___sys_sendmsg(struct socket *sock, struct user_msghdr __user *msg,
@@ -1921,8 +1916,8 @@ static int ___sys_sendmsg(struct socket *sock, struct user_msghdr __user *msg,
 	else
 		err = copy_msghdr_from_user(msg_sys, msg, NULL, &iov);
 	if (err < 0)
-		goto out_freeiov;
-	total_len = err;
+		return err;
+	total_len = iov_iter_count(&msg_sys->msg_iter);
 
 	err = -ENOBUFS;
 
@@ -1988,7 +1983,6 @@ static int ___sys_sendmsg(struct socket *sock, struct user_msghdr __user *msg,
 	if (ctl_buf != ctl)
 		sock_kfree_s(sock->sk, ctl_buf, ctl_len);
 out_freeiov:
-	if (iov != iovstack)
 	kfree(iov);
 	return err;
 }
@@ -2114,8 +2108,8 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
 	else
 		err = copy_msghdr_from_user(msg_sys, msg, &uaddr, &iov);
 	if (err < 0)
-		goto out_freeiov;
-	total_len = err;
+		return err;
+	total_len = iov_iter_count(&msg_sys->msg_iter);
 
 	cmsg_ptr = (unsigned long)msg_sys->msg_control;
 	msg_sys->msg_flags = flags & (MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT);
@@ -2153,7 +2147,6 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg,
 	err = len;
 
 out_freeiov:
-	if (iov != iovstack)
 	kfree(iov);
 	return err;
 }