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copy_msghdr_from_user(): get rid of field-by-field copyin 

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2017-06-27 19:32:04 -04:00
parent 0d0606060b
commit ffb07550c7
1 changed files with 14 additions and 17 deletions
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31
net/socket.c
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@ -1870,22 +1870,18 @@ static int copy_msghdr_from_user(struct msghdr *kmsg,
struct sockaddr __user **save_addr,
struct iovec **iov)
{
struct sockaddr __user *uaddr;
struct iovec __user *uiov;
size_t nr_segs;
struct user_msghdr msg;
ssize_t err;
if (!access_ok(VERIFY_READ, umsg, sizeof(*umsg)) ||
__get_user(uaddr, &umsg->msg_name) ||
__get_user(kmsg->msg_namelen, &umsg->msg_namelen) ||
__get_user(uiov, &umsg->msg_iov) ||
__get_user(nr_segs, &umsg->msg_iovlen) ||
__get_user(kmsg->msg_control, &umsg->msg_control) ||
__get_user(kmsg->msg_controllen, &umsg->msg_controllen) ||
__get_user(kmsg->msg_flags, &umsg->msg_flags))
if (copy_from_user(&msg, umsg, sizeof(*umsg)))
return -EFAULT;
if (!uaddr)
kmsg->msg_control = msg.msg_control;
kmsg->msg_controllen = msg.msg_controllen;
kmsg->msg_flags = msg.msg_flags;
kmsg->msg_namelen = msg.msg_namelen;
if (!msg.msg_name)
kmsg->msg_namelen = 0;
if (kmsg->msg_namelen < 0)
@ -1895,11 +1891,11 @@ static int copy_msghdr_from_user(struct msghdr *kmsg,
kmsg->msg_namelen = sizeof(struct sockaddr_storage);
if (save_addr)
*save_addr = uaddr;
*save_addr = msg.msg_name;
if (uaddr && kmsg->msg_namelen) {
if (msg.msg_name && kmsg->msg_namelen) {
if (!save_addr) {
err = move_addr_to_kernel(uaddr, kmsg->msg_namelen,
err = move_addr_to_kernel(msg.msg_name, kmsg->msg_namelen,
kmsg->msg_name);
if (err < 0)
return err;
@ -1909,12 +1905,13 @@ static int copy_msghdr_from_user(struct msghdr *kmsg,
kmsg->msg_namelen = 0;
}
if (nr_segs > UIO_MAXIOV)
if (msg.msg_iovlen > UIO_MAXIOV)
return -EMSGSIZE;
kmsg->msg_iocb = NULL;
return import_iovec(save_addr ? READ : WRITE, uiov, nr_segs,
return import_iovec(save_addr ? READ : WRITE,
msg.msg_iov, msg.msg_iovlen,
UIO_FASTIOV, iov, &kmsg->msg_iter);
}