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net/scm: cleanup scm_detach_fds 

Factor out two helpes to keep the code tidy.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Christoph Hellwig 2020-05-11 13:59:12 +02:00 committed by David S. Miller
parent 0462b6bdb6
commit 2618d530dd
1 changed files with 51 additions and 43 deletions
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94
net/core/scm.c
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@ -277,78 +277,86 @@ void put_cmsg_scm_timestamping(struct msghdr *msg, struct scm_timestamping_inter
}
EXPORT_SYMBOL(put_cmsg_scm_timestamping);
static int __scm_install_fd(struct file *file, int __user *ufd, int o_flags)
{
struct socket *sock;
int new_fd;
int error;
error = security_file_receive(file);
if (error)
return error;
new_fd = get_unused_fd_flags(o_flags);
if (new_fd < 0)
return new_fd;
error = put_user(new_fd, ufd);
if (error) {
put_unused_fd(new_fd);
return error;
}
/* Bump the usage count and install the file. */
sock = sock_from_file(file, &error);
if (sock) {
sock_update_netprioidx(&sock->sk->sk_cgrp_data);
sock_update_classid(&sock->sk->sk_cgrp_data);
}
fd_install(new_fd, get_file(file));
return error;
}
static int scm_max_fds(struct msghdr *msg)
{
if (msg->msg_controllen <= sizeof(struct cmsghdr))
return 0;
return (msg->msg_controllen - sizeof(struct cmsghdr)) / sizeof(int);
}
void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
{
struct cmsghdr __user *cm
= (__force struct cmsghdr __user*)msg->msg_control;
int fdmax = 0;
int fdnum = scm->fp->count;
struct file **fp = scm->fp->fp;
int __user *cmfptr;
int o_flags = (msg->msg_flags & MSG_CMSG_CLOEXEC) ? O_CLOEXEC : 0;
int fdmax = min_t(int, scm_max_fds(msg), scm->fp->count);
int __user *cmsg_data = CMSG_USER_DATA(cm);
int err = 0, i;
if (MSG_CMSG_COMPAT & msg->msg_flags) {
if (msg->msg_flags & MSG_CMSG_COMPAT) {
scm_detach_fds_compat(msg, scm);
return;
}
if (msg->msg_controllen > sizeof(struct cmsghdr))
fdmax = ((msg->msg_controllen - sizeof(struct cmsghdr))
/ sizeof(int));
if (fdnum < fdmax)
fdmax = fdnum;
for (i=0, cmfptr =(int __user *)CMSG_USER_DATA(cm); i<fdmax;
i++, cmfptr++)
{
struct socket *sock;
int new_fd;
err = security_file_receive(fp[i]);
for (i = 0; i < fdmax; i++) {
err = __scm_install_fd(scm->fp->fp[i], cmsg_data + i, o_flags);
if (err)
break;
err = get_unused_fd_flags(MSG_CMSG_CLOEXEC & msg->msg_flags
? O_CLOEXEC : 0);
if (err < 0)
break;
new_fd = err;
err = put_user(new_fd, cmfptr);
if (err) {
put_unused_fd(new_fd);
break;
}
/* Bump the usage count and install the file. */
sock = sock_from_file(fp[i], &err);
if (sock) {
sock_update_netprioidx(&sock->sk->sk_cgrp_data);
sock_update_classid(&sock->sk->sk_cgrp_data);
}
fd_install(new_fd, get_file(fp[i]));
}
if (i > 0)
{
int cmlen = CMSG_LEN(i*sizeof(int));
if (i > 0) {
int cmlen = CMSG_LEN(i * sizeof(int));
err = put_user(SOL_SOCKET, &cm->cmsg_level);
if (!err)
err = put_user(SCM_RIGHTS, &cm->cmsg_type);
if (!err)
err = put_user(cmlen, &cm->cmsg_len);
if (!err) {
cmlen = CMSG_SPACE(i*sizeof(int));
cmlen = CMSG_SPACE(i * sizeof(int));
if (msg->msg_controllen < cmlen)
cmlen = msg->msg_controllen;
msg->msg_control += cmlen;
msg->msg_controllen -= cmlen;
}
}
if (i < fdnum || (fdnum && fdmax <= 0))
if (i < scm->fp->count || (scm->fp->count && fdmax <= 0))
msg->msg_flags |= MSG_CTRUNC;
/*
* All of the files that fit in the message have had their
* usage counts incremented, so we just free the list.
* All of the files that fit in the message have had their usage counts
* incremented, so we just free the list.
*/
__scm_destroy(scm);
}