On Mon, Jun 15, 2020 at 08:25:15PM -0700, Kees Cook wrote:
In preparation for users of the "install a received file" logic outside of net/ (pidfd and seccomp), relocate and rename __scm_install_fd() from net/core/scm.c to __fd_install_received() in fs/file.c, and provide a wrapper named fd_install_received_user(), as future patches will change the interface to __fd_install_received().
Signed-off-by: Kees Cook keescook@chromium.org
fs/file.c | 47 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/file.h | 8 ++++++++ include/net/scm.h | 1 - net/compat.c | 2 +- net/core/scm.c | 32 +----------------------------- 5 files changed, 57 insertions(+), 33 deletions(-)
diff --git a/fs/file.c b/fs/file.c index abb8b7081d7a..fcfddae0d252 100644 --- a/fs/file.c +++ b/fs/file.c @@ -11,6 +11,7 @@ #include <linux/export.h> #include <linux/fs.h> #include <linux/mm.h> +#include <linux/net.h> #include <linux/sched/signal.h> #include <linux/slab.h> #include <linux/file.h> @@ -18,6 +19,8 @@ #include <linux/bitops.h> #include <linux/spinlock.h> #include <linux/rcupdate.h> +#include <net/cls_cgroup.h> +#include <net/netprio_cgroup.h> unsigned int sysctl_nr_open __read_mostly = 1024*1024; unsigned int sysctl_nr_open_min = BITS_PER_LONG; @@ -931,6 +934,50 @@ int replace_fd(unsigned fd, struct file *file, unsigned flags) return err; } +/**
- __fd_install_received() - Install received file into file descriptor table
- @fd: fd to install into (if negative, a new fd will be allocated)
- @file: struct file that was received from another process
- @ufd_required: true to use @ufd for writing fd number to userspace
- @ufd: __user pointer to write new fd number to
- @o_flags: the O_* flags to apply to the new fd entry
Probably doesn't matter, but this function doesn't take the fd, or ufd_required argument in this patch.
- Installs a received file into the file descriptor table, with appropriate
- checks and count updates. Optionally writes the fd number to userspace.
ufd does not apppear options here.
- Returns -ve on error.
- */
+int __fd_install_received(struct file *file, int __user *ufd, unsigned 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 0;
+}
static int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags) { int err = -EBADF; diff --git a/include/linux/file.h b/include/linux/file.h index 122f80084a3e..fe18a1a0d555 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -91,6 +91,14 @@ extern void put_unused_fd(unsigned int fd); extern void fd_install(unsigned int fd, struct file *file); +extern int __fd_install_received(struct file *file, int __user *ufd,
unsigned int o_flags);+static inline int fd_install_received_user(struct file *file, int __user *ufd,
unsigned int o_flags)+{
- return __fd_install_received(file, ufd, o_flags);
+}
extern void flush_delayed_fput(void); extern void __fput_sync(struct file *); diff --git a/include/net/scm.h b/include/net/scm.h index 581a94d6c613..1ce365f4c256 100644 --- a/include/net/scm.h +++ b/include/net/scm.h @@ -37,7 +37,6 @@ struct scm_cookie { #endif }; -int __scm_install_fd(struct file *file, int __user *ufd, unsigned int o_flags); void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm); void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm); int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm); diff --git a/net/compat.c b/net/compat.c index 27d477fdcaa0..94f288e8dac5 100644 --- a/net/compat.c +++ b/net/compat.c @@ -298,7 +298,7 @@ void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm) int err = 0, i; for (i = 0; i < fdmax; i++) {
err = __scm_install_fd(scm->fp->fp[i], cmsg_data + i, o_flags);
err = fd_install_received_user(scm->fp->fp[i], cmsg_data + i, o_flags);diff --git a/net/core/scm.c b/net/core/scm.c index 6151678c73ed..df190f1fdd28 100644 --- a/net/core/scm.c +++ b/net/core/scm.c @@ -280,36 +280,6 @@ void put_cmsg_scm_timestamping(struct msghdr *msg, struct scm_timestamping_inter } EXPORT_SYMBOL(put_cmsg_scm_timestamping); -int __scm_install_fd(struct file *file, int __user *ufd, unsigned 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 0;
-}
static int scm_max_fds(struct msghdr *msg) { if (msg->msg_controllen <= sizeof(struct cmsghdr)) @@ -336,7 +306,7 @@ void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm) } for (i = 0; i < fdmax; i++) {
err = __scm_install_fd(scm->fp->fp[i], cmsg_data + i, o_flags);
err = fd_install_received_user(scm->fp->fp[i], cmsg_data + i, o_flags);-- 2.25.1