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=== Description (from pull-request) ===
Signed-off-by: Christian Brauner <[email protected]>
From 23e70c1e33e701bccbef40415ee368fe82456338 Mon Sep 17 00:00:00 2001
From: Christian Brauner <[email protected]>
Date: Sat, 30 Jun 2018 11:10:12 +0200
Subject: [PATCH 1/2] conf: simplify lxc_setup_dev_console()

Signed-off-by: Christian Brauner <[email protected]>
---
 src/lxc/conf.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index ebf32eac1..bb483522d 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -1238,7 +1238,6 @@ struct lxc_device_node {
 };
 
 static const struct lxc_device_node lxc_devices[] = {
-       { "console", S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 5 },
        { "full",    S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 7 },
        { "null",    S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 3 },
        { "random",  S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO, 1, 8 },
@@ -1648,7 +1647,7 @@ static int setup_personality(int persona)
 static int lxc_setup_dev_console(const struct lxc_rootfs *rootfs,
                                 const struct lxc_terminal *console)
 {
-       int fd, ret;
+       int ret;
        char path[MAXPATHLEN];
        char *rootfs_path = rootfs->path ? rootfs->mount : "";
 
@@ -1675,17 +1674,15 @@ static int lxc_setup_dev_console(const struct 
lxc_rootfs *rootfs,
        /* For unprivileged containers autodev or automounts will already have
         * taken care of creating /dev/console.
         */
-       fd = open(path, O_CREAT | O_EXCL, S_IXUSR | S_IXGRP | S_IXOTH);
-       if (fd < 0) {
+       ret = mknod(path, S_IFREG | 0000, 0);
+       if (ret < 0) {
                if (errno != EEXIST) {
                        SYSERROR("Failed to create console");
                        return -errno;
                }
-       } else {
-               close(fd);
        }
 
-       ret = chmod(console->name, S_IXUSR | S_IXGRP | S_IXOTH);
+       ret = fchmod(console->slave, S_IXUSR | S_IXGRP | S_IXOTH);
        if (ret < 0) {
                SYSERROR("Failed to set mode \"0%o\" to \"%s\"",
                         S_IXUSR | S_IXGRP | S_IXOTH, console->name);

From 56517cfd8b1fcd291a44679a8d420c614b1bd177 Mon Sep 17 00:00:00 2001
From: Christian Brauner <[email protected]>
Date: Sat, 30 Jun 2018 11:15:36 +0200
Subject: [PATCH 2/2] terminal: safely retrieve path of slave device

openpty() is a horrible function that uses strcpy() into the char *name
argument if name != NULL. We can't rely on the path being sane in all cases so
let's split out the name retrieval to ttyname_r().

Signed-off-by: Christian Brauner <[email protected]>
---
 src/lxc/terminal.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/lxc/terminal.c b/src/lxc/terminal.c
index 614c07a13..04c7dabad 100644
--- a/src/lxc/terminal.c
+++ b/src/lxc/terminal.c
@@ -570,13 +570,20 @@ static int lxc_terminal_peer_proxy_alloc(struct 
lxc_terminal *terminal,
        /* This is the proxy terminal that will be given to the client, and
         * that the real terminal master will send to / recv from.
         */
-       ret = openpty(&terminal->proxy.master, &terminal->proxy.slave,
-                     terminal->proxy.name, NULL, NULL);
+       ret = openpty(&terminal->proxy.master, &terminal->proxy.slave, NULL,
+                     NULL, NULL);
        if (ret < 0) {
                SYSERROR("Failed to open proxy terminal");
                return -1;
        }
 
+       ret = ttyname_r(terminal->proxy.slave, terminal->proxy.name,
+                       sizeof(terminal->proxy.name));
+       if (ret < 0) {
+               SYSERROR("Failed to retrieve name of proxy terminal slave");
+               return -1;
+       }
+
        ret = lxc_setup_tios(terminal->proxy.slave, &oldtermio);
        if (ret < 0)
                goto on_error;
@@ -862,12 +869,18 @@ int lxc_terminal_create(struct lxc_terminal *terminal)
 {
        int ret;
 
-       ret = openpty(&terminal->master, &terminal->slave, terminal->name, 
NULL, NULL);
+       ret = openpty(&terminal->master, &terminal->slave, NULL, NULL, NULL);
        if (ret < 0) {
                SYSERROR("Failed to open terminal");
                return -1;
        }
 
+       ret = ttyname_r(terminal->slave, terminal->name, 
sizeof(terminal->name));
+       if (ret < 0) {
+               SYSERROR("Failed to retrieve name of terminal slave");
+               return -1;
+       }
+
        ret = fcntl(terminal->master, F_SETFD, FD_CLOEXEC);
        if (ret < 0) {
                SYSERROR("Failed to set FD_CLOEXEC flag on terminal master");
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