| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20211118181210.281359-5-y.karadz@gmail.com>
Date: Thu, 18 Nov 2021 20:12:10 +0200
From: "Yordan Karadzhov (VMware)" <y.karadz@...il.com>
To: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Cc: viro@...iv.linux.org.uk, ebiederm@...ssion.com,
rostedt@...dmis.org, mingo@...hat.com, hagen@...u.net,
rppt@...nel.org, James.Bottomley@...senPartnership.com,
akpm@...ux-foundation.org, vvs@...tuozzo.com, shakeelb@...gle.com,
christian.brauner@...ntu.com, mkoutny@...e.com,
"Yordan Karadzhov (VMware)" <y.karadz@...il.com>
Subject: [RFC PATCH 4/4] namespacefs: Couple namespacefs to the UTS namespace
When the UTS namespace gets initialized, a directory called 'uts'
is added to namespacesfs. This directory represents the main UTS
namespace and also serves as a trunk (parent) of all other UTS
namespaces. Every time when a new UTS namespace is created a
corresponding directory is added to 'namespacefs/uts/'. The 'inum'
of the new namespace gives the name of its directory. When a UTS
namespace is destroyed the corresponding directory is removed. Each
directory contains a file called 'uname' that can be used to get the
unique data fields of the uts namespaces(sysname, nodename, ...).
Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@...il.com>
---
fs/namespacefs/inode.c | 57 +++++++++++++++++++++++++++++++++++++
include/linux/namespacefs.h | 13 +++++++++
kernel/utsname.c | 9 ++++++
3 files changed, 79 insertions(+)
diff --git a/fs/namespacefs/inode.c b/fs/namespacefs/inode.c
index 55d71733164c..4b661bdd4d9c 100644
--- a/fs/namespacefs/inode.c
+++ b/fs/namespacefs/inode.c
@@ -14,6 +14,7 @@
#include <linux/proc_ns.h>
#include <linux/seq_file.h>
#include <linux/pid_namespace.h>
+#include <linux/utsname.h>
static struct vfsmount *namespacefs_mount;
static int namespacefs_mount_count;
@@ -309,6 +310,58 @@ void namespacefs_remove_pid_ns_dir(struct pid_namespace *ns)
namespacefs_remove_dir(ns->ns.dentry);
}
+#define _UNAME_N_FIELDS 6
+#define _UNAME_MAX_LEN ((__NEW_UTS_LEN + 1) * _UNAME_N_FIELDS)
+
+static ssize_t uts_ns_read(struct file *file, char __user *ubuf,
+ size_t count, loff_t *pos)
+{
+ struct new_utsname *name = file->private_data;
+ char buff[_UNAME_MAX_LEN + 1];
+ int n;
+
+ n = snprintf(buff, _UNAME_MAX_LEN + 1,
+ "%s %s %s %s %s %s\n",
+ name->sysname,
+ name->nodename,
+ name->release,
+ name->version,
+ name->machine,
+ name->domainname);
+
+ return simple_read_from_buffer(ubuf, count, pos, buff, n);
+}
+
+static const struct file_operations uts_fops = {
+ .open = simple_open,
+ .read = uts_ns_read,
+ .llseek = default_llseek,
+};
+
+int namespacefs_create_uts_ns_dir(struct uts_namespace *ns)
+{
+ struct dentry *dentry;
+ int err;
+
+ err = create_inode_dir(&ns->ns, init_uts_ns.ns.dentry, ns->user_ns);
+ if (err)
+ return err;
+
+ dentry = namespacefs_create_file("uname", ns->ns.dentry, ns->user_ns,
+ &uts_fops, &ns->name);
+ if (IS_ERR(dentry)) {
+ dput(ns->ns.dentry);
+ return PTR_ERR(dentry);
+ }
+
+ return 0;
+}
+
+void namespacefs_remove_uts_ns_dir(struct uts_namespace *ns)
+{
+ namespacefs_remove_dir(ns->ns.dentry);
+}
+
static int add_ns_dentry(struct ns_common *ns)
{
struct dentry *dentry =
@@ -340,6 +393,10 @@ static int __init namespacefs_init(void)
if (err)
goto unreg;
+ err = add_ns_dentry(&init_uts_ns.ns);
+ if (err)
+ goto unreg;
+
return 0;
unreg:
diff --git a/include/linux/namespacefs.h b/include/linux/namespacefs.h
index f41499a7635a..3815a7bbeb1c 100644
--- a/include/linux/namespacefs.h
+++ b/include/linux/namespacefs.h
@@ -21,6 +21,8 @@ namespacefs_create_dir(const char *name, struct dentry *parent,
void namespacefs_remove_dir(struct dentry *dentry);
int namespacefs_create_pid_ns_dir(struct pid_namespace *ns);
void namespacefs_remove_pid_ns_dir(struct pid_namespace *ns);
+int namespacefs_create_uts_ns_dir(struct uts_namespace *ns);
+void namespacefs_remove_uts_ns_dir(struct uts_namespace *ns);
#else
@@ -55,6 +57,17 @@ namespacefs_remove_pid_ns_dir(struct pid_namespace *ns)
{
}
+static inline int
+namespacefs_create_uts_ns_dir(struct uts_namespace *ns)
+{
+ return 0;
+}
+
+static inline void
+namespacefs_remove_uts_ns_dir(struct uts_namespace *ns)
+{
+}
+
#endif /* CONFIG_NAMESPACE_FS */
#endif
diff --git a/kernel/utsname.c b/kernel/utsname.c
index b1ac3ca870f2..d44b307cffdc 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -12,6 +12,7 @@
#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/user_namespace.h>
+#include <linux/namespacefs.h>
#include <linux/proc_ns.h>
#include <linux/sched/task.h>
@@ -70,8 +71,15 @@ static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns,
memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
ns->user_ns = get_user_ns(user_ns);
up_read(&uts_sem);
+
+ err = namespacefs_create_uts_ns_dir(ns);
+ if (err)
+ goto fail_free_inum;
+
return ns;
+fail_free_inum:
+ ns_free_inum(&ns->ns);
fail_free:
kmem_cache_free(uts_ns_cache, ns);
fail_dec:
@@ -105,6 +113,7 @@ struct uts_namespace *copy_utsname(unsigned long flags,
void free_uts_ns(struct uts_namespace *ns)
{
+ namespacefs_remove_uts_ns_dir(ns);
dec_uts_namespaces(ns->ucounts);
put_user_ns(ns->user_ns);
ns_free_inum(&ns->ns);
--
2.33.1
Powered by blists - more mailing lists