From: Ian Kent <ikent@redhat.com>
To: Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: "J. Bruce Fields" <bfields@fieldses.org>,
Oleg Nesterov <onestero@redhat.com>,
Stanislav Kinsbursky <skinsbursky@parallels.com>,
Trond Myklebust <trond.myklebust@primarydata.com>,
David Howells <dhowells@redhat.com>,
Benjamin Coddington <bcodding@redhat.com>,
Al Viro <viro@ZenIV.linux.org.uk>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: [RFC PATCH 3/4] kmod - add call_usermodehelper_ns() helper
Date: Tue, 25 Nov 2014 09:07:35 +0800 [thread overview]
Message-ID: <20141125010734.4974.85347.stgit@pluto.fritz.box> (raw)
In-Reply-To: <20141125005255.4974.54193.stgit@pluto.fritz.box>
The call_usermodehelper() function executes all binaries in the
global "init" root context. This doesn't allow a binary to be run
within the callers namespace (aka. a container). So create a new
function call_usermodehelper_ns() to do this.
Both containerized NFS client and NFS server need the ability to
execute a binary within their container. To do this create a new
nsproxy within the callers' context so it can be used for setup
prior to calling do_execve() from the user mode helper thread
runner.
Signed-off-by: Ian Kent <ikent@redhat.com>
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: Oleg Nesterov <onestero@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
---
include/linux/kmod.h | 17 +++++++++++++++++
kernel/kmod.c | 39 +++++++++++++++++++++++++++++++++++++++
2 files changed, 56 insertions(+)
diff --git a/include/linux/kmod.h b/include/linux/kmod.h
index 0555cc6..fd5509a 100644
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -69,6 +69,23 @@ struct subprocess_info {
extern int
call_usermodehelper(char *path, char **argv, char **envp, int wait);
+#if !defined(CONFIG_PROC_FS) || !defined(CONFIG_NAMESPACES)
+inline struct nsproxy *umh_open_ns(void)
+{
+ return NULL;
+}
+
+inline int
+call_usermodehelper_ns(char *path, char **argv, char **envp, int wait)
+{
+ return -ENOTSUP;
+}
+#else
+extern struct nsproxy *umh_open_ns(void);
+extern int
+call_usermodehelper_ns(char *path, char **argv, char **envp, int wait);
+#endif
+
extern struct subprocess_info *
call_usermodehelper_setup(char *path, char **argv, char **envp, gfp_t gfp_mask,
int (*init)(struct subprocess_info *info, struct cred *new),
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 80f7a6d..0ddcfbb 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -39,6 +39,7 @@
#include <linux/rwsem.h>
#include <linux/ptrace.h>
#include <linux/async.h>
+#include <linux/mount.h>
#include <asm/uaccess.h>
#include <trace/events/module.h>
@@ -642,6 +643,44 @@ int call_usermodehelper(char *path, char **argv, char **envp, int wait)
}
EXPORT_SYMBOL(call_usermodehelper);
+#if defined(CONFIG_PROC_FS) && defined(CONFIG_NAMESPACES)
+static int umh_set_ns(struct subprocess_info *info, struct cred *new)
+{
+ struct nsproxy *ns = info->data;
+
+ mntns_setfs(ns->mnt_ns);
+ switch_task_namespaces(current, ns);
+ return 0;
+}
+
+struct nsproxy *umh_open_ns(void)
+{
+ return create_new_namespaces(0, current, current_user_ns(), current->fs);
+}
+
+/* Call a usermode helper to execute within current namespace. */
+int call_usermodehelper_ns(char *path, char **argv, char **envp, int wait)
+{
+ struct subprocess_info *info;
+ struct nsproxy *ns;
+ gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;
+
+ ns = umh_open_ns();
+ if (IS_ERR(ns))
+ return PTR_ERR(ns);
+
+ info = call_usermodehelper_setup(path, argv, envp,
+ gfp_mask, umh_set_ns, NULL, ns);
+ if (!info) {
+ free_nsproxy(ns);
+ return -ENOMEM;
+ }
+
+ return call_usermodehelper_exec(info, wait);
+}
+EXPORT_SYMBOL(call_usermodehelper_ns);
+#endif
+
static int proc_cap_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
next prev parent reply other threads:[~2014-11-25 1:07 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-25 1:07 [RFC PATCH 0/4] Namespace contrained helper execution Ian Kent
2014-11-25 1:07 ` [RFC PATCH 1/4] vfs - fs/namespaces.c: break out mntns_setfs() from mntns_install() Ian Kent
2014-11-25 1:07 ` [RFC PATCH 2/4] nsproxy - make create_new_namespaces() non-static Ian Kent
2014-11-25 1:07 ` Ian Kent [this message]
2014-11-25 21:52 ` [RFC PATCH 3/4] kmod - add call_usermodehelper_ns() helper Oleg Nesterov
2014-11-25 22:06 ` Oleg Nesterov
2014-11-25 22:23 ` Eric W. Biederman
2014-11-25 23:07 ` Ian Kent
2014-11-25 23:19 ` Eric W. Biederman
2014-11-25 23:50 ` Ian Kent
2014-11-26 0:44 ` Ian Kent
2014-11-26 1:38 ` Eric W. Biederman
2014-12-01 21:56 ` Benjamin Coddington
2014-12-02 23:33 ` Ian Kent
2014-12-03 16:49 ` Eric W. Biederman
2014-12-03 18:14 ` Benjamin Coddington
2014-12-03 22:53 ` Ian Kent
2014-12-03 23:34 ` Ian Kent
2014-11-25 23:14 ` Ian Kent
2014-11-26 11:46 ` David Howells
2014-11-26 15:00 ` Eric W. Biederman
2014-11-26 22:57 ` J. Bruce Fields
2014-11-25 22:36 ` Ian Kent
2014-11-25 23:27 ` Eric W. Biederman
2014-11-28 0:19 ` Ian Kent
2014-11-27 1:30 ` Oleg Nesterov
2014-11-25 1:07 ` [RFC PATCH 4/4] KEYS: exec request-key within the requesting task's namespace Ian Kent
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