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authorEric W. Biederman <ebiederm@xmission.com>2012-08-02 15:25:10 +0400
committerEric W. Biederman <ebiederm@xmission.com>2012-11-19 17:57:31 +0400
commit49f4d8b93ccf9454284b6f524b96c66d8d7fbccc (patch)
tree06540b59a9d302687fd0519239729c1612d0e2b7 /kernel/pid_namespace.c
parentae06c7c83fc6e97ba247a261921c101960f3d28f (diff)
downloadlinux-49f4d8b93ccf9454284b6f524b96c66d8d7fbccc.tar.xz
pidns: Capture the user namespace and filter ns_last_pid
- Capture the the user namespace that creates the pid namespace - Use that user namespace to test if it is ok to write to /proc/sys/kernel/ns_last_pid. Zhao Hongjiang <zhaohongjiang@huawei.com> noticed I was missing a put_user_ns in when destroying a pid_ns. I have foloded his patch into this one so that bisects will work properly. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'kernel/pid_namespace.c')
-rw-r--r--kernel/pid_namespace.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 7b07cc0dfb75..b2604950aa50 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -10,6 +10,7 @@
#include <linux/pid.h>
#include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
#include <linux/syscalls.h>
#include <linux/err.h>
#include <linux/acct.h>
@@ -74,7 +75,8 @@ err_alloc:
/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
#define MAX_PID_NS_LEVEL 32
-static struct pid_namespace *create_pid_namespace(struct pid_namespace *parent_pid_ns)
+static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns,
+ struct pid_namespace *parent_pid_ns)
{
struct pid_namespace *ns;
unsigned int level = parent_pid_ns->level + 1;
@@ -102,6 +104,7 @@ static struct pid_namespace *create_pid_namespace(struct pid_namespace *parent_p
kref_init(&ns->kref);
ns->level = level;
ns->parent = get_pid_ns(parent_pid_ns);
+ ns->user_ns = get_user_ns(user_ns);
set_bit(0, ns->pidmap[0].page);
atomic_set(&ns->pidmap[0].nr_free, BITS_PER_PAGE - 1);
@@ -117,6 +120,7 @@ static struct pid_namespace *create_pid_namespace(struct pid_namespace *parent_p
out_put_parent_pid_ns:
put_pid_ns(parent_pid_ns);
+ put_user_ns(user_ns);
out_free_map:
kfree(ns->pidmap[0].page);
out_free:
@@ -131,16 +135,18 @@ static void destroy_pid_namespace(struct pid_namespace *ns)
for (i = 0; i < PIDMAP_ENTRIES; i++)
kfree(ns->pidmap[i].page);
+ put_user_ns(ns->user_ns);
kmem_cache_free(pid_ns_cachep, ns);
}
-struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns)
+struct pid_namespace *copy_pid_ns(unsigned long flags,
+ struct user_namespace *user_ns, struct pid_namespace *old_ns)
{
if (!(flags & CLONE_NEWPID))
return get_pid_ns(old_ns);
if (flags & (CLONE_THREAD|CLONE_PARENT))
return ERR_PTR(-EINVAL);
- return create_pid_namespace(old_ns);
+ return create_pid_namespace(user_ns, old_ns);
}
static void free_pid_ns(struct kref *kref)
@@ -239,9 +245,10 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
static int pid_ns_ctl_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
+ struct pid_namespace *pid_ns = task_active_pid_ns(current);
struct ctl_table tmp = *table;
- if (write && !capable(CAP_SYS_ADMIN))
+ if (write && !ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
/*
@@ -250,7 +257,7 @@ static int pid_ns_ctl_handler(struct ctl_table *table, int write,
* it should synchronize its usage with external means.
*/
- tmp.data = &current->nsproxy->pid_ns->last_pid;
+ tmp.data = &pid_ns->last_pid;
return proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
}