diff options
author | Eric W. Biederman <ebiederm@xmission.com> | 2012-12-21 23:27:12 -0500 |
---|---|---|
committer | Eric W. Biederman <ebiederm@xmission.com> | 2012-12-25 19:10:05 -0500 |
commit | c876ad7682155958d0c9c27afe9017925c230d64 (patch) | |
tree | 926064bd7909f60daed3b6b963555e57cab7b520 /include/linux | |
parent | 8382fcac1b813ad0a4e68a838fc7ae93fa39eda0 (diff) |
pidns: Stop pid allocation when init dies
Oleg pointed out that in a pid namespace the sequence.
- pid 1 becomes a zombie
- setns(thepidns), fork,...
- reaping pid 1.
- The injected processes exiting.
Can lead to processes attempting access their child reaper and
instead following a stale pointer.
That waitpid for init can return before all of the processes in
the pid namespace have exited is also unfortunate.
Avoid these problems by disabling the allocation of new pids in a pid
namespace when init dies, instead of when the last process in a pid
namespace is reaped.
Pointed-out-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'include/linux')
-rw-r--r-- | include/linux/pid.h | 1 | ||||
-rw-r--r-- | include/linux/pid_namespace.h | 4 |
2 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/pid.h b/include/linux/pid.h index b152d44fb18..2381c973d89 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h | |||
@@ -121,6 +121,7 @@ int next_pidmap(struct pid_namespace *pid_ns, unsigned int last); | |||
121 | 121 | ||
122 | extern struct pid *alloc_pid(struct pid_namespace *ns); | 122 | extern struct pid *alloc_pid(struct pid_namespace *ns); |
123 | extern void free_pid(struct pid *pid); | 123 | extern void free_pid(struct pid *pid); |
124 | extern void disable_pid_allocation(struct pid_namespace *ns); | ||
124 | 125 | ||
125 | /* | 126 | /* |
126 | * ns_of_pid() returns the pid namespace in which the specified pid was | 127 | * ns_of_pid() returns the pid namespace in which the specified pid was |
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h index bf285999273..215e5e3dda1 100644 --- a/include/linux/pid_namespace.h +++ b/include/linux/pid_namespace.h | |||
@@ -21,7 +21,7 @@ struct pid_namespace { | |||
21 | struct kref kref; | 21 | struct kref kref; |
22 | struct pidmap pidmap[PIDMAP_ENTRIES]; | 22 | struct pidmap pidmap[PIDMAP_ENTRIES]; |
23 | int last_pid; | 23 | int last_pid; |
24 | int nr_hashed; | 24 | unsigned int nr_hashed; |
25 | struct task_struct *child_reaper; | 25 | struct task_struct *child_reaper; |
26 | struct kmem_cache *pid_cachep; | 26 | struct kmem_cache *pid_cachep; |
27 | unsigned int level; | 27 | unsigned int level; |
@@ -42,6 +42,8 @@ struct pid_namespace { | |||
42 | 42 | ||
43 | extern struct pid_namespace init_pid_ns; | 43 | extern struct pid_namespace init_pid_ns; |
44 | 44 | ||
45 | #define PIDNS_HASH_ADDING (1U << 31) | ||
46 | |||
45 | #ifdef CONFIG_PID_NS | 47 | #ifdef CONFIG_PID_NS |
46 | static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns) | 48 | static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns) |
47 | { | 49 | { |