Apply after "[PATCH] Fix NULL ->nsproxy dereference in /proc/*/mounts".
Similar to get_task_mm(): get a reference to task's mnt namespace if any.
Suggested by Pavel Emelianov.
Signed-off-by: Alexey Dobriyan <[email protected]>
---
fs/proc/base.c | 15 ++-------------
include/linux/nsproxy.h | 1 +
kernel/nsproxy.c | 14 ++++++++++++++
3 files changed, 17 insertions(+), 13 deletions(-)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -370,13 +370,7 @@ static int mounts_open(struct inode *ino
int ret = -EINVAL;
if (task) {
- task_lock(task);
- if (task->nsproxy) {
- ns = task->nsproxy->mnt_ns;
- if (ns)
- get_mnt_ns(ns);
- }
- task_unlock(task);
+ ns = get_task_mnt_ns(task);
put_task_struct(task);
}
@@ -443,12 +437,7 @@ static int mountstats_open(struct inode
struct task_struct *task = get_proc_task(inode);
if (task) {
- task_lock(task);
- if (task->nsproxy)
- mnt_ns = task->nsproxy->mnt_ns;
- if (mnt_ns)
- get_mnt_ns(mnt_ns);
- task_unlock(task);
+ mnt_ns = get_task_mnt_ns(task);
put_task_struct(task);
}
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -35,6 +35,7 @@ struct nsproxy *dup_namespaces(struct ns
int copy_namespaces(int flags, struct task_struct *tsk);
void get_task_namespaces(struct task_struct *tsk);
void free_nsproxy(struct nsproxy *ns);
+struct mnt_namespace * get_task_mnt_ns(struct task_struct *tsk);
static inline void put_nsproxy(struct nsproxy *ns)
{
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -147,3 +147,17 @@ void free_nsproxy(struct nsproxy *ns)
put_pid_ns(ns->pid_ns);
kfree(ns);
}
+
+struct mnt_namespace * get_task_mnt_ns(struct task_struct *tsk)
+{
+ struct mnt_namespace *mnt_ns = NULL;
+
+ task_lock(tsk);
+ if (tsk->nsproxy)
+ mnt_ns = tsk->nsproxy->mnt_ns;
+ if (mnt_ns)
+ get_mnt_ns(mnt_ns);
+ task_unlock(tsk);
+
+ return mnt_ns;
+}
Quoting Alexey Dobriyan ([email protected]):
> Apply after "[PATCH] Fix NULL ->nsproxy dereference in /proc/*/mounts".
>
> Similar to get_task_mm(): get a reference to task's mnt namespace if any.
> Suggested by Pavel Emelianov.
>
> Signed-off-by: Alexey Dobriyan <[email protected]>
Yeah, that's nicer, thanks.
Acked-by: Serge Hallyn <[email protected]>
> ---
>
> fs/proc/base.c | 15 ++-------------
> include/linux/nsproxy.h | 1 +
> kernel/nsproxy.c | 14 ++++++++++++++
> 3 files changed, 17 insertions(+), 13 deletions(-)
>
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -370,13 +370,7 @@ static int mounts_open(struct inode *ino
> int ret = -EINVAL;
>
> if (task) {
> - task_lock(task);
> - if (task->nsproxy) {
> - ns = task->nsproxy->mnt_ns;
> - if (ns)
> - get_mnt_ns(ns);
> - }
> - task_unlock(task);
> + ns = get_task_mnt_ns(task);
> put_task_struct(task);
> }
>
> @@ -443,12 +437,7 @@ static int mountstats_open(struct inode
> struct task_struct *task = get_proc_task(inode);
>
> if (task) {
> - task_lock(task);
> - if (task->nsproxy)
> - mnt_ns = task->nsproxy->mnt_ns;
> - if (mnt_ns)
> - get_mnt_ns(mnt_ns);
> - task_unlock(task);
> + mnt_ns = get_task_mnt_ns(task);
> put_task_struct(task);
> }
>
> --- a/include/linux/nsproxy.h
> +++ b/include/linux/nsproxy.h
> @@ -35,6 +35,7 @@ struct nsproxy *dup_namespaces(struct ns
> int copy_namespaces(int flags, struct task_struct *tsk);
> void get_task_namespaces(struct task_struct *tsk);
> void free_nsproxy(struct nsproxy *ns);
> +struct mnt_namespace * get_task_mnt_ns(struct task_struct *tsk);
>
> static inline void put_nsproxy(struct nsproxy *ns)
> {
> --- a/kernel/nsproxy.c
> +++ b/kernel/nsproxy.c
> @@ -147,3 +147,17 @@ void free_nsproxy(struct nsproxy *ns)
> put_pid_ns(ns->pid_ns);
> kfree(ns);
> }
> +
> +struct mnt_namespace * get_task_mnt_ns(struct task_struct *tsk)
> +{
> + struct mnt_namespace *mnt_ns = NULL;
> +
> + task_lock(tsk);
> + if (tsk->nsproxy)
> + mnt_ns = tsk->nsproxy->mnt_ns;
> + if (mnt_ns)
> + get_mnt_ns(mnt_ns);
> + task_unlock(tsk);
> +
> + return mnt_ns;
> +}
>
> -
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