[v2,04/20] fork: provide a function for copying init_mm
diff mbox series

Message ID 20190129003422.9328-5-rick.p.edgecombe@intel.com
State New
Headers show
Series
  • Merge text_poke fixes and executable lockdowns
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Commit Message

Edgecombe, Rick P Jan. 29, 2019, 12:34 a.m. UTC
From: Nadav Amit <namit@vmware.com>

Provide a function for copying init_mm. This function will be later used
for setting a temporary mm.

Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
 include/linux/sched/task.h |  1 +
 kernel/fork.c              | 24 ++++++++++++++++++------
 2 files changed, 19 insertions(+), 6 deletions(-)

Comments

Borislav Petkov Feb. 5, 2019, 8:53 a.m. UTC | #1
On Mon, Jan 28, 2019 at 04:34:06PM -0800, Rick Edgecombe wrote:
> From: Nadav Amit <namit@vmware.com>
> 
> Provide a function for copying init_mm. This function will be later used
> for setting a temporary mm.
> 
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Dave Hansen <dave.hansen@intel.com>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
> Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
> Signed-off-by: Nadav Amit <namit@vmware.com>
> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
> ---
>  include/linux/sched/task.h |  1 +
>  kernel/fork.c              | 24 ++++++++++++++++++------
>  2 files changed, 19 insertions(+), 6 deletions(-)
> 
> diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
> index 44c6f15800ff..c5a00a7b3beb 100644
> --- a/include/linux/sched/task.h
> +++ b/include/linux/sched/task.h
> @@ -76,6 +76,7 @@ extern void exit_itimers(struct signal_struct *);
>  extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long);
>  extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
>  struct task_struct *fork_idle(int);
> +struct mm_struct *copy_init_mm(void);
>  extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
>  extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
>  
> diff --git a/kernel/fork.c b/kernel/fork.c
> index b69248e6f0e0..d7b156c49f29 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -1299,13 +1299,20 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
>  		complete_vfork_done(tsk);
>  }
>  
> -/*
> - * Allocate a new mm structure and copy contents from the
> - * mm structure of the passed in task structure.
> +/**
> + * dup_mm() - duplicates an existing mm structure
> + * @tsk: the task_struct with which the new mm will be associated.
> + * @oldmm: the mm to duplicate.
> + *
> + * Allocates a new mm structure and copy contents from the provided

s/copy/copies/
Nadav Amit Feb. 5, 2019, 9:03 a.m. UTC | #2
> On Feb 5, 2019, at 12:53 AM, Borislav Petkov <bp@alien8.de> wrote:
> 
> On Mon, Jan 28, 2019 at 04:34:06PM -0800, Rick Edgecombe wrote:
>> From: Nadav Amit <namit@vmware.com>
>> 
>> - * Allocate a new mm structure and copy contents from the
>> - * mm structure of the passed in task structure.
>> +/**
>> + * dup_mm() - duplicates an existing mm structure
>> + * @tsk: the task_struct with which the new mm will be associated.
>> + * @oldmm: the mm to duplicate.
>> + *
>> + * Allocates a new mm structure and copy contents from the provided
> 
> s/copy/copies/

Thanks, applied (I revised this sentence a bit).

Patch
diff mbox series

diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index 44c6f15800ff..c5a00a7b3beb 100644
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -76,6 +76,7 @@  extern void exit_itimers(struct signal_struct *);
 extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long);
 extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
 struct task_struct *fork_idle(int);
+struct mm_struct *copy_init_mm(void);
 extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
 
diff --git a/kernel/fork.c b/kernel/fork.c
index b69248e6f0e0..d7b156c49f29 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1299,13 +1299,20 @@  void mm_release(struct task_struct *tsk, struct mm_struct *mm)
 		complete_vfork_done(tsk);
 }
 
-/*
- * Allocate a new mm structure and copy contents from the
- * mm structure of the passed in task structure.
+/**
+ * dup_mm() - duplicates an existing mm structure
+ * @tsk: the task_struct with which the new mm will be associated.
+ * @oldmm: the mm to duplicate.
+ *
+ * Allocates a new mm structure and copy contents from the provided
+ * @oldmm structure.
+ *
+ * Return: the duplicated mm or NULL on failure.
  */
-static struct mm_struct *dup_mm(struct task_struct *tsk)
+static struct mm_struct *dup_mm(struct task_struct *tsk,
+				struct mm_struct *oldmm)
 {
-	struct mm_struct *mm, *oldmm = current->mm;
+	struct mm_struct *mm;
 	int err;
 
 	mm = allocate_mm();
@@ -1372,7 +1379,7 @@  static int copy_mm(unsigned long clone_flags, struct task_struct *tsk)
 	}
 
 	retval = -ENOMEM;
-	mm = dup_mm(tsk);
+	mm = dup_mm(tsk, current->mm);
 	if (!mm)
 		goto fail_nomem;
 
@@ -2187,6 +2194,11 @@  struct task_struct *fork_idle(int cpu)
 	return task;
 }
 
+struct mm_struct *copy_init_mm(void)
+{
+	return dup_mm(NULL, &init_mm);
+}
+
 /*
  *  Ok, this is the main fork-routine.
  *