Re: [PATCH] Remove READ_IMPLIES_EXEC during restart

[Oren Laadan <orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>]

Serge E. Hallyn wrote:
> Quoting Dan Smith (danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org):
>> On s390, all tasks have READ_IMPLIES_EXEC set in current->personality,
>> which causes the restart process to map things like the stack and heap as
>> executable.  During the restart process, remove this bit and restore the
>> original personality afterwards.
>>
>> This seems a little ugly, but I don't know that there's a better place for
>> it.
> 
> Well imo the only other thing to do would be to do the same thing but
> just around the main restart_memory function.
> 

I second that. Added.

Oren.


>> Cc: orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org
>> Signed-off-by: Dan Smith <danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
> 
> Acked-by: Serge Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
> 
>> ---
>>  checkpoint/restart.c |    7 +++++++
>>  1 files changed, 7 insertions(+), 0 deletions(-)
>>
>> diff --git a/checkpoint/restart.c b/checkpoint/restart.c
>> index adebc1c..8958ec7 100644
>> --- a/checkpoint/restart.c
>> +++ b/checkpoint/restart.c
>> @@ -13,6 +13,7 @@
>>  #include <linux/wait.h>
>>  #include <linux/file.h>
>>  #include <linux/magic.h>
>> +#include <linux/personality.h>
>>  #include <linux/checkpoint.h>
>>  #include <linux/checkpoint_hdr.h>
>>
>> @@ -535,12 +536,18 @@ static int do_restart_root(struct cr_ctx *ctx, pid_t pid)
>>  int do_restart(struct cr_ctx *ctx, pid_t pid)
>>  {
>>  	int ret;
>> +	unsigned int original_personality;
>> +	
>> +	original_personality = current->personality;
>> +	current->personality &= ~READ_IMPLIES_EXEC;
>>
>>  	if (ctx)
>>  		ret = do_restart_root(ctx, pid);
>>  	else
>>  		ret = do_restart_task(pid);
>>
>> +	current->personality = original_personality;
>> +
>>  	/* on success, adjust the return value if needed [TODO] */
>>  	return ret;
>>  }
>> -- 
>> 1.6.1
>>
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