Re: + proc-fix-null-dereference-when-reading-proc-pid-auxv.patch added to -mm tree
From: Alexey Dobriyan
Date: Fri Oct 21 2016 - 09:44:14 EST
On Fri, Oct 21, 2016 at 6:13 AM, <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> Reading auxv of any kernel thread results in NULL pointer dereferencing in
> auxv_read() where mm can be NULL. Fix that by checking for NULL mm and
> bailing out early. This is also the original behavior changed by recent
> commit c5317167854e ("proc: switch auxv to use of __mem_open()").
> --- a/fs/proc/base.c~proc-fix-null-dereference-when-reading-proc-pid-auxv
> +++ a/fs/proc/base.c
> @@ -1014,6 +1014,9 @@ static ssize_t auxv_read(struct file *fi
> struct mm_struct *mm = file->private_data;
> unsigned int nwords = 0;
> + if (!mm)
> + return 0;
Rhetorical question: who wrote such clever __mem_open() ?