From: Andrew Morton <akpm@linux-foundation.org>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: linux-kernel@vger.kernel.org, yeohc@au1.ibm.com, jann@thejh.net
Subject: Re: [PATCH] mm: relax ptrace mode in process_vm_readv(2)
Date: Mon, 5 Mar 2018 16:07:10 -0800 [thread overview]
Message-ID: <20180305160710.0ea9a6c0c4b784a457a48a2b@linux-foundation.org> (raw)
In-Reply-To: <20180303201116.GA10031@avx2>
On Sat, 3 Mar 2018 23:11:16 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:
> It is more natural to check for read-from-memory permissions in case of
> process_vm_readv() as PTRACE_MODE_ATTACH is equivalent to write
> permissions.
>
> ...
>
> --- a/mm/process_vm_access.c
> +++ b/mm/process_vm_access.c
> @@ -204,7 +204,7 @@ static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
> goto free_proc_pages;
> }
>
> - mm = mm_access(task, PTRACE_MODE_ATTACH_REALCREDS);
> + mm = mm_access(task, vm_write ? PTRACE_MODE_ATTACH_REALCREDS : PTRACE_MODE_READ_REALCREDS);
> if (!mm || IS_ERR(mm)) {
> rc = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
> /*
But what is the risk of breaking existing userspace?
next prev parent reply other threads:[~2018-03-06 0:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-03 20:11 Alexey Dobriyan
2018-03-06 0:07 ` Andrew Morton [this message]
2018-03-06 17:44 ` Alexey Dobriyan
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