Re: [PATCH 1/2] mm/madvise: introduce PR_MADV_SELF flag to process_madvise()
From: Arnd Bergmann
Date: Mon Sep 23 2024 - 17:50:48 EST
On Mon, Sep 23, 2024, at 19:34, Lorenzo Stoakes wrote:
> On Mon, Sep 23, 2024 at 11:56:06AM GMT, Shakeel Butt wrote:
>
> + /* Require PTRACE_MODE_READ to avoid leaking ASLR metadata. */
> + mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
> + if (IS_ERR_OR_NULL(mm)) {
> + ret = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
> + goto release_task;
> + }
Any chance we can fix mm_access() to not be able to return
a NULL pointer and an error pointer? IS_ERR_OR_NULL() is
usually an indication of a confusing API, and this is
clearly one of them, given that only one of the
callers actually wants the NULL value instead of -ESRCH.
Arnd