linux-hardening - Re: [PATCH v1 1/2] mseal: fix mmap(FIXED) error code.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <jxov546uro5lffibw5asff3m25pfnondbp3nrqc3fde322h3on@ypkdkju4xaho>
Date: Thu, 29 Aug 2024 00:38:19 +0100
From: Pedro Falcato <pedro.falcato@...il.com>
To: jeffxu@...omium.org
Cc: akpm@...ux-foundation.org, linux-kselftest@...r.kernel.org, 
	linux-mm@...ck.org, linux-hardening@...r.kernel.org, rientjes@...gle.com, 
	keescook@...omium.org, Liam.Howlett@...cle.com, vbabka@...e.cz, 
	lorenzo.stoakes@...cle.com
Subject: Re: [PATCH v1 1/2] mseal: fix mmap(FIXED) error code.

+CC vma reviewers
On Wed, Aug 28, 2024 at 10:55:21PM GMT, jeffxu@...omium.org wrote:
> From: Jeff Xu <jeffxu@...omium.org>
> 
> mmap(MAP_FIXED) should return EPERM when memory is sealed.
> 
> Fixes: 4205a39e06da ("mm/munmap: replace can_modify_mm with can_modify_vma")

Thank you for the patch!
This Fixes: is wrong, the bug was added during Liam's rebasing of his munmap patch
set on mine.

> Signed-off-by: Jeff Xu <jeffxu@...omium.org>
> ---
>  mm/mmap.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 80d70ed099cf..0cd0c0ef03c7 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1386,7 +1386,10 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
>  		mt_on_stack(mt_detach);
>  		mas_init(&mas_detach, &mt_detach, /* addr = */ 0);
>  		/* Prepare to unmap any existing mapping in the area */
> -		if (vms_gather_munmap_vmas(&vms, &mas_detach))
> +		error = vms_gather_munmap_vmas(&vms, &mas_detach);
> +		if (error == -EPERM)
> +			return -EPERM;

Not sure if it makes sense to special case this. We should probably deal with this inside
vms_gather_munmap_vmas and just pass through the error we get.

Otherwise LGTM. Liam?

(we should also squash this into the offending commit)

-- 
Pedro