linux-kernel - Re: [PATCH 2/3] mm: update core kernel code to use vm_flags

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] [day] [month] [year] [list]

Message-ID: <202508251436.762035B@keescook>
Date: Mon, 25 Aug 2025 14:37:11 -0700
From: Kees Cook <kees@...nel.org>
To: Uladzislau Rezki <urezki@...il.com>
Cc: Mike Rapoport <rppt@...nel.org>,
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
	Harry Yoo <harry.yoo@...cle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Russell King <linux@...linux.org.uk>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	Madhavan Srinivasan <maddy@...ux.ibm.com>,
	Michael Ellerman <mpe@...erman.id.au>,
	Nicholas Piggin <npiggin@...il.com>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	"David S . Miller" <davem@...emloft.net>,
	Andreas Larsson <andreas@...sler.com>,
	Jarkko Sakkinen <jarkko@...nel.org>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
	"H . Peter Anvin" <hpa@...or.com>,
	Andy Lutomirski <luto@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
	Peter Xu <peterx@...hat.com>, David Hildenbrand <david@...hat.com>,
	Zi Yan <ziy@...dia.com>,
	Baolin Wang <baolin.wang@...ux.alibaba.com>,
	"Liam R . Howlett" <Liam.Howlett@...cle.com>,
	Nico Pache <npache@...hat.com>, Ryan Roberts <ryan.roberts@....com>,
	Dev Jain <dev.jain@....com>, Barry Song <baohua@...nel.org>,
	Xu Xin <xu.xin16@....com.cn>,
	Chengming Zhou <chengming.zhou@...ux.dev>,
	Hugh Dickins <hughd@...gle.com>, Vlastimil Babka <vbabka@...e.cz>,
	Suren Baghdasaryan <surenb@...gle.com>,
	Michal Hocko <mhocko@...e.com>, Rik van Riel <riel@...riel.com>,
	Dan Williams <dan.j.williams@...el.com>,
	Matthew Wilcox <willy@...radead.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Masami Hiramatsu <mhiramat@...nel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	Jason Gunthorpe <jgg@...pe.ca>, John Hubbard <jhubbard@...dia.com>,
	Muchun Song <muchun.song@...ux.dev>,
	Oscar Salvador <osalvador@...e.de>, Jann Horn <jannh@...gle.com>,
	Pedro Falcato <pfalcato@...e.de>,
	Johannes Weiner <hannes@...xchg.org>,
	Qi Zheng <zhengqi.arch@...edance.com>,
	Shakeel Butt <shakeel.butt@...ux.dev>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org, kvm@...r.kernel.org,
	sparclinux@...r.kernel.org, linux-sgx@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, linux-mm@...ck.org,
	nvdimm@...ts.linux.dev, linux-trace-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] mm: update core kernel code to use vm_flags_t
 consistently

On Tue, Aug 05, 2025 at 06:13:56PM +0200, Uladzislau Rezki wrote:
> I agree. Also it can be even moved under vmalloc.c. There is only one
> user which needs it globally, it is usercopy.c. It uses find_vmap_area()
> which is wrong. See:
> 
> <snip>
> 	if (is_vmalloc_addr(ptr) && !pagefault_disabled()) {
> 		struct vmap_area *area = find_vmap_area(addr);
> 
> 		if (!area)
> 			usercopy_abort("vmalloc", "no area", to_user, 0, n);
> 
> 		if (n > area->va_end - addr) {
> 			offset = addr - area->va_start;
> 			usercopy_abort("vmalloc", NULL, to_user, offset, n);
> 		}
> 		return;
> 	}
> <snip>
> 
> we can add a function which just assign va_start, va_end as input
> parameters and use them in the usercopy.c. 

Yes please! I'd must rather use some exported validation routine than
having it hand-coded in usercopy.c. :)

-- 
Kees Cook