linux-kernel - Re: [PATCHv11 3/9] efi/libstub: Implement support for unaccepted memory

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: <20230514211324.fymzoa263wx2hs2p@box.shutemov.name>
Date:   Mon, 15 May 2023 00:13:24 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Mika Penttilä <mpenttil@...hat.com>,
        Ard Biesheuvel <ardb@...nel.org>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Borislav Petkov <bp@...en8.de>,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...el.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Joerg Roedel <jroedel@...e.de>,
        Andi Kleen <ak@...ux.intel.com>,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        David Rientjes <rientjes@...gle.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Tom Lendacky <thomas.lendacky@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Ingo Molnar <mingo@...hat.com>,
        Dario Faggioli <dfaggioli@...e.com>,
        Mike Rapoport <rppt@...nel.org>,
        David Hildenbrand <david@...hat.com>,
        Mel Gorman <mgorman@...hsingularity.net>,
        marcelo.cerri@...onical.com, tim.gardner@...onical.com,
        khalid.elmously@...onical.com, philip.cox@...onical.com,
        aarcange@...hat.com, peterx@...hat.com, x86@...nel.org,
        linux-mm@...ck.org, linux-coco@...ts.linux.dev,
        linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv11 3/9] efi/libstub: Implement support for unaccepted
 memory

On Sun, May 14, 2023 at 08:08:07AM +0300, Mika Penttilä wrote:
> > +	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
> > +			     sizeof(*unaccepted_table) + bitmap_size,
> > +			     (void **)&unaccepted_table);
> 
> 
> Wonder if EFI_LOADER_DATA guarantees bitmap not to be freed, or should some
> more persistent type be used. If EFI_LOADER_DATA is enough, maybe a comment
> why it is safe could be added.

Ughh.. I've lost the hunk that reserves the memory explicitly while
folding in the patch we discussed with Ard. See below.

But the question is solid.

Ard, do we want to allocate the memory as EFI_RUNTIME_SERVICES_DATA (or
something else?) that got reserved automatically without additional steps?

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index e15a2005ed93..d817e7afd266 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -765,6 +765,25 @@ int __init efi_config_parse_tables(const efi_config_table_t *config_tables,
 		}
 	}
 
+	if (IS_ENABLED(CONFIG_UNACCEPTED_MEMORY) &&
+	    efi.unaccepted != EFI_INVALID_TABLE_ADDR) {
+		struct efi_unaccepted_memory *unaccepted;
+
+		unaccepted = early_memremap(efi.unaccepted, sizeof(*unaccepted));
+		if (unaccepted) {
+			unsigned long size;
+
+			if (unaccepted->version == 1) {
+				size = sizeof(*unaccepted) + unaccepted->size;
+				memblock_reserve(efi.unaccepted, size);
+			} else {
+				efi.unaccepted = EFI_INVALID_TABLE_ADDR;
+			}
+
+			early_memunmap(unaccepted, sizeof(*unaccepted));
+		}
+	}
+
 	return 0;
 }
 
-- 
  Kiryl Shutsemau / Kirill A. Shutemov