From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>
Cc: Ard Biesheuvel <ardb@kernel.org>,
linux-kernel@vger.kernel.org,
Anshuman Khandual <anshuman.khandual@arm.com>,
Arnd Bergmann <arnd@arndb.de>,
Dan Williams <dan.j.williams@intel.com>,
Dave Young <dyoung@redhat.com>,
Saravana Kannan <saravanak@google.com>
Subject: [PATCH 04/13] x86/mm: fix NX bit clearing issue in kernel_map_pages_in_pgd
Date: Mon, 13 Jan 2020 18:22:36 +0100 [thread overview]
Message-ID: <20200113172245.27925-5-ardb@kernel.org> (raw)
In-Reply-To: <20200113172245.27925-1-ardb@kernel.org>
Commit 15f003d20782 ("x86/mm/pat: Don't implicitly allow _PAGE_RW in
kernel_map_pages_in_pgd()") modified kernel_map_pages_in_pgd() to
manage writable permissions of memory mappings in the EFI page
table in a different way, but in the process, it removed the
ability to clear NX attributes from read-only mappings, by
clobbering the clear mask if _PAGE_RW is not being requested.
Failure to remove the NX attribute from read-only mappings is
unlikely to be a security issue, but it does prevent us from
tightening the permissions in the EFI page tables going forward,
so let's fix it now.
Fixes: 15f003d20782 ("x86/mm/pat: Don't implicitly allow _PAGE_RW in kernel_map_pages_in_pgd()
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/mm/pat/set_memory.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 20823392f4f2..62a8ebe72a52 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -2215,7 +2215,7 @@ int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address,
.pgd = pgd,
.numpages = numpages,
.mask_set = __pgprot(0),
- .mask_clr = __pgprot(0),
+ .mask_clr = __pgprot(~page_flags & (_PAGE_NX|_PAGE_RW)),
.flags = 0,
};
@@ -2224,12 +2224,6 @@ int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address,
if (!(__supported_pte_mask & _PAGE_NX))
goto out;
- if (!(page_flags & _PAGE_NX))
- cpa.mask_clr = __pgprot(_PAGE_NX);
-
- if (!(page_flags & _PAGE_RW))
- cpa.mask_clr = __pgprot(_PAGE_RW);
-
if (!(page_flags & _PAGE_ENC))
cpa.mask_clr = pgprot_encrypted(cpa.mask_clr);
--
2.20.1
next prev parent reply other threads:[~2020-01-13 17:23 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-13 17:22 [GIT PULL 00/13] More EFI updates for v5.6 Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 01/13] efi/libstub/x86: use const attribute for efi_is_64bit() Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 02/13] efi/libstub/x86: use mandatory 16-byte stack alignment in mixed mode Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 03/13] efi/libstub/x86: fix unused-variable warning Ard Biesheuvel
2020-01-13 17:22 ` Ard Biesheuvel [this message]
2020-01-13 17:22 ` [PATCH 05/13] efi/x86: don't map the entire kernel text RW for mixed mode Ard Biesheuvel
2020-04-08 10:42 ` Jiri Slaby
2020-04-08 10:47 ` Ard Biesheuvel
2020-04-08 10:51 ` Jiri Slaby
2020-04-09 7:51 ` Ard Biesheuvel
2020-04-09 8:06 ` Gary Lin
2020-04-09 8:10 ` Jiri Slaby
2020-04-09 8:19 ` Ard Biesheuvel
2020-04-09 8:34 ` Jiri Slaby
2020-04-09 9:09 ` Ard Biesheuvel
2020-04-09 9:45 ` Ard Biesheuvel
2020-04-09 10:09 ` Jiri Slaby
2020-04-09 10:45 ` Ard Biesheuvel
2020-04-09 11:08 ` Ard Biesheuvel
2020-04-09 11:25 ` Ard Biesheuvel
2020-04-09 11:32 ` Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 06/13] efi/x86: avoid RWX mappings for all of DRAM Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 07/13] efi/x86: limit EFI old memory map to SGI UV machines Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 08/13] efi/arm: defer probe of PCIe backed efifb on DT systems Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 09/13] efi: Fix comment for efi_mem_type() wrt absent physical addresses Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 10/13] efi: Add a flags parameter to efi_memory_map Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 11/13] efi: Add tracking for dynamically allocated memmaps Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 12/13] efi: Fix efi_memmap_alloc() leaks Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 13/13] efi: Fix handling of multiple efi_fake_mem= entries Ard Biesheuvel
2020-01-20 8:25 ` [GIT PULL 00/13] More EFI updates for v5.6 Ingo Molnar
2020-01-20 8:45 ` Ard Biesheuvel
2020-01-22 7:03 ` Ingo Molnar
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