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Groups > linux.kernel > #1291914
| From | Andy Lutomirski <luto@kernel.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 1/2] x86_32/mm: Set NX in __supported_pte_mask before enabling paging |
| Date | 2015-12-15 09:10 +0100 |
| Message-ID | <qFSQj-1nP-15@gated-at.bofh.it> (permalink) |
| References | <qFSGD-14V-13@gated-at.bofh.it> <qFSQj-1nP-17@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
There's a short window in which very early mappings can end up with
NX clear because they are created before we've noticed that we have
NX.
It turns out that we detect NX very early, so there's no need to
defer __supported_pte_mask setup.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/kernel/head_32.S | 6 ++++++
arch/x86/mm/setup_nx.c | 5 ++---
2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 6bc9ae24b6d2..57fc3f8c85fd 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -389,6 +389,12 @@ default_entry:
/* Make changes effective */
wrmsr
+ /*
+ * And make sure that all the mappings we set up have NX set from
+ * the beginning.
+ */
+ orl $(1 << (_PAGE_BIT_NX - 32)), pa(__supported_pte_mask + 4)
+
enable_paging:
/*
diff --git a/arch/x86/mm/setup_nx.c b/arch/x86/mm/setup_nx.c
index 90555bf60aa4..5095ecb0719c 100644
--- a/arch/x86/mm/setup_nx.c
+++ b/arch/x86/mm/setup_nx.c
@@ -31,9 +31,8 @@ early_param("noexec", noexec_setup);
void x86_configure_nx(void)
{
- if (cpu_has_nx && !disable_nx)
- __supported_pte_mask |= _PAGE_NX;
- else
+ /* If disable_nx is set, clear NX on all new mappings going forward. */
+ if (disable_nx)
__supported_pte_mask &= ~_PAGE_NX;
}
--
2.5.0
--
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Re: 4.4-rc5: ugly warn on: 5 W+X pages found Borislav Petkov <bp@alien8.de> - 2015-12-14 10:00 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Pavel Machek <pavel@ucw.cz> - 2015-12-14 10:10 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Borislav Petkov <bp@alien8.de> - 2015-12-14 10:20 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Linus Torvalds <torvalds@linux-foundation.org> - 2015-12-14 20:20 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Pavel Machek <pavel@ucw.cz> - 2015-12-14 21:30 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Andy Lutomirski <luto@amacapital.net> - 2015-12-14 22:10 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Arjan van de Ven <arjan@linux.intel.com> - 2015-12-14 22:30 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Andy Lutomirski <luto@amacapital.net> - 2015-12-14 23:30 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Pavel Machek <pavel@ucw.cz> - 2015-12-15 10:50 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Linus Torvalds <torvalds@linux-foundation.org> - 2015-12-15 18:50 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Borislav Petkov <bp@alien8.de> - 2015-12-15 19:40 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Linus Torvalds <torvalds@linux-foundation.org> - 2015-12-15 20:10 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Borislav Petkov <bp@alien8.de> - 2015-12-15 20:20 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Andy Lutomirski <luto@amacapital.net> - 2015-12-15 19:50 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Linus Torvalds <torvalds@linux-foundation.org> - 2015-12-15 20:10 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Pavel Machek <pavel@ucw.cz> - 2015-12-15 22:00 +0100
4.4.-rc5: lguest causes ugly warn on: 5 W+X pages found Pavel Machek <pavel@ucw.cz> - 2015-12-15 22:20 +0100
Re: 4.4.-rc5: lguest causes ugly warn on: 5 W+X pages found Rusty Russell <rusty@rustcorp.com.au> - 2015-12-16 03:30 +0100
Re: 4.4.-rc5: lguest causes ugly warn on: 5 W+X pages found Pavel Machek <pavel@ucw.cz> - 2015-12-16 09:20 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Borislav Petkov <bp@alien8.de> - 2015-12-15 22:40 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Pavel Machek <pavel@ucw.cz> - 2015-12-15 23:10 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Borislav Petkov <bp@alien8.de> - 2015-12-15 23:20 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Pavel Machek <pavel@ucw.cz> - 2015-12-15 09:00 +0100
[PATCH 1/2] x86_32/mm: Set NX in __supported_pte_mask before enabling paging Andy Lutomirski <luto@kernel.org> - 2015-12-15 09:10 +0100
[PATCH 2/2] x86/mm: Make kmap_prot into a #define Andy Lutomirski <luto@kernel.org> - 2015-12-15 09:10 +0100
[PATCH 0/2] x86/mm: A _PAGE_NX fixlet and a kmap cleanup Andy Lutomirski <luto@kernel.org> - 2015-12-15 09:10 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Arjan van de Ven <arjan@linux.intel.com> - 2015-12-15 14:40 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Pavel Machek <pavel@ucw.cz> - 2015-12-15 15:10 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found "H. Peter Anvin" <hpa@zytor.com> - 2015-12-15 17:30 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Pavel Machek <pavel@ucw.cz> - 2015-12-15 18:50 +0100
Re: 4.4-rc5: ugly warn on: 5 W+X pages found Pavel Machek <pavel@ucw.cz> - 2015-12-14 13:40 +0100
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