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Groups > linux.kernel > #1291910
| From | Pavel Machek <pavel@ucw.cz> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: 4.4-rc5: ugly warn on: 5 W+X pages found |
| Date | 2015-12-15 09:00 +0100 |
| Message-ID | <qFSGD-14V-13@gated-at.bofh.it> (permalink) |
| References | (3 earlier) <qFxiN-43P-3@gated-at.bofh.it> <qFGP9-1UU-43@gated-at.bofh.it> <qFHUS-2Aa-7@gated-at.bofh.it> <qFIxA-34I-25@gated-at.bofh.it> <qFIQW-3c1-15@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Mon 2015-12-14 13:24:08, Arjan van de Ven wrote: > > >That's weird. The only API to do that seems to be manually setting > >kmap_prot to _PAGE_KERNEL_EXEC, and nothing does that. (Why is > >kmap_prot a variable on x86 at all? It has exactly one writer, and > >that's the code that initializes it in the first place. Shouldn't we > >#define kmap_prot _PAGE_KERNEL? > > iirc it changes based on runtime detection of NX capability Huh. Is it possible that core duo is so old that it has no NX? processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 14 model name : Genuine Intel(R) CPU T2400 @ 1.83GHz stepping : 8 microcode : 0x39 ... wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc arch_perfmon bts aperfmperf pni monitor vmx est tm2 xtpr pdcm dtherm No, it lists nx in flags. Linus asked me about trying without CONFIG_EFI. I should have no EFI here, but I'll try it. I turned off CONFIG_EFI, but CONFIG_UEFI_CPER can't seem to be disabled easily. Still: [ 3.269750] WARNING: CPU: 1 PID: 1 at arch/x86/mm/dump_pagetables.c:225 note_page+0x5ec/0x790() [ 3.271999] x86/mm: Found insecure W+X mapping at address ffe69000/0xffe69000 pavel@duo:~$ zcat /proc/config.gz | grep EFI # CONFIG_EFI_PARTITION is not set # CONFIG_EFI is not set CONFIG_DMI_SCAN_MACHINE_NON_EFI_FALLBACK=y CONFIG_UEFI_CPER=y pavel@duo:~$ Ok, I managed to turn off even CONFIG_UEFI_CPER after some fight, but result is the same. (Hmm... I'll probably regret it, but... I guess config.gz does contain some information useful for the attacker. How long till some "hardened distro" chmods it to 600?) Best regards, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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4.4-rc5: ugly warn on: 5 W+X pages found Pavel Machek <pavel@ucw.cz> - 2015-12-14 09:10 +0100
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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