From: Thomas Gleixner <tglx@linutronix.de>
To: Xose Vazquez Perez <xose.vazquez@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>, x86 team <x86@kernel.org>
Subject: [PATCH] x86/mm: Prevent bogus warnings with "noexec=off"
Date: Mon, 15 Apr 2019 10:46:07 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1904151037530.1729@nanos.tec.linutronix.de> (raw)
In-Reply-To: <92ac69b8-7e29-50e1-f460-4e7ac8c6b7ac@gmail.com>
Xose reported warnings when NX is disabled on the kernel command line.
__early_set_fixmap() triggers:
attempted to set unsupported pgprot: 8000000000000163
bits: 8000000000000000
supported: 7fffffffffffffff
WARNING: CPU: 0 PID: 0 at arch/x86/include/asm/pgtable.h:537
__early_set_fixmap+0xa2/0xff
because it uses __default_kernel_pte_mask to mask out unsupported bits.
Use __supported_pte_mask instead.
Disabling NX on the command line also triggers the NX warning in the page
table mapping check:
WARNING: CPU: 1 PID: 1 at arch/x86/mm/dump_pagetables.c:262 note_page+0x2ae/0x650
....
Make the warning depend on NX set in __supported_pte_mask.
Reported-by: Xose Vazquez Perez <xose.vazquez@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/mm/dump_pagetables.c | 3 ++-
arch/x86/mm/ioremap.c | 2 +-
2 files changed, 3 insertions(+), 2 deletions(-)
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -259,7 +259,8 @@ static void note_wx(struct pg_state *st)
#endif
/* Account the WX pages */
st->wx_pages += npages;
- WARN_ONCE(1, "x86/mm: Found insecure W+X mapping at address %pS\n",
+ WARN_ONCE(__supported_pte_mask & _PAGE_NX,
+ "x86/mm: Found insecure W+X mapping at address %pS\n",
(void *)st->start_address);
}
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -825,7 +825,7 @@ void __init __early_set_fixmap(enum fixe
pte = early_ioremap_pte(addr);
/* Sanitize 'prot' against any unsupported bits: */
- pgprot_val(flags) &= __default_kernel_pte_mask;
+ pgprot_val(flags) &= __supported_pte_mask;
if (pgprot_val(flags))
set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
next prev parent reply other threads:[~2019-04-15 8:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-13 20:53 bug disabling NX (noexec=off) Xose Vazquez Perez
2019-04-14 9:59 ` Thomas Gleixner
2019-04-14 21:26 ` Xose Vazquez Perez
2019-04-15 8:46 ` Thomas Gleixner [this message]
2019-04-15 22:57 ` [PATCH] x86/mm: Prevent bogus warnings with "noexec=off" Xose Vazquez Perez
2019-04-16 7:46 ` [tip:x86/urgent] " tip-bot for Thomas Gleixner
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