From cca98e9f8b5ebcd9640846a675172578249b11a0 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Mon, 1 Jun 2020 21:51:32 -0700
Subject: [PATCH] mm: enforce that vmap can't map pages executable
To help enforcing the W^X protection don't allow remapping existing pages
as executable.
x86 bits from Peter Zijlstra, arm64 bits from Mark Rutland.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Mark Rutland <mark.rutland@arm.com>.
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-20-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
arch/arm64/include/asm/pgtable.h | 3 +++
arch/x86/include/asm/pgtable_types.h | 6 ++++++
include/asm-generic/pgtable.h | 4 ++++
mm/vmalloc.c | 2 +-
4 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 538c85e62f86..47095216d6a8 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -407,6 +407,9 @@ static inline pmd_t pmd_mkdevmap(pmd_t pmd)
#define __pgprot_modify(prot,mask,bits) \
__pgprot((pgprot_val(prot) & ~(mask)) | (bits))
+#define pgprot_nx(prot) \
+ __pgprot_modify(prot, 0, PTE_PXN)
+
/*
* Mark the prot value as uncacheable and unbufferable.
*/
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 947867f112ea..2e7c442cc618 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -282,6 +282,12 @@ typedef struct pgprot { pgprotval_t pgprot; } pgprot_t;
typedef struct { pgdval_t pgd; } pgd_t;
+static inline pgprot_t pgprot_nx(pgprot_t prot)
+{
+ return __pgprot(pgprot_val(prot) | _PAGE_NX);
+}
+#define pgprot_nx pgprot_nx
+
#ifdef CONFIG_X86_PAE
/*
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 329b8c8ca703..8c5f9c29698b 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -491,6 +491,10 @@ static inline int arch_unmap_one(struct mm_struct *mm,
#define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
#endif
+#ifndef pgprot_nx
+#define pgprot_nx(prot) (prot)
+#endif
+
#ifndef pgprot_noncached
#define pgprot_noncached(prot) (prot)
#endif
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 9848156a1c6a..4d7c7108181a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2391,7 +2391,7 @@ void *vmap(struct page **pages, unsigned int count,
if (!area)
return NULL;
- if (map_kernel_range((unsigned long)area->addr, size, prot,
+ if (map_kernel_range((unsigned long)area->addr, size, pgprot_nx(prot),
pages) < 0) {
vunmap(area->addr);
return NULL;