The ARMv8 64-bit architecture supports execute-only user permissions by clearing the PTE_USER and PTE_UXN bits, practically making it a mostly privileged mapping but from which user running at EL0 can still execute. The downside, however, is that the kernel at EL1 inadvertently reading such mapping would not trip over the PAN (privileged access never) protection. Revert the relevant bits from commitcab15ce604("arm64: Introduce execute-only page access permissions") so that PROT_EXEC implies PROT_READ (and therefore PTE_USER) until the architecture gains proper support for execute-only user mappings. Fixes:cab15ce604("arm64: Introduce execute-only page access permissions") Cc: <stable@vger.kernel.org> # 4.9.x- Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
110 lines
4.3 KiB
C
110 lines
4.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2016 ARM Ltd.
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*/
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#ifndef __ASM_PGTABLE_PROT_H
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#define __ASM_PGTABLE_PROT_H
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#include <asm/memory.h>
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#include <asm/pgtable-hwdef.h>
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#include <linux/const.h>
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/*
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* Software defined PTE bits definition.
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*/
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#define PTE_WRITE (PTE_DBM) /* same as DBM (51) */
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#define PTE_DIRTY (_AT(pteval_t, 1) << 55)
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#define PTE_SPECIAL (_AT(pteval_t, 1) << 56)
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#define PTE_DEVMAP (_AT(pteval_t, 1) << 57)
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#define PTE_PROT_NONE (_AT(pteval_t, 1) << 58) /* only when !PTE_VALID */
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#ifndef __ASSEMBLY__
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#include <asm/pgtable-types.h>
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#define _PROT_DEFAULT (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
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#define _PROT_SECT_DEFAULT (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
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#define PTE_MAYBE_NG (arm64_kernel_use_ng_mappings() ? PTE_NG : 0)
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#define PMD_MAYBE_NG (arm64_kernel_use_ng_mappings() ? PMD_SECT_NG : 0)
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#define PROT_DEFAULT (_PROT_DEFAULT | PTE_MAYBE_NG)
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#define PROT_SECT_DEFAULT (_PROT_SECT_DEFAULT | PMD_MAYBE_NG)
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#define PROT_DEVICE_nGnRnE (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_WRITE | PTE_ATTRINDX(MT_DEVICE_nGnRnE))
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#define PROT_DEVICE_nGnRE (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_WRITE | PTE_ATTRINDX(MT_DEVICE_nGnRE))
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#define PROT_NORMAL_NC (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_WRITE | PTE_ATTRINDX(MT_NORMAL_NC))
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#define PROT_NORMAL_WT (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_WRITE | PTE_ATTRINDX(MT_NORMAL_WT))
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#define PROT_NORMAL (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_WRITE | PTE_ATTRINDX(MT_NORMAL))
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#define PROT_SECT_DEVICE_nGnRE (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_DEVICE_nGnRE))
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#define PROT_SECT_NORMAL (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
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#define PROT_SECT_NORMAL_EXEC (PROT_SECT_DEFAULT | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
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#define _PAGE_DEFAULT (_PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL))
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#define _HYP_PAGE_DEFAULT _PAGE_DEFAULT
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#define PAGE_KERNEL __pgprot(PROT_NORMAL)
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#define PAGE_KERNEL_RO __pgprot((PROT_NORMAL & ~PTE_WRITE) | PTE_RDONLY)
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#define PAGE_KERNEL_ROX __pgprot((PROT_NORMAL & ~(PTE_WRITE | PTE_PXN)) | PTE_RDONLY)
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#define PAGE_KERNEL_EXEC __pgprot(PROT_NORMAL & ~PTE_PXN)
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#define PAGE_KERNEL_EXEC_CONT __pgprot((PROT_NORMAL & ~PTE_PXN) | PTE_CONT)
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#define PAGE_HYP __pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_HYP_XN)
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#define PAGE_HYP_EXEC __pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY)
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#define PAGE_HYP_RO __pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY | PTE_HYP_XN)
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#define PAGE_HYP_DEVICE __pgprot(PROT_DEVICE_nGnRE | PTE_HYP)
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#define PAGE_S2_MEMATTR(attr) \
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({ \
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u64 __val; \
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if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) \
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__val = PTE_S2_MEMATTR(MT_S2_FWB_ ## attr); \
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else \
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__val = PTE_S2_MEMATTR(MT_S2_ ## attr); \
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__val; \
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})
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#define PAGE_S2_XN \
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({ \
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u64 __val; \
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if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC)) \
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__val = 0; \
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else \
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__val = PTE_S2_XN; \
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__val; \
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})
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#define PAGE_S2 __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(NORMAL) | PTE_S2_RDONLY | PAGE_S2_XN)
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#define PAGE_S2_DEVICE __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_S2_XN)
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#define PAGE_NONE __pgprot(((_PAGE_DEFAULT) & ~PTE_VALID) | PTE_PROT_NONE | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN)
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/* shared+writable pages are clean by default, hence PTE_RDONLY|PTE_WRITE */
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#define PAGE_SHARED __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)
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#define PAGE_SHARED_EXEC __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_WRITE)
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#define PAGE_READONLY __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN)
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#define PAGE_READONLY_EXEC __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN)
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#define __P000 PAGE_NONE
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#define __P001 PAGE_READONLY
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#define __P010 PAGE_READONLY
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#define __P011 PAGE_READONLY
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#define __P100 PAGE_READONLY_EXEC
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#define __P101 PAGE_READONLY_EXEC
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#define __P110 PAGE_READONLY_EXEC
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#define __P111 PAGE_READONLY_EXEC
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#define __S000 PAGE_NONE
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#define __S001 PAGE_READONLY
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#define __S010 PAGE_SHARED
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#define __S011 PAGE_SHARED
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#define __S100 PAGE_READONLY_EXEC
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#define __S101 PAGE_READONLY_EXEC
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#define __S110 PAGE_SHARED_EXEC
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#define __S111 PAGE_SHARED_EXEC
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_PGTABLE_PROT_H */
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