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69ebc01824
This reverts commit 50e3ed0f93.
The SCTLR_EL1.WXN control forces execute-never when a page has write
permissions. While the idea of hardening such write/exec combinations is
good, with permissions indirection enabled (FEAT_PIE) this control
becomes RES0. FEAT_PIE introduces a slightly different form of WXN which
only has an effect when the base permission is RWX and the write is
toggled by the permission overlay (FEAT_POE, not yet supported by the
arm64 kernel). Revert the patch for now.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/ZfGESD3a91lxH367@arm.com
64 lines
1.7 KiB
C
64 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_MMAN_H__
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#define __ASM_MMAN_H__
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#include <linux/compiler.h>
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#include <linux/types.h>
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#include <uapi/asm/mman.h>
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static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
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unsigned long pkey __always_unused)
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{
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unsigned long ret = 0;
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if (system_supports_bti() && (prot & PROT_BTI))
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ret |= VM_ARM64_BTI;
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if (system_supports_mte() && (prot & PROT_MTE))
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ret |= VM_MTE;
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return ret;
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}
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#define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey)
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static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags)
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{
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/*
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* Only allow MTE on anonymous mappings as these are guaranteed to be
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* backed by tags-capable memory. The vm_flags may be overridden by a
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* filesystem supporting MTE (RAM-based).
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*/
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if (system_supports_mte() && (flags & MAP_ANONYMOUS))
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return VM_MTE_ALLOWED;
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return 0;
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}
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#define arch_calc_vm_flag_bits(flags) arch_calc_vm_flag_bits(flags)
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static inline bool arch_validate_prot(unsigned long prot,
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unsigned long addr __always_unused)
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{
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unsigned long supported = PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM;
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if (system_supports_bti())
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supported |= PROT_BTI;
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if (system_supports_mte())
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supported |= PROT_MTE;
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return (prot & ~supported) == 0;
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}
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#define arch_validate_prot(prot, addr) arch_validate_prot(prot, addr)
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static inline bool arch_validate_flags(unsigned long vm_flags)
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{
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if (!system_supports_mte())
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return true;
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/* only allow VM_MTE if VM_MTE_ALLOWED has been set previously */
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return !(vm_flags & VM_MTE) || (vm_flags & VM_MTE_ALLOWED);
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}
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#define arch_validate_flags(vm_flags) arch_validate_flags(vm_flags)
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#endif /* ! __ASM_MMAN_H__ */
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