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57690554ab
Both __pkru_allows_write() and arch_set_user_pkey_access() shift
PKRU_WD_BIT (a signed constant) by up to 30 bits, hitting the
sign bit.
Use unsigned constants instead.
Clearly pkey 15 has not been used in combination with UBSAN yet.
Noticed by code inspection only. I can't actually provoke the
compiler into generating incorrect logic as far as this shift is
concerned.
[
dhansen: add stable@ tag, plus minor changelog massaging,
For anyone doing backports, these #defines were in
arch/x86/include/asm/pgtable.h before 784a46618f.
]
Fixes: 33a709b25a ("mm/gup, x86/mm/pkeys: Check VMAs and PTEs for protection keys")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20211216000856.4480-1-andrew.cooper3@citrix.com
63 lines
1.3 KiB
C
63 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_PKRU_H
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#define _ASM_X86_PKRU_H
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#include <asm/cpufeature.h>
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#define PKRU_AD_BIT 0x1u
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#define PKRU_WD_BIT 0x2u
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#define PKRU_BITS_PER_PKEY 2
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#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
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extern u32 init_pkru_value;
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#define pkru_get_init_value() READ_ONCE(init_pkru_value)
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#else
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#define init_pkru_value 0
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#define pkru_get_init_value() 0
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#endif
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static inline bool __pkru_allows_read(u32 pkru, u16 pkey)
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{
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int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY;
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return !(pkru & (PKRU_AD_BIT << pkru_pkey_bits));
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}
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static inline bool __pkru_allows_write(u32 pkru, u16 pkey)
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{
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int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY;
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/*
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* Access-disable disables writes too so we need to check
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* both bits here.
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*/
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return !(pkru & ((PKRU_AD_BIT|PKRU_WD_BIT) << pkru_pkey_bits));
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}
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static inline u32 read_pkru(void)
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{
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if (cpu_feature_enabled(X86_FEATURE_OSPKE))
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return rdpkru();
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return 0;
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}
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static inline void write_pkru(u32 pkru)
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{
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if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
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return;
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/*
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* WRPKRU is relatively expensive compared to RDPKRU.
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* Avoid WRPKRU when it would not change the value.
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*/
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if (pkru != rdpkru())
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wrpkru(pkru);
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}
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static inline void pkru_write_default(void)
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{
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if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
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return;
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wrpkru(pkru_get_init_value());
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}
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#endif
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