2679f9bd0a
This patch adds Kernel Userspace Access Protection on the 8xx. When a page is RO or RW, it is set RO or RW for Key 0 and NA for Key 1. Up to now, the User group is defined with Key 0 for both User and Supervisor. By changing the group to Key 0 for User and Key 1 for Supervisor, this patch prevents the Kernel from being able to access user data. At exception entry, the kernel saves SPRN_MD_AP in the regs struct, and reapply the protection. At exception exit it restores SPRN_MD_AP with the value saved on exception entry. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> [mpe: Drop allow_read/write_to/from_user() as they're now in kup.h] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
71 lines
1.6 KiB
C
71 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_KUP_H_
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#define _ASM_POWERPC_KUP_H_
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#ifdef CONFIG_PPC64
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#include <asm/book3s/64/kup-radix.h>
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#endif
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#ifdef CONFIG_PPC_8xx
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#include <asm/nohash/32/kup-8xx.h>
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#endif
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#ifdef __ASSEMBLY__
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#ifndef CONFIG_PPC_KUAP
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.macro kuap_save_and_lock sp, thread, gpr1, gpr2, gpr3
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.endm
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.macro kuap_restore sp, current, gpr1, gpr2, gpr3
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.endm
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.macro kuap_check current, gpr
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.endm
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#endif
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#else /* !__ASSEMBLY__ */
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#include <asm/pgtable.h>
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void setup_kup(void);
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#ifdef CONFIG_PPC_KUEP
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void setup_kuep(bool disabled);
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#else
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static inline void setup_kuep(bool disabled) { }
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#endif /* CONFIG_PPC_KUEP */
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#ifdef CONFIG_PPC_KUAP
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void setup_kuap(bool disabled);
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#else
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static inline void setup_kuap(bool disabled) { }
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static inline void allow_user_access(void __user *to, const void __user *from,
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unsigned long size) { }
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static inline void prevent_user_access(void __user *to, const void __user *from,
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unsigned long size) { }
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static inline bool bad_kuap_fault(struct pt_regs *regs, bool is_write) { return false; }
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#endif /* CONFIG_PPC_KUAP */
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static inline void allow_read_from_user(const void __user *from, unsigned long size)
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{
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allow_user_access(NULL, from, size);
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}
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static inline void allow_write_to_user(void __user *to, unsigned long size)
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{
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allow_user_access(to, NULL, size);
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}
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static inline void prevent_read_from_user(const void __user *from, unsigned long size)
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{
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prevent_user_access(NULL, from, size);
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}
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static inline void prevent_write_to_user(void __user *to, unsigned long size)
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{
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prevent_user_access(to, NULL, size);
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}
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#endif /* !__ASSEMBLY__ */
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#endif /* _ASM_POWERPC_KUP_H_ */
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