diff options
Diffstat (limited to 'arch/powerpc/include/asm/pkeys.h')
| -rw-r--r-- | arch/powerpc/include/asm/pkeys.h | 27 |
1 files changed, 21 insertions, 6 deletions
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 3312606fda07..20ebf153c871 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -13,7 +13,8 @@ DECLARE_STATIC_KEY_TRUE(pkey_disabled); extern int pkeys_total; /* total pkeys as per device tree */ -extern u32 initial_allocation_mask; /* bits set for reserved keys */ +extern u32 initial_allocation_mask; /* bits set for the initially allocated keys */ +extern u32 reserved_allocation_mask; /* bits set for reserved keys */ #define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \ VM_PKEY_BIT3 | VM_PKEY_BIT4) @@ -83,15 +84,19 @@ static inline u16 pte_to_pkey_bits(u64 pteflags) #define __mm_pkey_is_allocated(mm, pkey) \ (mm_pkey_allocation_map(mm) & pkey_alloc_mask(pkey)) -#define __mm_pkey_is_reserved(pkey) (initial_allocation_mask & \ +#define __mm_pkey_is_reserved(pkey) (reserved_allocation_mask & \ pkey_alloc_mask(pkey)) static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey) { - /* A reserved key is never considered as 'explicitly allocated' */ - return ((pkey < arch_max_pkey()) && - !__mm_pkey_is_reserved(pkey) && - __mm_pkey_is_allocated(mm, pkey)); + if (pkey < 0 || pkey >= arch_max_pkey()) + return false; + + /* Reserved keys are never allocated. */ + if (__mm_pkey_is_reserved(pkey)) + return false; + + return __mm_pkey_is_allocated(mm, pkey); } /* @@ -176,6 +181,16 @@ static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, { if (static_branch_likely(&pkey_disabled)) return -EINVAL; + + /* + * userspace should not change pkey-0 permissions. + * pkey-0 is associated with every page in the kernel. + * If userspace denies any permission on pkey-0, the + * kernel cannot operate. + */ + if (pkey == 0) + return init_val ? -EINVAL : 0; + return __arch_set_user_pkey_access(tsk, pkey, init_val); } |