diff options
| author | Ram Pai <linuxram@us.ibm.com> | 2018-07-17 06:51:04 -0700 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-07-24 21:34:08 +1000 |
| commit | 4a4a5e5d2aadc793be95024f454cf511d115b62d (patch) | |
| tree | 49417dd127929898f5929e9ef2caa200586cf4e6 /arch/powerpc/include/asm/pkeys.h | |
| parent | de113256f8c1c24d8c79ae388bf2a5abd70f7577 (diff) | |
powerpc/pkeys: key allocation/deallocation must not change pkey registers
Key allocation and deallocation has the side effect of programming the
UAMOR/AMR/IAMR registers. This is wrong, since its the responsibility of
the application and not that of the kernel, to modify the permission on
the key.
Do not modify the pkey registers at key allocation/deallocation.
This patch also fixes a bug where a sys_pkey_free() resets the UAMOR
bits of the key, thus making its permissions unmodifiable from user
space. Later if the same key gets reallocated from a different thread
this thread will no longer be able to change the permissions on the key.
Fixes: cf43d3b26452 ("powerpc: Enable pkey subsystem")
Cc: stable@vger.kernel.org # v4.16+
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm/pkeys.h')
| -rw-r--r-- | arch/powerpc/include/asm/pkeys.h | 11 |
1 files changed, 0 insertions, 11 deletions
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 5ba80cffb505..3312606fda07 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -94,8 +94,6 @@ static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey) __mm_pkey_is_allocated(mm, pkey)); } -extern void __arch_activate_pkey(int pkey); -extern void __arch_deactivate_pkey(int pkey); /* * Returns a positive, 5-bit key on success, or -1 on failure. * Relies on the mmap_sem to protect against concurrency in mm_pkey_alloc() and @@ -124,11 +122,6 @@ static inline int mm_pkey_alloc(struct mm_struct *mm) ret = ffz((u32)mm_pkey_allocation_map(mm)); __mm_pkey_allocated(mm, ret); - /* - * Enable the key in the hardware - */ - if (ret > 0) - __arch_activate_pkey(ret); return ret; } @@ -140,10 +133,6 @@ static inline int mm_pkey_free(struct mm_struct *mm, int pkey) if (!mm_pkey_is_allocated(mm, pkey)) return -EINVAL; - /* - * Disable the key in the hardware - */ - __arch_deactivate_pkey(pkey); __mm_pkey_free(mm, pkey); return 0; |