diff options
| author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2020-11-27 07:44:17 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-12-03 17:01:26 +0300 |
| commit | 4d6c551e9f548f7675a01eff229d09ab41162a25 (patch) | |
| tree | 401c9a20fe6ea4335b9c9dfbecd2faf12dc3b838 | |
| parent | 48a8ab4eeb8271f2a0e2ca3cf80844a59acca153 (diff) | |
| download | linux-4d6c551e9f548f7675a01eff229d09ab41162a25.tar.xz | |
powerpc/book3s64/kuap: Restrict access to userspace based on userspace AMR
If an application has configured address protection such that read/write is
denied using pkey even the kernel should receive a FAULT on accessing the same.
This patch use user AMR value stored in pt_regs.amr to achieve the same.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-16-aneesh.kumar@linux.ibm.com
| -rw-r--r-- | arch/powerpc/include/asm/book3s/64/kup.h | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h index f41f6f468002..4fa0760a47a4 100644 --- a/arch/powerpc/include/asm/book3s/64/kup.h +++ b/arch/powerpc/include/asm/book3s/64/kup.h @@ -314,14 +314,20 @@ bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) static __always_inline void allow_user_access(void __user *to, const void __user *from, unsigned long size, unsigned long dir) { + unsigned long thread_amr = 0; + // This is written so we can resolve to a single case at build time BUILD_BUG_ON(!__builtin_constant_p(dir)); + + if (mmu_has_feature(MMU_FTR_PKEY)) + thread_amr = current_thread_amr(); + if (dir == KUAP_READ) - set_kuap(AMR_KUAP_BLOCK_WRITE); + set_kuap(thread_amr | AMR_KUAP_BLOCK_WRITE); else if (dir == KUAP_WRITE) - set_kuap(AMR_KUAP_BLOCK_READ); + set_kuap(thread_amr | AMR_KUAP_BLOCK_READ); else if (dir == KUAP_READ_WRITE) - set_kuap(0); + set_kuap(thread_amr); else BUILD_BUG(); } |