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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	Sandipan Das <sandipan@linux.ibm.com>
Subject: [PATCH v7 15/22] powerpc/book3s64/kuap: Restrict access to userspace based on userspace AMR
Date: Fri, 27 Nov 2020 10:14:17 +0530	[thread overview]
Message-ID: <20201127044424.40686-16-aneesh.kumar@linux.ibm.com> (raw)
In-Reply-To: <20201127044424.40686-1-aneesh.kumar@linux.ibm.com>

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.

Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/kup.h | 12 +++++++++---
 1 file 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 97e81fd820be..a417b151cff7 100644
--- a/arch/powerpc/include/asm/book3s/64/kup.h
+++ b/arch/powerpc/include/asm/book3s/64/kup.h
@@ -312,14 +312,20 @@ 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();
 }
-- 
2.28.0


  parent reply	other threads:[~2020-11-27  5:14 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-27  4:44 [PATCH v7 00/22] Kernel userspace access/execution prevention with hash translation Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 01/22] powerpc: Add new macro to handle NESTED_IFCLR Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 02/22] KVM: PPC: BOOK3S: PR: Ignore UAMOR SPR Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 03/22] powerpc/book3s64/kuap/kuep: Add PPC_PKEY config on book3s64 Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 04/22] powerpc/book3s64/kuap/kuep: Move uamor setup to pkey init Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 05/22] powerpc/book3s64/kuap: Move KUAP related function outside radix Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 06/22] powerpc/book3s64/kuep: Move KUEP " Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 07/22] powerpc/book3s64/kuap: Rename MMU_FTR_RADIX_KUAP and MMU_FTR_KUEP Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 08/22] powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash translation Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 09/22] powerpc/exec: Set thread.regs early during exec Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 10/22] powerpc/book3s64/pkeys: Store/restore userspace AMR/IAMR correctly on entry and exit from kernel Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 11/22] powerpc/book3s64/pkeys: Inherit correctly on fork Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 12/22] powerpc/book3s64/pkeys: Reset userspace AMR correctly on exec Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 13/22] powerpc/ptrace-view: Use pt_regs values instead of thread_struct based one Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 14/22] powerpc/book3s64/pkeys: Don't update SPRN_AMR when in kernel mode Aneesh Kumar K.V
2020-11-27  4:44 ` Aneesh Kumar K.V [this message]
2020-11-27  4:44 ` [PATCH v7 16/22] powerpc/book3s64/kuap: Improve error reporting with KUAP Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 17/22] powerpc/book3s64/kuap: Use Key 3 to implement KUAP with hash translation Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 18/22] powerpc/book3s64/kuep: Use Key 3 to implement KUEP " Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 19/22] powerpc/book3s64/hash/kuap: Enable kuap on hash Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 20/22] powerpc/book3s64/hash/kuep: Enable KUEP " Aneesh Kumar K.V
2020-11-27  4:44 ` [PATCH v7 21/22] powerpc/book3s64/hash/kup: Don't hardcode kup key Aneesh Kumar K.V
2020-12-02  4:38   ` [PATCH v7 updated 21/22 ] powerpc/book3s64/kup: Check max key supported before enabling kup Aneesh Kumar K.V
2020-12-15 11:19     ` Michael Ellerman
2020-11-27  4:44 ` [PATCH v7 22/22] powerpc/book3s64/pkeys: Optimize KUAP and KUEP feature disabled case Aneesh Kumar K.V
2020-12-01  3:41 ` [PATCH v7 00/22] Kernel userspace access/execution prevention with hash translation Aneesh Kumar K.V
2020-12-10 11:29 ` Michael Ellerman

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