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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 v6 15/22] powerpc/book3s64/kuap: Restrict access to userspace based on userspace AMR
Date: Wed, 25 Nov 2020 10:46:27 +0530	[thread overview]
Message-ID: <20201125051634.509286-16-aneesh.kumar@linux.ibm.com> (raw)
In-Reply-To: <20201125051634.509286-1-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 47270596215b..4a3d0d601745 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:[~2020-11-25  5:46 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-25  5:16 [PATCH v6 00/22] Kernel userspace access/execution prevention with hash translation Aneesh Kumar K.V
2020-11-25  5:16 ` [PATCH v6 01/22] powerpc: Add new macro to handle NESTED_IFCLR Aneesh Kumar K.V
2020-11-25  5:16 ` [PATCH v6 02/22] KVM: PPC: BOOK3S: PR: Ignore UAMOR SPR Aneesh Kumar K.V
2020-11-25  5:16 ` [PATCH v6 03/22] powerpc/book3s64/kuap/kuep: Make KUAP and KUEP a subfeature of PPC_MEM_KEYS Aneesh Kumar K.V
2020-11-25 13:30   ` Christophe Leroy
2020-11-25 14:57     ` Aneesh Kumar K.V
2020-11-26  3:25   ` Michael Ellerman
2020-11-25  5:16 ` [PATCH v6 04/22] powerpc/book3s64/kuap/kuep: Move uamor setup to pkey init Aneesh Kumar K.V
2020-11-25 13:32   ` Christophe Leroy
2020-11-26  3:28   ` Michael Ellerman
2020-11-25  5:16 ` [PATCH v6 05/22] powerpc/book3s64/kuap: Move KUAP related function outside radix Aneesh Kumar K.V
2020-11-25  5:16 ` [PATCH v6 06/22] powerpc/book3s64/kuep: Move KUEP " Aneesh Kumar K.V
2020-11-25  5:16 ` [PATCH v6 07/22] powerpc/book3s64/kuap: Rename MMU_FTR_RADIX_KUAP to MMU_FTR_KUAP Aneesh Kumar K.V
2020-11-25 13:43   ` Christophe Leroy
2020-11-25 13:52     ` Aneesh Kumar K.V
2020-11-26  3:16   ` Michael Ellerman
2020-11-25  5:16 ` [PATCH v6 08/22] powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash translation Aneesh Kumar K.V
2020-11-25  5:16 ` [PATCH v6 09/22] powerpc/exec: Set thread.regs early during exec Aneesh Kumar K.V
2020-11-25 13:47   ` Christophe Leroy
2020-11-26  7:38     ` Aneesh Kumar K.V
2020-11-26  7:43       ` Christophe Leroy
2020-11-25  5:16 ` [PATCH v6 10/22] powerpc/book3s64/pkeys: Store/restore userspace AMR/IAMR correctly on entry and exit from kernel Aneesh Kumar K.V
2020-11-25 13:52   ` Christophe Leroy
2020-11-25 13:55     ` Aneesh Kumar K.V
2020-11-25 14:16       ` Christophe Leroy
2020-11-25  5:16 ` [PATCH v6 11/22] powerpc/book3s64/pkeys: Inherit correctly on fork Aneesh Kumar K.V
2020-11-25 13:54   ` Christophe Leroy
2020-11-25 13:56     ` Aneesh Kumar K.V
2020-11-25  5:16 ` [PATCH v6 12/22] powerpc/book3s64/pkeys: Reset userspace AMR correctly on exec Aneesh Kumar K.V
2020-11-25  5:16 ` [PATCH v6 13/22] powerpc/ptrace-view: Use pt_regs values instead of thread_struct based one Aneesh Kumar K.V
2020-11-25  5:16 ` [PATCH v6 14/22] powerpc/book3s64/pkeys: Don't update SPRN_AMR when in kernel mode Aneesh Kumar K.V
2020-11-25  5:16 ` Aneesh Kumar K.V [this message]
2020-11-25  5:16 ` [PATCH v6 16/22] powerpc/book3s64/kuap: Improve error reporting with KUAP Aneesh Kumar K.V
2020-11-25 14:04   ` Christophe Leroy
2020-11-26  7:44     ` Aneesh Kumar K.V
2020-11-26  9:29       ` Michael Ellerman
2020-11-26 10:39         ` Christophe Leroy
2020-11-25  5:16 ` [PATCH v6 17/22] powerpc/book3s64/kuap: Use Key 3 to implement KUAP with hash translation Aneesh Kumar K.V
2020-11-25  5:16 ` [PATCH v6 18/22] powerpc/book3s64/kuep: Use Key 3 to implement KUEP " Aneesh Kumar K.V
2020-11-25  5:16 ` [PATCH v6 19/22] powerpc/book3s64/hash/kuap: Enable kuap on hash Aneesh Kumar K.V
2021-03-15 12:06   ` Christophe Leroy
2021-03-15 12:59     ` Aneesh Kumar K.V
2021-03-15 13:02       ` Christophe Leroy
2021-10-08  9:32   ` Christophe Leroy
2021-10-11  3:28     ` Michael Ellerman
2020-11-25  5:16 ` [PATCH v6 20/22] powerpc/book3s64/hash/kuep: Enable KUEP " Aneesh Kumar K.V
2020-11-25  5:16 ` [PATCH v6 21/22] powerpc/book3s64/hash/kup: Don't hardcode kup key Aneesh Kumar K.V
2020-11-25  5:16 ` [PATCH v6 22/22] powerpc/book3s64/pkeys: Optimize FTR_KUAP and FTR_KUEP disabled case Aneesh Kumar K.V

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