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arm64: set UXN on swapper page tables

PATCH Applied Will Deacon 2 participants 6 messages Aug 8, 2022 – Aug 9, 2022

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Will Deacon

author maintainer
#0 lore raw

PATCH 1/1 arm64: set UXN on swapper page tables

From: Peter Collingbourne <[email protected]>

[ This issue was fixed upstream by accident in c3cee924bd85 ("arm64:
head: cover entire kernel image in initial ID map") as part of a large refactoring of the arm64 boot flow. This simple fix is therefore preferred for -stable backporting ]

On a system that implements FEAT_EPAN, read/write access to the idmap is denied because UXN is not set on the swapper PTEs. As a result, idmap_kpti_install_ng_mappings panics the kernel when accessing __idmap_kpti_flag. Fix it by setting UXN on these PTEs.

Fixes 18107f8a2df6 ("arm64: Support execute-only permissions with Enhanced PAN")
Cc <[email protected]> # 5.15
Link https://linux-review.googlesource.com/id/Ic452fa4b4f74753e54f71e61027e7222a0fae1b1
Signed-off-by Peter Collingbourne <[email protected]>
Acked-by Will Deacon <[email protected]>
Cc Ard Biesheuvel <[email protected]>
Cc Catalin Marinas <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Will Deacon <[email protected]>
---
 arch/arm64/include/asm/kernel-pgtable.h | 4 ++--
 arch/arm64/kernel/head.S                | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)
arch/arm64/include/asm/kernel-pgtable.h +2 -2
index 96dc0f7da258..a971d462f531 100644
@@ -103,8 +103,8 @@
 /*
  * Initial memory map attributes.
  */
-#define SWAPPER_PTE_FLAGS	(PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
-#define SWAPPER_PMD_FLAGS	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
+#define SWAPPER_PTE_FLAGS	(PTE_TYPE_PAGE | PTE_AF | PTE_SHARED | PTE_UXN)
+#define SWAPPER_PMD_FLAGS	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S | PMD_SECT_UXN)
 
 #if ARM64_KERNEL_USES_PMD_MAPS
 #define SWAPPER_MM_MMUFLAGS	(PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS)
arch/arm64/kernel/head.S +1 -1
index 6a98f1a38c29..8a93a0a7489b 100644
@@ -285,7 +285,7 @@ SYM_FUNC_START_LOCAL(__create_page_tables)
 	subs	x1, x1, #64
 	b.ne	1b
 
-	mov	x7, SWAPPER_MM_MMUFLAGS
+	mov_q	x7, SWAPPER_MM_MMUFLAGS
 
 	/*
 	 * Create the identity mapping.
Signature · 1 line
2.37.1.559.g78731f0fdb-goog
maintainer
#1 lore raw
Quoted 21 lines · Will Deacon

From: Peter Collingbourne <[email protected]>

[ This issue was fixed upstream by accident in c3cee924bd85 ("arm64:
head: cover entire kernel image in initial ID map") as part of a large refactoring of the arm64 boot flow. This simple fix is therefore preferred for -stable backporting ]

On a system that implements FEAT_EPAN, read/write access to the idmap is denied because UXN is not set on the swapper PTEs. As a result, idmap_kpti_install_ng_mappings panics the kernel when accessing __idmap_kpti_flag. Fix it by setting UXN on these PTEs.

Fixes 18107f8a2df6 ("arm64: Support execute-only permissions with Enhanced PAN")
Cc <[email protected]> # 5.15
Link https://linux-review.googlesource.com/id/Ic452fa4b4f74753e54f71e61027e7222a0fae1b1
Signed-off-by Peter Collingbourne <[email protected]>
Acked-by Will Deacon <[email protected]>
Cc Ard Biesheuvel <[email protected]>
Cc Catalin Marinas <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Will Deacon <[email protected]>
Quoted 4 lines
---
 arch/arm64/include/asm/kernel-pgtable.h | 4 ++--
 arch/arm64/kernel/head.S                | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

So this should be added to 5.15.y, 5.18.y, and 5.19.y? Or some subset?

thanks,

greg k-h

author maintainer
#2 lore raw
Quoted 27 lines · Greg KH
Quoted 21 lines · Will Deacon

From: Peter Collingbourne <[email protected]>

[ This issue was fixed upstream by accident in c3cee924bd85 ("arm64:
head: cover entire kernel image in initial ID map") as part of a large refactoring of the arm64 boot flow. This simple fix is therefore preferred for -stable backporting ]

On a system that implements FEAT_EPAN, read/write access to the idmap is denied because UXN is not set on the swapper PTEs. As a result, idmap_kpti_install_ng_mappings panics the kernel when accessing __idmap_kpti_flag. Fix it by setting UXN on these PTEs.

Fixes 18107f8a2df6 ("arm64: Support execute-only permissions with Enhanced PAN")
Cc <[email protected]> # 5.15
Link https://linux-review.googlesource.com/id/Ic452fa4b4f74753e54f71e61027e7222a0fae1b1
Signed-off-by Peter Collingbourne <[email protected]>
Acked-by Will Deacon <[email protected]>
Cc Ard Biesheuvel <[email protected]>
Cc Catalin Marinas <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Will Deacon <[email protected]>
Quoted 4 lines
---
 arch/arm64/include/asm/kernel-pgtable.h | 4 ++--
 arch/arm64/kernel/head.S                | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)
Quoted 1 line

So this should be added to 5.15.y, 5.18.y, and 5.19.y? Or some subset?

Yes, all of them. Basically anything still being updated which is >= 5.15 and <= 5.19.

Thanks,

Will

maintainer Applied
#3 lore raw

Patch "arm64: set UXN on swapper page tables" has been added to the 5.15-stable tree

In reply to Will Deacon

This is a note to let you know that I've just added the patch titled

arm64: set UXN on swapper page tables

to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm64-set-uxn-on-swapper-page-tables.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From [email protected] Mon Aug 8 15:23:59 2022
From: Will Deacon <[email protected]>
Date: Mon, 8 Aug 2022 13:53:21 +0100
Subject: arm64: set UXN on swapper page tables
To: [email protected]
Cc: [email protected], [email protected], Peter Collingbourne <[email protected]>, [email protected], Will Deacon <[email protected]>, Ard Biesheuvel <[email protected]>, Catalin Marinas <[email protected]>
Message-ID: <[email protected]>

From: Peter Collingbourne <[email protected]>

[ This issue was fixed upstream by accident in c3cee924bd85 ("arm64:
head: cover entire kernel image in initial ID map") as part of a large refactoring of the arm64 boot flow. This simple fix is therefore preferred for -stable backporting ]

On a system that implements FEAT_EPAN, read/write access to the idmap is denied because UXN is not set on the swapper PTEs. As a result, idmap_kpti_install_ng_mappings panics the kernel when accessing __idmap_kpti_flag. Fix it by setting UXN on these PTEs.

Fixes 18107f8a2df6 ("arm64: Support execute-only permissions with Enhanced PAN")
Cc <[email protected]> # 5.15
Link https://linux-review.googlesource.com/id/Ic452fa4b4f74753e54f71e61027e7222a0fae1b1
Signed-off-by Peter Collingbourne <[email protected]>
Acked-by Will Deacon <[email protected]>
Cc Ard Biesheuvel <[email protected]>
Cc Catalin Marinas <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Will Deacon <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 arch/arm64/include/asm/kernel-pgtable.h |    4 ++--
 arch/arm64/kernel/head.S                |    2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)
arch/arm64/include/asm/kernel-pgtable.h +2 -2
@@ -103,8 +103,8 @@
 /*
  * Initial memory map attributes.
  */
-#define SWAPPER_PTE_FLAGS	(PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
-#define SWAPPER_PMD_FLAGS	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
+#define SWAPPER_PTE_FLAGS	(PTE_TYPE_PAGE | PTE_AF | PTE_SHARED | PTE_UXN)
+#define SWAPPER_PMD_FLAGS	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S | PMD_SECT_UXN)
 
 #if ARM64_KERNEL_USES_PMD_MAPS
 #define SWAPPER_MM_MMUFLAGS	(PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS)
arch/arm64/kernel/head.S +1 -1
@@ -285,7 +285,7 @@ SYM_FUNC_START_LOCAL(__create_page_table
 	subs	x1, x1, #64
 	b.ne	1b
 
-	mov	x7, SWAPPER_MM_MMUFLAGS
+	mov_q	x7, SWAPPER_MM_MMUFLAGS
 
 	/*
 	 * Create the identity mapping.

Patches currently in stable-queue which might be from [email protected] are

queue-5.15/arm64-set-uxn-on-swapper-page-tables.patch queue-5.15/crypto-arm64-poly1305-fix-a-read-out-of-bound.patch

_______________________________________________
linux-arm-kernel mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

maintainer Applied
#4 lore raw

Patch "arm64: set UXN on swapper page tables" has been added to the 5.18-stable tree

In reply to Will Deacon

This is a note to let you know that I've just added the patch titled

arm64: set UXN on swapper page tables

to the 5.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm64-set-uxn-on-swapper-page-tables.patch
and it can be found in the queue-5.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From [email protected] Mon Aug 8 15:23:59 2022
From: Will Deacon <[email protected]>
Date: Mon, 8 Aug 2022 13:53:21 +0100
Subject: arm64: set UXN on swapper page tables
To: [email protected]
Cc: [email protected], [email protected], Peter Collingbourne <[email protected]>, [email protected], Will Deacon <[email protected]>, Ard Biesheuvel <[email protected]>, Catalin Marinas <[email protected]>
Message-ID: <[email protected]>

From: Peter Collingbourne <[email protected]>

[ This issue was fixed upstream by accident in c3cee924bd85 ("arm64:
head: cover entire kernel image in initial ID map") as part of a large refactoring of the arm64 boot flow. This simple fix is therefore preferred for -stable backporting ]

On a system that implements FEAT_EPAN, read/write access to the idmap is denied because UXN is not set on the swapper PTEs. As a result, idmap_kpti_install_ng_mappings panics the kernel when accessing __idmap_kpti_flag. Fix it by setting UXN on these PTEs.

Fixes 18107f8a2df6 ("arm64: Support execute-only permissions with Enhanced PAN")
Cc <[email protected]> # 5.15
Link https://linux-review.googlesource.com/id/Ic452fa4b4f74753e54f71e61027e7222a0fae1b1
Signed-off-by Peter Collingbourne <[email protected]>
Acked-by Will Deacon <[email protected]>
Cc Ard Biesheuvel <[email protected]>
Cc Catalin Marinas <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Will Deacon <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 arch/arm64/include/asm/kernel-pgtable.h |    4 ++--
 arch/arm64/kernel/head.S                |    2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)
arch/arm64/include/asm/kernel-pgtable.h +2 -2
@@ -103,8 +103,8 @@
 /*
  * Initial memory map attributes.
  */
-#define SWAPPER_PTE_FLAGS	(PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
-#define SWAPPER_PMD_FLAGS	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
+#define SWAPPER_PTE_FLAGS	(PTE_TYPE_PAGE | PTE_AF | PTE_SHARED | PTE_UXN)
+#define SWAPPER_PMD_FLAGS	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S | PMD_SECT_UXN)
 
 #if ARM64_KERNEL_USES_PMD_MAPS
 #define SWAPPER_MM_MMUFLAGS	(PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS)
arch/arm64/kernel/head.S +1 -1
@@ -285,7 +285,7 @@ SYM_FUNC_START_LOCAL(__create_page_table
 	subs	x1, x1, #64
 	b.ne	1b
 
-	mov	x7, SWAPPER_MM_MMUFLAGS
+	mov_q	x7, SWAPPER_MM_MMUFLAGS
 
 	/*
 	 * Create the identity mapping.

Patches currently in stable-queue which might be from [email protected] are

queue-5.18/arm64-set-uxn-on-swapper-page-tables.patch queue-5.18/crypto-arm64-poly1305-fix-a-read-out-of-bound.patch

_______________________________________________
linux-arm-kernel mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

maintainer Applied
#5 lore raw

Patch "arm64: set UXN on swapper page tables" has been added to the 5.19-stable tree

In reply to Will Deacon

This is a note to let you know that I've just added the patch titled

arm64: set UXN on swapper page tables

to the 5.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm64-set-uxn-on-swapper-page-tables.patch
and it can be found in the queue-5.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From [email protected] Mon Aug 8 15:23:59 2022
From: Will Deacon <[email protected]>
Date: Mon, 8 Aug 2022 13:53:21 +0100
Subject: arm64: set UXN on swapper page tables
To: [email protected]
Cc: [email protected], [email protected], Peter Collingbourne <[email protected]>, [email protected], Will Deacon <[email protected]>, Ard Biesheuvel <[email protected]>, Catalin Marinas <[email protected]>
Message-ID: <[email protected]>

From: Peter Collingbourne <[email protected]>

[ This issue was fixed upstream by accident in c3cee924bd85 ("arm64:
head: cover entire kernel image in initial ID map") as part of a large refactoring of the arm64 boot flow. This simple fix is therefore preferred for -stable backporting ]

On a system that implements FEAT_EPAN, read/write access to the idmap is denied because UXN is not set on the swapper PTEs. As a result, idmap_kpti_install_ng_mappings panics the kernel when accessing __idmap_kpti_flag. Fix it by setting UXN on these PTEs.

Fixes 18107f8a2df6 ("arm64: Support execute-only permissions with Enhanced PAN")
Cc <[email protected]> # 5.15
Link https://linux-review.googlesource.com/id/Ic452fa4b4f74753e54f71e61027e7222a0fae1b1
Signed-off-by Peter Collingbourne <[email protected]>
Acked-by Will Deacon <[email protected]>
Cc Ard Biesheuvel <[email protected]>
Cc Catalin Marinas <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Will Deacon <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 arch/arm64/include/asm/kernel-pgtable.h |    4 ++--
 arch/arm64/kernel/head.S                |    2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)
arch/arm64/include/asm/kernel-pgtable.h +2 -2
@@ -103,8 +103,8 @@
 /*
  * Initial memory map attributes.
  */
-#define SWAPPER_PTE_FLAGS	(PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
-#define SWAPPER_PMD_FLAGS	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
+#define SWAPPER_PTE_FLAGS	(PTE_TYPE_PAGE | PTE_AF | PTE_SHARED | PTE_UXN)
+#define SWAPPER_PMD_FLAGS	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S | PMD_SECT_UXN)
 
 #if ARM64_KERNEL_USES_PMD_MAPS
 #define SWAPPER_MM_MMUFLAGS	(PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS)
arch/arm64/kernel/head.S +1 -1
@@ -285,7 +285,7 @@ SYM_FUNC_START_LOCAL(__create_page_table
 	subs	x1, x1, #64
 	b.ne	1b
 
-	mov	x7, SWAPPER_MM_MMUFLAGS
+	mov_q	x7, SWAPPER_MM_MMUFLAGS
 
 	/*
 	 * Create the identity mapping.

Patches currently in stable-queue which might be from [email protected] are

queue-5.19/arm64-set-uxn-on-swapper-page-tables.patch queue-5.19/crypto-arm64-poly1305-fix-a-read-out-of-bound.patch

_______________________________________________
linux-arm-kernel mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel