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[RFC,2/8] mm: kpkeys: Introduce unrestricted level

Message ID 20250203102809.1223255-3-kevin.brodsky@arm.com (mailing list archive)
State New
Headers show
Series pkeys-based cred hardening | expand

Commit Message

Kevin Brodsky Feb. 3, 2025, 10:28 a.m. UTC 
Highly privileged components, such as allocators, may require write
access to arbitrary data. To that end, introduce a kpkeys level that
grants write access to all kpkeys.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
 arch/arm64/include/asm/kpkeys.h | 4 +++-
 include/linux/kpkeys.h          | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)
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Patch

diff --git a/arch/arm64/include/asm/kpkeys.h b/arch/arm64/include/asm/kpkeys.h
index 3f16584d495a..ab2305ca24b7 100644
--- a/arch/arm64/include/asm/kpkeys.h
+++ b/arch/arm64/include/asm/kpkeys.h
@@ -19,7 +19,9 @@  static inline u64 por_set_kpkeys_level(u64 por, int level)
 {
 	por = por_set_pkey_perms(por, KPKEYS_PKEY_DEFAULT, POE_RXW);
 	por = por_set_pkey_perms(por, KPKEYS_PKEY_PGTABLES,
-				 level == KPKEYS_LVL_PGTABLES ? POE_RW : POE_R);
+				 level == KPKEYS_LVL_PGTABLES ||
+				 level == KPKEYS_LVL_UNRESTRICTED
+				 ? POE_RW : POE_R);
 
 	return por;
 }
diff --git a/include/linux/kpkeys.h b/include/linux/kpkeys.h
index 645eaf00096c..9d9feec83ccf 100644
--- a/include/linux/kpkeys.h
+++ b/include/linux/kpkeys.h
@@ -10,9 +10,10 @@  struct folio;
 
 #define KPKEYS_LVL_DEFAULT	0
 #define KPKEYS_LVL_PGTABLES	1
+#define KPKEYS_LVL_UNRESTRICTED	2
 
 #define KPKEYS_LVL_MIN		KPKEYS_LVL_DEFAULT
-#define KPKEYS_LVL_MAX		KPKEYS_LVL_PGTABLES
+#define KPKEYS_LVL_MAX		KPKEYS_LVL_UNRESTRICTED
 
 #define __KPKEYS_GUARD(name, set_level, restore_pkey_reg, set_arg, ...)	\
 	__DEFINE_CLASS_IS_CONDITIONAL(name, false);			\