[PATCH AUTOSEL 5.4 099/205] powerpc/security: Fix debugfs data leak on 32-bit
From: Sasha Levin <sashal@kernel.org>
Date: 2020-01-16 16:52:23
Also in:
lkml, stable
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
From: Geert Uytterhoeven <geert+renesas@glider.be>
[ Upstream commit 3b05a1e517e1a8cfda4866ec31d28b2bc4fee4c4 ]
"powerpc_security_features" is "unsigned long", i.e. 32-bit or 64-bit,
depending on the platform (PPC_FSL_BOOK3E or PPC_BOOK3S_64). Hence
casting its address to "u64 *", and calling debugfs_create_x64() is
wrong, and leaks 32-bit of nearby data to userspace on 32-bit platforms.
While all currently defined SEC_FTR_* security feature flags fit in
32-bit, they all have "ULL" suffixes to make them 64-bit constants.
Hence fix the leak by changing the type of "powerpc_security_features"
(and the parameter types of its accessors) to "u64". This also allows
to drop the cast.
Fixes: 398af571128fe75f ("powerpc/security: Show powerpc_security_features in debugfs")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191021142309.28105-1-geert+renesas@glider.be (local)
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/include/asm/security_features.h | 8 ++++----
arch/powerpc/kernel/security.c | 4 ++--
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/include/asm/security_features.h b/arch/powerpc/include/asm/security_features.h
index ccf44c135389..7c05e95a5c44 100644
--- a/arch/powerpc/include/asm/security_features.h
+++ b/arch/powerpc/include/asm/security_features.h@@ -9,7 +9,7 @@ #define _ASM_POWERPC_SECURITY_FEATURES_H -extern unsigned long powerpc_security_features; +extern u64 powerpc_security_features; extern bool rfi_flush; /* These are bit flags */
@@ -24,17 +24,17 @@ void setup_stf_barrier(void); void do_stf_barrier_fixups(enum stf_barrier_type types); void setup_count_cache_flush(void); -static inline void security_ftr_set(unsigned long feature) +static inline void security_ftr_set(u64 feature) { powerpc_security_features |= feature; } -static inline void security_ftr_clear(unsigned long feature) +static inline void security_ftr_clear(u64 feature) { powerpc_security_features &= ~feature; } -static inline bool security_ftr_enabled(unsigned long feature) +static inline bool security_ftr_enabled(u64 feature) { return !!(powerpc_security_features & feature); }
diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index d341b464f23c..1740a66cea84 100644
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c@@ -16,7 +16,7 @@ #include <asm/setup.h> -unsigned long powerpc_security_features __read_mostly = SEC_FTR_DEFAULT; +u64 powerpc_security_features __read_mostly = SEC_FTR_DEFAULT; enum count_cache_flush_type { COUNT_CACHE_FLUSH_NONE = 0x1,
@@ -109,7 +109,7 @@ device_initcall(barrier_nospec_debugfs_init); static __init int security_feature_debugfs_init(void) { debugfs_create_x64("security_features", 0400, powerpc_debugfs_root, - (u64 *)&powerpc_security_features); + &powerpc_security_features); return 0; } device_initcall(security_feature_debugfs_init);
--
2.20.1