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| author | Geert Uytterhoeven <geert+renesas@glider.be> | 2019-10-21 16:23:09 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-11-05 22:29:27 +1100 |
| commit | 3b05a1e517e1a8cfda4866ec31d28b2bc4fee4c4 (patch) | |
| tree | d200d724507722b1c5bf0aa7de17fe3db7dfe8b0 | |
| parent | 16f6b67cf03cb43db7104acb2ca877bdc2606c92 (diff) | |
| download | lwn-3b05a1e517e1a8cfda4866ec31d28b2bc4fee4c4.tar.gz lwn-3b05a1e517e1a8cfda4866ec31d28b2bc4fee4c4.zip | |
powerpc/security: Fix debugfs data leak on 32-bit
"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
| -rw-r--r-- | arch/powerpc/include/asm/security_features.h | 8 | ||||
| -rw-r--r-- | 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 759597bf0fd8..a3e8ecd48dc7 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 ad7f4bf8447c..a3021e6faed8 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, @@ -108,7 +108,7 @@ 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); |