| Message ID | 20191021142309.28105-1-geert+renesas@glider.be (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 3b05a1e517e1a8cfda4866ec31d28b2bc4fee4c4 |
| Headers | show |
| Series | powerpc/security: Fix debugfs data leak on 32-bit | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch next (600802af9049be799465b24d14162918545634bf) |
| snowpatch_ozlabs/build-ppc64le | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64be | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64e | success | Build succeeded |
| snowpatch_ozlabs/build-pmac32 | success | Build succeeded |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 44 lines checked |
On Mon, 2019-10-21 at 14:23:09 UTC, Geert Uytterhoeven wrote: > "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> Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/3b05a1e517e1a8cfda4866ec31d28b2bc4fee4c4 cheers
diff --git a/arch/powerpc/include/asm/security_features.h b/arch/powerpc/include/asm/security_features.h index 759597bf0fd867bd..a3e8ecd48dc7ffa0 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 7cfcb294b11ca7be..2e9a7e20d05c5f79 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);
"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> --- Compile-tested only. Alternatively, powerpc_security_features could be changed to u32. However, that would require using debugfs_create_x32() instead of debugfs_create_x64(), which would change the debugfs file formatting from "0x%016llx" to "0x%08llx". --- arch/powerpc/include/asm/security_features.h | 8 ++++---- arch/powerpc/kernel/security.c | 4 ++-- 2 files changed, 6 insertions(+), 6 deletions(-)