diff options
| author | Dave Hansen <dave.hansen@linux.intel.com> | 2020-01-22 08:53:46 -0800 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-02-24 20:25:21 +0100 |
| commit | 16171bffc829272d5e6014bad48f680cb50943d9 (patch) | |
| tree | 949d53c86860ed8ad63f68917f3c68df88bb9842 /arch/x86/include/asm/pkeys.h | |
| parent | e70b100806d63fb79775858ea92e1a716da46186 (diff) | |
x86/pkeys: Add check for pkey "overflow"
Alex Shi reported the pkey macros above arch_set_user_pkey_access()
to be unused. They are unused, and even refer to a nonexistent
CONFIG option.
But, they might have served a good use, which was to ensure that
the code does not try to set values that would not fit in the
PKRU register. As it stands, a too-large 'pkey' value would
be likely to silently overflow the u32 new_pkru_bits.
Add a check to look for overflows. Also add a comment to remind
any future developer to closely examine the types used to store
pkey values if arch_max_pkey() ever changes.
This boots and passes the x86 pkey selftests.
Reported-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200122165346.AD4DA150@viggo.jf.intel.com
Diffstat (limited to 'arch/x86/include/asm/pkeys.h')
| -rw-r--r-- | arch/x86/include/asm/pkeys.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h index 19b137f1b3be..2ff9b98812b7 100644 --- a/arch/x86/include/asm/pkeys.h +++ b/arch/x86/include/asm/pkeys.h @@ -4,6 +4,11 @@ #define ARCH_DEFAULT_PKEY 0 +/* + * If more than 16 keys are ever supported, a thorough audit + * will be necessary to ensure that the types that store key + * numbers and masks have sufficient capacity. + */ #define arch_max_pkey() (boot_cpu_has(X86_FEATURE_OSPKE) ? 16 : 1) extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, |