The following commit has been merged into the x86/fpu branch of tip:
Commit-ID: 9fe8a6f5eed8fff6b2d7dbc99b911334e311732d
Gitweb: https://git.kernel.org/tip/9fe8a6f5eed8fff6b2d7dbc99b911334e311732d
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Wed, 23 Jun 2021 14:01:50 +02:00
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Wed, 23 Jun 2021 17:52:41 +02:00
x86/fpu: Cleanup arch_set_user_pkey_access()
The function does a sanity check with a WARN_ON_ONCE() but happily proceeds
when the pkey argument is out of range.
Clean it up.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Link: https://lkml.kernel.org/r/20210623121453.635764326@xxxxxxxxxxxxx
---
arch/x86/kernel/fpu/xstate.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 185cc5d..579e343 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -912,11 +912,10 @@ EXPORT_SYMBOL_GPL(get_xsave_addr);
* rights for @pkey to @init_val.
*/
int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
- unsigned long init_val)
+ unsigned long init_val)
{
- u32 old_pkru;
- int pkey_shift = (pkey * PKRU_BITS_PER_PKEY);
- u32 new_pkru_bits = 0;
+ u32 old_pkru, new_pkru_bits = 0;
+ int pkey_shift;
/*
* This check implies XSAVE support. OSPKE only gets
@@ -930,7 +929,8 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
* values originating from in-kernel users. Complain
* if a bad value is observed.
*/
- WARN_ON_ONCE(pkey >= arch_max_pkey());
+ if (WARN_ON_ONCE(pkey >= arch_max_pkey()))
+ return -EINVAL;
/* Set the bits we need in PKRU: */
if (init_val & PKEY_DISABLE_ACCESS)
@@ -939,6 +939,7 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
new_pkru_bits |= PKRU_WD_BIT;
/* Shift the bits in to the correct place in PKRU for pkey: */
+ pkey_shift = pkey * PKRU_BITS_PER_PKEY;
new_pkru_bits <<= pkey_shift;
/* Get old PKRU and mask off any old bits in place: */
|