Commit 9fe8a6f5 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Borislav Petkov
Browse files

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: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121453.635764326@linutronix.de
parent 71ef4533

arch/x86/kernel/fpu/xstate.c

+6 −5
Original line number Diff line number Diff line
@@ -914,9 +914,8 @@ EXPORT_SYMBOL_GPL(get_xsave_addr); 
int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,

			      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: */