1 files changed, 0 insertions, 177 deletions
diff --git a/kernel/stackleak.c b/kernel/stackleak.c
deleted file mode 100644
index bb65321761b4..000000000000
--- a/kernel/stackleak.c
+++ /dev/null
@@ -1,177 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * This code fills the used part of the kernel stack with a poison value
- * before returning to userspace. It's part of the STACKLEAK feature
- * ported from grsecurity/PaX.
- *
- * Author: Alexander Popov <alex.popov@linux.com>
- *
- * STACKLEAK reduces the information which kernel stack leak bugs can
- * reveal and blocks some uninitialized stack variable attacks.
- */
-
-#include <linux/stackleak.h>
-#include <linux/kprobes.h>
-
-#ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE
-#include <linux/jump_label.h>
-#include <linux/string_choices.h>
-#include <linux/sysctl.h>
-#include <linux/init.h>
-
-static DEFINE_STATIC_KEY_FALSE(stack_erasing_bypass);
-
-#ifdef CONFIG_SYSCTL
-static int stack_erasing_sysctl(const struct ctl_table *table, int write,
-			void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-	int ret = 0;
-	int state = !static_branch_unlikely(&stack_erasing_bypass);
-	int prev_state = state;
-	struct ctl_table table_copy = *table;
-
-	table_copy.data = &state;
-	ret = proc_dointvec_minmax(&table_copy, write, buffer, lenp, ppos);
-	state = !!state;
-	if (ret || !write || state == prev_state)
-		return ret;
-
-	if (state)
-		static_branch_disable(&stack_erasing_bypass);
-	else
-		static_branch_enable(&stack_erasing_bypass);
-
-	pr_warn("stackleak: kernel stack erasing is %s\n",
-					str_enabled_disabled(state));
-	return ret;
-}
-static const struct ctl_table stackleak_sysctls[] = {
-	{
-		.procname	= "stack_erasing",
-		.data		= NULL,
-		.maxlen		= sizeof(int),
-		.mode		= 0600,
-		.proc_handler	= stack_erasing_sysctl,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-};
-
-static int __init stackleak_sysctls_init(void)
-{
-	register_sysctl_init("kernel", stackleak_sysctls);
-	return 0;
-}
-late_initcall(stackleak_sysctls_init);
-#endif /* CONFIG_SYSCTL */
-
-#define skip_erasing()	static_branch_unlikely(&stack_erasing_bypass)
-#else
-#define skip_erasing()	false
-#endif /* CONFIG_STACKLEAK_RUNTIME_DISABLE */
-
-#ifndef __stackleak_poison
-static __always_inline void __stackleak_poison(unsigned long erase_low,
-					       unsigned long erase_high,
-					       unsigned long poison)
-{
-	while (erase_low < erase_high) {
-		*(unsigned long *)erase_low = poison;
-		erase_low += sizeof(unsigned long);
-	}
-}
-#endif
-
-static __always_inline void __stackleak_erase(bool on_task_stack)
-{
-	const unsigned long task_stack_low = stackleak_task_low_bound(current);
-	const unsigned long task_stack_high = stackleak_task_high_bound(current);
-	unsigned long erase_low, erase_high;
-
-	erase_low = stackleak_find_top_of_poison(task_stack_low,
-						 current->lowest_stack);
-
-#ifdef CONFIG_STACKLEAK_METRICS
-	current->prev_lowest_stack = erase_low;
-#endif
-
-	/*
-	 * Write poison to the task's stack between 'erase_low' and
-	 * 'erase_high'.
-	 *
-	 * If we're running on a different stack (e.g. an entry trampoline
-	 * stack) we can erase everything below the pt_regs at the top of the
-	 * task stack.
-	 *
-	 * If we're running on the task stack itself, we must not clobber any
-	 * stack used by this function and its caller. We assume that this
-	 * function has a fixed-size stack frame, and the current stack pointer
-	 * doesn't change while we write poison.
-	 */
-	if (on_task_stack)
-		erase_high = current_stack_pointer;
-	else
-		erase_high = task_stack_high;
-
-	__stackleak_poison(erase_low, erase_high, STACKLEAK_POISON);
-
-	/* Reset the 'lowest_stack' value for the next syscall */
-	current->lowest_stack = task_stack_high;
-}
-
-/*
- * Erase and poison the portion of the task stack used since the last erase.
- * Can be called from the task stack or an entry stack when the task stack is
- * no longer in use.
- */
-asmlinkage void noinstr stackleak_erase(void)
-{
-	if (skip_erasing())
-		return;
-
-	__stackleak_erase(on_thread_stack());
-}
-
-/*
- * Erase and poison the portion of the task stack used since the last erase.
- * Can only be called from the task stack.
- */
-asmlinkage void noinstr stackleak_erase_on_task_stack(void)
-{
-	if (skip_erasing())
-		return;
-
-	__stackleak_erase(true);
-}
-
-/*
- * Erase and poison the portion of the task stack used since the last erase.
- * Can only be called from a stack other than the task stack.
- */
-asmlinkage void noinstr stackleak_erase_off_task_stack(void)
-{
-	if (skip_erasing())
-		return;
-
-	__stackleak_erase(false);
-}
-
-void __used __no_caller_saved_registers noinstr stackleak_track_stack(void)
-{
-	unsigned long sp = current_stack_pointer;
-
-	/*
-	 * Having CONFIG_STACKLEAK_TRACK_MIN_SIZE larger than
-	 * STACKLEAK_SEARCH_DEPTH makes the poison search in
-	 * stackleak_erase() unreliable. Let's prevent that.
-	 */
-	BUILD_BUG_ON(CONFIG_STACKLEAK_TRACK_MIN_SIZE > STACKLEAK_SEARCH_DEPTH);
-
-	/* 'lowest_stack' should be aligned on the register width boundary */
-	sp = ALIGN(sp, sizeof(unsigned long));
-	if (sp < current->lowest_stack &&
-	    sp >= stackleak_task_low_bound(current)) {
-		current->lowest_stack = sp;
-	}
-}
-EXPORT_SYMBOL(stackleak_track_stack);