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https://github.com/torvalds/linux
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7d0dec57e5
Replace sprintf() with sysfs_emit() in cpu_show_ghostwrite(), which is preferred for formatting sysfs output because it provides safer bounds checking. While the current code only emits fixed strings that fit easily within PAGE_SIZE, use sysfs_emit() to follow secure coding best practices. Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev> Link: https://patch.msgid.link/20260510165420.109453-3-thorsten.blum@linux.dev Signed-off-by: Paul Walmsley <pjw@kernel.org>
61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2024 Rivos Inc.
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*/
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#include <linux/cpu.h>
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#include <linux/device.h>
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#include <linux/sysfs.h>
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#include <asm/bugs.h>
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#include <asm/vendor_extensions/thead.h>
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static enum mitigation_state ghostwrite_state;
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void ghostwrite_set_vulnerable(void)
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{
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ghostwrite_state = VULNERABLE;
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}
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/*
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* Vendor extension alternatives will use the value set at the time of boot
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* alternative patching, thus this must be called before boot alternatives are
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* patched (and after extension probing) to be effective.
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*
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* Returns true if mitgated, false otherwise.
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*/
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bool ghostwrite_enable_mitigation(void)
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{
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if (IS_ENABLED(CONFIG_RISCV_ISA_XTHEADVECTOR) &&
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ghostwrite_state == VULNERABLE && !cpu_mitigations_off()) {
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disable_xtheadvector();
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ghostwrite_state = MITIGATED;
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return true;
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}
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return false;
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}
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enum mitigation_state ghostwrite_get_state(void)
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{
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return ghostwrite_state;
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}
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ssize_t cpu_show_ghostwrite(struct device *dev, struct device_attribute *attr, char *buf)
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{
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if (IS_ENABLED(CONFIG_RISCV_ISA_XTHEADVECTOR)) {
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switch (ghostwrite_state) {
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case UNAFFECTED:
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return sysfs_emit(buf, "Not affected\n");
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case MITIGATED:
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return sysfs_emit(buf, "Mitigation: xtheadvector disabled\n");
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case VULNERABLE:
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fallthrough;
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default:
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return sysfs_emit(buf, "Vulnerable\n");
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}
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}
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return sysfs_emit(buf, "Not affected\n");
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}
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