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342db04ae7
show_opcodes() is used both for dumping kernel instructions and for dumping
user instructions. If userspace causes #PF by jumping to a kernel address,
show_opcodes() can be reached with regs->ip controlled by the user,
pointing to kernel code. Make sure that userspace can't trick us into
dumping kernel memory into dmesg.
Fixes: 7cccf0725c ("x86/dumpstack: Add a show_ip() function")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: security@kernel.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180828154901.112726-1-jannh@google.com
117 lines
2.7 KiB
C
117 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
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*/
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#ifndef _ASM_X86_STACKTRACE_H
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#define _ASM_X86_STACKTRACE_H
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#include <linux/uaccess.h>
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#include <linux/ptrace.h>
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#include <asm/switch_to.h>
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enum stack_type {
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STACK_TYPE_UNKNOWN,
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STACK_TYPE_TASK,
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STACK_TYPE_IRQ,
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STACK_TYPE_SOFTIRQ,
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STACK_TYPE_ENTRY,
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STACK_TYPE_EXCEPTION,
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STACK_TYPE_EXCEPTION_LAST = STACK_TYPE_EXCEPTION + N_EXCEPTION_STACKS-1,
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};
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struct stack_info {
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enum stack_type type;
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unsigned long *begin, *end, *next_sp;
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};
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bool in_task_stack(unsigned long *stack, struct task_struct *task,
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struct stack_info *info);
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bool in_entry_stack(unsigned long *stack, struct stack_info *info);
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int get_stack_info(unsigned long *stack, struct task_struct *task,
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struct stack_info *info, unsigned long *visit_mask);
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const char *stack_type_name(enum stack_type type);
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static inline bool on_stack(struct stack_info *info, void *addr, size_t len)
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{
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void *begin = info->begin;
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void *end = info->end;
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return (info->type != STACK_TYPE_UNKNOWN &&
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addr >= begin && addr < end &&
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addr + len > begin && addr + len <= end);
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}
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#ifdef CONFIG_X86_32
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#define STACKSLOTS_PER_LINE 8
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#else
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#define STACKSLOTS_PER_LINE 4
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#endif
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#ifdef CONFIG_FRAME_POINTER
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static inline unsigned long *
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get_frame_pointer(struct task_struct *task, struct pt_regs *regs)
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{
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if (regs)
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return (unsigned long *)regs->bp;
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if (task == current)
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return __builtin_frame_address(0);
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return &((struct inactive_task_frame *)task->thread.sp)->bp;
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}
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#else
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static inline unsigned long *
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get_frame_pointer(struct task_struct *task, struct pt_regs *regs)
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{
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return NULL;
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}
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#endif /* CONFIG_FRAME_POINTER */
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static inline unsigned long *
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get_stack_pointer(struct task_struct *task, struct pt_regs *regs)
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{
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if (regs)
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return (unsigned long *)kernel_stack_pointer(regs);
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if (task == current)
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return __builtin_frame_address(0);
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return (unsigned long *)task->thread.sp;
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}
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void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
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unsigned long *stack, char *log_lvl);
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/* The form of the top of the frame on the stack */
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struct stack_frame {
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struct stack_frame *next_frame;
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unsigned long return_address;
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};
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struct stack_frame_ia32 {
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u32 next_frame;
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u32 return_address;
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};
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static inline unsigned long caller_frame_pointer(void)
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{
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struct stack_frame *frame;
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frame = __builtin_frame_address(0);
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#ifdef CONFIG_FRAME_POINTER
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frame = frame->next_frame;
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#endif
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return (unsigned long)frame;
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}
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void show_opcodes(struct pt_regs *regs, const char *loglvl);
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void show_ip(struct pt_regs *regs, const char *loglvl);
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#endif /* _ASM_X86_STACKTRACE_H */
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