cregit-Linux how code gets into the kernel

Release 4.14 arch/arm64/kernel/probes/uprobes.c

/*
 * Copyright (C) 2014-2016 Pratyush Anand <panand@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/highmem.h>
#include <linux/ptrace.h>
#include <linux/uprobes.h>
#include <asm/cacheflush.h>

#include "decode-insn.h"


#define UPROBE_INV_FAULT_CODE	UINT_MAX


void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr, void *src, unsigned long len) { void *xol_page_kaddr = kmap_atomic(page); void *dst = xol_page_kaddr + (vaddr & ~PAGE_MASK); /* Initialize the slot */ memcpy(dst, src, len); /* flush caches (dcache/icache) */ sync_icache_aliases(dst, len); kunmap_atomic(xol_page_kaddr); }

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Pratyush Anand67100.00%1100.00%
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unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) { return instruction_pointer(regs); }

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int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long addr) { probe_opcode_t insn; /* TODO: Currently we do not support AARCH32 instruction probing */ if (mm->context.flags & MMCF_AARCH32) return -ENOTSUPP; else if (!IS_ALIGNED(addr, AARCH64_INSN_SIZE)) return -EINVAL; insn = *(probe_opcode_t *)(&auprobe->insn[0]); switch (arm_probe_decode_insn(insn, &auprobe->api)) { case INSN_REJECTED: return -EINVAL; case INSN_GOOD_NO_SLOT: auprobe->simulate = true; break; default: break; } return 0; }

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Pratyush Anand10398.10%150.00%
Yury Norov21.90%150.00%
Total105100.00%2100.00%


int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) { struct uprobe_task *utask = current->utask; /* Initialize with an invalid fault code to detect if ol insn trapped */ current->thread.fault_code = UPROBE_INV_FAULT_CODE; /* Instruction points to execute ol */ instruction_pointer_set(regs, utask->xol_vaddr); user_enable_single_step(current); return 0; }

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int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) { struct uprobe_task *utask = current->utask; WARN_ON_ONCE(current->thread.fault_code != UPROBE_INV_FAULT_CODE); /* Instruction points to execute next to breakpoint address */ instruction_pointer_set(regs, utask->vaddr + 4); user_disable_single_step(current); return 0; }

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Pratyush Anand55100.00%1100.00%
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bool arch_uprobe_xol_was_trapped(struct task_struct *t) { /* * Between arch_uprobe_pre_xol and arch_uprobe_post_xol, if an xol * insn itself is trapped, then detect the case with the help of * invalid fault code which is being set in arch_uprobe_pre_xol */ if (t->thread.fault_code != UPROBE_INV_FAULT_CODE) return true; return false; }

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bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs) { probe_opcode_t insn; unsigned long addr; if (!auprobe->simulate) return false; insn = *(probe_opcode_t *)(&auprobe->insn[0]); addr = instruction_pointer(regs); if (auprobe->api.handler) auprobe->api.handler(insn, addr, regs); return true; }

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void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) { struct uprobe_task *utask = current->utask; /* * Task has received a fatal signal, so reset back to probbed * address. */ instruction_pointer_set(regs, utask->vaddr); user_disable_single_step(current); }

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Pratyush Anand39100.00%1100.00%
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bool arch_uretprobe_is_alive(struct return_instance *ret, enum rp_check ctx, struct pt_regs *regs) { /* * If a simple branch instruction (B) was called for retprobed * assembly label then return true even when regs->sp and ret->stack * are same. It will ensure that cleanup and reporting of return * instances corresponding to callee label is done when * handle_trampoline for called function is executed. */ if (ctx == RP_CHECK_CHAIN_CALL) return regs->sp <= ret->stack; else return regs->sp < ret->stack; }

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unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs) { unsigned long orig_ret_vaddr; orig_ret_vaddr = procedure_link_pointer(regs); /* Replace the return addr with trampoline addr */ procedure_link_pointer_set(regs, trampoline_vaddr); return orig_ret_vaddr; }

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int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data) { return NOTIFY_DONE; }

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static int uprobe_breakpoint_handler(struct pt_regs *regs, unsigned int esr) { if (user_mode(regs) && uprobe_pre_sstep_notifier(regs)) return DBG_HOOK_HANDLED; return DBG_HOOK_ERROR; }

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static int uprobe_single_step_handler(struct pt_regs *regs, unsigned int esr) { struct uprobe_task *utask = current->utask; if (user_mode(regs)) { WARN_ON(utask && (instruction_pointer(regs) != utask->xol_vaddr + 4)); if (uprobe_post_sstep_notifier(regs)) return DBG_HOOK_HANDLED; } return DBG_HOOK_ERROR; }

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Pratyush Anand64100.00%1100.00%
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/* uprobe breakpoint handler hook */ static struct break_hook uprobes_break_hook = { .esr_mask = BRK64_ESR_MASK, .esr_val = BRK64_ESR_UPROBES, .fn = uprobe_breakpoint_handler, }; /* uprobe single step handler hook */ static struct step_hook uprobes_step_hook = { .fn = uprobe_single_step_handler, };
static int __init arch_init_uprobes(void) { register_break_hook(&uprobes_break_hook); register_step_hook(&uprobes_step_hook); return 0; }

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device_initcall(arch_init_uprobes);

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Pratyush Anand72499.72%150.00%
Yury Norov20.28%150.00%
Total726100.00%2100.00%
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