From 95099d4622f8cb224d94e314c7a8e0df60b13f87 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Sat, 09 Dec 2023 08:38:01 +0000
Subject: [PATCH] enable docker ppp
---
kernel/arch/arm64/kernel/probes/kprobes.c | 280 +++++++++++++++----------------------------------------
1 files changed, 77 insertions(+), 203 deletions(-)
diff --git a/kernel/arch/arm64/kernel/probes/kprobes.c b/kernel/arch/arm64/kernel/probes/kprobes.c
index 2d63df1..798c3e7 100644
--- a/kernel/arch/arm64/kernel/probes/kprobes.c
+++ b/kernel/arch/arm64/kernel/probes/kprobes.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* arch/arm64/kernel/probes/kprobes.c
*
@@ -5,16 +6,6 @@
*
* Copyright (C) 2013 Linaro Limited.
* Author: Sandeepa Prabhu <sandeepa.prabhu@linaro.org>
- *
- * 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.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
*/
#include <linux/kasan.h>
#include <linux/kernel.h>
@@ -30,6 +21,7 @@
#include <asm/ptrace.h>
#include <asm/cacheflush.h>
#include <asm/debug-monitors.h>
+#include <asm/daifflags.h>
#include <asm/system_misc.h>
#include <asm/insn.h>
#include <linux/uaccess.h>
@@ -44,25 +36,16 @@
static void __kprobes
post_kprobe_handler(struct kprobe_ctlblk *, struct pt_regs *);
-static int __kprobes patch_text(kprobe_opcode_t *addr, u32 opcode)
-{
- void *addrs[1];
- u32 insns[1];
-
- addrs[0] = addr;
- insns[0] = opcode;
-
- return aarch64_insn_patch_text(addrs, insns, 1);
-}
-
static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
{
- /* prepare insn slot */
- patch_text(p->ainsn.api.insn, p->opcode);
+ kprobe_opcode_t *addr = p->ainsn.api.insn;
+ void *addrs[] = {addr, addr + 1};
+ u32 insns[] = {p->opcode, BRK64_OPCODE_KPROBES_SS};
- flush_icache_range((uintptr_t) (p->ainsn.api.insn),
- (uintptr_t) (p->ainsn.api.insn) +
- MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+ /* prepare insn slot */
+ aarch64_insn_patch_text(addrs, insns, 2);
+
+ flush_icache_range((uintptr_t)addr, (uintptr_t)(addr + MAX_INSN_SIZE));
/*
* Needs restoring of return address after stepping xol.
@@ -91,8 +74,6 @@
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
unsigned long probe_addr = (unsigned long)p->addr;
- extern char __start_rodata[];
- extern char __end_rodata[];
if (probe_addr & 0x3)
return -EINVAL;
@@ -100,10 +81,7 @@
/* copy instruction */
p->opcode = le32_to_cpu(*p->addr);
- if (in_exception_text(probe_addr))
- return -EINVAL;
- if (probe_addr >= (unsigned long) __start_rodata &&
- probe_addr <= (unsigned long) __end_rodata)
+ if (search_exception_tables(probe_addr))
return -EINVAL;
/* decode instruction */
@@ -120,7 +98,7 @@
if (!p->ainsn.api.insn)
return -ENOMEM;
break;
- };
+ }
/* prepare the instruction */
if (p->ainsn.api.insn)
@@ -133,25 +111,26 @@
void *alloc_insn_page(void)
{
- void *page;
-
- page = vmalloc_exec(PAGE_SIZE);
- if (page)
- set_memory_ro((unsigned long)page, 1);
-
- return page;
+ return __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
+ GFP_KERNEL, PAGE_KERNEL_ROX, VM_FLUSH_RESET_PERMS,
+ NUMA_NO_NODE, __builtin_return_address(0));
}
/* arm kprobe: install breakpoint in text */
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
- patch_text(p->addr, BRK64_OPCODE_KPROBES);
+ void *addr = p->addr;
+ u32 insn = BRK64_OPCODE_KPROBES;
+
+ aarch64_insn_patch_text(&addr, &insn, 1);
}
/* disarm kprobe: remove breakpoint from text */
void __kprobes arch_disarm_kprobe(struct kprobe *p)
{
- patch_text(p->addr, p->opcode);
+ void *addr = p->addr;
+
+ aarch64_insn_patch_text(&addr, &p->opcode, 1);
}
void __kprobes arch_remove_kprobe(struct kprobe *p)
@@ -180,54 +159,22 @@
}
/*
- * When PSTATE.D is set (masked), then software step exceptions can not be
- * generated.
- * SPSR's D bit shows the value of PSTATE.D immediately before the
- * exception was taken. PSTATE.D is set while entering into any exception
- * mode, however software clears it for any normal (none-debug-exception)
- * mode in the exception entry. Therefore, when we are entering into kprobe
- * breakpoint handler from any normal mode then SPSR.D bit is already
- * cleared, however it is set when we are entering from any debug exception
- * mode.
- * Since we always need to generate single step exception after a kprobe
- * breakpoint exception therefore we need to clear it unconditionally, when
- * we become sure that the current breakpoint exception is for kprobe.
- */
-static void __kprobes
-spsr_set_debug_flag(struct pt_regs *regs, int mask)
-{
- unsigned long spsr = regs->pstate;
-
- if (mask)
- spsr |= PSR_D_BIT;
- else
- spsr &= ~PSR_D_BIT;
-
- regs->pstate = spsr;
-}
-
-/*
- * Interrupts need to be disabled before single-step mode is set, and not
- * reenabled until after single-step mode ends.
- * Without disabling interrupt on local CPU, there is a chance of
- * interrupt occurrence in the period of exception return and start of
- * out-of-line single-step, that result in wrongly single stepping
- * into the interrupt handler.
+ * Mask all of DAIF while executing the instruction out-of-line, to keep things
+ * simple and avoid nesting exceptions. Interrupts do have to be disabled since
+ * the kprobe state is per-CPU and doesn't get migrated.
*/
static void __kprobes kprobes_save_local_irqflag(struct kprobe_ctlblk *kcb,
struct pt_regs *regs)
{
- kcb->saved_irqflag = regs->pstate;
- regs->pstate |= PSR_I_BIT;
+ kcb->saved_irqflag = regs->pstate & DAIF_MASK;
+ regs->pstate |= DAIF_MASK;
}
static void __kprobes kprobes_restore_local_irqflag(struct kprobe_ctlblk *kcb,
struct pt_regs *regs)
{
- if (kcb->saved_irqflag & PSR_I_BIT)
- regs->pstate |= PSR_I_BIT;
- else
- regs->pstate &= ~PSR_I_BIT;
+ regs->pstate &= ~DAIF_MASK;
+ regs->pstate |= kcb->saved_irqflag;
}
static void __kprobes
@@ -263,12 +210,7 @@
slot = (unsigned long)p->ainsn.api.insn;
set_ss_context(kcb, slot); /* mark pending ss */
-
- spsr_set_debug_flag(regs, 0);
-
- /* IRQs and single stepping do not mix well. */
kprobes_save_local_irqflag(kcb, regs);
- kernel_enable_single_step(regs);
instruction_pointer_set(regs, slot);
} else {
/* insn simulation */
@@ -319,12 +261,8 @@
}
/* call post handler */
kcb->kprobe_status = KPROBE_HIT_SSDONE;
- if (cur->post_handler) {
- /* post_handler can hit breakpoint and single step
- * again, so we enable D-flag for recursive exception.
- */
+ if (cur->post_handler)
cur->post_handler(cur, regs, 0);
- }
reset_current_kprobe();
}
@@ -348,12 +286,12 @@
if (!instruction_pointer(regs))
BUG();
- kernel_disable_single_step();
-
- if (kcb->kprobe_status == KPROBE_REENTER)
+ if (kcb->kprobe_status == KPROBE_REENTER) {
restore_previous_kprobe(kcb);
- else
+ } else {
+ kprobes_restore_local_irqflag(kcb, regs);
reset_current_kprobe();
+ }
break;
case KPROBE_HIT_ACTIVE:
@@ -411,10 +349,6 @@
* pre-handler and it returned non-zero, it will
* modify the execution path and no need to single
* stepping. Let's just reset current kprobe and exit.
- *
- * pre_handler can hit a breakpoint and can step thru
- * before return, keep PSTATE D-flag enabled until
- * pre_handler return back.
*/
if (!p->pre_handler || !p->pre_handler(p, regs)) {
setup_singlestep(p, regs, kcb, 0);
@@ -444,143 +378,80 @@
return DBG_HOOK_ERROR;
}
-int __kprobes
-kprobe_single_step_handler(struct pt_regs *regs, unsigned int esr)
+static int __kprobes
+kprobe_breakpoint_ss_handler(struct pt_regs *regs, unsigned int esr)
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
int retval;
-
- if (user_mode(regs))
- return DBG_HOOK_ERROR;
/* return error if this is not our step */
retval = kprobe_ss_hit(kcb, instruction_pointer(regs));
if (retval == DBG_HOOK_HANDLED) {
kprobes_restore_local_irqflag(kcb, regs);
- kernel_disable_single_step();
-
post_kprobe_handler(kcb, regs);
}
return retval;
}
-int __kprobes
+static struct break_hook kprobes_break_ss_hook = {
+ .imm = KPROBES_BRK_SS_IMM,
+ .fn = kprobe_breakpoint_ss_handler,
+};
+
+static int __kprobes
kprobe_breakpoint_handler(struct pt_regs *regs, unsigned int esr)
{
- if (user_mode(regs))
- return DBG_HOOK_ERROR;
-
kprobe_handler(regs);
return DBG_HOOK_HANDLED;
}
-bool arch_within_kprobe_blacklist(unsigned long addr)
+static struct break_hook kprobes_break_hook = {
+ .imm = KPROBES_BRK_IMM,
+ .fn = kprobe_breakpoint_handler,
+};
+
+/*
+ * Provide a blacklist of symbols identifying ranges which cannot be kprobed.
+ * This blacklist is exposed to userspace via debugfs (kprobes/blacklist).
+ */
+int __init arch_populate_kprobe_blacklist(void)
{
- if ((addr >= (unsigned long)__kprobes_text_start &&
- addr < (unsigned long)__kprobes_text_end) ||
- (addr >= (unsigned long)__entry_text_start &&
- addr < (unsigned long)__entry_text_end) ||
- (addr >= (unsigned long)__idmap_text_start &&
- addr < (unsigned long)__idmap_text_end) ||
- (addr >= (unsigned long)__hyp_text_start &&
- addr < (unsigned long)__hyp_text_end) ||
- !!search_exception_tables(addr))
- return true;
+ int ret;
- if (!is_kernel_in_hyp_mode()) {
- if ((addr >= (unsigned long)__hyp_idmap_text_start &&
- addr < (unsigned long)__hyp_idmap_text_end))
- return true;
- }
-
- return false;
+ ret = kprobe_add_area_blacklist((unsigned long)__entry_text_start,
+ (unsigned long)__entry_text_end);
+ if (ret)
+ return ret;
+ ret = kprobe_add_area_blacklist((unsigned long)__irqentry_text_start,
+ (unsigned long)__irqentry_text_end);
+ if (ret)
+ return ret;
+ ret = kprobe_add_area_blacklist((unsigned long)__idmap_text_start,
+ (unsigned long)__idmap_text_end);
+ if (ret)
+ return ret;
+ ret = kprobe_add_area_blacklist((unsigned long)__hyp_text_start,
+ (unsigned long)__hyp_text_end);
+ if (ret || is_kernel_in_hyp_mode())
+ return ret;
+ ret = kprobe_add_area_blacklist((unsigned long)__hyp_idmap_text_start,
+ (unsigned long)__hyp_idmap_text_end);
+ return ret;
}
void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
{
- struct kretprobe_instance *ri = NULL;
- struct hlist_head *head, empty_rp;
- struct hlist_node *tmp;
- unsigned long flags, orig_ret_address = 0;
- unsigned long trampoline_address =
- (unsigned long)&kretprobe_trampoline;
- kprobe_opcode_t *correct_ret_addr = NULL;
-
- INIT_HLIST_HEAD(&empty_rp);
- kretprobe_hash_lock(current, &head, &flags);
-
- /*
- * It is possible to have multiple instances associated with a given
- * task either because multiple functions in the call path have
- * return probes installed on them, and/or more than one
- * return probe was registered for a target function.
- *
- * We can handle this because:
- * - instances are always pushed into the head of the list
- * - when multiple return probes are registered for the same
- * function, the (chronologically) first instance's ret_addr
- * will be the real return address, and all the rest will
- * point to kretprobe_trampoline.
- */
- hlist_for_each_entry_safe(ri, tmp, head, hlist) {
- if (ri->task != current)
- /* another task is sharing our hash bucket */
- continue;
-
- orig_ret_address = (unsigned long)ri->ret_addr;
-
- if (orig_ret_address != trampoline_address)
- /*
- * This is the real return address. Any other
- * instances associated with this task are for
- * other calls deeper on the call stack
- */
- break;
- }
-
- kretprobe_assert(ri, orig_ret_address, trampoline_address);
-
- correct_ret_addr = ri->ret_addr;
- hlist_for_each_entry_safe(ri, tmp, head, hlist) {
- if (ri->task != current)
- /* another task is sharing our hash bucket */
- continue;
-
- orig_ret_address = (unsigned long)ri->ret_addr;
- if (ri->rp && ri->rp->handler) {
- __this_cpu_write(current_kprobe, &ri->rp->kp);
- get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
- ri->ret_addr = correct_ret_addr;
- ri->rp->handler(ri, regs);
- __this_cpu_write(current_kprobe, NULL);
- }
-
- recycle_rp_inst(ri, &empty_rp);
-
- if (orig_ret_address != trampoline_address)
- /*
- * This is the real return address. Any other
- * instances associated with this task are for
- * other calls deeper on the call stack
- */
- break;
- }
-
- kretprobe_hash_unlock(current, &flags);
-
- hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
- hlist_del(&ri->hlist);
- kfree(ri);
- }
- return (void *)orig_ret_address;
+ return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline,
+ (void *)kernel_stack_pointer(regs));
}
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
ri->ret_addr = (kprobe_opcode_t *)regs->regs[30];
+ ri->fp = (void *)kernel_stack_pointer(regs);
/* replace return addr (x30) with trampoline */
regs->regs[30] = (long)&kretprobe_trampoline;
@@ -593,5 +464,8 @@
int __init arch_init_kprobes(void)
{
+ register_kernel_break_hook(&kprobes_break_hook);
+ register_kernel_break_hook(&kprobes_break_ss_hook);
+
return 0;
}
--
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