| 1 | |
| 2 | |
| 3 | * linux/kernel/ptrace.c
|
| 4 | *
|
| 5 | * (C) Copyright 1999 Linus Torvalds
|
| 6 | *
|
| 7 | * Common interfaces for "ptrace()" which we do not want
|
| 8 | * to continually duplicate across every architecture.
|
| 9 |
|
| 10 |
|
| 11 | #include <linux/capability.h>
|
| 12 | #include <linux/export.h>
|
| 13 | #include <linux/sched.h>
|
| 14 | #include <linux/sched/mm.h>
|
| 15 | #include <linux/sched/coredump.h>
|
| 16 | #include <linux/sched/exec_state.h>
|
| 17 | #include <linux/sched/task.h>
|
| 18 | #include <linux/errno.h>
|
| 19 | #include <linux/mm.h>
|
| 20 | #include <linux/highmem.h>
|
| 21 | #include <linux/pagemap.h>
|
| 22 | #include <linux/ptrace.h>
|
| 23 | #include <linux/security.h>
|
| 24 | #include <linux/signal.h>
|
| 25 | #include <linux/uio.h>
|
| 26 | #include <linux/audit.h>
|
| 27 | #include <linux/pid_namespace.h>
|
| 28 | #include <linux/syscalls.h>
|
| 29 | #include <linux/uaccess.h>
|
| 30 | #include <linux/regset.h>
|
| 31 | #include <linux/hw_breakpoint.h>
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| 32 | #include <linux/cn_proc.h>
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| 33 | #include <linux/compat.h>
|
| 34 | #include <linux/sched/signal.h>
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| 35 | #include <linux/minmax.h>
|
| 36 | #include <linux/syscall_user_dispatch.h>
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| 37 |
|
| 38 | #include <asm/syscall.h>
|
| 39 |
|
| 40 | |
| 41 | * ptracer_access_allowed - may current peek/poke @tsk's address space?
|
| 42 | * @tsk: tracee
|
| 43 | *
|
| 44 | * Per-access check used by ptrace_access_vm() and architecture-specific
|
| 45 | * tag/register accessors. Returns true iff current is the registered
|
| 46 | * ptracer of @tsk and either @tsk is owner-dumpable or current holds
|
| 47 | * CAP_SYS_PTRACE in @tsk's exec namespace. Lighter than
|
| 48 | * __ptrace_may_access(): it re-validates only dumpability and
|
| 49 | * capability on every access, without re-running LSM hooks or
|
| 50 | * cred_cap_issubset() checks performed at attach time.
|
| 51 |
|
| 52 | bool ptracer_access_allowed(struct task_struct *tsk)
|
| 53 | {
|
| 54 | const struct task_exec_state *es;
|
| 55 |
|
| 56 | guard(rcu)();
|
| 57 | if (ptrace_parent(tsk) != current)
|
| 58 | return false;
|
| 59 | es = task_exec_state_rcu(tsk);
|
| 60 | return READ_ONCE(es->dumpable) == TASK_DUMPABLE_OWNER ||
|
| 61 | ptracer_capable(tsk, es->user_ns);
|
| 62 | }
|
| 63 |
|
| 64 | |
| 65 | * Access another process' address space via ptrace.
|
| 66 | * Source/target buffer must be kernel space,
|
| 67 | * Do not walk the page table directly, use get_user_pages
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| 68 |
|
| 69 | int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
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| 70 | void *buf, int len, unsigned int gup_flags)
|
| 71 | {
|
| 72 | struct mm_struct *mm;
|
| 73 | int ret = 0;
|
| 74 |
|
| 75 | mm = get_task_mm(tsk);
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| 76 | if (!mm)
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| 77 | return 0;
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| 78 |
|
| 79 | if (ptracer_access_allowed(tsk))
|
| 80 | ret = access_remote_vm(mm, addr, buf, len, gup_flags);
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| 81 | mmput(mm);
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| 82 |
|
| 83 | return ret;
|
| 84 | }
|
| 85 |
|
| 86 |
|
| 87 | void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
|
| 88 | const struct cred *ptracer_cred)
|
| 89 | {
|
| 90 | BUG_ON(!list_empty(&child->ptrace_entry));
|
| 91 | list_add(&child->ptrace_entry, &new_parent->ptraced);
|
| 92 | child->parent = new_parent;
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| 93 | child->ptracer_cred = get_cred(ptracer_cred);
|
| 94 | }
|
| 95 |
|
| 96 | |
| 97 | * ptrace a task: make the debugger its new parent and
|
| 98 | * move it to the ptrace list.
|
| 99 | *
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| 100 | * Must be called with the tasklist lock write-held.
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| 101 |
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| 102 | static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
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| 103 | {
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| 104 | __ptrace_link(child, new_parent, current_cred());
|
| 105 | }
|
| 106 |
|
| 107 | |
| 108 | * __ptrace_unlink - unlink ptracee and restore its execution state
|
| 109 | * @child: ptracee to be unlinked
|
| 110 | *
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| 111 | * Remove @child from the ptrace list, move it back to the original parent,
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| 112 | * and restore the execution state so that it conforms to the group stop
|
| 113 | * state.
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| 114 | *
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| 115 | * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
|
| 116 | * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
|
| 117 | * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
|
| 118 | * If the ptracer is exiting, the ptracee can be in any state.
|
| 119 | *
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| 120 | * After detach, the ptracee should be in a state which conforms to the
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| 121 | * group stop. If the group is stopped or in the process of stopping, the
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| 122 | * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
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| 123 | * up from TASK_TRACED.
|
| 124 | *
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| 125 | * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
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| 126 | * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
|
| 127 | * to but in the opposite direction of what happens while attaching to a
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| 128 | * stopped task. However, in this direction, the intermediate RUNNING
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| 129 | * state is not hidden even from the current ptracer and if it immediately
|
| 130 | * re-attaches and performs a WNOHANG wait(2), it may fail.
|
| 131 | *
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| 132 | * CONTEXT:
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| 133 | * write_lock_irq(tasklist_lock)
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| 134 |
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| 135 | void __ptrace_unlink(struct task_struct *child)
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| 136 | {
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| 137 | const struct cred *old_cred;
|
| 138 | BUG_ON(!child->ptrace);
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| 139 |
|
| 140 | clear_task_syscall_work(child, SYSCALL_TRACE);
|
| 141 | #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
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| 142 | clear_task_syscall_work(child, SYSCALL_EMU);
|
| 143 | #endif
|
| 144 |
|
| 145 | child->parent = child->real_parent;
|
| 146 | list_del_init(&child->ptrace_entry);
|
| 147 | old_cred = child->ptracer_cred;
|
| 148 | child->ptracer_cred = NULL;
|
| 149 | put_cred(old_cred);
|
| 150 |
|
| 151 | spin_lock(&child->sighand->siglock);
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| 152 | child->ptrace = 0;
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| 153 | |
| 154 | * Clear all pending traps and TRAPPING. TRAPPING should be
|
| 155 | * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
|
| 156 |
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| 157 | task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
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| 158 | task_clear_jobctl_trapping(child);
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| 159 |
|
| 160 | |
| 161 | * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
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| 162 | * @child isn't dead.
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| 163 |
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| 164 | if (!(child->flags & PF_EXITING) &&
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| 165 | (child->signal->flags & SIGNAL_STOP_STOPPED ||
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| 166 | child->signal->group_stop_count))
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| 167 | child->jobctl |= JOBCTL_STOP_PENDING;
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| 168 |
|
| 169 | |
| 170 | * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
|
| 171 | * @child in the butt. Note that @resume should be used iff @child
|
| 172 | * is in TASK_TRACED; otherwise, we might unduly disrupt
|
| 173 | * TASK_KILLABLE sleeps.
|
| 174 |
|
| 175 | if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
|
| 176 | ptrace_signal_wake_up(child, true);
|
| 177 |
|
| 178 | spin_unlock(&child->sighand->siglock);
|
| 179 | }
|
| 180 |
|
| 181 | static bool looks_like_a_spurious_pid(struct task_struct *task)
|
| 182 | {
|
| 183 | if (task->exit_code != ((PTRACE_EVENT_EXEC << 8) | SIGTRAP))
|
| 184 | return false;
|
| 185 |
|
| 186 | if (task_pid_vnr(task) == task->ptrace_message)
|
| 187 | return false;
|
| 188 | |
| 189 | * The tracee changed its pid but the PTRACE_EVENT_EXEC event
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| 190 | * was not wait()'ed, most probably debugger targets the old
|
| 191 | * leader which was destroyed in de_thread().
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| 192 |
|
| 193 | return true;
|
| 194 | }
|
| 195 |
|
| 196 | |
| 197 | * Ensure that nothing can wake it up, even SIGKILL
|
| 198 | *
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| 199 | * A task is switched to this state while a ptrace operation is in progress;
|
| 200 | * such that the ptrace operation is uninterruptible.
|
| 201 |
|
| 202 | static bool ptrace_freeze_traced(struct task_struct *task)
|
| 203 | {
|
| 204 | bool ret = false;
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| 205 |
|
| 206 |
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| 207 | if (task->jobctl & JOBCTL_LISTENING)
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| 208 | return ret;
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| 209 |
|
| 210 | spin_lock_irq(&task->sighand->siglock);
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| 211 | if (task_is_traced(task) && !looks_like_a_spurious_pid(task) &&
|
| 212 | !__fatal_signal_pending(task)) {
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| 213 | task->jobctl |= JOBCTL_PTRACE_FROZEN;
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| 214 | ret = true;
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| 215 | }
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| 216 | spin_unlock_irq(&task->sighand->siglock);
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| 217 |
|
| 218 | return ret;
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| 219 | }
|
| 220 |
|
| 221 | static void ptrace_unfreeze_traced(struct task_struct *task)
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| 222 | {
|
| 223 | unsigned long flags;
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| 224 |
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| 225 | |
| 226 | * The child may be awake and may have cleared
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| 227 | * JOBCTL_PTRACE_FROZEN (see ptrace_resume). The child will
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| 228 | * not set JOBCTL_PTRACE_FROZEN or enter __TASK_TRACED anew.
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| 229 |
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| 230 | if (lock_task_sighand(task, &flags)) {
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| 231 | task->jobctl &= ~JOBCTL_PTRACE_FROZEN;
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| 232 | if (__fatal_signal_pending(task)) {
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| 233 | task->jobctl &= ~JOBCTL_TRACED;
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| 234 | wake_up_state(task, __TASK_TRACED);
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| 235 | }
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| 236 | unlock_task_sighand(task, &flags);
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| 237 | }
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| 238 | }
|
| 239 |
|
| 240 | |
| 241 | * ptrace_check_attach - check whether ptracee is ready for ptrace operation
|
| 242 | * @child: ptracee to check for
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| 243 | * @ignore_state: don't check whether @child is currently %TASK_TRACED
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| 244 | *
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| 245 | * Check whether @child is being ptraced by %current and ready for further
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| 246 | * ptrace operations. If @ignore_state is %false, @child also should be in
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| 247 | * %TASK_TRACED state and on return the child is guaranteed to be traced
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| 248 | * and not executing. If @ignore_state is %true, @child can be in any
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| 249 | * state.
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| 250 | *
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| 251 | * CONTEXT:
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| 252 | * Grabs and releases tasklist_lock and @child->sighand->siglock.
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| 253 | *
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| 254 | * RETURNS:
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| 255 | * 0 on success, -ESRCH if %child is not ready.
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| 256 |
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| 257 | static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
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| 258 | {
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| 259 | int ret = -ESRCH;
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| 260 |
|
| 261 | |
| 262 | * We take the read lock around doing both checks to close a
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| 263 | * possible race where someone else was tracing our child and
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| 264 | * detached between these two checks. After this locked check,
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| 265 | * we are sure that this is our traced child and that can only
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| 266 | * be changed by us so it's not changing right after this.
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| 267 |
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| 268 | read_lock(&tasklist_lock);
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| 269 | if (child->ptrace && child->parent == current) {
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| 270 | |
| 271 | * child->sighand can't be NULL, release_task()
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| 272 | * does ptrace_unlink() before __exit_signal().
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| 273 |
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| 274 | if (ignore_state || ptrace_freeze_traced(child))
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| 275 | ret = 0;
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| 276 | }
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| 277 | read_unlock(&tasklist_lock);
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| 278 |
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| 279 | if (!ret && !ignore_state &&
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| 280 | WARN_ON_ONCE(!wait_task_inactive(child, __TASK_TRACED|TASK_FROZEN)))
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| 281 | ret = -ESRCH;
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| 282 |
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| 283 | return ret;
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| 284 | }
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| 285 |
|
| 286 | static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
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| 287 | {
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| 288 | if (mode & PTRACE_MODE_NOAUDIT)
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| 289 | return ns_capable_noaudit(ns, CAP_SYS_PTRACE);
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| 290 | return ns_capable(ns, CAP_SYS_PTRACE);
|
| 291 | }
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| 292 |
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| 293 | static bool task_still_dumpable(struct task_struct *task, unsigned int mode)
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| 294 | {
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| 295 | const struct task_exec_state *exec_state;
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| 296 |
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| 297 | guard(rcu)();
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| 298 | exec_state = task_exec_state_rcu(task);
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| 299 | if (READ_ONCE(exec_state->dumpable) == TASK_DUMPABLE_OWNER)
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| 300 | return true;
|
| 301 | return ptrace_has_cap(exec_state->user_ns, mode);
|
| 302 | }
|
| 303 |
|
| 304 |
|
| 305 | static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
|
| 306 | {
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| 307 | const struct cred *cred = current_cred(), *tcred;
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| 308 | kuid_t caller_uid;
|
| 309 | kgid_t caller_gid;
|
| 310 |
|
| 311 | if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
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| 312 | WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
|
| 313 | return -EPERM;
|
| 314 | }
|
| 315 |
|
| 316 | |
| 317 | * This check is used both for attaching with ptrace
|
| 318 | * and for allowing access to sensitive information in /proc.
|
| 319 | *
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| 320 | * ptrace_attach denies several cases that /proc allows
|
| 321 | * because setting up the necessary parent/child relationship
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| 322 | * or halting the specified task is impossible.
|
| 323 |
|
| 324 |
|
| 325 |
|
| 326 | if (same_thread_group(task, current))
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| 327 | return 0;
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| 328 | rcu_read_lock();
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| 329 | if (mode & PTRACE_MODE_FSCREDS) {
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| 330 | caller_uid = cred->fsuid;
|
| 331 | caller_gid = cred->fsgid;
|
| 332 | } else {
|
| 333 | |
| 334 | * Using the euid would make more sense here, but something
|
| 335 | * in userland might rely on the old behavior, and this
|
| 336 | * shouldn't be a security problem since
|
| 337 | * PTRACE_MODE_REALCREDS implies that the caller explicitly
|
| 338 | * used a syscall that requests access to another process
|
| 339 | * (and not a filesystem syscall to procfs).
|
| 340 |
|
| 341 | caller_uid = cred->uid;
|
| 342 | caller_gid = cred->gid;
|
| 343 | }
|
| 344 | tcred = __task_cred(task);
|
| 345 | if (uid_eq(caller_uid, tcred->euid) &&
|
| 346 | uid_eq(caller_uid, tcred->suid) &&
|
| 347 | uid_eq(caller_uid, tcred->uid) &&
|
| 348 | gid_eq(caller_gid, tcred->egid) &&
|
| 349 | gid_eq(caller_gid, tcred->sgid) &&
|
| 350 | gid_eq(caller_gid, tcred->gid))
|
| 351 | goto ok;
|
| 352 | if (ptrace_has_cap(tcred->user_ns, mode))
|
| 353 | goto ok;
|
| 354 | rcu_read_unlock();
|
| 355 | return -EPERM;
|
| 356 | ok:
|
| 357 | rcu_read_unlock();
|
| 358 | |
| 359 | * If a task drops privileges and becomes nondumpable (through a syscall
|
| 360 | * like setresuid()) while we are trying to access it, we must ensure
|
| 361 | * that the dumpability is read after the credentials; otherwise,
|
| 362 | * we may be able to attach to a task that we shouldn't be able to
|
| 363 | * attach to (as if the task had dropped privileges without becoming
|
| 364 | * nondumpable).
|
| 365 | * Pairs with a write barrier in commit_creds().
|
| 366 |
|
| 367 | smp_rmb();
|
| 368 | if (!task_still_dumpable(task, mode))
|
| 369 | return -EPERM;
|
| 370 |
|
| 371 | return security_ptrace_access_check(task, mode);
|
| 372 | }
|
| 373 |
|
| 374 | bool ptrace_may_access(struct task_struct *task, unsigned int mode)
|
| 375 | {
|
| 376 | int err;
|
| 377 | task_lock(task);
|
| 378 | err = __ptrace_may_access(task, mode);
|
| 379 | task_unlock(task);
|
| 380 | return !err;
|
| 381 | }
|
| 382 |
|
| 383 | static int check_ptrace_options(unsigned long data)
|
| 384 | {
|
| 385 | if (data & ~(unsigned long)PTRACE_O_MASK)
|
| 386 | return -EINVAL;
|
| 387 |
|
| 388 | if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
|
| 389 | if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
|
| 390 | !IS_ENABLED(CONFIG_SECCOMP))
|
| 391 | return -EINVAL;
|
| 392 |
|
| 393 | if (!capable(CAP_SYS_ADMIN))
|
| 394 | return -EPERM;
|
| 395 |
|
| 396 | if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
|
| 397 | current->ptrace & PT_SUSPEND_SECCOMP)
|
| 398 | return -EPERM;
|
| 399 | }
|
| 400 | return 0;
|
| 401 | }
|
| 402 |
|
| 403 | static inline void ptrace_set_stopped(struct task_struct *task, bool seize)
|
| 404 | {
|
| 405 | guard(spinlock)(&task->sighand->siglock);
|
| 406 |
|
| 407 |
|
| 408 | if (!seize)
|
| 409 | send_signal_locked(SIGSTOP, SEND_SIG_PRIV, task, PIDTYPE_PID);
|
| 410 | |
| 411 | * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
|
| 412 | * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
|
| 413 | * will be cleared if the child completes the transition or any
|
| 414 | * event which clears the group stop states happens. We'll wait
|
| 415 | * for the transition to complete before returning from this
|
| 416 | * function.
|
| 417 | *
|
| 418 | * This hides STOPPED -> RUNNING -> TRACED transition from the
|
| 419 | * attaching thread but a different thread in the same group can
|
| 420 | * still observe the transient RUNNING state. IOW, if another
|
| 421 | * thread's WNOHANG wait(2) on the stopped tracee races against
|
| 422 | * ATTACH, the wait(2) may fail due to the transient RUNNING.
|
| 423 | *
|
| 424 | * The following task_is_stopped() test is safe as both transitions
|
| 425 | * in and out of STOPPED are protected by siglock.
|
| 426 |
|
| 427 | if (task_is_stopped(task) &&
|
| 428 | task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) {
|
| 429 | task->jobctl &= ~JOBCTL_STOPPED;
|
| 430 | signal_wake_up_state(task, __TASK_STOPPED);
|
| 431 | }
|
| 432 | }
|
| 433 |
|
| 434 | static int ptrace_attach(struct task_struct *task, long request,
|
| 435 | unsigned long addr,
|
| 436 | unsigned long flags)
|
| 437 | {
|
| 438 | bool seize = (request == PTRACE_SEIZE);
|
| 439 | int retval;
|
| 440 |
|
| 441 | if (seize) {
|
| 442 | if (addr != 0)
|
| 443 | return -EIO;
|
| 444 | |
| 445 | * This duplicates the check in check_ptrace_options() because
|
| 446 | * ptrace_attach() and ptrace_setoptions() have historically
|
| 447 | * used different error codes for unknown ptrace options.
|
| 448 |
|
| 449 | if (flags & ~(unsigned long)PTRACE_O_MASK)
|
| 450 | return -EIO;
|
| 451 |
|
| 452 | retval = check_ptrace_options(flags);
|
| 453 | if (retval)
|
| 454 | return retval;
|
| 455 | flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
|
| 456 | } else {
|
| 457 | flags = PT_PTRACED;
|
| 458 | }
|
| 459 |
|
| 460 | audit_ptrace(task);
|
| 461 |
|
| 462 | if (unlikely(task->flags & PF_KTHREAD))
|
| 463 | return -EPERM;
|
| 464 | if (same_thread_group(task, current))
|
| 465 | return -EPERM;
|
| 466 |
|
| 467 | |
| 468 | * Protect exec's credential calculations against our interference;
|
| 469 | * SUID, SGID and LSM creds get determined differently
|
| 470 | * under ptrace.
|
| 471 |
|
| 472 | scoped_cond_guard (mutex_intr, return -ERESTARTNOINTR,
|
| 473 | &task->signal->cred_guard_mutex) {
|
| 474 |
|
| 475 | scoped_guard (task_lock, task) {
|
| 476 | retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
|
| 477 | if (retval)
|
| 478 | return retval;
|
| 479 | }
|
| 480 |
|
| 481 | scoped_guard (write_lock_irq, &tasklist_lock) {
|
| 482 | if (unlikely(task->exit_state))
|
| 483 | return -EPERM;
|
| 484 | if (task->ptrace)
|
| 485 | return -EPERM;
|
| 486 |
|
| 487 | task->ptrace = flags;
|
| 488 | ptrace_link(task, current);
|
| 489 | ptrace_set_stopped(task, seize);
|
| 490 | }
|
| 491 | }
|
| 492 |
|
| 493 | |
| 494 | * We do not bother to change retval or clear JOBCTL_TRAPPING
|
| 495 | * if wait_on_bit() was interrupted by SIGKILL. The tracer will
|
| 496 | * not return to user-mode, it will exit and clear this bit in
|
| 497 | * __ptrace_unlink() if it wasn't already cleared by the tracee;
|
| 498 | * and until then nobody can ptrace this task.
|
| 499 |
|
| 500 | wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
|
| 501 | proc_ptrace_connector(task, PTRACE_ATTACH);
|
| 502 |
|
| 503 | return 0;
|
| 504 | }
|
| 505 |
|
| 506 | |
| 507 | * ptrace_traceme -- helper for PTRACE_TRACEME
|
| 508 | *
|
| 509 | * Performs checks and sets PT_PTRACED.
|
| 510 | * Should be used by all ptrace implementations for PTRACE_TRACEME.
|
| 511 |
|
| 512 | static int ptrace_traceme(void)
|
| 513 | {
|
| 514 | int ret = -EPERM;
|
| 515 |
|
| 516 | write_lock_irq(&tasklist_lock);
|
| 517 |
|
| 518 | if (!current->ptrace) {
|
| 519 | ret = security_ptrace_traceme(current->parent);
|
| 520 | |
| 521 | * Check PF_EXITING to ensure ->real_parent has not passed
|
| 522 | * exit_ptrace(). Otherwise we don't report the error but
|
| 523 | * pretend ->real_parent untraces us right after return.
|
| 524 |
|
| 525 | if (!ret && !(current->real_parent->flags & PF_EXITING)) {
|
| 526 | current->ptrace = PT_PTRACED;
|
| 527 | ptrace_link(current, current->real_parent);
|
| 528 | }
|
| 529 | }
|
| 530 | write_unlock_irq(&tasklist_lock);
|
| 531 |
|
| 532 | return ret;
|
| 533 | }
|
| 534 |
|
| 535 | |
| 536 | * Called with irqs disabled, returns true if childs should reap themselves.
|
| 537 |
|
| 538 | static int ignoring_children(struct sighand_struct *sigh)
|
| 539 | {
|
| 540 | int ret;
|
| 541 | spin_lock(&sigh->siglock);
|
| 542 | ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
|
| 543 | (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
|
| 544 | spin_unlock(&sigh->siglock);
|
| 545 | return ret;
|
| 546 | }
|
| 547 |
|
| 548 | |
| 549 | * Called with tasklist_lock held for writing.
|
| 550 | * Unlink a traced task, and clean it up if it was a traced zombie.
|
| 551 | * Return true if it needs to be reaped with release_task().
|
| 552 | * (We can't call release_task() here because we already hold tasklist_lock.)
|
| 553 | *
|
| 554 | * If it's a zombie, our attachedness prevented normal parent notification
|
| 555 | * or self-reaping. Do notification now if it would have happened earlier.
|
| 556 | * If it should reap itself, return true.
|
| 557 | *
|
| 558 | * If it's our own child, there is no notification to do. But if our normal
|
| 559 | * children self-reap, then this child was prevented by ptrace and we must
|
| 560 | * reap it now, in that case we must also wake up sub-threads sleeping in
|
| 561 | * do_wait().
|
| 562 |
|
| 563 | static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
|
| 564 | {
|
| 565 | bool dead;
|
| 566 |
|
| 567 | __ptrace_unlink(p);
|
| 568 |
|
| 569 | if (p->exit_state != EXIT_ZOMBIE)
|
| 570 | return false;
|
| 571 |
|
| 572 | dead = !thread_group_leader(p);
|
| 573 |
|
| 574 | if (!dead && thread_group_empty(p)) {
|
| 575 | if (!same_thread_group(p->real_parent, tracer))
|
| 576 | dead = do_notify_parent(p, p->exit_signal);
|
| 577 | else if (ignoring_children(tracer->sighand) ||
|
| 578 | p->signal->autoreap) {
|
| 579 | __wake_up_parent(p, tracer);
|
| 580 | dead = true;
|
| 581 | }
|
| 582 | }
|
| 583 |
|
| 584 | if (dead)
|
| 585 | p->exit_state = EXIT_DEAD;
|
| 586 | return dead;
|
| 587 | }
|
| 588 |
|
| 589 | static int ptrace_detach(struct task_struct *child, unsigned int data)
|
| 590 | {
|
| 591 | if (!valid_signal(data))
|
| 592 | return -EIO;
|
| 593 |
|
| 594 |
|
| 595 | ptrace_disable(child);
|
| 596 |
|
| 597 | write_lock_irq(&tasklist_lock);
|
| 598 | |
| 599 | * We rely on ptrace_freeze_traced(). It can't be killed and
|
| 600 | * untraced by another thread, it can't be a zombie.
|
| 601 |
|
| 602 | WARN_ON(!child->ptrace || child->exit_state);
|
| 603 | |
| 604 | * tasklist_lock avoids the race with wait_task_stopped(), see
|
| 605 | * the comment in ptrace_resume().
|
| 606 |
|
| 607 | child->exit_code = data;
|
| 608 | __ptrace_detach(current, child);
|
| 609 | write_unlock_irq(&tasklist_lock);
|
| 610 |
|
| 611 | proc_ptrace_connector(child, PTRACE_DETACH);
|
| 612 |
|
| 613 | return 0;
|
| 614 | }
|
| 615 |
|
| 616 | |
| 617 | * Detach all tasks we were using ptrace on. Called with tasklist held
|
| 618 | * for writing.
|
| 619 |
|
| 620 | void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
|
| 621 | {
|
| 622 | struct task_struct *p, *n;
|
| 623 |
|
| 624 | list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
|
| 625 | if (unlikely(p->ptrace & PT_EXITKILL))
|
| 626 | send_sig_info(SIGKILL, SEND_SIG_PRIV, p);
|
| 627 |
|
| 628 | if (__ptrace_detach(tracer, p))
|
| 629 | list_add(&p->ptrace_entry, dead);
|
| 630 | }
|
| 631 | }
|
| 632 |
|
| 633 | int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
|
| 634 | {
|
| 635 | int copied = 0;
|
| 636 |
|
| 637 | while (len > 0) {
|
| 638 | char buf[128];
|
| 639 | int this_len, retval;
|
| 640 |
|
| 641 | this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
|
| 642 | retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
|
| 643 |
|
| 644 | if (!retval) {
|
| 645 | if (copied)
|
| 646 | break;
|
| 647 | return -EIO;
|
| 648 | }
|
| 649 | if (copy_to_user(dst, buf, retval))
|
| 650 | return -EFAULT;
|
| 651 | copied += retval;
|
| 652 | src += retval;
|
| 653 | dst += retval;
|
| 654 | len -= retval;
|
| 655 | }
|
| 656 | return copied;
|
| 657 | }
|
| 658 |
|
| 659 | int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
|
| 660 | {
|
| 661 | int copied = 0;
|
| 662 |
|
| 663 | while (len > 0) {
|
| 664 | char buf[128];
|
| 665 | int this_len, retval;
|
| 666 |
|
| 667 | this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
|
| 668 | if (copy_from_user(buf, src, this_len))
|
| 669 | return -EFAULT;
|
| 670 | retval = ptrace_access_vm(tsk, dst, buf, this_len,
|
| 671 | FOLL_FORCE | FOLL_WRITE);
|
| 672 | if (!retval) {
|
| 673 | if (copied)
|
| 674 | break;
|
| 675 | return -EIO;
|
| 676 | }
|
| 677 | copied += retval;
|
| 678 | src += retval;
|
| 679 | dst += retval;
|
| 680 | len -= retval;
|
| 681 | }
|
| 682 | return copied;
|
| 683 | }
|
| 684 |
|
| 685 | static int ptrace_setoptions(struct task_struct *child, unsigned long data)
|
| 686 | {
|
| 687 | unsigned flags;
|
| 688 | int ret;
|
| 689 |
|
| 690 | ret = check_ptrace_options(data);
|
| 691 | if (ret)
|
| 692 | return ret;
|
| 693 |
|
| 694 |
|
| 695 | flags = child->ptrace;
|
| 696 | flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
|
| 697 | flags |= (data << PT_OPT_FLAG_SHIFT);
|
| 698 | child->ptrace = flags;
|
| 699 |
|
| 700 | return 0;
|
| 701 | }
|
| 702 |
|
| 703 | static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info)
|
| 704 | {
|
| 705 | unsigned long flags;
|
| 706 | int error = -ESRCH;
|
| 707 |
|
| 708 | if (lock_task_sighand(child, &flags)) {
|
| 709 | error = -EINVAL;
|
| 710 | if (likely(child->last_siginfo != NULL)) {
|
| 711 | copy_siginfo(info, child->last_siginfo);
|
| 712 | error = 0;
|
| 713 | }
|
| 714 | unlock_task_sighand(child, &flags);
|
| 715 | }
|
| 716 | return error;
|
| 717 | }
|
| 718 |
|
| 719 | static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info)
|
| 720 | {
|
| 721 | unsigned long flags;
|
| 722 | int error = -ESRCH;
|
| 723 |
|
| 724 | if (lock_task_sighand(child, &flags)) {
|
| 725 | error = -EINVAL;
|
| 726 | if (likely(child->last_siginfo != NULL)) {
|
| 727 | copy_siginfo(child->last_siginfo, info);
|
| 728 | error = 0;
|
| 729 | }
|
| 730 | unlock_task_sighand(child, &flags);
|
| 731 | }
|
| 732 | return error;
|
| 733 | }
|
| 734 |
|
| 735 | static int ptrace_peek_siginfo(struct task_struct *child,
|
| 736 | unsigned long addr,
|
| 737 | unsigned long data)
|
| 738 | {
|
| 739 | struct ptrace_peeksiginfo_args arg;
|
| 740 | struct sigpending *pending;
|
| 741 | struct sigqueue *q;
|
| 742 | int ret, i;
|
| 743 |
|
| 744 | ret = copy_from_user(&arg, (void __user *) addr,
|
| 745 | sizeof(struct ptrace_peeksiginfo_args));
|
| 746 | if (ret)
|
| 747 | return -EFAULT;
|
| 748 |
|
| 749 | if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
|
| 750 | return -EINVAL;
|
| 751 |
|
| 752 | if (arg.nr < 0)
|
| 753 | return -EINVAL;
|
| 754 |
|
| 755 |
|
| 756 | if (arg.off > ULONG_MAX)
|
| 757 | return 0;
|
| 758 |
|
| 759 | if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
|
| 760 | pending = &child->signal->shared_pending;
|
| 761 | else
|
| 762 | pending = &child->pending;
|
| 763 |
|
| 764 | for (i = 0; i < arg.nr; ) {
|
| 765 | kernel_siginfo_t info;
|
| 766 | unsigned long off = arg.off + i;
|
| 767 | bool found = false;
|
| 768 |
|
| 769 | spin_lock_irq(&child->sighand->siglock);
|
| 770 | list_for_each_entry(q, &pending->list, list) {
|
| 771 | if (!off--) {
|
| 772 | found = true;
|
| 773 | copy_siginfo(&info, &q->info);
|
| 774 | break;
|
| 775 | }
|
| 776 | }
|
| 777 | spin_unlock_irq(&child->sighand->siglock);
|
| 778 |
|
| 779 | if (!found)
|
| 780 | break;
|
| 781 |
|
| 782 | #ifdef CONFIG_COMPAT
|
| 783 | if (unlikely(in_compat_syscall())) {
|
| 784 | compat_siginfo_t __user *uinfo = compat_ptr(data);
|
| 785 |
|
| 786 | if (copy_siginfo_to_user32(uinfo, &info)) {
|
| 787 | ret = -EFAULT;
|
| 788 | break;
|
| 789 | }
|
| 790 |
|
| 791 | } else
|
| 792 | #endif
|
| 793 | {
|
| 794 | siginfo_t __user *uinfo = (siginfo_t __user *) data;
|
| 795 |
|
| 796 | if (copy_siginfo_to_user(uinfo, &info)) {
|
| 797 | ret = -EFAULT;
|
| 798 | break;
|
| 799 | }
|
| 800 | }
|
| 801 |
|
| 802 | data += sizeof(siginfo_t);
|
| 803 | i++;
|
| 804 |
|
| 805 | if (signal_pending(current))
|
| 806 | break;
|
| 807 |
|
| 808 | cond_resched();
|
| 809 | }
|
| 810 |
|
| 811 | if (i > 0)
|
| 812 | return i;
|
| 813 |
|
| 814 | return ret;
|
| 815 | }
|
| 816 |
|
| 817 | #ifdef CONFIG_RSEQ
|
| 818 | static long ptrace_get_rseq_configuration(struct task_struct *task,
|
| 819 | unsigned long size, void __user *data)
|
| 820 | {
|
| 821 | struct ptrace_rseq_configuration conf = {
|
| 822 | .rseq_abi_pointer = (u64)(uintptr_t)task->rseq.usrptr,
|
| 823 | .rseq_abi_size = task->rseq.len,
|
| 824 | .signature = task->rseq.sig,
|
| 825 | .flags = 0,
|
| 826 | };
|
| 827 |
|
| 828 | size = min_t(unsigned long, size, sizeof(conf));
|
| 829 | if (copy_to_user(data, &conf, size))
|
| 830 | return -EFAULT;
|
| 831 | return sizeof(conf);
|
| 832 | }
|
| 833 | #endif
|
| 834 |
|
| 835 | #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
|
| 836 |
|
| 837 | #ifdef PTRACE_SINGLEBLOCK
|
| 838 | #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
|
| 839 | #else
|
| 840 | #define is_singleblock(request) 0
|
| 841 | #endif
|
| 842 |
|
| 843 | #ifdef PTRACE_SYSEMU
|
| 844 | #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
|
| 845 | #else
|
| 846 | #define is_sysemu_singlestep(request) 0
|
| 847 | #endif
|
| 848 |
|
| 849 | static int ptrace_resume(struct task_struct *child, long request,
|
| 850 | unsigned long data)
|
| 851 | {
|
| 852 | if (!valid_signal(data))
|
| 853 | return -EIO;
|
| 854 |
|
| 855 | if (request == PTRACE_SYSCALL)
|
| 856 | set_task_syscall_work(child, SYSCALL_TRACE);
|
| 857 | else
|
| 858 | clear_task_syscall_work(child, SYSCALL_TRACE);
|
| 859 |
|
| 860 | #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
|
| 861 | if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
|
| 862 | set_task_syscall_work(child, SYSCALL_EMU);
|
| 863 | else
|
| 864 | clear_task_syscall_work(child, SYSCALL_EMU);
|
| 865 | #endif
|
| 866 |
|
| 867 | if (is_singleblock(request)) {
|
| 868 | if (unlikely(!arch_has_block_step()))
|
| 869 | return -EIO;
|
| 870 | user_enable_block_step(child);
|
| 871 | } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
|
| 872 | if (unlikely(!arch_has_single_step()))
|
| 873 | return -EIO;
|
| 874 | user_enable_single_step(child);
|
| 875 | } else {
|
| 876 | user_disable_single_step(child);
|
| 877 | }
|
| 878 |
|
| 879 | |
| 880 | * Change ->exit_code and ->state under siglock to avoid the race
|
| 881 | * with wait_task_stopped() in between; a non-zero ->exit_code will
|
| 882 | * wrongly look like another report from tracee.
|
| 883 | *
|
| 884 | * Note that we need siglock even if ->exit_code == data and/or this
|
| 885 | * status was not reported yet, the new status must not be cleared by
|
| 886 | * wait_task_stopped() after resume.
|
| 887 |
|
| 888 | spin_lock_irq(&child->sighand->siglock);
|
| 889 | child->exit_code = data;
|
| 890 | child->jobctl &= ~JOBCTL_TRACED;
|
| 891 | wake_up_state(child, __TASK_TRACED);
|
| 892 | spin_unlock_irq(&child->sighand->siglock);
|
| 893 |
|
| 894 | return 0;
|
| 895 | }
|
| 896 |
|
| 897 | #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
|
| 898 |
|
| 899 | static const struct user_regset *
|
| 900 | find_regset(const struct user_regset_view *view, unsigned int type)
|
| 901 | {
|
| 902 | const struct user_regset *regset;
|
| 903 | int n;
|
| 904 |
|
| 905 | for (n = 0; n < view->n; ++n) {
|
| 906 | regset = view->regsets + n;
|
| 907 | if (regset->core_note_type == type)
|
| 908 | return regset;
|
| 909 | }
|
| 910 |
|
| 911 | return NULL;
|
| 912 | }
|
| 913 |
|
| 914 | static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
|
| 915 | struct iovec *kiov)
|
| 916 | {
|
| 917 | const struct user_regset_view *view = task_user_regset_view(task);
|
| 918 | const struct user_regset *regset = find_regset(view, type);
|
| 919 | int regset_no;
|
| 920 |
|
| 921 | if (!regset || (kiov->iov_len % regset->size) != 0)
|
| 922 | return -EINVAL;
|
| 923 |
|
| 924 | regset_no = regset - view->regsets;
|
| 925 | kiov->iov_len = min(kiov->iov_len,
|
| 926 | (__kernel_size_t) (regset->n * regset->size));
|
| 927 |
|
| 928 | if (req == PTRACE_GETREGSET)
|
| 929 | return copy_regset_to_user(task, view, regset_no, 0,
|
| 930 | kiov->iov_len, kiov->iov_base);
|
| 931 | else
|
| 932 | return copy_regset_from_user(task, view, regset_no, 0,
|
| 933 | kiov->iov_len, kiov->iov_base);
|
| 934 | }
|
| 935 |
|
| 936 | |
| 937 | * This is declared in linux/regset.h and defined in machine-dependent
|
| 938 | * code. We put the export here, near the primary machine-neutral use,
|
| 939 | * to ensure no machine forgets it.
|
| 940 |
|
| 941 | EXPORT_SYMBOL_GPL(task_user_regset_view);
|
| 942 |
|
| 943 | static unsigned long
|
| 944 | ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
|
| 945 | struct ptrace_syscall_info *info)
|
| 946 | {
|
| 947 | unsigned long args[ARRAY_SIZE(info->entry.args)];
|
| 948 | int i;
|
| 949 |
|
| 950 | info->entry.nr = syscall_get_nr(child, regs);
|
| 951 | syscall_get_arguments(child, regs, args);
|
| 952 | for (i = 0; i < ARRAY_SIZE(args); i++)
|
| 953 | info->entry.args[i] = args[i];
|
| 954 |
|
| 955 |
|
| 956 | return offsetofend(struct ptrace_syscall_info, entry.args);
|
| 957 | }
|
| 958 |
|
| 959 | static unsigned long
|
| 960 | ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
|
| 961 | struct ptrace_syscall_info *info)
|
| 962 | {
|
| 963 | |
| 964 | * As struct ptrace_syscall_info.entry is currently a subset
|
| 965 | * of struct ptrace_syscall_info.seccomp, it makes sense to
|
| 966 | * initialize that subset using ptrace_get_syscall_info_entry().
|
| 967 | * This can be reconsidered in the future if these structures
|
| 968 | * diverge significantly enough.
|
| 969 |
|
| 970 | ptrace_get_syscall_info_entry(child, regs, info);
|
| 971 | info->seccomp.ret_data = child->ptrace_message;
|
| 972 |
|
| 973 | |
| 974 | * ret_data is the last non-reserved field
|
| 975 | * in struct ptrace_syscall_info.seccomp
|
| 976 |
|
| 977 | return offsetofend(struct ptrace_syscall_info, seccomp.ret_data);
|
| 978 | }
|
| 979 |
|
| 980 | static unsigned long
|
| 981 | ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
|
| 982 | struct ptrace_syscall_info *info)
|
| 983 | {
|
| 984 | info->exit.rval = syscall_get_error(child, regs);
|
| 985 | info->exit.is_error = !!info->exit.rval;
|
| 986 | if (!info->exit.is_error)
|
| 987 | info->exit.rval = syscall_get_return_value(child, regs);
|
| 988 |
|
| 989 |
|
| 990 | return offsetofend(struct ptrace_syscall_info, exit.is_error);
|
| 991 | }
|
| 992 |
|
| 993 | static int
|
| 994 | ptrace_get_syscall_info_op(struct task_struct *child)
|
| 995 | {
|
| 996 | |
| 997 | * This does not need lock_task_sighand() to access
|
| 998 | * child->last_siginfo because ptrace_freeze_traced()
|
| 999 | * called earlier by ptrace_check_attach() ensures that
|
| 1000 | * the tracee cannot go away and clear its last_siginfo.
|
| 1001 |
|
| 1002 | switch (child->last_siginfo ? child->last_siginfo->si_code : 0) {
|
| 1003 | case SIGTRAP | 0x80:
|
| 1004 | switch (child->ptrace_message) {
|
| 1005 | case PTRACE_EVENTMSG_SYSCALL_ENTRY:
|
| 1006 | return PTRACE_SYSCALL_INFO_ENTRY;
|
| 1007 | case PTRACE_EVENTMSG_SYSCALL_EXIT:
|
| 1008 | return PTRACE_SYSCALL_INFO_EXIT;
|
| 1009 | default:
|
| 1010 | return PTRACE_SYSCALL_INFO_NONE;
|
| 1011 | }
|
| 1012 | case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8):
|
| 1013 | return PTRACE_SYSCALL_INFO_SECCOMP;
|
| 1014 | default:
|
| 1015 | return PTRACE_SYSCALL_INFO_NONE;
|
| 1016 | }
|
| 1017 | }
|
| 1018 |
|
| 1019 | static int
|
| 1020 | ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
|
| 1021 | void __user *datavp)
|
| 1022 | {
|
| 1023 | struct pt_regs *regs = task_pt_regs(child);
|
| 1024 | struct ptrace_syscall_info info = {
|
| 1025 | .op = ptrace_get_syscall_info_op(child),
|
| 1026 | .arch = syscall_get_arch(child),
|
| 1027 | .instruction_pointer = instruction_pointer(regs),
|
| 1028 | .stack_pointer = user_stack_pointer(regs),
|
| 1029 | };
|
| 1030 | unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
|
| 1031 | unsigned long write_size;
|
| 1032 |
|
| 1033 | switch (info.op) {
|
| 1034 | case PTRACE_SYSCALL_INFO_ENTRY:
|
| 1035 | actual_size = ptrace_get_syscall_info_entry(child, regs, &info);
|
| 1036 | break;
|
| 1037 | case PTRACE_SYSCALL_INFO_EXIT:
|
| 1038 | actual_size = ptrace_get_syscall_info_exit(child, regs, &info);
|
| 1039 | break;
|
| 1040 | case PTRACE_SYSCALL_INFO_SECCOMP:
|
| 1041 | actual_size = ptrace_get_syscall_info_seccomp(child, regs, &info);
|
| 1042 | break;
|
| 1043 | }
|
| 1044 |
|
| 1045 | write_size = min(actual_size, user_size);
|
| 1046 | return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size;
|
| 1047 | }
|
| 1048 |
|
| 1049 | static int
|
| 1050 | ptrace_set_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
|
| 1051 | struct ptrace_syscall_info *info)
|
| 1052 | {
|
| 1053 | unsigned long args[ARRAY_SIZE(info->entry.args)];
|
| 1054 | int nr = info->entry.nr;
|
| 1055 | int i;
|
| 1056 |
|
| 1057 | |
| 1058 | * Check that the syscall number specified in info->entry.nr
|
| 1059 | * is either a value of type "int" or a sign-extended value
|
| 1060 | * of type "int".
|
| 1061 |
|
| 1062 | if (nr != info->entry.nr)
|
| 1063 | return -ERANGE;
|
| 1064 |
|
| 1065 | for (i = 0; i < ARRAY_SIZE(args); i++) {
|
| 1066 | args[i] = info->entry.args[i];
|
| 1067 | |
| 1068 | * Check that the syscall argument specified in
|
| 1069 | * info->entry.args[i] is either a value of type
|
| 1070 | * "unsigned long" or a sign-extended value of type "long".
|
| 1071 |
|
| 1072 | if (args[i] != info->entry.args[i])
|
| 1073 | return -ERANGE;
|
| 1074 | }
|
| 1075 |
|
| 1076 | syscall_set_nr(child, regs, nr);
|
| 1077 | |
| 1078 | * If the syscall number is set to -1, setting syscall arguments is not
|
| 1079 | * just pointless, it would also clobber the syscall return value on
|
| 1080 | * those architectures that share the same register both for the first
|
| 1081 | * argument of syscall and its return value.
|
| 1082 |
|
| 1083 | if (nr != -1)
|
| 1084 | syscall_set_arguments(child, regs, args);
|
| 1085 |
|
| 1086 | return 0;
|
| 1087 | }
|
| 1088 |
|
| 1089 | static int
|
| 1090 | ptrace_set_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
|
| 1091 | struct ptrace_syscall_info *info)
|
| 1092 | {
|
| 1093 | |
| 1094 | * info->entry is currently a subset of info->seccomp,
|
| 1095 | * info->seccomp.ret_data is currently ignored.
|
| 1096 |
|
| 1097 | return ptrace_set_syscall_info_entry(child, regs, info);
|
| 1098 | }
|
| 1099 |
|
| 1100 | static int
|
| 1101 | ptrace_set_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
|
| 1102 | struct ptrace_syscall_info *info)
|
| 1103 | {
|
| 1104 | long rval = info->exit.rval;
|
| 1105 |
|
| 1106 | |
| 1107 | * Check that the return value specified in info->exit.rval
|
| 1108 | * is either a value of type "long" or a sign-extended value
|
| 1109 | * of type "long".
|
| 1110 |
|
| 1111 | if (rval != info->exit.rval)
|
| 1112 | return -ERANGE;
|
| 1113 |
|
| 1114 | if (info->exit.is_error)
|
| 1115 | syscall_set_return_value(child, regs, rval, 0);
|
| 1116 | else
|
| 1117 | syscall_set_return_value(child, regs, 0, rval);
|
| 1118 |
|
| 1119 | return 0;
|
| 1120 | }
|
| 1121 |
|
| 1122 | static int
|
| 1123 | ptrace_set_syscall_info(struct task_struct *child, unsigned long user_size,
|
| 1124 | const void __user *datavp)
|
| 1125 | {
|
| 1126 | struct pt_regs *regs = task_pt_regs(child);
|
| 1127 | struct ptrace_syscall_info info;
|
| 1128 |
|
| 1129 | if (user_size < sizeof(info))
|
| 1130 | return -EINVAL;
|
| 1131 |
|
| 1132 | |
| 1133 | * The compatibility is tracked by info.op and info.flags: if user-space
|
| 1134 | * does not instruct us to use unknown extra bits from future versions
|
| 1135 | * of ptrace_syscall_info, we are not going to read them either.
|
| 1136 |
|
| 1137 | if (copy_from_user(&info, datavp, sizeof(info)))
|
| 1138 | return -EFAULT;
|
| 1139 |
|
| 1140 |
|
| 1141 | if (info.flags || info.reserved)
|
| 1142 | return -EINVAL;
|
| 1143 |
|
| 1144 |
|
| 1145 | if (ptrace_get_syscall_info_op(child) != info.op)
|
| 1146 | return -EINVAL;
|
| 1147 |
|
| 1148 | switch (info.op) {
|
| 1149 | case PTRACE_SYSCALL_INFO_ENTRY:
|
| 1150 | return ptrace_set_syscall_info_entry(child, regs, &info);
|
| 1151 | case PTRACE_SYSCALL_INFO_EXIT:
|
| 1152 | return ptrace_set_syscall_info_exit(child, regs, &info);
|
| 1153 | case PTRACE_SYSCALL_INFO_SECCOMP:
|
| 1154 | return ptrace_set_syscall_info_seccomp(child, regs, &info);
|
| 1155 | default:
|
| 1156 |
|
| 1157 | return -EINVAL;
|
| 1158 | }
|
| 1159 | }
|
| 1160 | #endif
|
| 1161 |
|
| 1162 | int ptrace_request(struct task_struct *child, long request,
|
| 1163 | unsigned long addr, unsigned long data)
|
| 1164 | {
|
| 1165 | bool seized = child->ptrace & PT_SEIZED;
|
| 1166 | int ret = -EIO;
|
| 1167 | kernel_siginfo_t siginfo, *si;
|
| 1168 | void __user *datavp = (void __user *) data;
|
| 1169 | unsigned long __user *datalp = datavp;
|
| 1170 | unsigned long flags;
|
| 1171 |
|
| 1172 | switch (request) {
|
| 1173 | case PTRACE_PEEKTEXT:
|
| 1174 | case PTRACE_PEEKDATA:
|
| 1175 | return generic_ptrace_peekdata(child, addr, data);
|
| 1176 | case PTRACE_POKETEXT:
|
| 1177 | case PTRACE_POKEDATA:
|
| 1178 | return generic_ptrace_pokedata(child, addr, data);
|
| 1179 |
|
| 1180 | #ifdef PTRACE_OLDSETOPTIONS
|
| 1181 | case PTRACE_OLDSETOPTIONS:
|
| 1182 | #endif
|
| 1183 | case PTRACE_SETOPTIONS:
|
| 1184 | ret = ptrace_setoptions(child, data);
|
| 1185 | break;
|
| 1186 | case PTRACE_GETEVENTMSG:
|
| 1187 | ret = put_user(child->ptrace_message, datalp);
|
| 1188 | break;
|
| 1189 |
|
| 1190 | case PTRACE_PEEKSIGINFO:
|
| 1191 | ret = ptrace_peek_siginfo(child, addr, data);
|
| 1192 | break;
|
| 1193 |
|
| 1194 | case PTRACE_GETSIGINFO:
|
| 1195 | ret = ptrace_getsiginfo(child, &siginfo);
|
| 1196 | if (!ret)
|
| 1197 | ret = copy_siginfo_to_user(datavp, &siginfo);
|
| 1198 | break;
|
| 1199 |
|
| 1200 | case PTRACE_SETSIGINFO:
|
| 1201 | ret = copy_siginfo_from_user(&siginfo, datavp);
|
| 1202 | if (!ret)
|
| 1203 | ret = ptrace_setsiginfo(child, &siginfo);
|
| 1204 | break;
|
| 1205 |
|
| 1206 | case PTRACE_GETSIGMASK: {
|
| 1207 | sigset_t *mask;
|
| 1208 |
|
| 1209 | if (addr != sizeof(sigset_t)) {
|
| 1210 | ret = -EINVAL;
|
| 1211 | break;
|
| 1212 | }
|
| 1213 |
|
| 1214 | if (test_tsk_restore_sigmask(child))
|
| 1215 | mask = &child->saved_sigmask;
|
| 1216 | else
|
| 1217 | mask = &child->blocked;
|
| 1218 |
|
| 1219 | if (copy_to_user(datavp, mask, sizeof(sigset_t)))
|
| 1220 | ret = -EFAULT;
|
| 1221 | else
|
| 1222 | ret = 0;
|
| 1223 |
|
| 1224 | break;
|
| 1225 | }
|
| 1226 |
|
| 1227 | case PTRACE_SETSIGMASK: {
|
| 1228 | sigset_t new_set;
|
| 1229 |
|
| 1230 |
|
| 1231 | if (child->flags & PF_USER_WORKER) {
|
| 1232 | ret = -EPERM;
|
| 1233 | break;
|
| 1234 | }
|
| 1235 |
|
| 1236 | if (addr != sizeof(sigset_t)) {
|
| 1237 | ret = -EINVAL;
|
| 1238 | break;
|
| 1239 | }
|
| 1240 |
|
| 1241 | if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
|
| 1242 | ret = -EFAULT;
|
| 1243 | break;
|
| 1244 | }
|
| 1245 |
|
| 1246 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
|
| 1247 |
|
| 1248 | |
| 1249 | * Every thread does recalc_sigpending() after resume, so
|
| 1250 | * retarget_shared_pending() and recalc_sigpending() are not
|
| 1251 | * called here.
|
| 1252 |
|
| 1253 | spin_lock_irq(&child->sighand->siglock);
|
| 1254 | child->blocked = new_set;
|
| 1255 | spin_unlock_irq(&child->sighand->siglock);
|
| 1256 |
|
| 1257 | clear_tsk_restore_sigmask(child);
|
| 1258 |
|
| 1259 | ret = 0;
|
| 1260 | break;
|
| 1261 | }
|
| 1262 |
|
| 1263 | case PTRACE_INTERRUPT:
|
| 1264 | |
| 1265 | * Stop tracee without any side-effect on signal or job
|
| 1266 | * control. At least one trap is guaranteed to happen
|
| 1267 | * after this request. If @child is already trapped, the
|
| 1268 | * current trap is not disturbed and another trap will
|
| 1269 | * happen after the current trap is ended with PTRACE_CONT.
|
| 1270 | *
|
| 1271 | * The actual trap might not be PTRACE_EVENT_STOP trap but
|
| 1272 | * the pending condition is cleared regardless.
|
| 1273 |
|
| 1274 | if (unlikely(!seized || !lock_task_sighand(child, &flags)))
|
| 1275 | break;
|
| 1276 |
|
| 1277 | |
| 1278 | * INTERRUPT doesn't disturb existing trap sans one
|
| 1279 | * exception. If ptracer issued LISTEN for the current
|
| 1280 | * STOP, this INTERRUPT should clear LISTEN and re-trap
|
| 1281 | * tracee into STOP.
|
| 1282 |
|
| 1283 | if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
|
| 1284 | ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
|
| 1285 |
|
| 1286 | unlock_task_sighand(child, &flags);
|
| 1287 | ret = 0;
|
| 1288 | break;
|
| 1289 |
|
| 1290 | case PTRACE_LISTEN:
|
| 1291 | |
| 1292 | * Listen for events. Tracee must be in STOP. It's not
|
| 1293 | * resumed per-se but is not considered to be in TRACED by
|
| 1294 | * wait(2) or ptrace(2). If an async event (e.g. group
|
| 1295 | * stop state change) happens, tracee will enter STOP trap
|
| 1296 | * again. Alternatively, ptracer can issue INTERRUPT to
|
| 1297 | * finish listening and re-trap tracee into STOP.
|
| 1298 |
|
| 1299 | if (unlikely(!seized || !lock_task_sighand(child, &flags)))
|
| 1300 | break;
|
| 1301 |
|
| 1302 | si = child->last_siginfo;
|
| 1303 | if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
|
| 1304 | child->jobctl |= JOBCTL_LISTENING;
|
| 1305 | |
| 1306 | * If NOTIFY is set, it means event happened between
|
| 1307 | * start of this trap and now. Trigger re-trap.
|
| 1308 |
|
| 1309 | if (child->jobctl & JOBCTL_TRAP_NOTIFY)
|
| 1310 | ptrace_signal_wake_up(child, true);
|
| 1311 | ret = 0;
|
| 1312 | }
|
| 1313 | unlock_task_sighand(child, &flags);
|
| 1314 | break;
|
| 1315 |
|
| 1316 | case PTRACE_DETACH:
|
| 1317 | ret = ptrace_detach(child, data);
|
| 1318 | break;
|
| 1319 |
|
| 1320 | #ifdef CONFIG_BINFMT_ELF_FDPIC
|
| 1321 | case PTRACE_GETFDPIC: {
|
| 1322 | struct mm_struct *mm = get_task_mm(child);
|
| 1323 | unsigned long tmp = 0;
|
| 1324 |
|
| 1325 | ret = -ESRCH;
|
| 1326 | if (!mm)
|
| 1327 | break;
|
| 1328 |
|
| 1329 | switch (addr) {
|
| 1330 | case PTRACE_GETFDPIC_EXEC:
|
| 1331 | tmp = mm->context.exec_fdpic_loadmap;
|
| 1332 | break;
|
| 1333 | case PTRACE_GETFDPIC_INTERP:
|
| 1334 | tmp = mm->context.interp_fdpic_loadmap;
|
| 1335 | break;
|
| 1336 | default:
|
| 1337 | break;
|
| 1338 | }
|
| 1339 | mmput(mm);
|
| 1340 |
|
| 1341 | ret = put_user(tmp, datalp);
|
| 1342 | break;
|
| 1343 | }
|
| 1344 | #endif
|
| 1345 |
|
| 1346 | case PTRACE_SINGLESTEP:
|
| 1347 | #ifdef PTRACE_SINGLEBLOCK
|
| 1348 | case PTRACE_SINGLEBLOCK:
|
| 1349 | #endif
|
| 1350 | #ifdef PTRACE_SYSEMU
|
| 1351 | case PTRACE_SYSEMU:
|
| 1352 | case PTRACE_SYSEMU_SINGLESTEP:
|
| 1353 | #endif
|
| 1354 | case PTRACE_SYSCALL:
|
| 1355 | case PTRACE_CONT:
|
| 1356 | return ptrace_resume(child, request, data);
|
| 1357 |
|
| 1358 | case PTRACE_KILL:
|
| 1359 | send_sig_info(SIGKILL, SEND_SIG_NOINFO, child);
|
| 1360 | return 0;
|
| 1361 |
|
| 1362 | #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
|
| 1363 | case PTRACE_GETREGSET:
|
| 1364 | case PTRACE_SETREGSET: {
|
| 1365 | struct iovec kiov;
|
| 1366 | struct iovec __user *uiov = datavp;
|
| 1367 |
|
| 1368 | if (!access_ok(uiov, sizeof(*uiov)))
|
| 1369 | return -EFAULT;
|
| 1370 |
|
| 1371 | if (__get_user(kiov.iov_base, &uiov->iov_base) ||
|
| 1372 | __get_user(kiov.iov_len, &uiov->iov_len))
|
| 1373 | return -EFAULT;
|
| 1374 |
|
| 1375 | ret = ptrace_regset(child, request, addr, &kiov);
|
| 1376 | if (!ret)
|
| 1377 | ret = __put_user(kiov.iov_len, &uiov->iov_len);
|
| 1378 | break;
|
| 1379 | }
|
| 1380 |
|
| 1381 | case PTRACE_GET_SYSCALL_INFO:
|
| 1382 | ret = ptrace_get_syscall_info(child, addr, datavp);
|
| 1383 | break;
|
| 1384 |
|
| 1385 | case PTRACE_SET_SYSCALL_INFO:
|
| 1386 | ret = ptrace_set_syscall_info(child, addr, datavp);
|
| 1387 | break;
|
| 1388 | #endif
|
| 1389 |
|
| 1390 | case PTRACE_SECCOMP_GET_FILTER:
|
| 1391 | ret = seccomp_get_filter(child, addr, datavp);
|
| 1392 | break;
|
| 1393 |
|
| 1394 | case PTRACE_SECCOMP_GET_METADATA:
|
| 1395 | ret = seccomp_get_metadata(child, addr, datavp);
|
| 1396 | break;
|
| 1397 |
|
| 1398 | #ifdef CONFIG_RSEQ
|
| 1399 | case PTRACE_GET_RSEQ_CONFIGURATION:
|
| 1400 | ret = ptrace_get_rseq_configuration(child, addr, datavp);
|
| 1401 | break;
|
| 1402 | #endif
|
| 1403 |
|
| 1404 | case PTRACE_SET_SYSCALL_USER_DISPATCH_CONFIG:
|
| 1405 | ret = syscall_user_dispatch_set_config(child, addr, datavp);
|
| 1406 | break;
|
| 1407 |
|
| 1408 | case PTRACE_GET_SYSCALL_USER_DISPATCH_CONFIG:
|
| 1409 | ret = syscall_user_dispatch_get_config(child, addr, datavp);
|
| 1410 | break;
|
| 1411 |
|
| 1412 | default:
|
| 1413 | break;
|
| 1414 | }
|
| 1415 |
|
| 1416 | return ret;
|
| 1417 | }
|
| 1418 |
|
| 1419 | SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
|
| 1420 | unsigned long, data)
|
| 1421 | {
|
| 1422 | struct task_struct *child;
|
| 1423 | long ret;
|
| 1424 |
|
| 1425 | if (request == PTRACE_TRACEME) {
|
| 1426 | ret = ptrace_traceme();
|
| 1427 | goto out;
|
| 1428 | }
|
| 1429 |
|
| 1430 | child = find_get_task_by_vpid(pid);
|
| 1431 | if (!child) {
|
| 1432 | ret = -ESRCH;
|
| 1433 | goto out;
|
| 1434 | }
|
| 1435 |
|
| 1436 | if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
|
| 1437 | ret = ptrace_attach(child, request, addr, data);
|
| 1438 | goto out_put_task_struct;
|
| 1439 | }
|
| 1440 |
|
| 1441 | ret = ptrace_check_attach(child, request == PTRACE_KILL ||
|
| 1442 | request == PTRACE_INTERRUPT);
|
| 1443 | if (ret < 0)
|
| 1444 | goto out_put_task_struct;
|
| 1445 |
|
| 1446 | ret = arch_ptrace(child, request, addr, data);
|
| 1447 | if (ret || request != PTRACE_DETACH)
|
| 1448 | ptrace_unfreeze_traced(child);
|
| 1449 |
|
| 1450 | out_put_task_struct:
|
| 1451 | put_task_struct(child);
|
| 1452 | out:
|
| 1453 | return ret;
|
| 1454 | }
|
| 1455 |
|
| 1456 | int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
|
| 1457 | unsigned long data)
|
| 1458 | {
|
| 1459 | unsigned long tmp;
|
| 1460 | int copied;
|
| 1461 |
|
| 1462 | copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
|
| 1463 | if (copied != sizeof(tmp))
|
| 1464 | return -EIO;
|
| 1465 | return put_user(tmp, (unsigned long __user *)data);
|
| 1466 | }
|
| 1467 |
|
| 1468 | int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
|
| 1469 | unsigned long data)
|
| 1470 | {
|
| 1471 | int copied;
|
| 1472 |
|
| 1473 | copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
|
| 1474 | FOLL_FORCE | FOLL_WRITE);
|
| 1475 | return (copied == sizeof(data)) ? 0 : -EIO;
|
| 1476 | }
|
| 1477 |
|
| 1478 | #if defined CONFIG_COMPAT
|
| 1479 |
|
| 1480 | int compat_ptrace_request(struct task_struct *child, compat_long_t request,
|
| 1481 | compat_ulong_t addr, compat_ulong_t data)
|
| 1482 | {
|
| 1483 | compat_ulong_t __user *datap = compat_ptr(data);
|
| 1484 | compat_ulong_t word;
|
| 1485 | kernel_siginfo_t siginfo;
|
| 1486 | int ret;
|
| 1487 |
|
| 1488 | switch (request) {
|
| 1489 | case PTRACE_PEEKTEXT:
|
| 1490 | case PTRACE_PEEKDATA:
|
| 1491 | ret = ptrace_access_vm(child, addr, &word, sizeof(word),
|
| 1492 | FOLL_FORCE);
|
| 1493 | if (ret != sizeof(word))
|
| 1494 | ret = -EIO;
|
| 1495 | else
|
| 1496 | ret = put_user(word, datap);
|
| 1497 | break;
|
| 1498 |
|
| 1499 | case PTRACE_POKETEXT:
|
| 1500 | case PTRACE_POKEDATA:
|
| 1501 | ret = ptrace_access_vm(child, addr, &data, sizeof(data),
|
| 1502 | FOLL_FORCE | FOLL_WRITE);
|
| 1503 | ret = (ret != sizeof(data) ? -EIO : 0);
|
| 1504 | break;
|
| 1505 |
|
| 1506 | case PTRACE_GETEVENTMSG:
|
| 1507 | ret = put_user((compat_ulong_t) child->ptrace_message, datap);
|
| 1508 | break;
|
| 1509 |
|
| 1510 | case PTRACE_GETSIGINFO:
|
| 1511 | ret = ptrace_getsiginfo(child, &siginfo);
|
| 1512 | if (!ret)
|
| 1513 | ret = copy_siginfo_to_user32(
|
| 1514 | (struct compat_siginfo __user *) datap,
|
| 1515 | &siginfo);
|
| 1516 | break;
|
| 1517 |
|
| 1518 | case PTRACE_SETSIGINFO:
|
| 1519 | ret = copy_siginfo_from_user32(
|
| 1520 | &siginfo, (struct compat_siginfo __user *) datap);
|
| 1521 | if (!ret)
|
| 1522 | ret = ptrace_setsiginfo(child, &siginfo);
|
| 1523 | break;
|
| 1524 | #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
|
| 1525 | case PTRACE_GETREGSET:
|
| 1526 | case PTRACE_SETREGSET:
|
| 1527 | {
|
| 1528 | struct iovec kiov;
|
| 1529 | struct compat_iovec __user *uiov =
|
| 1530 | (struct compat_iovec __user *) datap;
|
| 1531 | compat_uptr_t ptr;
|
| 1532 | compat_size_t len;
|
| 1533 |
|
| 1534 | if (!access_ok(uiov, sizeof(*uiov)))
|
| 1535 | return -EFAULT;
|
| 1536 |
|
| 1537 | if (__get_user(ptr, &uiov->iov_base) ||
|
| 1538 | __get_user(len, &uiov->iov_len))
|
| 1539 | return -EFAULT;
|
| 1540 |
|
| 1541 | kiov.iov_base = compat_ptr(ptr);
|
| 1542 | kiov.iov_len = len;
|
| 1543 |
|
| 1544 | ret = ptrace_regset(child, request, addr, &kiov);
|
| 1545 | if (!ret)
|
| 1546 | ret = __put_user(kiov.iov_len, &uiov->iov_len);
|
| 1547 | break;
|
| 1548 | }
|
| 1549 | #endif
|
| 1550 |
|
| 1551 | default:
|
| 1552 | ret = ptrace_request(child, request, addr, data);
|
| 1553 | }
|
| 1554 |
|
| 1555 | return ret;
|
| 1556 | }
|
| 1557 |
|
| 1558 | COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
|
| 1559 | compat_long_t, addr, compat_long_t, data)
|
| 1560 | {
|
| 1561 | struct task_struct *child;
|
| 1562 | long ret;
|
| 1563 |
|
| 1564 | if (request == PTRACE_TRACEME) {
|
| 1565 | ret = ptrace_traceme();
|
| 1566 | goto out;
|
| 1567 | }
|
| 1568 |
|
| 1569 | child = find_get_task_by_vpid(pid);
|
| 1570 | if (!child) {
|
| 1571 | ret = -ESRCH;
|
| 1572 | goto out;
|
| 1573 | }
|
| 1574 |
|
| 1575 | if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
|
| 1576 | ret = ptrace_attach(child, request, addr, data);
|
| 1577 | goto out_put_task_struct;
|
| 1578 | }
|
| 1579 |
|
| 1580 | ret = ptrace_check_attach(child, request == PTRACE_KILL ||
|
| 1581 | request == PTRACE_INTERRUPT);
|
| 1582 | if (!ret) {
|
| 1583 | ret = compat_arch_ptrace(child, request, addr, data);
|
| 1584 | if (ret || request != PTRACE_DETACH)
|
| 1585 | ptrace_unfreeze_traced(child);
|
| 1586 | }
|
| 1587 |
|
| 1588 | out_put_task_struct:
|
| 1589 | put_task_struct(child);
|
| 1590 | out:
|
| 1591 | return ret;
|
| 1592 | }
|
| 1593 | #endif
|