[PATCH 4/4] implement utrace-ptrace

The patch adds the new file, kernel/ptrace-utrace.c, which contains the new implementation of ptrace over utrace. It's supposed to be an invisible implementation change, nothing should change to userland when CONFIG_UTRACE is enabled. Signed-off-by: Roland McGrath <roland(a)redhat.com&gt; Signed-off-by: Oleg Nesterov <oleg(a)redhat.com&gt; --- include/linux/ptrace.h | 3 + kernel/Makefile | 1 + kernel/ptrace-utrace.c | 1173 ++++++++++++++++++++++++++++++++++++++++++++++++ kernel/ptrace.c | 638 +++++++++++++------------- kernel/utrace.c | 16 + 5 files changed, 1513 insertions(+), 318 deletions(-) create mode 100644 kernel/ptrace-utrace.c diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index 446ed8f..5b0562e 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -101,6 +101,9 @@ extern bool __ptrace_detach(struct task_struct *tracer, struct task_struct *tracee); +extern int ptrace_traceme(void); +extern int ptrace_attach(struct task_struct *tsk); +extern void ptrace_notify_stop(struct task_struct *tracee); extern long arch_ptrace(struct task_struct *child, long request, unsigned long addr, unsigned long data); diff --git a/kernel/Makefile b/kernel/Makefile index 4a22e81..5c280dc 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -69,6 +69,7 @@ obj-$(CONFIG_RESOURCE_COUNTERS) += res_counter.o obj-$(CONFIG_SMP) += stop_machine.o obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o obj-$(CONFIG_UTRACE) += utrace.o +obj-$(CONFIG_UTRACE) += ptrace-utrace.o obj-$(CONFIG_AUDIT) += audit.o auditfilter.o obj-$(CONFIG_AUDITSYSCALL) += auditsc.o obj-$(CONFIG_AUDIT_WATCH) += audit_watch.o diff --git a/kernel/ptrace-utrace.c b/kernel/ptrace-utrace.c new file mode 100644 index 0000000..7a9b396 --- /dev/null +++ b/kernel/ptrace-utrace.c @@ -0,0 +1,1173 @@ +/* + * linux/kernel/ptrace.c + * + * (C) Copyright 1999 Linus Torvalds + * + * Common interfaces for "ptrace()" which we do not want + * to continually duplicate across every architecture. + */ + +#include <linux/capability.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/errno.h> +#include <linux/mm.h> +#include <linux/highmem.h> +#include <linux/pagemap.h> +#include <linux/ptrace.h> +#include <linux/utrace.h> +#include <linux/security.h> +#include <linux/signal.h> +#include <linux/audit.h> +#include <linux/pid_namespace.h> +#include <linux/syscalls.h> +#include <linux/uaccess.h> + +/* + * unptrace a task: move it back to its original parent and + * remove it from the ptrace list. + * + * Must be called with the tasklist lock write-held. + */ +void __ptrace_unlink(struct task_struct *child) +{ + BUG_ON(!child->ptrace); + + child->ptrace = 0; + child->parent = child->real_parent; + list_del_init(&child->ptrace_entry); +} + +struct ptrace_context { + int options; + + int signr; + siginfo_t *siginfo; + + int stop_code; + unsigned long eventmsg; + + enum utrace_resume_action resume; +}; + +#define PT_UTRACED 0x00001000 + +#define PTRACE_O_SYSEMU 0x100 +#define PTRACE_O_DETACHED 0x200 + +#define PTRACE_EVENT_SYSCALL (1 << 16) +#define PTRACE_EVENT_SIGTRAP (2 << 16) +#define PTRACE_EVENT_SIGNAL (3 << 16) +/* events visible to user-space */ +#define PTRACE_EVENT_MASK 0xFFFF + +static inline bool ptrace_event_pending(struct ptrace_context *ctx) +{ + return ctx->stop_code != 0; +} + +static inline int get_stop_event(struct ptrace_context *ctx) +{ + return ctx->stop_code >> 8; +} + +static inline void set_stop_code(struct ptrace_context *ctx, int event) +{ + ctx->stop_code = (event << 8) | SIGTRAP; +} + +static inline struct ptrace_context * +ptrace_context(struct utrace_engine *engine) +{ + return engine->data; +} + +static const struct utrace_engine_ops ptrace_utrace_ops; /* forward decl */ + +static struct utrace_engine *ptrace_lookup_engine(struct task_struct *tracee) +{ + return utrace_attach_task(tracee, UTRACE_ATTACH_MATCH_OPS, + &ptrace_utrace_ops, NULL); +} + +static int utrace_barrier_uninterruptible(struct task_struct *target, + struct utrace_engine *engine) +{ + for (;;) { + int err = utrace_barrier(target, engine); + + if (err != -ERESTARTSYS) + return err; + + schedule_timeout_uninterruptible(1); + } +} + +static struct utrace_engine * +ptrace_reuse_engine(struct task_struct *tracee) +{ + struct utrace_engine *engine; + struct ptrace_context *ctx; + int err = -EPERM; + + engine = ptrace_lookup_engine(tracee); + if (IS_ERR(engine)) + return engine; + + ctx = ptrace_context(engine); + if (unlikely(ctx->options == PTRACE_O_DETACHED)) { + /* + * Try to reuse this self-detaching engine. + * The only caller which can hit this case is ptrace_attach(), + * it holds ->cred_guard_mutex. + */ + ctx->options = 0; + ctx->eventmsg = 0; + + /* make sure we don't get unwanted reports */ + err = utrace_set_events(tracee, engine, UTRACE_EVENT(QUIESCE)); + if (!err || err == -EINPROGRESS) { + ctx->resume = UTRACE_RESUME; + /* synchronize with ptrace_report_signal() */ + err = utrace_barrier_uninterruptible(tracee, engine); + } + + if (!err) { + WARN_ON(engine->ops != &ptrace_utrace_ops && + !tracee->exit_state); + return engine; + } + + WARN_ON(engine->ops == &ptrace_utrace_ops); + } + + utrace_engine_put(engine); + return ERR_PTR(err); +} + +static struct utrace_engine * +ptrace_attach_engine(struct task_struct *tracee) +{ + struct utrace_engine *engine; + struct ptrace_context *ctx; + + if (unlikely(task_utrace_flags(tracee))) { + engine = ptrace_reuse_engine(tracee); + if (!IS_ERR(engine) || IS_ERR(engine) == -EPERM) + return engine; + } + + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); + if (unlikely(!ctx)) + return ERR_PTR(-ENOMEM); + + ctx->resume = UTRACE_RESUME; + + engine = utrace_attach_task(tracee, UTRACE_ATTACH_CREATE | + UTRACE_ATTACH_EXCLUSIVE | + UTRACE_ATTACH_MATCH_OPS, + &ptrace_utrace_ops, ctx); + if (unlikely(IS_ERR(engine))) { + if (engine != ERR_PTR(-ESRCH) && + engine != ERR_PTR(-ERESTARTNOINTR)) + engine = ERR_PTR(-EPERM); + kfree(ctx); + } + + return engine; +} + +static inline int ptrace_set_events(struct task_struct *target, + struct utrace_engine *engine, + unsigned long options) +{ + struct ptrace_context *ctx = ptrace_context(engine); + /* + * We need QUIESCE for resume handling, CLONE to check + * for CLONE_PTRACE, other events are always reported. + */ + unsigned long events = UTRACE_EVENT(QUIESCE) | UTRACE_EVENT(CLONE) | + UTRACE_EVENT(EXEC) | UTRACE_EVENT_SIGNAL_ALL; + + ctx->options = options; + if (options & PTRACE_O_TRACEEXIT) + events |= UTRACE_EVENT(EXIT); + + return utrace_set_events(target, engine, events); +} + +/* + * Attach a utrace engine for ptrace and set up its event mask. + * Returns error code or 0 on success. + */ +static int ptrace_attach_task(struct task_struct *tracee, int options) +{ + struct utrace_engine *engine; + int err; + + engine = ptrace_attach_engine(tracee); + if (IS_ERR(engine)) + return PTR_ERR(engine); + /* + * It can fail only if the tracee is dead, the caller + * must notice this before setting PT_UTRACED. + */ + err = ptrace_set_events(tracee, engine, options); + WARN_ON(err && !tracee->exit_state); + utrace_engine_put(engine); + return 0; +} + +static int ptrace_wake_up(struct task_struct *tracee, + struct utrace_engine *engine, + enum utrace_resume_action action, + bool force_wakeup) +{ + if (force_wakeup) { + unsigned long flags; + /* + * Preserve the compatibility bug. Historically ptrace + * wakes up the tracee even if it should not. Clear + * SIGNAL_STOP_STOPPED for utrace_wakeup(). + */ + if (lock_task_sighand(tracee, &flags)) { + tracee->signal->flags &= ~SIGNAL_STOP_STOPPED; + unlock_task_sighand(tracee, &flags); + } + } + + if (action != UTRACE_REPORT) + ptrace_context(engine)->stop_code = 0; + + return utrace_control(tracee, engine, action); +} + +static void ptrace_detach_task(struct task_struct *tracee, int sig) +{ + /* + * If true, the caller is PTRACE_DETACH, otherwise + * the tracer detaches implicitly during exit. + */ + bool explicit = (sig >= 0); + struct utrace_engine *engine = ptrace_lookup_engine(tracee); + enum utrace_resume_action action = UTRACE_DETACH; + struct ptrace_context *ctx; + + if (unlikely(IS_ERR(engine))) + return; + + ctx = ptrace_context(engine); + + if (!explicit) { + int err; + + /* + * We are going to detach, the tracee can be running. + * Ensure ptrace_report_signal() won't report a signal. + */ + ctx->resume = UTRACE_DETACH; + err = utrace_barrier_uninterruptible(tracee, engine); + + if (!err && ctx->siginfo) { + /* + * The tracee has already reported a signal + * before utrace_barrier(). + * + * Resume it like we do in PTRACE_EVENT_SIGNAL + * case below. The difference is that we can race + * with ptrace_report_signal() if the tracee is + * running but this doesn't matter. In any case + * UTRACE_SIGNAL_REPORT must be pending and it + * can return nothing but UTRACE_DETACH. + */ + action = UTRACE_RESUME; + } + + } else if (sig) { + switch (get_stop_event(ctx)) { + case PTRACE_EVENT_SYSCALL: + send_sig_info(sig, SEND_SIG_PRIV, tracee); + break; + + case PTRACE_EVENT_SIGNAL: + ctx->signr = sig; + ctx->resume = UTRACE_DETACH; + action = UTRACE_RESUME; + break; + } + } + + ptrace_wake_up(tracee, engine, action, explicit); + + if (action != UTRACE_DETACH) + ctx->options = PTRACE_O_DETACHED; + + utrace_engine_put(engine); +} + +static void ptrace_abort_attach(struct task_struct *tracee) +{ + ptrace_detach_task(tracee, 0); +} + +static u32 ptrace_report_exit(u32 action, struct utrace_engine *engine, + long orig_code, long *code) +{ + struct ptrace_context *ctx = ptrace_context(engine); + + WARN_ON(ptrace_event_pending(ctx) && + !signal_group_exit(current->signal)); + + set_stop_code(ctx, PTRACE_EVENT_EXIT); + ctx->eventmsg = *code; + + return UTRACE_STOP; +} + +static void ptrace_clone_attach(struct task_struct *child, + int options) +{ + struct task_struct *parent = current; + struct task_struct *tracer; + bool abort = true; + + if (unlikely(ptrace_attach_task(child, options))) { + WARN_ON(1); + return; + } + + write_lock_irq(&tasklist_lock); + tracer = parent->parent; + if (!(tracer->flags & PF_EXITING) && parent->ptrace) { + child->ptrace = parent->ptrace; + __ptrace_link(child, tracer); + abort = false; + } + write_unlock_irq(&tasklist_lock); + if (unlikely(abort)) { + ptrace_abort_attach(child); + return; + } + + sigaddset(&child->pending.signal, SIGSTOP); + set_tsk_thread_flag(child, TIF_SIGPENDING); +} + +static u32 ptrace_report_clone(u32 action, struct utrace_engine *engine, + unsigned long clone_flags, + struct task_struct *child) +{ + struct ptrace_context *ctx = ptrace_context(engine); + int event = 0; + + WARN_ON(ptrace_event_pending(ctx)); + + if (clone_flags & CLONE_UNTRACED) { + /* no events reported */ + } else if (clone_flags & CLONE_VFORK) { + if (ctx->options & PTRACE_O_TRACEVFORK) + event = PTRACE_EVENT_VFORK; + else if (ctx->options & PTRACE_O_TRACEVFORKDONE) + event = PTRACE_EVENT_VFORK_DONE; + } else if ((clone_flags & CSIGNAL) != SIGCHLD) { + if (ctx->options & PTRACE_O_TRACECLONE) + event = PTRACE_EVENT_CLONE; + } else if (ctx->options & PTRACE_O_TRACEFORK) { + event = PTRACE_EVENT_FORK; + } + /* + * Any of these reports implies auto-attaching the new child. + * So does CLONE_PTRACE, even with no event to report. + */ + if ((event && event != PTRACE_EVENT_VFORK_DONE) || + (clone_flags & CLONE_PTRACE)) + ptrace_clone_attach(child, ctx->options); + + if (!event) + return UTRACE_RESUME; + + set_stop_code(ctx, event); + ctx->eventmsg = child->pid; + /* + * We shouldn't stop now, inside the do_fork() path. + * We will stop later, before return to user-mode. + */ + if (event == PTRACE_EVENT_VFORK_DONE) + return UTRACE_REPORT; + else + return UTRACE_STOP; +} + +static inline void set_syscall_code(struct ptrace_context *ctx) +{ + set_stop_code(ctx, PTRACE_EVENT_SYSCALL); + if (ctx->options & PTRACE_O_TRACESYSGOOD) + ctx->stop_code |= 0x80; +} + +static u32 ptrace_report_syscall_entry(u32 action, struct utrace_engine *engine, + struct pt_regs *regs) +{ + struct ptrace_context *ctx = ptrace_context(engine); + + if (action & UTRACE_SYSCALL_RESUMED) { + /* + * We already reported the first time. + * Nothing more to do now. + */ + if (unlikely(ctx->options & PTRACE_O_SYSEMU)) + return UTRACE_SYSCALL_ABORT | UTRACE_REPORT; + return utrace_syscall_action(action) | UTRACE_RESUME; + } + + WARN_ON(ptrace_event_pending(ctx)); + + set_syscall_code(ctx); + + if (unlikely(ctx->options & PTRACE_O_SYSEMU)) + return UTRACE_SYSCALL_ABORT | UTRACE_REPORT; + /* + * Stop now to report. We will get another callback after + * we resume, with the UTRACE_SYSCALL_RESUMED flag set. + */ + return UTRACE_SYSCALL_RUN | UTRACE_STOP; +} + +static inline bool is_step_resume(enum utrace_resume_action resume) +{ + return resume == UTRACE_BLOCKSTEP || resume == UTRACE_SINGLESTEP; +} + +static u32 ptrace_report_syscall_exit(u32 action, struct utrace_engine *engine, + struct pt_regs *regs) +{ + struct ptrace_context *ctx = ptrace_context(engine); + + if (ptrace_event_pending(ctx)) + return UTRACE_STOP; + + if (is_step_resume(ctx->resume)) { + ctx->signr = SIGTRAP; + return UTRACE_INTERRUPT; + } + + set_syscall_code(ctx); + return UTRACE_STOP; +} + +static u32 ptrace_report_exec(u32 action, struct utrace_engine *engine, + const struct linux_binfmt *fmt, + const struct linux_binprm *bprm, + struct pt_regs *regs) +{ + struct ptrace_context *ctx = ptrace_context(engine); + + WARN_ON(ptrace_event_pending(ctx)); + + if (!(ctx->options & PTRACE_O_TRACEEXEC)) { + /* + * Old-fashioned ptrace'd exec just posts a plain signal. + */ + send_sig(SIGTRAP, current, 0); + return UTRACE_RESUME; + } + + set_stop_code(ctx, PTRACE_EVENT_EXEC); + return UTRACE_STOP; +} + +static enum utrace_signal_action resume_signal(struct ptrace_context *ctx, + struct k_sigaction *return_ka) +{ + siginfo_t *info = ctx->siginfo; + int signr = ctx->signr; + + ctx->siginfo = NULL; + ctx->signr = 0; + + /* Did the debugger cancel the sig? */ + if (!signr) + return UTRACE_SIGNAL_IGN; + /* + * Update the siginfo structure if the signal has changed. + * If the debugger wanted something specific in the siginfo + * then it should have updated *info via PTRACE_SETSIGINFO. + */ + if (info->si_signo != signr) { + info->si_signo = signr; + info->si_errno = 0; + info->si_code = SI_USER; + info->si_pid = task_pid_vnr(current->parent); + info->si_uid = task_uid(current->parent); + } + + /* If the (new) signal is now blocked, requeue it. */ + if (sigismember(&current->blocked, signr)) { + send_sig_info(signr, info, current); + return UTRACE_SIGNAL_IGN; + } + + spin_lock_irq(&current->sighand->siglock); + *return_ka = current->sighand->action[signr - 1]; + spin_unlock_irq(&current->sighand->siglock); + + return UTRACE_SIGNAL_DELIVER; +} + +static u32 ptrace_report_signal(u32 action, struct utrace_engine *engine, + struct pt_regs *regs, + siginfo_t *info, + const struct k_sigaction *orig_ka, + struct k_sigaction *return_ka) +{ + struct ptrace_context *ctx = ptrace_context(engine); + enum utrace_resume_action resume = ctx->resume; + + if (ptrace_event_pending(ctx)) { + action = utrace_signal_action(action); + WARN_ON(action != UTRACE_SIGNAL_REPORT); + return action | UTRACE_STOP; + } + + switch (utrace_signal_action(action)) { + case UTRACE_SIGNAL_HANDLER: + if (WARN_ON(ctx->siginfo)) + ctx->siginfo = NULL; + + if (is_step_resume(resume)) { + set_stop_code(ctx, PTRACE_EVENT_SIGTRAP); + return UTRACE_STOP | UTRACE_SIGNAL_IGN; + } + + case UTRACE_SIGNAL_REPORT: + if (!ctx->siginfo) { + if (ctx->signr) { + /* set by ptrace_resume(SYSCALL_EXIT) */ + WARN_ON(ctx->signr != SIGTRAP); + user_single_step_siginfo(current, regs, info); + force_sig_info(SIGTRAP, info, current); + } + + return resume | UTRACE_SIGNAL_IGN; + } + + if (WARN_ON(ctx->siginfo != info)) + return resume | UTRACE_SIGNAL_IGN; + + return resume | resume_signal(ctx, return_ka); + + default: + break; + } + + WARN_ON(ctx->siginfo); + + /* Raced with the exiting tracer ? */ + if (resume == UTRACE_DETACH) + return action; + + ctx->siginfo = info; + /* + * ctx->siginfo points to the caller's stack. + * Make sure the subsequent UTRACE_SIGNAL_REPORT clears + * ->siginfo before return from get_signal_to_deliver(). + */ + if (utrace_control(current, engine, UTRACE_INTERRUPT)) + WARN_ON(1); + + ctx->signr = info->si_signo; + ctx->stop_code = (PTRACE_EVENT_SIGNAL << 8) | ctx->signr; + + return UTRACE_STOP | UTRACE_SIGNAL_IGN; +} + +static u32 ptrace_report_quiesce(u32 action, struct utrace_engine *engine, + unsigned long event) +{ + struct ptrace_context *ctx = ptrace_context(engine); + + if (ptrace_event_pending(ctx)) + return UTRACE_STOP; + + return event ? UTRACE_RESUME : ctx->resume; +} + +static void ptrace_release(void *data) +{ + kfree(data); +} + +static const struct utrace_engine_ops ptrace_utrace_ops = { + .report_signal = ptrace_report_signal, + .report_quiesce = ptrace_report_quiesce, + .report_exec = ptrace_report_exec, + .report_exit = ptrace_report_exit, + .report_clone = ptrace_report_clone, + .report_syscall_entry = ptrace_report_syscall_entry, + .report_syscall_exit = ptrace_report_syscall_exit, + .release = ptrace_release, +}; + +int ptrace_check_attach(struct task_struct *child, int kill) +{ + struct utrace_engine *engine; + struct utrace_examiner exam; + int ret = -ESRCH; + + engine = ptrace_lookup_engine(child); + if (IS_ERR(engine)) + return ret; + + if (child->parent != current) + goto out; + + if (unlikely(kill)) + ret = 0; + + if (!task_is_stopped_or_traced(child)) + goto out; + /* + * Make sure our engine has already stopped the child. + * Then wait for it to be off the CPU. + */ + if (!utrace_control(child, engine, UTRACE_STOP) && + !utrace_prepare_examine(child, engine, &exam)) + ret = 0; +out: + utrace_engine_put(engine); + return ret; +} + +int ptrace_attach(struct task_struct *task) +{ + int retval; + + audit_ptrace(task); + + retval = -EPERM; + if (unlikely(task->flags & PF_KTHREAD)) + goto out; + if (same_thread_group(task, current)) + goto out; + + /* + * Protect exec's credential calculations against our interference; + * interference; SUID, SGID and LSM creds get determined differently + * under ptrace. + */ + retval = -ERESTARTNOINTR; + if (mutex_lock_interruptible(&task->signal->cred_guard_mutex)) + goto out; + + task_lock(task); + retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH); + task_unlock(task); + if (retval) + goto unlock_creds; + + retval = ptrace_attach_task(task, 0); + if (unlikely(retval)) + goto unlock_creds; + + write_lock_irq(&tasklist_lock); + retval = -EPERM; + if (unlikely(task->exit_state)) + goto unlock_tasklist; + + BUG_ON(task->ptrace); + task->ptrace = PT_UTRACED; + if (capable(CAP_SYS_PTRACE)) + task->ptrace |= PT_PTRACE_CAP; + + __ptrace_link(task, current); + send_sig_info(SIGSTOP, SEND_SIG_FORCED, task); + + retval = 0; +unlock_tasklist: + write_unlock_irq(&tasklist_lock); +unlock_creds: + mutex_unlock(&task->signal->cred_guard_mutex); +out: + return retval; +} + +/* + * Performs checks and sets PT_UTRACED. + * Should be used by all ptrace implementations for PTRACE_TRACEME. + */ +int ptrace_traceme(void) +{ + bool detach = true; + int ret = ptrace_attach_task(current, 0); + + if (unlikely(ret)) + return ret; + + ret = -EPERM; + write_lock_irq(&tasklist_lock); + BUG_ON(current->ptrace); + ret = security_ptrace_traceme(current->parent); + /* + * Check PF_EXITING to ensure ->real_parent has not passed + * exit_ptrace(). Otherwise we don't report the error but + * pretend ->real_parent untraces us right after return. + */ + if (!ret && !(current->real_parent->flags & PF_EXITING)) { + current->ptrace = PT_UTRACED; + __ptrace_link(current, current->real_parent); + detach = false; + } + write_unlock_irq(&tasklist_lock); + + if (detach) + ptrace_abort_attach(current); + return ret; +} + +static void ptrace_do_detach(struct task_struct *tracee, unsigned int data) +{ + bool detach, release; + + write_lock_irq(&tasklist_lock); + /* + * This tracee can be already killed. Make sure de_thread() or + * our sub-thread doing do_wait() didn't do release_task() yet. + */ + detach = tracee->ptrace != 0; + release = false; + if (likely(detach)) + release = __ptrace_detach(current, tracee); + write_unlock_irq(&tasklist_lock); + + if (unlikely(release)) + release_task(tracee); + else if (likely(detach)) + ptrace_detach_task(tracee, data); +} + +static int ptrace_detach(struct task_struct *child, unsigned int data) +{ + if (!valid_signal(data)) + return -EIO; + + ptrace_do_detach(child, data); + + return 0; +} + +/* + * Detach all tasks we were using ptrace on. Called with tasklist held + * for writing, and returns with it held too. But note it can release + * and reacquire the lock. + */ +void exit_ptrace(struct task_struct *tracer) +{ + bool locked = true; + + for (;;) { + struct task_struct *tracee = NULL; + + if (!locked) + read_lock(&tasklist_lock); + if (!list_empty(&tracer->ptraced)) { + tracee = list_first_entry(&tracer->ptraced, + struct task_struct, ptrace_entry); + get_task_struct(tracee); + } + if (!locked) + read_unlock(&tasklist_lock); + if (!tracee) + break; + + if (locked) { + write_unlock_irq(&tasklist_lock); + locked = false; + } + ptrace_do_detach(tracee, -1); + put_task_struct(tracee); + } + + if (!locked) + write_lock_irq(&tasklist_lock); +} + +static int ptrace_set_options(struct task_struct *tracee, + struct utrace_engine *engine, long data) +{ + BUILD_BUG_ON(PTRACE_O_MASK & (PTRACE_O_SYSEMU | PTRACE_O_DETACHED)); + + ptrace_set_events(tracee, engine, data & PTRACE_O_MASK); + return (data & ~PTRACE_O_MASK) ? -EINVAL : 0; +} + +static int ptrace_rw_siginfo(struct task_struct *tracee, + struct ptrace_context *ctx, + siginfo_t *info, bool write) +{ + unsigned long flags; + int err; + + switch (get_stop_event(ctx)) { + case 0: /* jctl stop */ + return -EINVAL; + + case PTRACE_EVENT_SIGNAL: + err = -ESRCH; + if (lock_task_sighand(tracee, &flags)) { + if (likely(task_is_traced(tracee))) { + if (write) + *ctx->siginfo = *info; + else + *info = *ctx->siginfo; + err = 0; + } + unlock_task_sighand(tracee, &flags); + } + + return err; + + default: + if (!write) { + memset(info, 0, sizeof(*info)); + info->si_signo = SIGTRAP; + info->si_code = ctx->stop_code & PTRACE_EVENT_MASK; + info->si_pid = task_pid_vnr(tracee); + info->si_uid = task_uid(tracee); + } + + return 0; + } +} + +static void do_ptrace_notify_stop(struct ptrace_context *ctx, + struct task_struct *tracee) +{ + /* + * This can race with SIGKILL, but we borrow this race from + * the old ptrace implementation. ->exit_code is only needed + * for wait_task_stopped()->task_stopped_code(), we should + * change it to use ptrace_context. + */ + tracee->exit_code = ctx->stop_code & PTRACE_EVENT_MASK; + WARN_ON(!tracee->exit_code); + + read_lock(&tasklist_lock); + /* + * Don't want to allow preemption here, because + * sys_ptrace() needs this task to be inactive. + */ + preempt_disable(); + /* + * It can be killed and then released by our subthread, + * or ptrace_attach() has not completed yet. + */ + if (task_ptrace(tracee)) + do_notify_parent_cldstop(tracee, CLD_TRAPPED); + read_unlock(&tasklist_lock); + preempt_enable_no_resched(); +} + +void ptrace_notify_stop(struct task_struct *tracee) +{ + struct utrace_engine *engine = ptrace_lookup_engine(tracee); + + if (IS_ERR(engine)) + return; + + do_ptrace_notify_stop(ptrace_context(engine), tracee); + utrace_engine_put(engine); +} + +static int ptrace_resume_action(struct task_struct *tracee, + struct utrace_engine *engine, long request) +{ + struct ptrace_context *ctx = ptrace_context(engine); + unsigned long events; + int action; + + ctx->options &= ~PTRACE_O_SYSEMU; + events = engine->flags & ~UTRACE_EVENT_SYSCALL; + action = UTRACE_RESUME; + + switch (request) { +#ifdef PTRACE_SINGLEBLOCK + case PTRACE_SINGLEBLOCK: + if (unlikely(!arch_has_block_step())) + return -EIO; + action = UTRACE_BLOCKSTEP; + events |= UTRACE_EVENT(SYSCALL_EXIT); + break; +#endif + +#ifdef PTRACE_SINGLESTEP + case PTRACE_SINGLESTEP: + if (unlikely(!arch_has_single_step())) + return -EIO; + action = UTRACE_SINGLESTEP; + events |= UTRACE_EVENT(SYSCALL_EXIT); + break; +#endif + +#ifdef PTRACE_SYSEMU + case PTRACE_SYSEMU_SINGLESTEP: + if (unlikely(!arch_has_single_step())) + return -EIO; + action = UTRACE_SINGLESTEP; + case PTRACE_SYSEMU: + ctx->options |= PTRACE_O_SYSEMU; + events |= UTRACE_EVENT(SYSCALL_ENTRY); + break; +#endif + + case PTRACE_SYSCALL: + events |= UTRACE_EVENT_SYSCALL; + break; + + case PTRACE_CONT: + break; + default: + return -EIO; + } + + if (events != engine->flags && + utrace_set_events(tracee, engine, events)) + return -ESRCH; + + return action; +} + +static int ptrace_resume(struct task_struct *tracee, + struct utrace_engine *engine, + long request, long data) +{ + struct ptrace_context *ctx = ptrace_context(engine); + int action; + + if (!valid_signal(data)) + return -EIO; + + action = ptrace_resume_action(tracee, engine, request); + if (action < 0) + return action; + + switch (get_stop_event(ctx)) { + case PTRACE_EVENT_VFORK: + if (ctx->options & PTRACE_O_TRACEVFORKDONE) { + set_stop_code(ctx, PTRACE_EVENT_VFORK_DONE); + action = UTRACE_REPORT; + } + break; + + case PTRACE_EVENT_EXEC: + case PTRACE_EVENT_FORK: + case PTRACE_EVENT_CLONE: + case PTRACE_EVENT_VFORK_DONE: + if (request == PTRACE_SYSCALL) { + set_syscall_code(ctx); + do_ptrace_notify_stop(ctx, tracee); + return 0; + } + + if (action != UTRACE_RESUME) { + /* + * single-stepping. UTRACE_SIGNAL_REPORT will + * synthesize a trap to follow the syscall insn. + */ + ctx->signr = SIGTRAP; + action = UTRACE_INTERRUPT; + } + break; + + case PTRACE_EVENT_SYSCALL: + if (data) + send_sig_info(data, SEND_SIG_PRIV, tracee); + break; + + case PTRACE_EVENT_SIGNAL: + ctx->signr = data; + break; + } + + ctx->resume = action; + ptrace_wake_up(tracee, engine, action, true); + return 0; +} + +extern int ptrace_regset(struct task_struct *task, int req, unsigned int type, + struct iovec *kiov); + +int ptrace_request(struct task_struct *child, long request, + unsigned long addr, unsigned long data) +{ + struct utrace_engine *engine = ptrace_lookup_engine(child); + siginfo_t siginfo; + int ret; + + if (unlikely(IS_ERR(engine))) + return -ESRCH; + + switch (request) { + case PTRACE_PEEKTEXT: + case PTRACE_PEEKDATA: + ret = generic_ptrace_peekdata(child, addr, data); + break; + case PTRACE_POKETEXT: + case PTRACE_POKEDATA: + ret = generic_ptrace_pokedata(child, addr, data); + break; + +#ifdef PTRACE_OLDSETOPTIONS + case PTRACE_OLDSETOPTIONS: +#endif + case PTRACE_SETOPTIONS: + ret = ptrace_set_options(child, engine, data); + break; + case PTRACE_GETEVENTMSG: + ret = put_user(ptrace_context(engine)->eventmsg, + (unsigned long __user *) data); + break; + + case PTRACE_GETSIGINFO: + ret = ptrace_rw_siginfo(child, ptrace_context(engine), + &siginfo, false); + if (!ret) + ret = copy_siginfo_to_user((siginfo_t __user *) data, + &siginfo); + break; + + case PTRACE_SETSIGINFO: + if (copy_from_user(&siginfo, (siginfo_t __user *) data, + sizeof siginfo)) + ret = -EFAULT; + else + ret = ptrace_rw_siginfo(child, ptrace_context(engine), + &siginfo, true); + break; + + case PTRACE_DETACH: /* detach a process that was attached. */ + ret = ptrace_detach(child, data); + break; + + case PTRACE_KILL: + /* Ugly historical behaviour. */ + if (task_is_traced(child)) + ptrace_resume(child, engine, PTRACE_CONT, SIGKILL); + ret = 0; + break; + + case PTRACE_GETREGSET: + case PTRACE_SETREGSET: + { + struct iovec kiov; + struct iovec __user *uiov = (struct iovec __user *) data; + + if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov))) + return -EFAULT; + + if (__get_user(kiov.iov_base, &uiov->iov_base) || + __get_user(kiov.iov_len, &uiov->iov_len)) + return -EFAULT; + + ret = ptrace_regset(child, request, addr, &kiov); + if (!ret) + ret = __put_user(kiov.iov_len, &uiov->iov_len); + break; + } + + default: + ret = ptrace_resume(child, engine, request, data); + break; + } + + utrace_engine_put(engine); + return ret; +} + +#if defined CONFIG_COMPAT +#include <linux/compat.h> + +int compat_ptrace_request(struct task_struct *child, compat_long_t request, + compat_ulong_t addr, compat_ulong_t data) +{ + struct utrace_engine *engine = ptrace_lookup_engine(child); + compat_ulong_t __user *datap = compat_ptr(data); + compat_ulong_t word; + siginfo_t siginfo; + int ret; + + if (unlikely(IS_ERR(engine))) + return -ESRCH; + + switch (request) { + case PTRACE_PEEKTEXT: + case PTRACE_PEEKDATA: + ret = access_process_vm(child, addr, &word, sizeof(word), 0); + if (ret != sizeof(word)) + ret = -EIO; + else + ret = put_user(word, datap); + break; + + case PTRACE_POKETEXT: + case PTRACE_POKEDATA: + ret = access_process_vm(child, addr, &data, sizeof(data), 1); + ret = (ret != sizeof(data) ? -EIO : 0); + break; + + case PTRACE_GETEVENTMSG: + ret = put_user((compat_ulong_t)ptrace_context(engine)->eventmsg, + datap); + break; + + case PTRACE_GETSIGINFO: + ret = ptrace_rw_siginfo(child, ptrace_context(engine), + &siginfo, false); + if (!ret) + ret = copy_siginfo_to_user32( + (struct compat_siginfo __user *) datap, + &siginfo); + break; + + case PTRACE_SETSIGINFO: + memset(&siginfo, 0, sizeof siginfo); + if (copy_siginfo_from_user32( + &siginfo, (struct compat_siginfo __user *) datap)) + ret = -EFAULT; + else + ret = ptrace_rw_siginfo(child, ptrace_context(engine), + &siginfo, true); + break; + + case PTRACE_GETREGSET: + case PTRACE_SETREGSET: + { + struct iovec kiov; + struct compat_iovec __user *uiov = + (struct compat_iovec __user *) datap; + compat_uptr_t ptr; + compat_size_t len; + + if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov))) + return -EFAULT; + + if (__get_user(ptr, &uiov->iov_base) || + __get_user(len, &uiov->iov_len)) + return -EFAULT; + + kiov.iov_base = compat_ptr(ptr); + kiov.iov_len = len; + + ret = ptrace_regset(child, request, addr, &kiov); + if (!ret) + ret = __put_user(kiov.iov_len, &uiov->iov_len); + break; + } + + default: + ret = ptrace_request(child, request, addr, data); + } + + utrace_engine_put(engine); + return ret; +} +#endif /* CONFIG_COMPAT */ diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 72e7ad4..ecfba8a 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -24,7 +24,6 @@ #include <linux/regset.h> #include <linux/hw_breakpoint.h> - /* * ptrace a task: make the debugger its new parent and * move it to the ptrace list. @@ -38,6 +37,323 @@ void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) child->parent = new_parent; } +int __ptrace_may_access(struct task_struct *task, unsigned int mode) +{ + const struct cred *cred = current_cred(), *tcred; + + /* May we inspect the given task? + * This check is used both for attaching with ptrace + * and for allowing access to sensitive information in /proc. + * + * ptrace_attach denies several cases that /proc allows + * because setting up the necessary parent/child relationship + * or halting the specified task is impossible. + */ + int dumpable = 0; + /* Don't let security modules deny introspection */ + if (task == current) + return 0; + rcu_read_lock(); + tcred = __task_cred(task); + if (cred->user->user_ns == tcred->user->user_ns && + (cred->uid == tcred->euid && + cred->uid == tcred->suid && + cred->uid == tcred->uid && + cred->gid == tcred->egid && + cred->gid == tcred->sgid && + cred->gid == tcred->gid)) + goto ok; + if (ns_capable(tcred->user->user_ns, CAP_SYS_PTRACE)) + goto ok; + rcu_read_unlock(); + return -EPERM; +ok: + rcu_read_unlock(); + smp_rmb(); + if (task->mm) + dumpable = get_dumpable(task->mm); + if (!dumpable && !task_ns_capable(task, CAP_SYS_PTRACE)) + return -EPERM; + + return security_ptrace_access_check(task, mode); +} + +bool ptrace_may_access(struct task_struct *task, unsigned int mode) +{ + int err; + task_lock(task); + err = __ptrace_may_access(task, mode); + task_unlock(task); + return !err; +} + +/* + * Called with irqs disabled, returns true if childs should reap themselves. + */ +static int ignoring_children(struct sighand_struct *sigh) +{ + int ret; + spin_lock(&sigh->siglock); + ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || + (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); + spin_unlock(&sigh->siglock); + return ret; +} + +/* + * Called with tasklist_lock held for writing. + * Unlink a traced task, and clean it up if it was a traced zombie. + * Return true if it needs to be reaped with release_task(). + * (We can't call release_task() here because we already hold tasklist_lock.) + * + * If it's a zombie, our attachedness prevented normal parent notification + * or self-reaping. Do notification now if it would have happened earlier. + * If it should reap itself, return true. + * + * If it's our own child, there is no notification to do. But if our normal + * children self-reap, then this child was prevented by ptrace and we must + * reap it now, in that case we must also wake up sub-threads sleeping in + * do_wait(). + */ +bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) +{ + __ptrace_unlink(p); + + if (p->exit_state == EXIT_ZOMBIE) { + if (!task_detached(p) && thread_group_empty(p)) { + if (!same_thread_group(p->real_parent, tracer)) + do_notify_parent(p, p->exit_signal); + else if (ignoring_children(tracer->sighand)) { + __wake_up_parent(p, tracer); + p->exit_signal = -1; + } + } + if (task_detached(p)) { + /* Mark it as in the process of being reaped. */ + p->exit_state = EXIT_DEAD; + return true; + } + } + + return false; +} + +int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) +{ + int copied = 0; + + while (len > 0) { + char buf[128]; + int this_len, retval; + + this_len = (len > sizeof(buf)) ? sizeof(buf) : len; + retval = access_process_vm(tsk, src, buf, this_len, 0); + if (!retval) { + if (copied) + break; + return -EIO; + } + if (copy_to_user(dst, buf, retval)) + return -EFAULT; + copied += retval; + src += retval; + dst += retval; + len -= retval; + } + return copied; +} + +int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) +{ + int copied = 0; + + while (len > 0) { + char buf[128]; + int this_len, retval; + + this_len = (len > sizeof(buf)) ? sizeof(buf) : len; + if (copy_from_user(buf, src, this_len)) + return -EFAULT; + retval = access_process_vm(tsk, dst, buf, this_len, 1); + if (!retval) { + if (copied) + break; + return -EIO; + } + copied += retval; + src += retval; + dst += retval; + len -= retval; + } + return copied; +} + +#ifdef CONFIG_HAVE_ARCH_TRACEHOOK + +static const struct user_regset * +find_regset(const struct user_regset_view *view, unsigned int type) +{ + const struct user_regset *regset; + int n; + + for (n = 0; n < view->n; ++n) { + regset = view->regsets + n; + if (regset->core_note_type == type) + return regset; + } + + return NULL; +} + +int ptrace_regset(struct task_struct *task, int req, unsigned int type, + struct iovec *kiov) +{ + const struct user_regset_view *view = task_user_regset_view(task); + const struct user_regset *regset = find_regset(view, type); + int regset_no; + + if (!regset || (kiov->iov_len % regset->size) != 0) + return -EINVAL; + + regset_no = regset - view->regsets; + kiov->iov_len = min(kiov->iov_len, + (__kernel_size_t) (regset->n * regset->size)); + + if (req == PTRACE_GETREGSET) + return copy_regset_to_user(task, view, regset_no, 0, + kiov->iov_len, kiov->iov_base); + else + return copy_regset_from_user(task, view, regset_no, 0, + kiov->iov_len, kiov->iov_base); +} + +#endif + +static struct task_struct *ptrace_get_task_struct(pid_t pid) +{ + struct task_struct *child; + + rcu_read_lock(); + child = find_task_by_vpid(pid); + if (child) + get_task_struct(child); + rcu_read_unlock(); + + if (!child) + return ERR_PTR(-ESRCH); + return child; +} + +#ifndef arch_ptrace_attach +#define arch_ptrace_attach(child) do { } while (0) +#endif + +SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, + unsigned long, data) +{ + struct task_struct *child; + long ret; + + if (request == PTRACE_TRACEME) { + ret = ptrace_traceme(); + if (!ret) + arch_ptrace_attach(current); + goto out; + } + + child = ptrace_get_task_struct(pid); + if (IS_ERR(child)) { + ret = PTR_ERR(child); + goto out; + } + + if (request == PTRACE_ATTACH) { + ret = ptrace_attach(child); + /* + * Some architectures need to do book-keeping after + * a ptrace attach. + */ + if (!ret) + arch_ptrace_attach(child); + goto out_put_task_struct; + } + + ret = ptrace_check_attach(child, request == PTRACE_KILL); + if (ret < 0) + goto out_put_task_struct; + + ret = arch_ptrace(child, request, addr, data); + + out_put_task_struct: + put_task_struct(child); + out: + return ret; +} + +int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, + unsigned long data) +{ + unsigned long tmp; + int copied; + + copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0); + if (copied != sizeof(tmp)) + return -EIO; + return put_user(tmp, (unsigned long __user *)data); +} + +int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, + unsigned long data) +{ + int copied; + + copied = access_process_vm(tsk, addr, &data, sizeof(data), 1); + return (copied == sizeof(data)) ? 0 : -EIO; +} + +#if defined CONFIG_COMPAT +#include <linux/compat.h> + +asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid, + compat_long_t addr, compat_long_t data) +{ + struct task_struct *child; + long ret; + + if (request == PTRACE_TRACEME) { + ret = ptrace_traceme(); + goto out; + } + + child = ptrace_get_task_struct(pid); + if (IS_ERR(child)) { + ret = PTR_ERR(child); + goto out; + } + + if (request == PTRACE_ATTACH) { + ret = ptrace_attach(child); + /* + * Some architectures need to do book-keeping after + * a ptrace attach. + */ + if (!ret) + arch_ptrace_attach(child); + goto out_put_task_struct; + } + + ret = ptrace_check_attach(child, request == PTRACE_KILL); + if (!ret) + ret = compat_arch_ptrace(child, request, addr, data); + + out_put_task_struct: + put_task_struct(child); + out: + return ret; +} +#endif /* CONFIG_COMPAT */ + +#ifndef CONFIG_UTRACE /* * Turn a tracing stop into a normal stop now, since with no tracer there * would be no way to wake it up with SIGCONT or SIGKILL. If there was a @@ -117,57 +433,7 @@ int ptrace_check_attach(struct task_struct *child, int kill) return ret; } -int __ptrace_may_access(struct task_struct *task, unsigned int mode) -{ - const struct cred *cred = current_cred(), *tcred; - - /* May we inspect the given task? - * This check is used both for attaching with ptrace - * and for allowing access to sensitive information in /proc. - * - * ptrace_attach denies several cases that /proc allows - * because setting up the necessary parent/child relationship - * or halting the specified task is impossible. - */ - int dumpable = 0; - /* Don't let security modules deny introspection */ - if (task == current) - return 0; - rcu_read_lock(); - tcred = __task_cred(task); - if (cred->user->user_ns == tcred->user->user_ns && - (cred->uid == tcred->euid && - cred->uid == tcred->suid && - cred->uid == tcred->uid && - cred->gid == tcred->egid && - cred->gid == tcred->sgid && - cred->gid == tcred->gid)) - goto ok; - if (ns_capable(tcred->user->user_ns, CAP_SYS_PTRACE)) - goto ok; - rcu_read_unlock(); - return -EPERM; -ok: - rcu_read_unlock(); - smp_rmb(); - if (task->mm) - dumpable = get_dumpable(task->mm); - if (!dumpable && !task_ns_capable(task, CAP_SYS_PTRACE)) - return -EPERM; - - return security_ptrace_access_check(task, mode); -} - -bool ptrace_may_access(struct task_struct *task, unsigned int mode) -{ - int err; - task_lock(task); - err = __ptrace_may_access(task, mode); - task_unlock(task); - return !err; -} - -static int ptrace_attach(struct task_struct *task) +int ptrace_attach(struct task_struct *task) { int retval; @@ -223,7 +489,7 @@ out: * Performs checks and sets PT_PTRACED. * Should be used by all ptrace implementations for PTRACE_TRACEME. */ -static int ptrace_traceme(void) +int ptrace_traceme(void) { int ret = -EPERM; @@ -246,57 +512,6 @@ static int ptrace_traceme(void) return ret; } -/* - * Called with irqs disabled, returns true if childs should reap themselves. - */ -static int ignoring_children(struct sighand_struct *sigh) -{ - int ret; - spin_lock(&sigh->siglock); - ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || - (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); - spin_unlock(&sigh->siglock); - return ret; -} - -/* - * Called with tasklist_lock held for writing. - * Unlink a traced task, and clean it up if it was a traced zombie. - * Return true if it needs to be reaped with release_task(). - * (We can't call release_task() here because we already hold tasklist_lock.) - * - * If it's a zombie, our attachedness prevented normal parent notification - * or self-reaping. Do notification now if it would have happened earlier. - * If it should reap itself, return true. - * - * If it's our own child, there is no notification to do. But if our normal - * children self-reap, then this child was prevented by ptrace and we must - * reap it now, in that case we must also wake up sub-threads sleeping in - * do_wait(). - */ -bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) -{ - __ptrace_unlink(p); - - if (p->exit_state == EXIT_ZOMBIE) { - if (!task_detached(p) && thread_group_empty(p)) { - if (!same_thread_group(p->real_parent, tracer)) - do_notify_parent(p, p->exit_signal); - else if (ignoring_children(tracer->sighand)) { - __wake_up_parent(p, tracer); - p->exit_signal = -1; - } - } - if (task_detached(p)) { - /* Mark it as in the process of being reaped. */ - p->exit_state = EXIT_DEAD; - return true; - } - } - - return false; -} - static int ptrace_detach(struct task_struct *child, unsigned int data) { bool dead = false; @@ -356,56 +571,6 @@ void exit_ptrace(struct task_struct *tracer) write_lock_irq(&tasklist_lock); } -int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) -{ - int copied = 0; - - while (len > 0) { - char buf[128]; - int this_len, retval; - - this_len = (len > sizeof(buf)) ? sizeof(buf) : len; - retval = access_process_vm(tsk, src, buf, this_len, 0); - if (!retval) { - if (copied) - break; - return -EIO; - } - if (copy_to_user(dst, buf, retval)) - return -EFAULT; - copied += retval; - src += retval; - dst += retval; - len -= retval; - } - return copied; -} - -int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) -{ - int copied = 0; - - while (len > 0) { - char buf[128]; - int this_len, retval; - - this_len = (len > sizeof(buf)) ? sizeof(buf) : len; - if (copy_from_user(buf, src, this_len)) - return -EFAULT; - retval = access_process_vm(tsk, dst, buf, this_len, 1); - if (!retval) { - if (copied) - break; - return -EIO; - } - copied += retval; - src += retval; - dst += retval; - len -= retval; - } - return copied; -} - static int ptrace_setoptions(struct task_struct *child, unsigned long data) { child->ptrace &= ~PT_TRACE_MASK; @@ -466,7 +631,6 @@ static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info) return error; } - #ifdef PTRACE_SINGLESTEP #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) #else @@ -521,47 +685,6 @@ static int ptrace_resume(struct task_struct *child, long request, return 0; } -#ifdef CONFIG_HAVE_ARCH_TRACEHOOK - -static const struct user_regset * -find_regset(const struct user_regset_view *view, unsigned int type) -{ - const struct user_regset *regset; - int n; - - for (n = 0; n < view->n; ++n) { - regset = view->regsets + n; - if (regset->core_note_type == type) - return regset; - } - - return NULL; -} - -static int ptrace_regset(struct task_struct *task, int req, unsigned int type, - struct iovec *kiov) -{ - const struct user_regset_view *view = task_user_regset_view(task); - const struct user_regset *regset = find_regset(view, type); - int regset_no; - - if (!regset || (kiov->iov_len % regset->size) != 0) - return -EINVAL; - - regset_no = regset - view->regsets; - kiov->iov_len = min(kiov->iov_len, - (__kernel_size_t) (regset->n * regset->size)); - - if (req == PTRACE_GETREGSET) - return copy_regset_to_user(task, view, regset_no, 0, - kiov->iov_len, kiov->iov_base); - else - return copy_regset_from_user(task, view, regset_no, 0, - kiov->iov_len, kiov->iov_base); -} - -#endif - int ptrace_request(struct task_struct *child, long request, unsigned long addr, unsigned long data) { @@ -677,91 +800,7 @@ int ptrace_request(struct task_struct *child, long request, return ret; } -static struct task_struct *ptrace_get_task_struct(pid_t pid) -{ - struct task_struct *child; - - rcu_read_lock(); - child = find_task_by_vpid(pid); - if (child) - get_task_struct(child); - rcu_read_unlock(); - - if (!child) - return ERR_PTR(-ESRCH); - return child; -} - -#ifndef arch_ptrace_attach -#define arch_ptrace_attach(child) do { } while (0) -#endif - -SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, - unsigned long, data) -{ - struct task_struct *child; - long ret; - - if (request == PTRACE_TRACEME) { - ret = ptrace_traceme(); - if (!ret) - arch_ptrace_attach(current); - goto out; - } - - child = ptrace_get_task_struct(pid); - if (IS_ERR(child)) { - ret = PTR_ERR(child); - goto out; - } - - if (request == PTRACE_ATTACH) { - ret = ptrace_attach(child); - /* - * Some architectures need to do book-keeping after - * a ptrace attach. - */ - if (!ret) - arch_ptrace_attach(child); - goto out_put_task_struct; - } - - ret = ptrace_check_attach(child, request == PTRACE_KILL); - if (ret < 0) - goto out_put_task_struct; - - ret = arch_ptrace(child, request, addr, data); - - out_put_task_struct: - put_task_struct(child); - out: - return ret; -} - -int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr, - unsigned long data) -{ - unsigned long tmp; - int copied; - - copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0); - if (copied != sizeof(tmp)) - return -EIO; - return put_user(tmp, (unsigned long __user *)data); -} - -int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr, - unsigned long data) -{ - int copied; - - copied = access_process_vm(tsk, addr, &data, sizeof(data), 1); - return (copied == sizeof(data)) ? 0 : -EIO; -} - #if defined CONFIG_COMPAT -#include <linux/compat.h> - int compat_ptrace_request(struct task_struct *child, compat_long_t request, compat_ulong_t addr, compat_ulong_t data) { @@ -839,45 +878,8 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request, return ret; } - -asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid, - compat_long_t addr, compat_long_t data) -{ - struct task_struct *child; - long ret; - - if (request == PTRACE_TRACEME) { - ret = ptrace_traceme(); - goto out; - } - - child = ptrace_get_task_struct(pid); - if (IS_ERR(child)) { - ret = PTR_ERR(child); - goto out; - } - - if (request == PTRACE_ATTACH) { - ret = ptrace_attach(child); - /* - * Some architectures need to do book-keeping after - * a ptrace attach. - */ - if (!ret) - arch_ptrace_attach(child); - goto out_put_task_struct; - } - - ret = ptrace_check_attach(child, request == PTRACE_KILL); - if (!ret) - ret = compat_arch_ptrace(child, request, addr, data); - - out_put_task_struct: - put_task_struct(child); - out: - return ret; -} #endif /* CONFIG_COMPAT */ +#endif /* CONFIG_UTRACE */ #ifdef CONFIG_HAVE_HW_BREAKPOINT int ptrace_get_breakpoints(struct task_struct *tsk) diff --git a/kernel/utrace.c b/kernel/utrace.c index 26d6faf..37dce16 100644 --- a/kernel/utrace.c +++ b/kernel/utrace.c @@ -816,6 +816,22 @@ relock: spin_unlock_irq(&task->sighand->siglock); spin_unlock(&utrace->lock); + /* + * If ptrace is among the reasons for this stop, do its + * notification now. This could not just be done in + * ptrace's own event report callbacks because it has to + * be done after we are in TASK_TRACED. This makes the + * synchronization with ptrace_do_wait() work right. + * + * It's only because of the bad old overloading of the do_wait() + * logic for handling ptrace stops that we need this special case + * here. One day we will clean up ptrace so it does not need to + * work this way. New things that are designed sensibly don't need + * a wakeup that synchronizes with tasklist_lock and ->state, so + * the proper utrace API does not try to support this weirdness. + */ + ptrace_notify_stop(task); + schedule(); utrace_finish_stop(); -- 1.5.5.1