From 446c970d88eb03b920d43467c25ca7b448cb33ef Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 18 Dec 2009 02:11:40 +0100 Subject: [PATCH] implement utrace-ptrace The patch adds the new file, kernel/ptrace-utrace.c, which contains the new implementation of ptrace over utrace. This file is not compiled until we have CONFIG_UTRACE option, will be added by the next "utrace core" patch. It's supposed to be an invisible implementation change, nothing should change to userland when CONFIG_UTRACE is enabled. Signed-off-by: Roland McGrath Signed-off-by: Oleg Nesterov --- include/linux/ptrace.h | 2 +- kernel/Makefile | 1 + kernel/ptrace-utrace.c | 1080 ++++++++++++++++++++++++++++++++++++++++++++++++ kernel/ptrace.c | 2 + 4 files changed, 1084 insertions(+), 1 deletions(-) create mode 100644 kernel/ptrace-utrace.c diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index 4802e2a..03f8fc7 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -79,7 +79,7 @@ #include /* For unlikely. */ #include /* For struct task_struct. */ - +extern void ptrace_notify_stop(struct task_struct *tracee); extern long arch_ptrace(struct task_struct *child, long request, long addr, long data); extern int ptrace_traceme(void); extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len); diff --git a/kernel/Makefile b/kernel/Makefile index 864ff75..e080dfe 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -69,6 +69,7 @@ obj-$(CONFIG_IKCONFIG) += configs.o obj-$(CONFIG_RESOURCE_COUNTERS) += res_counter.o obj-$(CONFIG_STOP_MACHINE) += stop_machine.o obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o +obj-$(CONFIG_UTRACE) += ptrace-utrace.o obj-$(CONFIG_AUDIT) += audit.o auditfilter.o audit_watch.o obj-$(CONFIG_AUDITSYSCALL) += auditsc.o obj-$(CONFIG_GCOV_KERNEL) += gcov/ diff --git a/kernel/ptrace-utrace.c b/kernel/ptrace-utrace.c new file mode 100644 index 0000000..ea419ee --- /dev/null +++ b/kernel/ptrace-utrace.c @@ -0,0 +1,1080 @@ +/* + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * ptrace a task: make the debugger its new parent and + * move it to the ptrace list. + * + * Must be called with the tasklist lock write-held. + */ +void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) +{ + BUG_ON(!list_empty(&child->ptrace_entry)); + list_add(&child->ptrace_entry, &new_parent->ptraced); + child->parent = new_parent; +} + +/* + * 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); + + arch_ptrace_untrace(child); +} + +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_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 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->resume == UTRACE_DETACH)) { + /* + * 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(tracee, engine); + } + WARN_ON(!err != (engine->ops == &ptrace_utrace_ops)); + + if (!err) + return engine; + } + + 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 voluntary = (sig >= 0); + struct utrace_engine *engine = ptrace_lookup_engine(tracee); + enum utrace_resume_action action = UTRACE_DETACH; + + if (unlikely(IS_ERR(engine))) + return; + + if (sig) { + struct ptrace_context *ctx = ptrace_context(engine); + + switch (get_stop_event(ctx)) { + case PTRACE_EVENT_SYSCALL: + if (voluntary) + send_sig_info(sig, SEND_SIG_PRIV, tracee); + break; + + case PTRACE_EVENT_SIGNAL: + if (voluntary) + ctx->signr = sig; + ctx->resume = UTRACE_DETACH; + action = UTRACE_RESUME; + break; + } + } + + ptrace_wake_up(tracee, engine, action, voluntary); + 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 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 (ctx->resume != UTRACE_RESUME) { + WARN_ON(ctx->resume != UTRACE_BLOCKSTEP && + ctx->resume != UTRACE_SINGLESTEP); + ctx->resume = UTRACE_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(¤t->blocked, signr)) { + send_sig_info(signr, info, current); + return UTRACE_SIGNAL_IGN; + } + + spin_lock_irq(¤t->sighand->siglock); + *return_ka = current->sighand->action[signr - 1]; + spin_unlock_irq(¤t->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 (resume != UTRACE_RESUME) { + WARN_ON(resume != UTRACE_BLOCKSTEP && + resume != UTRACE_SINGLESTEP); + + 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); + 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->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->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); +} + +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. + */ +void exit_ptrace(struct task_struct *tracer) +{ + for (;;) { + struct task_struct *tracee = NULL; + + read_lock(&tasklist_lock); + if (!list_empty(&tracer->ptraced)) { + tracee = list_first_entry(&tracer->ptraced, + struct task_struct, ptrace_entry); + get_task_struct(tracee); + } + read_unlock(&tasklist_lock); + if (!tracee) + break; + + ptrace_do_detach(tracee, -1); + put_task_struct(tracee); + } +} + +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_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; +} + +int ptrace_request(struct task_struct *child, long request, + long addr, 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; + + default: + ret = ptrace_resume(child, engine, request, data); + break; + } + + utrace_engine_put(engine); + return ret; +} + +#if defined CONFIG_COMPAT +#include + +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; + + 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 5cb560c..4e87441 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -302,6 +302,7 @@ asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid, } #endif /* CONFIG_COMPAT */ +#ifndef CONFIG_UTRACE /* * ptrace a task: make the debugger its new parent and * move it to the ptrace list. @@ -762,3 +763,4 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request, return ret; } #endif /* CONFIG_COMPAT */ +#endif /* CONFIG_UTRACE */ -- 1.7.4