1 files changed, 229 insertions, 111 deletions

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 54482193e1ed..392ec2f75f01 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -32,6 +32,7 @@
 #include <linux/compat.h>
 #include <linux/sched/signal.h>
 #include <linux/minmax.h>
+#include <linux/syscall_user_dispatch.h>
 
 #include <asm/syscall.h>	/* for syscall_get_* */
 
@@ -58,7 +59,7 @@ int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
 		return 0;
 	}
 
-	ret = __access_remote_vm(mm, addr, buf, len, gup_flags);
+	ret = access_remote_vm(mm, addr, buf, len, gup_flags);
 	mmput(mm);
 
 	return ret;
@@ -144,20 +145,9 @@ void __ptrace_unlink(struct task_struct *child)
 	 */
 	if (!(child->flags & PF_EXITING) &&
 	    (child->signal->flags & SIGNAL_STOP_STOPPED ||
-	     child->signal->group_stop_count)) {
+	     child->signal->group_stop_count))
 		child->jobctl |= JOBCTL_STOP_PENDING;
 
-		/*
-		 * This is only possible if this thread was cloned by the
-		 * traced task running in the stopped group, set the signal
-		 * for the future reports.
-		 * FIXME: we should change ptrace_init_task() to handle this
-		 * case.
-		 */
-		if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
-			child->jobctl |= SIGSTOP;
-	}
-
 	/*
 	 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
 	 * @child in the butt.  Note that @resume should be used iff @child
@@ -385,6 +375,37 @@ static int check_ptrace_options(unsigned long data)
 	return 0;
 }
 
+static inline void ptrace_set_stopped(struct task_struct *task, bool seize)
+{
+	guard(spinlock)(&task->sighand->siglock);
+
+	/* SEIZE doesn't trap tracee on attach */
+	if (!seize)
+		send_signal_locked(SIGSTOP, SEND_SIG_PRIV, task, PIDTYPE_PID);
+	/*
+	 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
+	 * TRAPPING, and kick it so that it transits to TRACED.  TRAPPING
+	 * will be cleared if the child completes the transition or any
+	 * event which clears the group stop states happens.  We'll wait
+	 * for the transition to complete before returning from this
+	 * function.
+	 *
+	 * This hides STOPPED -> RUNNING -> TRACED transition from the
+	 * attaching thread but a different thread in the same group can
+	 * still observe the transient RUNNING state.  IOW, if another
+	 * thread's WNOHANG wait(2) on the stopped tracee races against
+	 * ATTACH, the wait(2) may fail due to the transient RUNNING.
+	 *
+	 * The following task_is_stopped() test is safe as both transitions
+	 * in and out of STOPPED are protected by siglock.
+	 */
+	if (task_is_stopped(task) &&
+	    task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) {
+		task->jobctl &= ~JOBCTL_STOPPED;
+		signal_wake_up_state(task, __TASK_STOPPED);
+	}
+}
+
 static int ptrace_attach(struct task_struct *task, long request,
 			 unsigned long addr,
 			 unsigned long flags)
@@ -392,17 +413,17 @@ static int ptrace_attach(struct task_struct *task, long request,
 	bool seize = (request == PTRACE_SEIZE);
 	int retval;
 
-	retval = -EIO;
 	if (seize) {
 		if (addr != 0)
-			goto out;
+			return -EIO;
 		/*
 		 * This duplicates the check in check_ptrace_options() because
 		 * ptrace_attach() and ptrace_setoptions() have historically
 		 * used different error codes for unknown ptrace options.
 		 */
 		if (flags & ~(unsigned long)PTRACE_O_MASK)
-			goto out;
+			return -EIO;
+
 		retval = check_ptrace_options(flags);
 		if (retval)
 			return retval;
@@ -413,88 +434,48 @@ static int ptrace_attach(struct task_struct *task, long request,
 
 	audit_ptrace(task);
 
-	retval = -EPERM;
 	if (unlikely(task->flags & PF_KTHREAD))
-		goto out;
+		return -EPERM;
 	if (same_thread_group(task, current))
-		goto out;
+		return -EPERM;
 
 	/*
 	 * Protect exec's credential calculations against our 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_REALCREDS);
-	task_unlock(task);
-	if (retval)
-		goto unlock_creds;
-
-	write_lock_irq(&tasklist_lock);
-	retval = -EPERM;
-	if (unlikely(task->exit_state))
-		goto unlock_tasklist;
-	if (task->ptrace)
-		goto unlock_tasklist;
+	scoped_cond_guard (mutex_intr, return -ERESTARTNOINTR,
+			   &task->signal->cred_guard_mutex) {
 
-	task->ptrace = flags;
-
-	ptrace_link(task, current);
+		scoped_guard (task_lock, task) {
+			retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
+			if (retval)
+				return retval;
+		}
 
-	/* SEIZE doesn't trap tracee on attach */
-	if (!seize)
-		send_sig_info(SIGSTOP, SEND_SIG_PRIV, task);
+		scoped_guard (write_lock_irq, &tasklist_lock) {
+			if (unlikely(task->exit_state))
+				return -EPERM;
+			if (task->ptrace)
+				return -EPERM;
 
-	spin_lock(&task->sighand->siglock);
+			task->ptrace = flags;
+			ptrace_link(task, current);
+			ptrace_set_stopped(task, seize);
+		}
+	}
 
 	/*
-	 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
-	 * TRAPPING, and kick it so that it transits to TRACED.  TRAPPING
-	 * will be cleared if the child completes the transition or any
-	 * event which clears the group stop states happens.  We'll wait
-	 * for the transition to complete before returning from this
-	 * function.
-	 *
-	 * This hides STOPPED -> RUNNING -> TRACED transition from the
-	 * attaching thread but a different thread in the same group can
-	 * still observe the transient RUNNING state.  IOW, if another
-	 * thread's WNOHANG wait(2) on the stopped tracee races against
-	 * ATTACH, the wait(2) may fail due to the transient RUNNING.
-	 *
-	 * The following task_is_stopped() test is safe as both transitions
-	 * in and out of STOPPED are protected by siglock.
+	 * We do not bother to change retval or clear JOBCTL_TRAPPING
+	 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
+	 * not return to user-mode, it will exit and clear this bit in
+	 * __ptrace_unlink() if it wasn't already cleared by the tracee;
+	 * and until then nobody can ptrace this task.
 	 */
-	if (task_is_stopped(task) &&
-	    task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING)) {
-		task->jobctl &= ~JOBCTL_STOPPED;
-		signal_wake_up_state(task, __TASK_STOPPED);
-	}
-
-	spin_unlock(&task->sighand->siglock);
+	wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
+	proc_ptrace_connector(task, PTRACE_ATTACH);
 
-	retval = 0;
-unlock_tasklist:
-	write_unlock_irq(&tasklist_lock);
-unlock_creds:
-	mutex_unlock(&task->signal->cred_guard_mutex);
-out:
-	if (!retval) {
-		/*
-		 * We do not bother to change retval or clear JOBCTL_TRAPPING
-		 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
-		 * not return to user-mode, it will exit and clear this bit in
-		 * __ptrace_unlink() if it wasn't already cleared by the tracee;
-		 * and until then nobody can ptrace this task.
-		 */
-		wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
-		proc_ptrace_connector(task, PTRACE_ATTACH);
-	}
-
-	return retval;
+	return 0;
 }
 
 /**
@@ -812,9 +793,9 @@ static long ptrace_get_rseq_configuration(struct task_struct *task,
 					  unsigned long size, void __user *data)
 {
 	struct ptrace_rseq_configuration conf = {
-		.rseq_abi_pointer = (u64)(uintptr_t)task->rseq,
-		.rseq_abi_size = sizeof(*task->rseq),
-		.signature = task->rseq_sig,
+		.rseq_abi_pointer = (u64)(uintptr_t)task->rseq.usrptr,
+		.rseq_abi_size = task->rseq.len,
+		.signature = task->rseq.sig,
 		.flags = 0,
 	};
 
@@ -940,7 +921,6 @@ ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
 	unsigned long args[ARRAY_SIZE(info->entry.args)];
 	int i;
 
-	info->op = PTRACE_SYSCALL_INFO_ENTRY;
 	info->entry.nr = syscall_get_nr(child, regs);
 	syscall_get_arguments(child, regs, args);
 	for (i = 0; i < ARRAY_SIZE(args); i++)
@@ -962,10 +942,12 @@ ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
 	 * diverge significantly enough.
 	 */
 	ptrace_get_syscall_info_entry(child, regs, info);
-	info->op = PTRACE_SYSCALL_INFO_SECCOMP;
 	info->seccomp.ret_data = child->ptrace_message;
 
-	/* ret_data is the last field in struct ptrace_syscall_info.seccomp */
+	/*
+	 * ret_data is the last non-reserved field
+	 * in struct ptrace_syscall_info.seccomp
+	 */
 	return offsetofend(struct ptrace_syscall_info, seccomp.ret_data);
 }
 
@@ -973,7 +955,6 @@ static unsigned long
 ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
 			     struct ptrace_syscall_info *info)
 {
-	info->op = PTRACE_SYSCALL_INFO_EXIT;
 	info->exit.rval = syscall_get_error(child, regs);
 	info->exit.is_error = !!info->exit.rval;
 	if (!info->exit.is_error)
@@ -984,19 +965,8 @@ ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
 }
 
 static int
-ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
-			void __user *datavp)
+ptrace_get_syscall_info_op(struct task_struct *child)
 {
-	struct pt_regs *regs = task_pt_regs(child);
-	struct ptrace_syscall_info info = {
-		.op = PTRACE_SYSCALL_INFO_NONE,
-		.arch = syscall_get_arch(child),
-		.instruction_pointer = instruction_pointer(regs),
-		.stack_pointer = user_stack_pointer(regs),
-	};
-	unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
-	unsigned long write_size;
-
 	/*
 	 * This does not need lock_task_sighand() to access
 	 * child->last_siginfo because ptrace_freeze_traced()
@@ -1007,24 +977,160 @@ ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
 	case SIGTRAP | 0x80:
 		switch (child->ptrace_message) {
 		case PTRACE_EVENTMSG_SYSCALL_ENTRY:
-			actual_size = ptrace_get_syscall_info_entry(child, regs,
-								    &info);
-			break;
+			return PTRACE_SYSCALL_INFO_ENTRY;
 		case PTRACE_EVENTMSG_SYSCALL_EXIT:
-			actual_size = ptrace_get_syscall_info_exit(child, regs,
-								   &info);
-			break;
+			return PTRACE_SYSCALL_INFO_EXIT;
+		default:
+			return PTRACE_SYSCALL_INFO_NONE;
 		}
-		break;
 	case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8):
-		actual_size = ptrace_get_syscall_info_seccomp(child, regs,
-							      &info);
+		return PTRACE_SYSCALL_INFO_SECCOMP;
+	default:
+		return PTRACE_SYSCALL_INFO_NONE;
+	}
+}
+
+static int
+ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
+			void __user *datavp)
+{
+	struct pt_regs *regs = task_pt_regs(child);
+	struct ptrace_syscall_info info = {
+		.op = ptrace_get_syscall_info_op(child),
+		.arch = syscall_get_arch(child),
+		.instruction_pointer = instruction_pointer(regs),
+		.stack_pointer = user_stack_pointer(regs),
+	};
+	unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
+	unsigned long write_size;
+
+	switch (info.op) {
+	case PTRACE_SYSCALL_INFO_ENTRY:
+		actual_size = ptrace_get_syscall_info_entry(child, regs, &info);
+		break;
+	case PTRACE_SYSCALL_INFO_EXIT:
+		actual_size = ptrace_get_syscall_info_exit(child, regs, &info);
+		break;
+	case PTRACE_SYSCALL_INFO_SECCOMP:
+		actual_size = ptrace_get_syscall_info_seccomp(child, regs, &info);
 		break;
 	}
 
 	write_size = min(actual_size, user_size);
 	return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size;
 }
+
+static int
+ptrace_set_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
+			      struct ptrace_syscall_info *info)
+{
+	unsigned long args[ARRAY_SIZE(info->entry.args)];
+	int nr = info->entry.nr;
+	int i;
+
+	/*
+	 * Check that the syscall number specified in info->entry.nr
+	 * is either a value of type "int" or a sign-extended value
+	 * of type "int".
+	 */
+	if (nr != info->entry.nr)
+		return -ERANGE;
+
+	for (i = 0; i < ARRAY_SIZE(args); i++) {
+		args[i] = info->entry.args[i];
+		/*
+		 * Check that the syscall argument specified in
+		 * info->entry.args[i] is either a value of type
+		 * "unsigned long" or a sign-extended value of type "long".
+		 */
+		if (args[i] != info->entry.args[i])
+			return -ERANGE;
+	}
+
+	syscall_set_nr(child, regs, nr);
+	/*
+	 * If the syscall number is set to -1, setting syscall arguments is not
+	 * just pointless, it would also clobber the syscall return value on
+	 * those architectures that share the same register both for the first
+	 * argument of syscall and its return value.
+	 */
+	if (nr != -1)
+		syscall_set_arguments(child, regs, args);
+
+	return 0;
+}
+
+static int
+ptrace_set_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
+				struct ptrace_syscall_info *info)
+{
+	/*
+	 * info->entry is currently a subset of info->seccomp,
+	 * info->seccomp.ret_data is currently ignored.
+	 */
+	return ptrace_set_syscall_info_entry(child, regs, info);
+}
+
+static int
+ptrace_set_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
+			     struct ptrace_syscall_info *info)
+{
+	long rval = info->exit.rval;
+
+	/*
+	 * Check that the return value specified in info->exit.rval
+	 * is either a value of type "long" or a sign-extended value
+	 * of type "long".
+	 */
+	if (rval != info->exit.rval)
+		return -ERANGE;
+
+	if (info->exit.is_error)
+		syscall_set_return_value(child, regs, rval, 0);
+	else
+		syscall_set_return_value(child, regs, 0, rval);
+
+	return 0;
+}
+
+static int
+ptrace_set_syscall_info(struct task_struct *child, unsigned long user_size,
+			const void __user *datavp)
+{
+	struct pt_regs *regs = task_pt_regs(child);
+	struct ptrace_syscall_info info;
+
+	if (user_size < sizeof(info))
+		return -EINVAL;
+
+	/*
+	 * The compatibility is tracked by info.op and info.flags: if user-space
+	 * does not instruct us to use unknown extra bits from future versions
+	 * of ptrace_syscall_info, we are not going to read them either.
+	 */
+	if (copy_from_user(&info, datavp, sizeof(info)))
+		return -EFAULT;
+
+	/* Reserved for future use. */
+	if (info.flags || info.reserved)
+		return -EINVAL;
+
+	/* Changing the type of the system call stop is not supported yet. */
+	if (ptrace_get_syscall_info_op(child) != info.op)
+		return -EINVAL;
+
+	switch (info.op) {
+	case PTRACE_SYSCALL_INFO_ENTRY:
+		return ptrace_set_syscall_info_entry(child, regs, &info);
+	case PTRACE_SYSCALL_INFO_EXIT:
+		return ptrace_set_syscall_info_exit(child, regs, &info);
+	case PTRACE_SYSCALL_INFO_SECCOMP:
+		return ptrace_set_syscall_info_seccomp(child, regs, &info);
+	default:
+		/* Other types of system call stops are not supported yet. */
+		return -EINVAL;
+	}
+}
 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 
 int ptrace_request(struct task_struct *child, long request,
@@ -1243,6 +1349,10 @@ int ptrace_request(struct task_struct *child, long request,
 	case PTRACE_GET_SYSCALL_INFO:
 		ret = ptrace_get_syscall_info(child, addr, datavp);
 		break;
+
+	case PTRACE_SET_SYSCALL_INFO:
+		ret = ptrace_set_syscall_info(child, addr, datavp);
+		break;
 #endif
 
 	case PTRACE_SECCOMP_GET_FILTER:
@@ -1259,6 +1369,14 @@ int ptrace_request(struct task_struct *child, long request,
 		break;
 #endif
 
+	case PTRACE_SET_SYSCALL_USER_DISPATCH_CONFIG:
+		ret = syscall_user_dispatch_set_config(child, addr, datavp);
+		break;
+
+	case PTRACE_GET_SYSCALL_USER_DISPATCH_CONFIG:
+		ret = syscall_user_dispatch_get_config(child, addr, datavp);
+		break;
+
 	default:
 		break;
 	}