1 files changed, 88 insertions, 108 deletions

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index e6db475164ed..8f6dcd88202e 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -189,7 +189,7 @@ int fixup_bug(struct pt_regs *regs, int trapnr)
 }
 
 static nokprobe_inline int
-do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
+do_trap_no_signal(struct task_struct *tsk, int trapnr, const char *str,
 		  struct pt_regs *regs,	long error_code)
 {
 	if (v8086_mode(regs)) {
@@ -202,11 +202,8 @@ do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
 						error_code, trapnr))
 				return 0;
 		}
-		return -1;
-	}
-
-	if (!user_mode(regs)) {
-		if (fixup_exception(regs, trapnr))
+	} else if (!user_mode(regs)) {
+		if (fixup_exception(regs, trapnr, error_code, 0))
 			return 0;
 
 		tsk->thread.error_code = error_code;
@@ -214,49 +211,6 @@ do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
 		die(str, regs, error_code);
 	}
 
-	return -1;
-}
-
-static siginfo_t *fill_trap_info(struct pt_regs *regs, int signr, int trapnr,
-				siginfo_t *info)
-{
-	unsigned long siaddr;
-	int sicode;
-
-	switch (trapnr) {
-	default:
-		return SEND_SIG_PRIV;
-
-	case X86_TRAP_DE:
-		sicode = FPE_INTDIV;
-		siaddr = uprobe_get_trap_addr(regs);
-		break;
-	case X86_TRAP_UD:
-		sicode = ILL_ILLOPN;
-		siaddr = uprobe_get_trap_addr(regs);
-		break;
-	case X86_TRAP_AC:
-		sicode = BUS_ADRALN;
-		siaddr = 0;
-		break;
-	}
-
-	info->si_signo = signr;
-	info->si_errno = 0;
-	info->si_code = sicode;
-	info->si_addr = (void __user *)siaddr;
-	return info;
-}
-
-static void
-do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
-	long error_code, siginfo_t *info)
-{
-	struct task_struct *tsk = current;
-
-
-	if (!do_trap_no_signal(tsk, trapnr, str, regs, error_code))
-		return;
 	/*
 	 * We want error_code and trap_nr set for userspace faults and
 	 * kernelspace faults which result in die(), but not
@@ -269,24 +223,45 @@ do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
 	tsk->thread.error_code = error_code;
 	tsk->thread.trap_nr = trapnr;
 
+	return -1;
+}
+
+static void show_signal(struct task_struct *tsk, int signr,
+			const char *type, const char *desc,
+			struct pt_regs *regs, long error_code)
+{
 	if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
 	    printk_ratelimit()) {
-		pr_info("%s[%d] trap %s ip:%lx sp:%lx error:%lx",
-			tsk->comm, tsk->pid, str,
+		pr_info("%s[%d] %s%s ip:%lx sp:%lx error:%lx",
+			tsk->comm, task_pid_nr(tsk), type, desc,
 			regs->ip, regs->sp, error_code);
 		print_vma_addr(KERN_CONT " in ", regs->ip);
 		pr_cont("\n");
 	}
+}
 
-	force_sig_info(signr, info ?: SEND_SIG_PRIV, tsk);
+static void
+do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
+	long error_code, int sicode, void __user *addr)
+{
+	struct task_struct *tsk = current;
+
+
+	if (!do_trap_no_signal(tsk, trapnr, str, regs, error_code))
+		return;
+
+	show_signal(tsk, signr, "trap ", str, regs, error_code);
+
+	if (!sicode)
+		force_sig(signr, tsk);
+	else
+		force_sig_fault(signr, sicode, addr, tsk);
 }
 NOKPROBE_SYMBOL(do_trap);
 
 static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
-			  unsigned long trapnr, int signr)
+	unsigned long trapnr, int signr, int sicode, void __user *addr)
 {
-	siginfo_t info;
-
 	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
 
 	/*
@@ -299,26 +274,26 @@ static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
 	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=
 			NOTIFY_STOP) {
 		cond_local_irq_enable(regs);
-		clear_siginfo(&info);
-		do_trap(trapnr, signr, str, regs, error_code,
-			fill_trap_info(regs, signr, trapnr, &info));
+		do_trap(trapnr, signr, str, regs, error_code, sicode, addr);
 	}
 }
 
-#define DO_ERROR(trapnr, signr, str, name)				\
-dotraplinkage void do_##name(struct pt_regs *regs, long error_code)	\
-{									\
-	do_error_trap(regs, error_code, str, trapnr, signr);		\
+#define IP ((void __user *)uprobe_get_trap_addr(regs))
+#define DO_ERROR(trapnr, signr, sicode, addr, str, name)		   \
+dotraplinkage void do_##name(struct pt_regs *regs, long error_code)	   \
+{									   \
+	do_error_trap(regs, error_code, str, trapnr, signr, sicode, addr); \
 }
 
-DO_ERROR(X86_TRAP_DE,     SIGFPE,  "divide error",		divide_error)
-DO_ERROR(X86_TRAP_OF,     SIGSEGV, "overflow",			overflow)
-DO_ERROR(X86_TRAP_UD,     SIGILL,  "invalid opcode",		invalid_op)
-DO_ERROR(X86_TRAP_OLD_MF, SIGFPE,  "coprocessor segment overrun",coprocessor_segment_overrun)
-DO_ERROR(X86_TRAP_TS,     SIGSEGV, "invalid TSS",		invalid_TSS)
-DO_ERROR(X86_TRAP_NP,     SIGBUS,  "segment not present",	segment_not_present)
-DO_ERROR(X86_TRAP_SS,     SIGBUS,  "stack segment",		stack_segment)
-DO_ERROR(X86_TRAP_AC,     SIGBUS,  "alignment check",		alignment_check)
+DO_ERROR(X86_TRAP_DE,     SIGFPE,  FPE_INTDIV,   IP, "divide error",        divide_error)
+DO_ERROR(X86_TRAP_OF,     SIGSEGV,          0, NULL, "overflow",            overflow)
+DO_ERROR(X86_TRAP_UD,     SIGILL,  ILL_ILLOPN,   IP, "invalid opcode",      invalid_op)
+DO_ERROR(X86_TRAP_OLD_MF, SIGFPE,           0, NULL, "coprocessor segment overrun", coprocessor_segment_overrun)
+DO_ERROR(X86_TRAP_TS,     SIGSEGV,          0, NULL, "invalid TSS",         invalid_TSS)
+DO_ERROR(X86_TRAP_NP,     SIGBUS,           0, NULL, "segment not present", segment_not_present)
+DO_ERROR(X86_TRAP_SS,     SIGBUS,           0, NULL, "stack segment",       stack_segment)
+DO_ERROR(X86_TRAP_AC,     SIGBUS,  BUS_ADRALN, NULL, "alignment check",     alignment_check)
+#undef IP
 
 #ifdef CONFIG_VMAP_STACK
 __visible void __noreturn handle_stack_overflow(const char *message,
@@ -383,6 +358,10 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
 		 * we won't enable interupts or schedule before we invoke
 		 * general_protection, so nothing will clobber the stack
 		 * frame we just set up.
+		 *
+		 * We will enter general_protection with kernel GSBASE,
+		 * which is what the stub expects, given that the faulting
+		 * RIP will be the IRET instruction.
 		 */
 		regs->ip = (unsigned long)general_protection;
 		regs->sp = (unsigned long)&gpregs->orig_ax;
@@ -455,7 +434,6 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
 dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
 {
 	const struct mpx_bndcsr *bndcsr;
-	siginfo_t *info;
 
 	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
 	if (notify_die(DIE_TRAP, "bounds", regs, error_code,
@@ -493,8 +471,11 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
 			goto exit_trap;
 		break; /* Success, it was handled */
 	case 1: /* Bound violation. */
-		info = mpx_generate_siginfo(regs);
-		if (IS_ERR(info)) {
+	{
+		struct task_struct *tsk = current;
+		struct mpx_fault_info mpx;
+
+		if (mpx_fault_info(&mpx, regs)) {
 			/*
 			 * We failed to decode the MPX instruction.  Act as if
 			 * the exception was not caused by MPX.
@@ -503,14 +484,20 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
 		}
 		/*
 		 * Success, we decoded the instruction and retrieved
-		 * an 'info' containing the address being accessed
+		 * an 'mpx' containing the address being accessed
 		 * which caused the exception.  This information
 		 * allows and application to possibly handle the
 		 * #BR exception itself.
 		 */
-		do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs, error_code, info);
-		kfree(info);
+		if (!do_trap_no_signal(tsk, X86_TRAP_BR, "bounds", regs,
+				       error_code))
+			break;
+
+		show_signal(tsk, SIGSEGV, "trap ", "bounds", regs, error_code);
+
+		force_sig_bnderr(mpx.addr, mpx.lower, mpx.upper);
 		break;
+	}
 	case 0: /* No exception caused by Intel MPX operations. */
 		goto exit_trap;
 	default:
@@ -527,12 +514,13 @@ exit_trap:
 	 * up here if the kernel has MPX turned off at compile
 	 * time..
 	 */
-	do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs, error_code, NULL);
+	do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs, error_code, 0, NULL);
 }
 
 dotraplinkage void
 do_general_protection(struct pt_regs *regs, long error_code)
 {
+	const char *desc = "general protection fault";
 	struct task_struct *tsk;
 
 	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
@@ -551,30 +539,33 @@ do_general_protection(struct pt_regs *regs, long error_code)
 
 	tsk = current;
 	if (!user_mode(regs)) {
-		if (fixup_exception(regs, X86_TRAP_GP))
+		if (fixup_exception(regs, X86_TRAP_GP, error_code, 0))
 			return;
 
 		tsk->thread.error_code = error_code;
 		tsk->thread.trap_nr = X86_TRAP_GP;
-		if (notify_die(DIE_GPF, "general protection fault", regs, error_code,
+
+		/*
+		 * To be potentially processing a kprobe fault and to
+		 * trust the result from kprobe_running(), we have to
+		 * be non-preemptible.
+		 */
+		if (!preemptible() && kprobe_running() &&
+		    kprobe_fault_handler(regs, X86_TRAP_GP))
+			return;
+
+		if (notify_die(DIE_GPF, desc, regs, error_code,
 			       X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP)
-			die("general protection fault", regs, error_code);
+			die(desc, regs, error_code);
 		return;
 	}
 
 	tsk->thread.error_code = error_code;
 	tsk->thread.trap_nr = X86_TRAP_GP;
 
-	if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
-			printk_ratelimit()) {
-		pr_info("%s[%d] general protection ip:%lx sp:%lx error:%lx",
-			tsk->comm, task_pid_nr(tsk),
-			regs->ip, regs->sp, error_code);
-		print_vma_addr(KERN_CONT " in ", regs->ip);
-		pr_cont("\n");
-	}
+	show_signal(tsk, SIGSEGV, "", desc, regs, error_code);
 
-	force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
+	force_sig(SIGSEGV, tsk);
 }
 NOKPROBE_SYMBOL(do_general_protection);
 
@@ -617,7 +608,7 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
 		goto exit;
 
 	cond_local_irq_enable(regs);
-	do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
+	do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, 0, NULL);
 	cond_local_irq_disable(regs);
 
 exit:
@@ -831,14 +822,14 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
 {
 	struct task_struct *task = current;
 	struct fpu *fpu = &task->thread.fpu;
-	siginfo_t info;
+	int si_code;
 	char *str = (trapnr == X86_TRAP_MF) ? "fpu exception" :
 						"simd exception";
 
 	cond_local_irq_enable(regs);
 
 	if (!user_mode(regs)) {
-		if (fixup_exception(regs, trapnr))
+		if (fixup_exception(regs, trapnr, error_code, 0))
 			return;
 
 		task->thread.error_code = error_code;
@@ -857,18 +848,14 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
 
 	task->thread.trap_nr	= trapnr;
 	task->thread.error_code = error_code;
-	clear_siginfo(&info);
-	info.si_signo		= SIGFPE;
-	info.si_errno		= 0;
-	info.si_addr		= (void __user *)uprobe_get_trap_addr(regs);
-
-	info.si_code = fpu__exception_code(fpu, trapnr);
 
+	si_code = fpu__exception_code(fpu, trapnr);
 	/* Retry when we get spurious exceptions: */
-	if (!info.si_code)
+	if (!si_code)
 		return;
 
-	force_sig_info(SIGFPE, &info, task);
+	force_sig_fault(SIGFPE, si_code,
+			(void __user *)uprobe_get_trap_addr(regs), task);
 }
 
 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
@@ -928,20 +915,13 @@ NOKPROBE_SYMBOL(do_device_not_available);
 #ifdef CONFIG_X86_32
 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 {
-	siginfo_t info;
-
 	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
 	local_irq_enable();
 
-	clear_siginfo(&info);
-	info.si_signo = SIGILL;
-	info.si_errno = 0;
-	info.si_code = ILL_BADSTK;
-	info.si_addr = NULL;
 	if (notify_die(DIE_TRAP, "iret exception", regs, error_code,
 			X86_TRAP_IRET, SIGILL) != NOTIFY_STOP) {
 		do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
-			&info);
+			ILL_BADSTK, (void __user *)NULL);
 	}
 }
 #endif