[RFC v2 -tip 3/3] x86: ia32_signal: use {get|put}_user_try and catch

[Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>]

From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>

Impact: use new framework

Use {get|put}_user_try, catch, and _ex in arch/x86/ia32/ia32_signal.c.

Note: this patch contains "WARNING: line over 80 characters", because when
introducing new block I insert an indent to avoid mistakes by edit.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
---
 arch/x86/ia32/ia32_signal.c |  365 +++++++++++++++++++++++--------------------
 1 files changed, 195 insertions(+), 170 deletions(-)

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 9dabd00..dd77ac0 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -46,78 +46,83 @@ void signal_fault(struct pt_regs *regs, void __user *frame, char *where);
 
 int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
 {
-	int err;
+	int err = 0;
 
 	if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
 		return -EFAULT;
 
-	/* If you change siginfo_t structure, please make sure that
-	   this code is fixed accordingly.
-	   It should never copy any pad contained in the structure
-	   to avoid security leaks, but must copy the generic
-	   3 ints plus the relevant union member.  */
-	err = __put_user(from->si_signo, &to->si_signo);
-	err |= __put_user(from->si_errno, &to->si_errno);
-	err |= __put_user((short)from->si_code, &to->si_code);
-
-	if (from->si_code < 0) {
-		err |= __put_user(from->si_pid, &to->si_pid);
-		err |= __put_user(from->si_uid, &to->si_uid);
-		err |= __put_user(ptr_to_compat(from->si_ptr), &to->si_ptr);
-	} else {
-		/*
-		 * First 32bits of unions are always present:
-		 * si_pid === si_band === si_tid === si_addr(LS half)
-		 */
-		err |= __put_user(from->_sifields._pad[0],
-				  &to->_sifields._pad[0]);
-		switch (from->si_code >> 16) {
-		case __SI_FAULT >> 16:
-			break;
-		case __SI_CHLD >> 16:
-			err |= __put_user(from->si_utime, &to->si_utime);
-			err |= __put_user(from->si_stime, &to->si_stime);
-			err |= __put_user(from->si_status, &to->si_status);
-			/* FALL THROUGH */
-		default:
-		case __SI_KILL >> 16:
-			err |= __put_user(from->si_uid, &to->si_uid);
-			break;
-		case __SI_POLL >> 16:
-			err |= __put_user(from->si_fd, &to->si_fd);
-			break;
-		case __SI_TIMER >> 16:
-			err |= __put_user(from->si_overrun, &to->si_overrun);
-			err |= __put_user(ptr_to_compat(from->si_ptr),
-					  &to->si_ptr);
-			break;
-			 /* This is not generated by the kernel as of now.  */
-		case __SI_RT >> 16:
-		case __SI_MESGQ >> 16:
-			err |= __put_user(from->si_uid, &to->si_uid);
-			err |= __put_user(from->si_int, &to->si_int);
-			break;
+	put_user_try {
+		/* If you change siginfo_t structure, please make sure that
+		   this code is fixed accordingly.
+		   It should never copy any pad contained in the structure
+		   to avoid security leaks, but must copy the generic
+		   3 ints plus the relevant union member.  */
+		put_user_ex(from->si_signo, &to->si_signo);
+		put_user_ex(from->si_errno, &to->si_errno);
+		put_user_ex((short)from->si_code, &to->si_code);
+
+		if (from->si_code < 0) {
+			put_user_ex(from->si_pid, &to->si_pid);
+			put_user_ex(from->si_uid, &to->si_uid);
+			put_user_ex(ptr_to_compat(from->si_ptr), &to->si_ptr);
+		} else {
+			/*
+			 * First 32bits of unions are always present:
+			 * si_pid === si_band === si_tid === si_addr(LS half)
+			 */
+			put_user_ex(from->_sifields._pad[0],
+					  &to->_sifields._pad[0]);
+			switch (from->si_code >> 16) {
+			case __SI_FAULT >> 16:
+				break;
+			case __SI_CHLD >> 16:
+				put_user_ex(from->si_utime, &to->si_utime);
+				put_user_ex(from->si_stime, &to->si_stime);
+				put_user_ex(from->si_status, &to->si_status);
+				/* FALL THROUGH */
+			default:
+			case __SI_KILL >> 16:
+				put_user_ex(from->si_uid, &to->si_uid);
+				break;
+			case __SI_POLL >> 16:
+				put_user_ex(from->si_fd, &to->si_fd);
+				break;
+			case __SI_TIMER >> 16:
+				put_user_ex(from->si_overrun, &to->si_overrun);
+				put_user_ex(ptr_to_compat(from->si_ptr),
+					    &to->si_ptr);
+				break;
+				 /* This is not generated by the kernel as of now.  */
+			case __SI_RT >> 16:
+			case __SI_MESGQ >> 16:
+				put_user_ex(from->si_uid, &to->si_uid);
+				put_user_ex(from->si_int, &to->si_int);
+				break;
+			}
 		}
-	}
+	} put_user_catch(err);
+
 	return err;
 }
 
 int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
 {
-	int err;
+	int err = 0;
 	u32 ptr32;
 
 	if (!access_ok(VERIFY_READ, from, sizeof(compat_siginfo_t)))
 		return -EFAULT;
 
-	err = __get_user(to->si_signo, &from->si_signo);
-	err |= __get_user(to->si_errno, &from->si_errno);
-	err |= __get_user(to->si_code, &from->si_code);
+	get_user_try {
+		get_user_ex(to->si_signo, &from->si_signo);
+		get_user_ex(to->si_errno, &from->si_errno);
+		get_user_ex(to->si_code, &from->si_code);
 
-	err |= __get_user(to->si_pid, &from->si_pid);
-	err |= __get_user(to->si_uid, &from->si_uid);
-	err |= __get_user(ptr32, &from->si_ptr);
-	to->si_ptr = compat_ptr(ptr32);
+		get_user_ex(to->si_pid, &from->si_pid);
+		get_user_ex(to->si_uid, &from->si_uid);
+		get_user_ex(ptr32, &from->si_ptr);
+		to->si_ptr = compat_ptr(ptr32);
+	} get_user_catch(err);
 
 	return err;
 }
@@ -142,17 +147,23 @@ asmlinkage long sys32_sigaltstack(const stack_ia32_t __user *uss_ptr,
 				  struct pt_regs *regs)
 {
 	stack_t uss, uoss;
-	int ret;
+	int ret, err = 0;
 	mm_segment_t seg;
 
 	if (uss_ptr) {
 		u32 ptr;
 
 		memset(&uss, 0, sizeof(stack_t));
-		if (!access_ok(VERIFY_READ, uss_ptr, sizeof(stack_ia32_t)) ||
-			    __get_user(ptr, &uss_ptr->ss_sp) ||
-			    __get_user(uss.ss_flags, &uss_ptr->ss_flags) ||
-			    __get_user(uss.ss_size, &uss_ptr->ss_size))
+		if (!access_ok(VERIFY_READ, uss_ptr, sizeof(stack_ia32_t)))
+			return -EFAULT;
+
+		get_user_try {
+			get_user_ex(ptr, &uss_ptr->ss_sp);
+			get_user_ex(uss.ss_flags, &uss_ptr->ss_flags);
+			get_user_ex(uss.ss_size, &uss_ptr->ss_size);
+		} get_user_catch(err);
+
+		if (err)
 			return -EFAULT;
 		uss.ss_sp = compat_ptr(ptr);
 	}
@@ -161,10 +172,16 @@ asmlinkage long sys32_sigaltstack(const stack_ia32_t __user *uss_ptr,
 	ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss, regs->sp);
 	set_fs(seg);
 	if (ret >= 0 && uoss_ptr)  {
-		if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(stack_ia32_t)) ||
-		    __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
-		    __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
-		    __put_user(uoss.ss_size, &uoss_ptr->ss_size))
+		if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(stack_ia32_t)))
+			return -EFAULT;
+
+		put_user_try {
+			put_user_ex(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp);
+			put_user_ex(uoss.ss_flags, &uoss_ptr->ss_flags);
+			put_user_ex(uoss.ss_size, &uoss_ptr->ss_size);
+		} put_user_catch(err);
+
+		if (err)
 			ret = -EFAULT;
 	}
 	return ret;
@@ -174,18 +191,18 @@ asmlinkage long sys32_sigaltstack(const stack_ia32_t __user *uss_ptr,
  * Do a signal return; undo the signal stack.
  */
 #define COPY(x)			{		\
-	err |= __get_user(regs->x, &sc->x);	\
+	get_user_ex(regs->x, &sc->x);		\
 }
 
 #define COPY_SEG_CPL3(seg)	{			\
 		unsigned short tmp;			\
-		err |= __get_user(tmp, &sc->seg);	\
+		get_user_ex(tmp, &sc->seg);		\
 		regs->seg = tmp | 3;			\
 }
 
 #define RELOAD_SEG(seg)		{		\
 	unsigned int cur, pre;			\
-	err |= __get_user(pre, &sc->seg);	\
+	get_user_ex(pre, &sc->seg);		\
 	savesegment(seg, cur);			\
 	pre |= 3;				\
 	if (pre != cur)				\
@@ -209,39 +226,42 @@ static int ia32_restore_sigcontext(struct pt_regs *regs,
 	       sc, sc->err, sc->ip, sc->cs, sc->flags);
 #endif
 
-	/*
-	 * Reload fs and gs if they have changed in the signal
-	 * handler.  This does not handle long fs/gs base changes in
-	 * the handler, but does not clobber them at least in the
-	 * normal case.
-	 */
-	err |= __get_user(gs, &sc->gs);
-	gs |= 3;
-	savesegment(gs, oldgs);
-	if (gs != oldgs)
-		load_gs_index(gs);
-
-	RELOAD_SEG(fs);
-	RELOAD_SEG(ds);
-	RELOAD_SEG(es);
-
-	COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
-	COPY(dx); COPY(cx); COPY(ip);
-	/* Don't touch extended registers */
-
-	COPY_SEG_CPL3(cs);
-	COPY_SEG_CPL3(ss);
-
-	err |= __get_user(tmpflags, &sc->flags);
-	regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
-	/* disable syscall checks */
-	regs->orig_ax = -1;
-
-	err |= __get_user(tmp, &sc->fpstate);
-	buf = compat_ptr(tmp);
-	err |= restore_i387_xstate_ia32(buf);
-
-	err |= __get_user(*pax, &sc->ax);
+	get_user_try {
+		/*
+		 * Reload fs and gs if they have changed in the signal
+		 * handler.  This does not handle long fs/gs base changes in
+		 * the handler, but does not clobber them at least in the
+		 * normal case.
+		 */
+		get_user_ex(gs, &sc->gs);
+		gs |= 3;
+		savesegment(gs, oldgs);
+		if (gs != oldgs)
+			load_gs_index(gs);
+
+		RELOAD_SEG(fs);
+		RELOAD_SEG(ds);
+		RELOAD_SEG(es);
+
+		COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
+		COPY(dx); COPY(cx); COPY(ip);
+		/* Don't touch extended registers */
+
+		COPY_SEG_CPL3(cs);
+		COPY_SEG_CPL3(ss);
+
+		get_user_ex(tmpflags, &sc->flags);
+		regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
+		/* disable syscall checks */
+		regs->orig_ax = -1;
+
+		get_user_ex(tmp, &sc->fpstate);
+		buf = compat_ptr(tmp);
+		err |= restore_i387_xstate_ia32(buf);
+
+		get_user_ex(*pax, &sc->ax);
+	} get_user_catch(err);
+
 	return err;
 }
 
@@ -319,36 +339,38 @@ static int ia32_setup_sigcontext(struct sigcontext_ia32 __user *sc,
 {
 	int tmp, err = 0;
 
-	savesegment(gs, tmp);
-	err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
-	savesegment(fs, tmp);
-	err |= __put_user(tmp, (unsigned int __user *)&sc->fs);
-	savesegment(ds, tmp);
-	err |= __put_user(tmp, (unsigned int __user *)&sc->ds);
-	savesegment(es, tmp);
-	err |= __put_user(tmp, (unsigned int __user *)&sc->es);
-
-	err |= __put_user(regs->di, &sc->di);
-	err |= __put_user(regs->si, &sc->si);
-	err |= __put_user(regs->bp, &sc->bp);
-	err |= __put_user(regs->sp, &sc->sp);
-	err |= __put_user(regs->bx, &sc->bx);
-	err |= __put_user(regs->dx, &sc->dx);
-	err |= __put_user(regs->cx, &sc->cx);
-	err |= __put_user(regs->ax, &sc->ax);
-	err |= __put_user(current->thread.trap_no, &sc->trapno);
-	err |= __put_user(current->thread.error_code, &sc->err);
-	err |= __put_user(regs->ip, &sc->ip);
-	err |= __put_user(regs->cs, (unsigned int __user *)&sc->cs);
-	err |= __put_user(regs->flags, &sc->flags);
-	err |= __put_user(regs->sp, &sc->sp_at_signal);
-	err |= __put_user(regs->ss, (unsigned int __user *)&sc->ss);
-
-	err |= __put_user(ptr_to_compat(fpstate), &sc->fpstate);
-
-	/* non-iBCS2 extensions.. */
-	err |= __put_user(mask, &sc->oldmask);
-	err |= __put_user(current->thread.cr2, &sc->cr2);
+	put_user_try {
+		savesegment(gs, tmp);
+		put_user_ex(tmp, (unsigned int __user *)&sc->gs);
+		savesegment(fs, tmp);
+		put_user_ex(tmp, (unsigned int __user *)&sc->fs);
+		savesegment(ds, tmp);
+		put_user_ex(tmp, (unsigned int __user *)&sc->ds);
+		savesegment(es, tmp);
+		put_user_ex(tmp, (unsigned int __user *)&sc->es);
+
+		put_user_ex(regs->di, &sc->di);
+		put_user_ex(regs->si, &sc->si);
+		put_user_ex(regs->bp, &sc->bp);
+		put_user_ex(regs->sp, &sc->sp);
+		put_user_ex(regs->bx, &sc->bx);
+		put_user_ex(regs->dx, &sc->dx);
+		put_user_ex(regs->cx, &sc->cx);
+		put_user_ex(regs->ax, &sc->ax);
+		put_user_ex(current->thread.trap_no, &sc->trapno);
+		put_user_ex(current->thread.error_code, &sc->err);
+		put_user_ex(regs->ip, &sc->ip);
+		put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
+		put_user_ex(regs->flags, &sc->flags);
+		put_user_ex(regs->sp, &sc->sp_at_signal);
+		put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
+
+		put_user_ex(ptr_to_compat(fpstate), &sc->fpstate);
+
+		/* non-iBCS2 extensions.. */
+		put_user_ex(mask, &sc->oldmask);
+		put_user_ex(current->thread.cr2, &sc->cr2);
+	} put_user_catch(err);
 
 	return err;
 }
@@ -437,13 +459,17 @@ int ia32_setup_frame(int sig, struct k_sigaction *ka,
 		else
 			restorer = &frame->retcode;
 	}
-	err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);
 
-	/*
-	 * These are actually not used anymore, but left because some
-	 * gdb versions depend on them as a marker.
-	 */
-	err |= __put_user(*((u64 *)&code), (u64 *)frame->retcode);
+	put_user_try {
+		put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
+
+		/*
+		 * These are actually not used anymore, but left because some
+		 * gdb versions depend on them as a marker.
+		 */
+		put_user_ex(*((u64 *)&code), (u64 *)frame->retcode);
+	} put_user_catch(err);
+
 	if (err)
 		return -EFAULT;
 
@@ -496,41 +522,40 @@ int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 		return -EFAULT;
 
-	err |= __put_user(sig, &frame->sig);
-	err |= __put_user(ptr_to_compat(&frame->info), &frame->pinfo);
-	err |= __put_user(ptr_to_compat(&frame->uc), &frame->puc);
-	err |= copy_siginfo_to_user32(&frame->info, info);
-	if (err)
-		return -EFAULT;
+	put_user_try {
+		put_user_ex(sig, &frame->sig);
+		put_user_ex(ptr_to_compat(&frame->info), &frame->pinfo);
+		put_user_ex(ptr_to_compat(&frame->uc), &frame->puc);
+		err |= copy_siginfo_to_user32(&frame->info, info);
 
-	/* Create the ucontext.  */
-	if (cpu_has_xsave)
-		err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
-	else
-		err |= __put_user(0, &frame->uc.uc_flags);
-	err |= __put_user(0, &frame->uc.uc_link);
-	err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
-	err |= __put_user(sas_ss_flags(regs->sp),
-			  &frame->uc.uc_stack.ss_flags);
-	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
-	err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
-				     regs, set->sig[0]);
-	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
-	if (err)
-		return -EFAULT;
+		/* Create the ucontext.  */
+		if (cpu_has_xsave)
+			put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
+		else
+			put_user_ex(0, &frame->uc.uc_flags);
+		put_user_ex(0, &frame->uc.uc_link);
+		put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
+		put_user_ex(sas_ss_flags(regs->sp),
+			    &frame->uc.uc_stack.ss_flags);
+		put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
+		err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
+					     regs, set->sig[0]);
+		err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+		if (ka->sa.sa_flags & SA_RESTORER)
+			restorer = ka->sa.sa_restorer;
+		else
+			restorer = VDSO32_SYMBOL(current->mm->context.vdso,
+						 rt_sigreturn);
+		put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
+
+		/*
+		 * Not actually used anymore, but left because some gdb
+		 * versions need it.
+		 */
+		put_user_ex(*((u64 *)&code), (u64 *)frame->retcode);
+	} put_user_catch(err);
 
-	if (ka->sa.sa_flags & SA_RESTORER)
-		restorer = ka->sa.sa_restorer;
-	else
-		restorer = VDSO32_SYMBOL(current->mm->context.vdso,
-					 rt_sigreturn);
-	err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);
-
-	/*
-	 * Not actually used anymore, but left because some gdb
-	 * versions need it.
-	 */
-	err |= __put_user(*((u64 *)&code), (u64 *)frame->retcode);
 	if (err)
 		return -EFAULT;
 
-- 
1.6.0.4