Re: [PATCH v6 06/10] powerpc/signal64: Replace setup_sigcontext() w/ unsafe_setup_sigcontext()

Signed-off-by: Christopher M. Riedl <redacted>
---
  arch/powerpc/kernel/signal_64.c | 71 ++++++++++++++++++++-------------
  1 file changed, 44 insertions(+), 27 deletions(-)

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index bd8d210c9115..3faaa736ed62 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c

@@ -101,9 +101,13 @@ static void prepare_setup_sigcontext(struct task_struct *tsk)
   * Set up the sigcontext for the signal frame.
   */
  
-static long setup_sigcontext(struct sigcontext __user *sc,
-		struct task_struct *tsk, int signr, sigset_t *set,
-		unsigned long handler, int ctx_has_vsx_region)
+#define unsafe_setup_sigcontext(sc, tsk, signr, set, handler,		\
+				ctx_has_vsx_region, e)			\
+	unsafe_op_wrap(__unsafe_setup_sigcontext(sc, tsk, signr, set,	\
+			handler, ctx_has_vsx_region), e)
+static long notrace __unsafe_setup_sigcontext(struct sigcontext __user *sc,
+					struct task_struct *tsk, int signr, sigset_t *set,
+					unsigned long handler, int ctx_has_vsx_region)
  {
  	/* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
  	 * process never used altivec yet (MSR_VEC is zero in pt_regs of

@@ -118,20 +122,19 @@ static long setup_sigcontext(struct sigcontext __user *sc,
  #endif
  	struct pt_regs *regs = tsk->thread.regs;
  	unsigned long msr = regs->msr;
-	long err = 0;
  	/* Force usr to alway see softe as 1 (interrupts enabled) */
  	unsigned long softe = 0x1;
  
  	BUG_ON(tsk != current);
  
  #ifdef CONFIG_ALTIVEC
-	err |= __put_user(v_regs, &sc->v_regs);
+	unsafe_put_user(v_regs, &sc->v_regs, efault_out);
  
  	/* save altivec registers */
  	if (tsk->thread.used_vr) {
  		/* Copy 33 vec registers (vr0..31 and vscr) to the stack */
-		err |= __copy_to_user(v_regs, &tsk->thread.vr_state,
-				      33 * sizeof(vector128));
+		unsafe_copy_to_user(v_regs, &tsk->thread.vr_state,
+				    33 * sizeof(vector128), efault_out);
  		/* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
  		 * contains valid data.
  		 */

@@ -140,12 +143,12 @@ static long setup_sigcontext(struct sigcontext __user *sc,
  	/* We always copy to/from vrsave, it's 0 if we don't have or don't
  	 * use altivec.
  	 */
-	err |= __put_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33]);
+	unsafe_put_user(tsk->thread.vrsave, (u32 __user *)&v_regs[33], efault_out);
  #else /* CONFIG_ALTIVEC */
-	err |= __put_user(0, &sc->v_regs);
+	unsafe_put_user(0, &sc->v_regs, efault_out);
  #endif /* CONFIG_ALTIVEC */
  	/* copy fpr regs and fpscr */
-	err |= copy_fpr_to_user(&sc->fp_regs, tsk);
+	unsafe_copy_fpr_to_user(&sc->fp_regs, tsk, efault_out);
  
  	/*
  	 * Clear the MSR VSX bit to indicate there is no valid state attached

@@ -160,24 +163,27 @@ static long setup_sigcontext(struct sigcontext __user *sc,
  	 */
  	if (tsk->thread.used_vsr && ctx_has_vsx_region) {
  		v_regs += ELF_NVRREG;
-		err |= copy_vsx_to_user(v_regs, tsk);
+		unsafe_copy_vsx_to_user(v_regs, tsk, efault_out);
  		/* set MSR_VSX in the MSR value in the frame to
  		 * indicate that sc->vs_reg) contains valid data.
  		 */
  		msr |= MSR_VSX;
  	}
  #endif /* CONFIG_VSX */
-	err |= __put_user(&sc->gp_regs, &sc->regs);
+	unsafe_put_user(&sc->gp_regs, &sc->regs, efault_out);
  	WARN_ON(!FULL_REGS(regs));
-	err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
-	err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
-	err |= __put_user(softe, &sc->gp_regs[PT_SOFTE]);
-	err |= __put_user(signr, &sc->signal);
-	err |= __put_user(handler, &sc->handler);
+	unsafe_copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE, efault_out);
+	unsafe_put_user(msr, &sc->gp_regs[PT_MSR], efault_out);
+	unsafe_put_user(softe, &sc->gp_regs[PT_SOFTE], efault_out);
+	unsafe_put_user(signr, &sc->signal, efault_out);
+	unsafe_put_user(handler, &sc->handler, efault_out);
  	if (set != NULL)
-		err |=  __put_user(set->sig[0], &sc->oldmask);
+		unsafe_put_user(set->sig[0], &sc->oldmask, efault_out);
  
-	return err;
+	return 0;
+
+efault_out:
+	return -EFAULT;
  }
  
  #ifdef CONFIG_PPC_TRANSACTIONAL_MEM

@@ -670,12 +676,15 @@ SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
  
  	if (old_ctx != NULL) {
  		prepare_setup_sigcontext(current);
-		if (!access_ok(old_ctx, ctx_size)
-		    || setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL, 0,
-					ctx_has_vsx_region)
-		    || __copy_to_user(&old_ctx->uc_sigmask,
-				      &current->blocked, sizeof(sigset_t)))
+		if (!user_write_access_begin(old_ctx, ctx_size))
  			return -EFAULT;
+
+		unsafe_setup_sigcontext(&old_ctx->uc_mcontext, current, 0, NULL,
+					0, ctx_has_vsx_region, efault_out);
+		unsafe_copy_to_user(&old_ctx->uc_sigmask, &current->blocked,
+				    sizeof(sigset_t), efault_out);
+
+		user_write_access_end();
  	}
  	if (new_ctx == NULL)
  		return 0;

@@ -704,6 +713,10 @@ SYSCALL_DEFINE3(swapcontext, struct ucontext __user *, old_ctx,
  	/* This returns like rt_sigreturn */
  	set_thread_flag(TIF_RESTOREALL);
  	return 0;
+
+efault_out:
+	user_write_access_end();
+	return -EFAULT;
  }
  
  

@@ -854,9 +867,13 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
  	} else {
  		err |= __put_user(0, &frame->uc.uc_link);
  		prepare_setup_sigcontext(tsk);
-		err |= setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig,
-					NULL, (unsigned long)ksig->ka.sa.sa_handler,
-					1);
+		if (!user_write_access_begin(&frame->uc.uc_mcontext,
+					     sizeof(frame->uc.uc_mcontext)))
+			return -EFAULT;
+		err |= __unsafe_setup_sigcontext(&frame->uc.uc_mcontext, tsk,
+						ksig->sig, NULL,
+						(unsigned long)ksig->ka.sa.sa_handler, 1);
+		user_write_access_end();
  	}
  	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
  	if (err)