Merge branch 'security-fixes' into fixes

arch/arm/include/asm/elf.h

@@ -130,8 +130,10 @@ struct mm_struct;
 extern unsigned long arch_randomize_brk(struct mm_struct *mm);
 #define arch_randomize_brk arch_randomize_brk
 
+#ifdef CONFIG_MMU
 #define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
 struct linux_binprm;
 int arch_setup_additional_pages(struct linux_binprm *, int);
+#endif
 
 #endif

arch/arm/kernel/process.c

@@ -474,17 +474,18 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 		 "[sigpage]" : NULL;
 }
 
+static struct page *signal_page;
 extern struct page *get_signal_page(void);
 
 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 {
 	struct mm_struct *mm = current->mm;
-	struct page *page;
 	unsigned long addr;
 	int ret;
 
-	page = get_signal_page();
-	if (!page)
+	if (!signal_page)
+		signal_page = get_signal_page();
+	if (!signal_page)
 		return -ENOMEM;
 
 	down_write(&mm->mmap_sem);
@@ -496,7 +497,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 
 	ret = install_special_mapping(mm, addr, PAGE_SIZE,
 		VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
-		&page);
+		&signal_page);
 
 	if (ret == 0)
 		mm->context.sigpage = addr;

arch/arm/kernel/signal.c

@@ -402,7 +402,8 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig,
 		    __put_user(sigreturn_codes[idx+1], rc+1))
 			return 1;
 
-		if ((cpsr & MODE32_BIT) && !IS_ENABLED(CONFIG_ARM_MPU)) {
+#ifdef CONFIG_MMU
+		if (cpsr & MODE32_BIT) {
 			struct mm_struct *mm = current->mm;
 
 			/*
@@ -412,7 +413,9 @@ setup_return(struct pt_regs *regs, struct ksignal *ksig,
 			 */
 			retcode = mm->context.sigpage + signal_return_offset +
 				  (idx << 2) + thumb;
-		} else {
+		} else
+#endif
+		{
 			/*
 			 * Ensure that the instruction cache sees
 			 * the return code written onto the stack.
@@ -614,21 +617,19 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 	return 0;
 }
 
-static struct page *signal_page;
-
 struct page *get_signal_page(void)
 {
-	if (!signal_page) {
 	unsigned long ptr;
 	unsigned offset;
+	struct page *page;
 	void *addr;
 
-		signal_page = alloc_pages(GFP_KERNEL, 0);
+	page = alloc_pages(GFP_KERNEL, 0);
 
-		if (!signal_page)
+	if (!page)
 		return NULL;
 
-		addr = page_address(signal_page);
+	addr = page_address(page);
 
 	/* Give the signal return code some randomness */
 	offset = 0x200 + (get_random_int() & 0x7fc);
@@ -642,7 +643,6 @@ struct page *get_signal_page(void)
 
 	ptr = (unsigned long)addr + offset;
 	flush_icache_range(ptr, ptr + sizeof(sigreturn_codes));
-	}
 
-	return signal_page;
+	return page;
 }