mm/core: Do not enforce PKEY permissions on remote mm access

[cascardo/linux.git] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index 30991f8..76c44e5 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -65,6 +65,7 @@
 #include <linux/userfaultfd_k.h>
 
 #include <asm/io.h>
+#include <asm/mmu_context.h>
 #include <asm/pgalloc.h>
 #include <asm/uaccess.h>
 #include <asm/tlb.h>
@@ -1550,9 +1551,30 @@ out:
  */
 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
                        unsigned long pfn)
+{
+       return vm_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot);
+}
+EXPORT_SYMBOL(vm_insert_pfn);
+
+/**
+ * vm_insert_pfn_prot - insert single pfn into user vma with specified pgprot
+ * @vma: user vma to map to
+ * @addr: target user address of this page
+ * @pfn: source kernel pfn
+ * @pgprot: pgprot flags for the inserted page
+ *
+ * This is exactly like vm_insert_pfn, except that it allows drivers to
+ * to override pgprot on a per-page basis.
+ *
+ * This only makes sense for IO mappings, and it makes no sense for
+ * cow mappings.  In general, using multiple vmas is preferable;
+ * vm_insert_pfn_prot should only be used if using multiple VMAs is
+ * impractical.
+ */
+int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
+                       unsigned long pfn, pgprot_t pgprot)
 {
        int ret;
-       pgprot_t pgprot = vma->vm_page_prot;
        /*
         * Technically, architectures with pte_special can avoid all these
         * restrictions (same for remap_pfn_range).  However we would like
@@ -1574,7 +1596,7 @@ int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
 
        return ret;
 }
-EXPORT_SYMBOL(vm_insert_pfn);
+EXPORT_SYMBOL(vm_insert_pfn_prot);
 
 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
                        pfn_t pfn)
@@ -1591,10 +1613,15 @@ int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
         * than insert_pfn).  If a zero_pfn were inserted into a VM_MIXEDMAP
         * without pte special, it would there be refcounted as a normal page.
         */
-       if (!HAVE_PTE_SPECIAL && pfn_t_valid(pfn)) {
+       if (!HAVE_PTE_SPECIAL && !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) {
                struct page *page;
 
-               page = pfn_t_to_page(pfn);
+               /*
+                * At this point we are committed to insert_page()
+                * regardless of whether the caller specified flags that
+                * result in pfn_t_has_page() == false.
+                */
+               page = pfn_to_page(pfn_t_to_pfn(pfn));
                return insert_page(vma, addr, page, vma->vm_page_prot);
        }
        return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
@@ -2232,11 +2259,6 @@ static int wp_page_shared(struct mm_struct *mm, struct vm_area_struct *vma,
 
        page_cache_get(old_page);
 
-       /*
-        * Only catch write-faults on shared writable pages,
-        * read-only shared pages can get COWed by
-        * get_user_pages(.write=1, .force=1).
-        */
        if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
                int tmp;
 
@@ -3357,6 +3379,10 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
        pmd_t *pmd;
        pte_t *pte;
 
+       if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE,
+                                           flags & FAULT_FLAG_REMOTE))
+               return VM_FAULT_SIGSEGV;
+
        if (unlikely(is_vm_hugetlb_page(vma)))
                return hugetlb_fault(mm, vma, address, flags);
 
@@ -3664,7 +3690,7 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
                void *maddr;
                struct page *page = NULL;
 
-               ret = get_user_pages(tsk, mm, addr, 1,
+               ret = get_user_pages_remote(tsk, mm, addr, 1,
                                write, 1, &page, &vma);
                if (ret <= 0) {
 #ifndef CONFIG_HAVE_IOREMAP_PROT