kaiser: ENOMEM if kaiser_pagetable_walk() NULL

kaiser_add_user_map() took no notice when kaiser_pagetable_walk() failed.
And avoid its might_sleep() when atomic (though atomic at present unused).

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 407c3ff6a24c7cb418b77a124d17e282f9622037)
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Orabug: 27333760
CVE: CVE-2017-5754

Conflicts:
	arch/x86/mm/kaiser.c

Signed-off-by: Kirtikar Kashyap <kirtikar.kashyap@oracle.com>

diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c
index df7f6591d5aa116ba8113adcef07e2955c657210..058d0886086bb99687846ea335a0d84b7f74e419 100644 (file)
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -99,11 +99,11 @@ static pte_t *kaiser_pagetable_walk(unsigned long address, bool is_atomic)
        pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(address));
        gfp_t gfp = (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO);
 
-       might_sleep();
        if (is_atomic) {
                gfp &= ~GFP_KERNEL;
                gfp |= __GFP_HIGH;
-       }
+       } else
+               might_sleep();
 
        if (pgd_none(*pgd)) {
                WARN_ONCE(1, "All shadow pgds should have been populated");
@@ -160,13 +160,17 @@ int kaiser_add_user_map(const void *__start_addr, unsigned long size,
        unsigned long end_addr = PAGE_ALIGN(start_addr + size);
        unsigned long target_address;
 
-       for (;address < end_addr; address += PAGE_SIZE) {
+       for (; address < end_addr; address += PAGE_SIZE) {
                target_address = get_pa_from_mapping(address);
                if (target_address == -1) {
                        ret = -EIO;
                        break;
                }
                pte = kaiser_pagetable_walk(address, false);
+               if (!pte) {
+                       ret = -ENOMEM;
+                       break;
+               }
                if (pte_none(*pte)) {
                        set_pte(pte, __pte(flags | target_address));
                } else {