[Xen-ia64-devel] [PATCH 5/5] fix efi_emulate_set_virtual_address_map()

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

IA64: fix efi_emulate_set_virtual_address_map()

get_page() before touching guest pages.
Otherwise pages may be freed during those operations.

Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>

diff --git a/xen/arch/ia64/xen/fw_emul.c b/xen/arch/ia64/xen/fw_emul.c
--- a/xen/arch/ia64/xen/fw_emul.c
+++ b/xen/arch/ia64/xen/fw_emul.c
@@ -1334,6 +1334,10 @@ efi_emulate_set_virtual_address_map(
        efi_desc_size = sizeof(efi_memory_desc_t);
 
        for (p = efi_map_start; p < efi_map_end; p += efi_desc_size) {
+               struct page_info *efi_runtime_page = NULL;
+               struct page_info *fpswa_inf_page = NULL;
+               struct page_info *fw_table_page = NULL;
+               
                if (copy_from_user(&entry, p, sizeof(efi_memory_desc_t))) {
                        printk ("efi_emulate_set_virtual_address_map: 
copy_from_user() fault. addr=0x%p\n", p);
                        return EFI_UNSUPPORTED;
@@ -1342,6 +1346,27 @@ efi_emulate_set_virtual_address_map(
                /* skip over non-PAL_CODE memory descriptors; EFI_RUNTIME is 
included in PAL_CODE. */
                 if (md->type != EFI_PAL_CODE)
                         continue;
+
+               /* get pages to prevend them from being freed 
+                * during touching them.
+                * those entres are in [FW_TABLES_BASE_PADDR, ...]
+                * see dom_fw.h for its layout.
+                */
+               efi_runtime_page = virt_to_page(efi_runtime);
+               fpswa_inf_page = virt_to_page(fpswa_inf);
+               fw_table_page = virt_to_page(
+                       domain_mpa_to_imva(d, FW_TABLES_BASE_PADDR));
+               if (get_page(efi_runtime_page, d) == 0)
+                       return EFI_INVALID_PARAMETER;
+               if (get_page(fpswa_inf_page, d) == 0) {
+                       put_page(efi_runtime_page);
+                       return EFI_INVALID_PARAMETER;
+               }
+               if (get_page(fw_table_page, d) == 0) {
+                       put_page(fpswa_inf_page);
+                       put_page(efi_runtime_page);
+                       return EFI_INVALID_PARAMETER;
+               }
 
 #define EFI_HYPERCALL_PATCH_TO_VIRT(tgt,call) \
        do { \
@@ -1365,6 +1390,10 @@ efi_emulate_set_virtual_address_map(
                *vfn++ = FW_HYPERCALL_FPSWA_PATCH_INDEX * 16UL + md->virt_addr;
                *vfn   = 0;
                fpswa_inf->fpswa = (void *) (FW_HYPERCALL_FPSWA_ENTRY_INDEX * 
16UL + md->virt_addr);
+
+               put_page(fw_table_page);
+               put_page(fpswa_inf_page);
+               put_page(efi_runtime_page);
                break;
        }

efi-virtual-map.patch
Description: Text Data

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