PM: hibernate: Don't ignore return from set_memory_ro()

set_memory_ro() and set_memory_rw() can fail, leaving memory
unprotected.

Take the returned value into account and abort in case of
failure.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 16 insertions, 9 deletions

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 5c96ff067c64..405eddbda4fc 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -58,22 +58,24 @@ static inline void hibernate_restore_protection_end(void)
 	hibernate_restore_protection_active = false;
 }
 
-static inline void hibernate_restore_protect_page(void *page_address)
+static inline int __must_check hibernate_restore_protect_page(void *page_address)
 {
 	if (hibernate_restore_protection_active)
-		set_memory_ro((unsigned long)page_address, 1);
+		return set_memory_ro((unsigned long)page_address, 1);
+	return 0;
 }
 
-static inline void hibernate_restore_unprotect_page(void *page_address)
+static inline int hibernate_restore_unprotect_page(void *page_address)
 {
 	if (hibernate_restore_protection_active)
-		set_memory_rw((unsigned long)page_address, 1);
+		return set_memory_rw((unsigned long)page_address, 1);
+	return 0;
 }
 #else
 static inline void hibernate_restore_protection_begin(void) {}
 static inline void hibernate_restore_protection_end(void) {}
-static inline void hibernate_restore_protect_page(void *page_address) {}
-static inline void hibernate_restore_unprotect_page(void *page_address) {}
+static inline int __must_check hibernate_restore_protect_page(void *page_address) {return 0; }
+static inline int hibernate_restore_unprotect_page(void *page_address) {return 0; }
 #endif /* CONFIG_STRICT_KERNEL_RWX  && CONFIG_ARCH_HAS_SET_MEMORY */
 
 
@@ -2832,7 +2834,9 @@ next:
 		}
 	} else {
 		copy_last_highmem_page();
-		hibernate_restore_protect_page(handle->buffer);
+		error = hibernate_restore_protect_page(handle->buffer);
+		if (error)
+			return error;
 		handle->buffer = get_buffer(&orig_bm, &ca);
 		if (IS_ERR(handle->buffer))
 			return PTR_ERR(handle->buffer);
@@ -2858,15 +2862,18 @@ next:
  * stored in highmem.  Additionally, it recycles bitmap memory that's not
  * necessary any more.
  */
-void snapshot_write_finalize(struct snapshot_handle *handle)
+int snapshot_write_finalize(struct snapshot_handle *handle)
 {
+	int error;
+
 	copy_last_highmem_page();
-	hibernate_restore_protect_page(handle->buffer);
+	error = hibernate_restore_protect_page(handle->buffer);
 	/* Do that only if we have loaded the image entirely */
 	if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages + nr_zero_pages) {
 		memory_bm_recycle(&orig_bm);
 		free_highmem_data();
 	}
+	return error;
 }
 
 int snapshot_image_loaded(struct snapshot_handle *handle)