Changeset 962c89af in mainline for kernel/generic/src/mm/as.c

Timestamp:

2019-06-20T14:51:57Z (5 years ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Parents:

5acf533

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2019-06-20 14:48:53)

git-committer:

Jiří Zárevúcky <zarevucky.jiri@…> (2019-06-20 14:51:57)

Message:

Prevent leaking kernel stack bytes via sys_as_area_get_info()

The compiler will try to avoid initializing the padding bytes if it
doesn't have to, so copying the whole structure would copy whatever
bytes were on the stack before. We prevent that by clearing the whole
structure using memset().

File:

• kernel/generic/src/mm/as.c (modified) (2 diffs)

kernel/generic/src/mm/as.c

@@ -2128 +2128 @@
 {
         as_area_t *area;
+        as_area_info_t info;
+
+        /* Prevent leaking stack bytes via structure padding. */
+        memset(&info, 0, sizeof(info));
 
         mutex_lock(&AS->lock);
@@ -2136 +2140 @@
         }
 
-        as_area_info_t info = {
-                .start_addr = area->base,
-                .size = P2SZ(area->pages),
-                .flags = area->flags,
-        };
+        info.start_addr = area->base;
+        info.size = P2SZ(area->pages);
+        info.flags = area->flags;
 
         mutex_unlock(&area->lock);