lib/list_debug.c: print unmangled addresses

The entire point of printing the pointers in list_debug is to see if
there's any useful information in them (eg poison values, ASCII, etc);
obscuring them to see if they compare equal makes them much less useful.
If an attacker can force this message to be printed, we've already lost.

Link: http://lkml.kernel.org/r/20180401223237.GV13332@bombadil.infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: Tobin C. Harding <me@tobin.cc>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/list_debug.c b/lib/list_debug.c
index a34db8d..5d5424b 100644 (file)
--- a/lib/list_debug.c
+++ b/lib/list_debug.c
@@ -21,13 +21,13 @@ bool __list_add_valid(struct list_head *new, struct list_head *prev,
                      struct list_head *next)
 {
        if (CHECK_DATA_CORRUPTION(next->prev != prev,
-                       "list_add corruption. next->prev should be prev (%p), but was %p. (next=%p).\n",
+                       "list_add corruption. next->prev should be prev (%px), but was %px. (next=%px).\n",
                        prev, next->prev, next) ||
            CHECK_DATA_CORRUPTION(prev->next != next,
-                       "list_add corruption. prev->next should be next (%p), but was %p. (prev=%p).\n",
+                       "list_add corruption. prev->next should be next (%px), but was %px. (prev=%px).\n",
                        next, prev->next, prev) ||
            CHECK_DATA_CORRUPTION(new == prev || new == next,
-                       "list_add double add: new=%p, prev=%p, next=%p.\n",
+                       "list_add double add: new=%px, prev=%px, next=%px.\n",
                        new, prev, next))
                return false;
 
@@ -43,16 +43,16 @@ bool __list_del_entry_valid(struct list_head *entry)
        next = entry->next;
 
        if (CHECK_DATA_CORRUPTION(next == LIST_POISON1,
-                       "list_del corruption, %p->next is LIST_POISON1 (%p)\n",
+                       "list_del corruption, %px->next is LIST_POISON1 (%px)\n",
                        entry, LIST_POISON1) ||
            CHECK_DATA_CORRUPTION(prev == LIST_POISON2,
-                       "list_del corruption, %p->prev is LIST_POISON2 (%p)\n",
+                       "list_del corruption, %px->prev is LIST_POISON2 (%px)\n",
                        entry, LIST_POISON2) ||
            CHECK_DATA_CORRUPTION(prev->next != entry,
-                       "list_del corruption. prev->next should be %p, but was %p\n",
+                       "list_del corruption. prev->next should be %px, but was %px\n",
                        entry, prev->next) ||
            CHECK_DATA_CORRUPTION(next->prev != entry,
-                       "list_del corruption. next->prev should be %p, but was %p\n",
+                       "list_del corruption. next->prev should be %px, but was %px\n",
                        entry, next->prev))
                return false;