Commit-ID:  0cacbfbeb5077b63d5d3cf6df88b14ac12ad584b
Gitweb:     http://git.kernel.org/tip/0cacbfbeb5077b63d5d3cf6df88b14ac12ad584b
Author:     Kees Cook <[email protected]>
AuthorDate: Thu, 11 Sep 2014 09:19:31 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 19 Sep 2014 13:04:29 +0200

x86/kaslr: Avoid the setup_data area when picking location

The KASLR location-choosing logic needs to avoid the setup_data
list memory areas as well. Without this, it would be possible to
have the ASLR position stomp on the memory, ultimately causing
the boot to fail.

Signed-off-by: Kees Cook <[email protected]>
Tested-by: Baoquan He <[email protected]>
Cc: [email protected]
Cc: Vivek Goyal <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Wei Yongjun <[email protected]>
Cc: Pavel Machek <[email protected]>
Cc: Linus Torvalds <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
 arch/x86/boot/compressed/aslr.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch/x86/boot/compressed/aslr.c b/arch/x86/boot/compressed/aslr.c
index fc6091a..d39189b 100644
--- a/arch/x86/boot/compressed/aslr.c
+++ b/arch/x86/boot/compressed/aslr.c
@@ -183,12 +183,27 @@ static void mem_avoid_init(unsigned long input, unsigned 
long input_size,
 static bool mem_avoid_overlap(struct mem_vector *img)
 {
        int i;
+       struct setup_data *ptr;
 
        for (i = 0; i < MEM_AVOID_MAX; i++) {
                if (mem_overlaps(img, &mem_avoid[i]))
                        return true;
        }
 
+       /* Avoid all entries in the setup_data linked list. */
+       ptr = (struct setup_data *)(unsigned long)real_mode->hdr.setup_data;
+       while (ptr) {
+               struct mem_vector avoid;
+
+               avoid.start = (u64)ptr;
+               avoid.size = sizeof(*ptr) + ptr->len;
+
+               if (mem_overlaps(img, &avoid))
+                       return true;
+
+               ptr = (struct setup_data *)(unsigned long)ptr->next;
+       }
+
        return false;
 }
 
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