lkml.org 
[lkml]   [2020]   [Jul]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v3 21/21] x86/kaslr: Add a check that the random address is in range
Date
Check in find_random_phys_addr that the chosen address is inside the
range that was required.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
---
arch/x86/boot/compressed/kaslr.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 38ecbf2e61c5..903ccdca0551 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -802,6 +802,8 @@ static void process_e820_entries(unsigned long minimum,
static unsigned long find_random_phys_addr(unsigned long minimum,
unsigned long image_size)
{
+ u64 phys_addr;
+
/* Bail out early if it's impossible to succeed. */
if (minimum + image_size > mem_limit)
return 0;
@@ -815,7 +817,15 @@ static unsigned long find_random_phys_addr(unsigned long minimum,
if (!process_efi_entries(minimum, image_size))
process_e820_entries(minimum, image_size);

- return slots_fetch_random();
+ phys_addr = slots_fetch_random();
+
+ /* Perform a final check to make sure the address is in range. */
+ if (phys_addr < minimum || phys_addr + image_size > mem_limit) {
+ warn("Invalid physical address chosen!\n");
+ return 0;
+ }
+
+ return (unsigned long)phys_addr;
}

static unsigned long find_random_virt_addr(unsigned long minimum,
--
2.26.2
\
 
 \ /
  Last update: 2020-07-29 00:58    [W:0.349 / U:0.120 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site