The following commit has been merged into the x86/kaslr branch of tip:
Commit-ID: f49236ae424d499d02ee3ce35fb9130ddf95b03f
Gitweb: https://git.kernel.org/tip/f49236ae424d499d02ee3ce35fb9130ddf95b03f
Author: Arvind Sankar <nivedita@xxxxxxxxxxxx>
AuthorDate: Tue, 28 Jul 2020 18:57:22 -04:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Fri, 31 Jul 2020 11:08:17 +02:00
x86/kaslr: Add a check that the random address is in range
Check in find_random_phys_addr() that the chosen address is inside the
range that was required.
Signed-off-by: Arvind Sankar <nivedita@xxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200728225722.67457-22-nivedita@xxxxxxxxxxxx
---
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 80cdd20..735fcb2 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -803,6 +803,8 @@ 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;
@@ -816,7 +818,15 @@ 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,
|