-
Notifications
You must be signed in to change notification settings - Fork 102
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
x86/kaslr: Initialize mem_limit to the real maximum address
[ Upstream commit 4512869 ] On 64-bit, the kernel must be placed below MAXMEM (64TiB with 4-level paging or 4PiB with 5-level paging). This is currently not enforced by KASLR, which thus implicitly relies on physical memory being limited to less than 64TiB. On 32-bit, the limit is KERNEL_IMAGE_SIZE (512MiB). This is enforced by special checks in __process_mem_region(). Initialize mem_limit to the maximum (depending on architecture), instead of ULLONG_MAX, and make sure the command-line arguments can only decrease it. This makes the enforcement explicit on 64-bit, and eliminates the 32-bit specific checks to keep the kernel below 512M. Check upfront to make sure the minimum address is below the limit before doing any work. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200727230801.3468620-5-nivedita@alum.mit.edu Signed-off-by: Sasha Levin <sashal@kernel.org>
- Loading branch information
1 parent
3fc85e7
commit ad9d55d
Showing
1 changed file
with
22 additions
and
19 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters