diff options
| author | Kees Cook <keescook@chromium.org> | 2024-02-16 22:25:43 -0800 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-02-27 00:23:55 +0100 |
| commit | 44c76825d6eefee9eb7ce06c38e1a6632ac7eb7d (patch) | |
| tree | 9df5154fb922c2d63d695be90c83ec5f7bc0052d /arch/x86/kernel | |
| parent | 3c6539b4c177695aaa77893c4ce91d21dea7bb3d (diff) | |
x86: Increase brk randomness entropy for 64-bit systems
In commit c1d171a00294 ("x86: randomize brk"), arch_randomize_brk() was
defined to use a 32MB range (13 bits of entropy), but was never increased
when moving to 64-bit. The default arch_randomize_brk() uses 32MB for
32-bit tasks, and 1GB (18 bits of entropy) for 64-bit tasks.
Update x86_64 to match the entropy used by arm64 and other 64-bit
architectures.
Reported-by: y0un9n132@gmail.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Jiri Kosina <jkosina@suse.com>
Closes: https://lore.kernel.org/linux-hardening/CA+2EKTVLvc8hDZc+2Yhwmus=dzOUG5E4gV7ayCbu0MPJTZzWkw@mail.gmail.com/
Link: https://lore.kernel.org/r/20240217062545.1631668-1-keescook@chromium.org
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/process.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index ab49ade31b0d..45a9d496fe2a 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -1030,7 +1030,10 @@ unsigned long arch_align_stack(unsigned long sp) unsigned long arch_randomize_brk(struct mm_struct *mm) { - return randomize_page(mm->brk, 0x02000000); + if (mmap_is_ia32()) + return randomize_page(mm->brk, SZ_32M); + + return randomize_page(mm->brk, SZ_1G); } /* |