diff options
| -rw-r--r-- | arch/arm64/Kconfig | 19 | ||||
| -rw-r--r-- | arch/arm64/mm/mmap.c | 11 |
2 files changed, 27 insertions, 3 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 1d4b6e08e..ff50d39c3 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -23,6 +23,8 @@ config ARM64 select HARDIRQS_SW_RESEND select HAVE_ARCH_JUMP_LABEL select HAVE_ARCH_AUDITSYSCALL + select HAVE_ARCH_MMAP_RND_BITS + select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_KGDB select HAVE_ARCH_TRACEHOOK @@ -75,6 +77,23 @@ config NO_IOPORT config STACKTRACE_SUPPORT def_bool y +config ARCH_MMAP_RND_BITS_MIN + default 14 if ARM64_64K_PAGES + default 18 + +# max bits determined by the following formula: +# VA_BITS - PAGE_SHIFT - 3 +# VA_BITS is always 39 +config ARCH_MMAP_RND_BITS_MAX + default 20 if ARM64_64K_PAGES + default 24 + +config ARCH_MMAP_RND_COMPAT_BITS_MIN + default 11 + +config ARCH_MMAP_RND_COMPAT_BITS_MAX + default 16 + config ILLEGAL_POINTER_VALUE hex default 0xdead000000000000 diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c index 8aaf073ee..8af07b65e 100644 --- a/arch/arm64/mm/mmap.c +++ b/arch/arm64/mm/mmap.c @@ -51,9 +51,14 @@ static unsigned long mmap_rnd(void) { unsigned long rnd = 0; - if (current->flags & PF_RANDOMIZE) - rnd = (long)get_random_int() & STACK_RND_MASK; - + if (current->flags & PF_RANDOMIZE) { +#ifdef CONFIG_COMPAT + if (test_thread_flag(TIF_32BIT)) + rnd = (unsigned long)get_random_int() & ((1 << mmap_rnd_compat_bits) - 1); + else +#endif + rnd = (unsigned long)get_random_int() & ((1 << mmap_rnd_bits) - 1); + } return rnd << PAGE_SHIFT; } |