From: Jason Cooper <jason@xxxxxxxxxxxxxx> Subject: x86: use simpler API for random address requests Currently, all callers to randomize_range() set the length to 0 and calculate end by adding a constant to the start address. We can simplify the API to remove a bunch of needless checks and variables. Use the new randomize_addr(start, range) call to set the requested address. Link: http://lkml.kernel.org/r/20160803233913.32511-3-jason@xxxxxxxxxxxxxx Signed-off-by: Jason Cooper <jason@xxxxxxxxxxxxxx> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx> Cc: "Theodore Ts'o" <tytso@xxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: "H . Peter Anvin" <hpa@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/process.c | 3 +-- arch/x86/kernel/sys_x86_64.c | 5 +---- 2 files changed, 2 insertions(+), 6 deletions(-) diff -puN arch/x86/kernel/process.c~x86-use-simpler-api-for-random-address-requests arch/x86/kernel/process.c --- a/arch/x86/kernel/process.c~x86-use-simpler-api-for-random-address-requests +++ a/arch/x86/kernel/process.c @@ -509,8 +509,7 @@ unsigned long arch_align_stack(unsigned unsigned long arch_randomize_brk(struct mm_struct *mm) { - unsigned long range_end = mm->brk + 0x02000000; - return randomize_range(mm->brk, range_end, 0) ? : mm->brk; + return randomize_page(mm->brk, 0x02000000); } /* diff -puN arch/x86/kernel/sys_x86_64.c~x86-use-simpler-api-for-random-address-requests arch/x86/kernel/sys_x86_64.c --- a/arch/x86/kernel/sys_x86_64.c~x86-use-simpler-api-for-random-address-requests +++ a/arch/x86/kernel/sys_x86_64.c @@ -101,7 +101,6 @@ static void find_start_end(unsigned long unsigned long *end) { if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT)) { - unsigned long new_begin; /* This is usually used needed to map code in small model, so it needs to be in the first 31bit. Limit it to that. This means we need to move the @@ -112,9 +111,7 @@ static void find_start_end(unsigned long *begin = 0x40000000; *end = 0x80000000; if (current->flags & PF_RANDOMIZE) { - new_begin = randomize_range(*begin, *begin + 0x02000000, 0); - if (new_begin) - *begin = new_begin; + *begin = randomize_page(*begin, 0x02000000); } } else { *begin = current->mm->mmap_legacy_base; _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
