On Mon, Sep 24, 2018 at 11:57 AM, Edgecombe, Rick P <[email protected]> wrote: > On Fri, 2018-09-21 at 12:05 -0700, Kees Cook wrote: >> On Thu, Sep 13, 2018 at 2:31 PM, Rick Edgecombe >> <[email protected]> wrote: >> I would find this much more readable as: >> static unsigned long get_module_vmalloc_start(void) >> { >> unsigned long addr = MODULES_VADDR; >> >> if (kaslr_randomize_base()) >> addr += get_module_load_offset(); >> >> if (kaslr_randomize_each_module()) >> addr += get_modules_rand_len(); >> >> return addr; >> } > Thanks, that looks better. > >> >> > void *module_alloc(unsigned long size) >> > { >> > @@ -84,16 +201,18 @@ void *module_alloc(unsigned long size) >> > if (PAGE_ALIGN(size) > MODULES_LEN) >> > return NULL; >> > >> > - p = __vmalloc_node_range(size, MODULE_ALIGN, >> > - MODULES_VADDR + >> > get_module_load_offset(), >> > - MODULES_END, GFP_KERNEL, >> > - PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, >> > - __builtin_return_address(0)); >> > + p = try_module_randomize_each(size); >> > + >> > + if (!p) >> > + p = __vmalloc_node_range(size, MODULE_ALIGN, >> > + get_module_vmalloc_start(), MODULES_END, >> > + GFP_KERNEL, PAGE_KERNEL_EXEC, 0, >> > + NUMA_NO_NODE, __builtin_return_address(0)); >> Instead of having two open-coded __vmalloc_node_range() calls left in >> this after the change, can this be done in terms of a call to >> try_module_alloc() instead? I see they're slightly different, but it >> might be nice for making the two paths share more code. > Not sure what you mean. Across the whole change, there is one call > to __vmalloc_node_range, and one to __vmalloc_node_try_addr.
I guess I meant the vmalloc calls -- one for node_range and one for node_try_addr. I was wondering if the logic could be combined in some way so that the __vmalloc_node_range() could be made in terms of the the helper that try_module_randomize_each() uses. But this could just be me hoping for nice-to-read changes. ;) -Kees -- Kees Cook Pixel Security
