From 168e47f2a6581fdbc5bb1845aeca1e50e2bc5c4b Mon Sep 17 00:00:00 2001 From: Laura Abbott Date: Wed, 25 Feb 2015 14:14:57 -0800 Subject: kernel/module.c: Update debug alignment after symtable generation When CONFIG_DEBUG_SET_MODULE_RONX is enabled, the sizes of module sections are aligned up so appropriate permissions can be applied. Adjusting for the symbol table may cause them to become unaligned. Make sure to re-align the sizes afterward. Signed-off-by: Laura Abbott Acked-by: Rusty Russell Signed-off-by: Catalin Marinas --- kernel/module.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index b34813f725e9..cc93cf68653c 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2313,11 +2313,13 @@ static void layout_symtab(struct module *mod, struct load_info *info) info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1); info->stroffs = mod->core_size = info->symoffs + ndst * sizeof(Elf_Sym); mod->core_size += strtab_size; + mod->core_size = debug_align(mod->core_size); /* Put string table section at end of init part of module. */ strsect->sh_flags |= SHF_ALLOC; strsect->sh_entsize = get_offset(mod, &mod->init_size, strsect, info->index.str) | INIT_OFFSET_MASK; + mod->init_size = debug_align(mod->init_size); pr_debug("\t%s\n", info->secstrings + strsect->sh_name); } -- cgit v1.2.3 From a5af5aa8b67dfdba36c853b70564fd2dfe73d478 Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Thu, 12 Mar 2015 16:26:11 -0700 Subject: kasan, module, vmalloc: rework shadow allocation for modules Current approach in handling shadow memory for modules is broken. Shadow memory could be freed only after memory shadow corresponds it is no longer used. vfree() called from interrupt context could use memory its freeing to store 'struct llist_node' in it: void vfree(const void *addr) { ... if (unlikely(in_interrupt())) { struct vfree_deferred *p = this_cpu_ptr(&vfree_deferred); if (llist_add((struct llist_node *)addr, &p->list)) schedule_work(&p->wq); Later this list node used in free_work() which actually frees memory. Currently module_memfree() called in interrupt context will free shadow before freeing module's memory which could provoke kernel crash. So shadow memory should be freed after module's memory. However, such deallocation order could race with kasan_module_alloc() in module_alloc(). Free shadow right before releasing vm area. At this point vfree()'d memory is not used anymore and yet not available for other allocations. New VM_KASAN flag used to indicate that vm area has dynamically allocated shadow memory so kasan frees shadow only if it was previously allocated. Signed-off-by: Andrey Ryabinin Acked-by: Rusty Russell Cc: Dmitry Vyukov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/module.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index cc93cf68653c..b3d634ed06c9 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -56,7 +56,6 @@ #include #include #include -#include #include #include #include @@ -1814,7 +1813,6 @@ static void unset_module_init_ro_nx(struct module *mod) { } void __weak module_memfree(void *module_region) { vfree(module_region); - kasan_module_free(module_region); } void __weak module_arch_cleanup(struct module *mod) -- cgit v1.2.3