mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-14 12:49:08 +00:00
modules: add ro_after_init support
Add ro_after_init support for modules by adding a new page-aligned section in the module layout (after rodata) for ro_after_init data and enabling RO protection for that section after module init runs. Signed-off-by: Jessica Yu <jeyu@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Jessica Yu
Rusty Russell
parent
bdc9f37355
commit
444d13ff10
@ -298,6 +298,8 @@ struct module_layout {
|
||||
unsigned int text_size;
|
||||
/* Size of RO section of the module (text+rodata) */
|
||||
unsigned int ro_size;
|
||||
/* Size of RO after init section */
|
||||
unsigned int ro_after_init_size;
|
||||
|
||||
#ifdef CONFIG_MODULES_TREE_LOOKUP
|
||||
struct mod_tree_node mtn;
|
||||
@ -765,12 +767,12 @@ extern int module_sysfs_initialized;
|
||||
#ifdef CONFIG_DEBUG_SET_MODULE_RONX
|
||||
extern void set_all_modules_text_rw(void);
|
||||
extern void set_all_modules_text_ro(void);
|
||||
extern void module_enable_ro(const struct module *mod);
|
||||
extern void module_enable_ro(const struct module *mod, bool after_init);
|
||||
extern void module_disable_ro(const struct module *mod);
|
||||
#else
|
||||
static inline void set_all_modules_text_rw(void) { }
|
||||
static inline void set_all_modules_text_ro(void) { }
|
||||
static inline void module_enable_ro(const struct module *mod) { }
|
||||
static inline void module_enable_ro(const struct module *mod, bool after_init) { }
|
||||
static inline void module_disable_ro(const struct module *mod) { }
|
||||
#endif
|
||||
|
||||
|
||||
@ -286,6 +286,7 @@ typedef struct elf64_phdr {
|
||||
#define SHF_ALLOC 0x2
|
||||
#define SHF_EXECINSTR 0x4
|
||||
#define SHF_RELA_LIVEPATCH 0x00100000
|
||||
#define SHF_RO_AFTER_INIT 0x00200000
|
||||
#define SHF_MASKPROC 0xf0000000
|
||||
|
||||
/* special section indexes */
|
||||
|
||||
@ -309,7 +309,7 @@ static int klp_write_object_relocations(struct module *pmod,
|
||||
break;
|
||||
}
|
||||
|
||||
module_enable_ro(pmod);
|
||||
module_enable_ro(pmod, true);
|
||||
return ret;
|
||||
}
|
||||
|
||||
|
||||
@ -1857,10 +1857,11 @@ static void mod_sysfs_teardown(struct module *mod)
|
||||
* from modification and any data from execution.
|
||||
*
|
||||
* General layout of module is:
|
||||
* [text] [read-only-data] [writable data]
|
||||
* text_size -----^ ^ ^
|
||||
* ro_size ------------------------| |
|
||||
* size -------------------------------------------|
|
||||
* [text] [read-only-data] [ro-after-init] [writable data]
|
||||
* text_size -----^ ^ ^ ^
|
||||
* ro_size ------------------------| | |
|
||||
* ro_after_init_size -----------------------------| |
|
||||
* size -----------------------------------------------------------|
|
||||
*
|
||||
* These values are always page-aligned (as is base)
|
||||
*/
|
||||
@ -1883,14 +1884,24 @@ static void frob_rodata(const struct module_layout *layout,
|
||||
(layout->ro_size - layout->text_size) >> PAGE_SHIFT);
|
||||
}
|
||||
|
||||
static void frob_ro_after_init(const struct module_layout *layout,
|
||||
int (*set_memory)(unsigned long start, int num_pages))
|
||||
{
|
||||
BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1));
|
||||
BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1));
|
||||
BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1));
|
||||
set_memory((unsigned long)layout->base + layout->ro_size,
|
||||
(layout->ro_after_init_size - layout->ro_size) >> PAGE_SHIFT);
|
||||
}
|
||||
|
||||
static void frob_writable_data(const struct module_layout *layout,
|
||||
int (*set_memory)(unsigned long start, int num_pages))
|
||||
{
|
||||
BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1));
|
||||
BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1));
|
||||
BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1));
|
||||
BUG_ON((unsigned long)layout->size & (PAGE_SIZE-1));
|
||||
set_memory((unsigned long)layout->base + layout->ro_size,
|
||||
(layout->size - layout->ro_size) >> PAGE_SHIFT);
|
||||
set_memory((unsigned long)layout->base + layout->ro_after_init_size,
|
||||
(layout->size - layout->ro_after_init_size) >> PAGE_SHIFT);
|
||||
}
|
||||
|
||||
/* livepatching wants to disable read-only so it can frob module. */
|
||||
@ -1898,21 +1909,26 @@ void module_disable_ro(const struct module *mod)
|
||||
{
|
||||
frob_text(&mod->core_layout, set_memory_rw);
|
||||
frob_rodata(&mod->core_layout, set_memory_rw);
|
||||
frob_ro_after_init(&mod->core_layout, set_memory_rw);
|
||||
frob_text(&mod->init_layout, set_memory_rw);
|
||||
frob_rodata(&mod->init_layout, set_memory_rw);
|
||||
}
|
||||
|
||||
void module_enable_ro(const struct module *mod)
|
||||
void module_enable_ro(const struct module *mod, bool after_init)
|
||||
{
|
||||
frob_text(&mod->core_layout, set_memory_ro);
|
||||
frob_rodata(&mod->core_layout, set_memory_ro);
|
||||
frob_text(&mod->init_layout, set_memory_ro);
|
||||
frob_rodata(&mod->init_layout, set_memory_ro);
|
||||
|
||||
if (after_init)
|
||||
frob_ro_after_init(&mod->core_layout, set_memory_ro);
|
||||
}
|
||||
|
||||
static void module_enable_nx(const struct module *mod)
|
||||
{
|
||||
frob_rodata(&mod->core_layout, set_memory_nx);
|
||||
frob_ro_after_init(&mod->core_layout, set_memory_nx);
|
||||
frob_writable_data(&mod->core_layout, set_memory_nx);
|
||||
frob_rodata(&mod->init_layout, set_memory_nx);
|
||||
frob_writable_data(&mod->init_layout, set_memory_nx);
|
||||
@ -1921,6 +1937,7 @@ static void module_enable_nx(const struct module *mod)
|
||||
static void module_disable_nx(const struct module *mod)
|
||||
{
|
||||
frob_rodata(&mod->core_layout, set_memory_x);
|
||||
frob_ro_after_init(&mod->core_layout, set_memory_x);
|
||||
frob_writable_data(&mod->core_layout, set_memory_x);
|
||||
frob_rodata(&mod->init_layout, set_memory_x);
|
||||
frob_writable_data(&mod->init_layout, set_memory_x);
|
||||
@ -1963,6 +1980,8 @@ static void disable_ro_nx(const struct module_layout *layout)
|
||||
frob_text(layout, set_memory_rw);
|
||||
frob_rodata(layout, set_memory_rw);
|
||||
frob_rodata(layout, set_memory_x);
|
||||
frob_ro_after_init(layout, set_memory_rw);
|
||||
frob_ro_after_init(layout, set_memory_x);
|
||||
frob_writable_data(layout, set_memory_x);
|
||||
}
|
||||
|
||||
@ -2305,6 +2324,7 @@ static void layout_sections(struct module *mod, struct load_info *info)
|
||||
* finder in the two loops below */
|
||||
{ SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL },
|
||||
{ SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL },
|
||||
{ SHF_RO_AFTER_INIT | SHF_ALLOC, ARCH_SHF_SMALL },
|
||||
{ SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL },
|
||||
{ ARCH_SHF_SMALL | SHF_ALLOC, 0 }
|
||||
};
|
||||
@ -2336,7 +2356,11 @@ static void layout_sections(struct module *mod, struct load_info *info)
|
||||
mod->core_layout.size = debug_align(mod->core_layout.size);
|
||||
mod->core_layout.ro_size = mod->core_layout.size;
|
||||
break;
|
||||
case 3: /* whole core */
|
||||
case 2: /* RO after init */
|
||||
mod->core_layout.size = debug_align(mod->core_layout.size);
|
||||
mod->core_layout.ro_after_init_size = mod->core_layout.size;
|
||||
break;
|
||||
case 4: /* whole core */
|
||||
mod->core_layout.size = debug_align(mod->core_layout.size);
|
||||
break;
|
||||
}
|
||||
@ -2366,7 +2390,14 @@ static void layout_sections(struct module *mod, struct load_info *info)
|
||||
mod->init_layout.size = debug_align(mod->init_layout.size);
|
||||
mod->init_layout.ro_size = mod->init_layout.size;
|
||||
break;
|
||||
case 3: /* whole init */
|
||||
case 2:
|
||||
/*
|
||||
* RO after init doesn't apply to init_layout (only
|
||||
* core_layout), so it just takes the value of ro_size.
|
||||
*/
|
||||
mod->init_layout.ro_after_init_size = mod->init_layout.ro_size;
|
||||
break;
|
||||
case 4: /* whole init */
|
||||
mod->init_layout.size = debug_align(mod->init_layout.size);
|
||||
break;
|
||||
}
|
||||
@ -3193,6 +3224,7 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
|
||||
{
|
||||
/* Module within temporary copy. */
|
||||
struct module *mod;
|
||||
unsigned int ndx;
|
||||
int err;
|
||||
|
||||
mod = setup_load_info(info, flags);
|
||||
@ -3215,6 +3247,15 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
|
||||
/* We will do a special allocation for per-cpu sections later. */
|
||||
info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
|
||||
|
||||
/*
|
||||
* Mark ro_after_init section with SHF_RO_AFTER_INIT so that
|
||||
* layout_sections() can put it in the right place.
|
||||
* Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set.
|
||||
*/
|
||||
ndx = find_sec(info, ".data..ro_after_init");
|
||||
if (ndx)
|
||||
info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
|
||||
|
||||
/* Determine total sizes, and put offsets in sh_entsize. For now
|
||||
this is done generically; there doesn't appear to be any
|
||||
special cases for the architectures. */
|
||||
@ -3381,12 +3422,14 @@ static noinline int do_init_module(struct module *mod)
|
||||
/* Switch to core kallsyms now init is done: kallsyms may be walking! */
|
||||
rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms);
|
||||
#endif
|
||||
module_enable_ro(mod, true);
|
||||
mod_tree_remove_init(mod);
|
||||
disable_ro_nx(&mod->init_layout);
|
||||
module_arch_freeing_init(mod);
|
||||
mod->init_layout.base = NULL;
|
||||
mod->init_layout.size = 0;
|
||||
mod->init_layout.ro_size = 0;
|
||||
mod->init_layout.ro_after_init_size = 0;
|
||||
mod->init_layout.text_size = 0;
|
||||
/*
|
||||
* We want to free module_init, but be aware that kallsyms may be
|
||||
@ -3478,8 +3521,7 @@ static int complete_formation(struct module *mod, struct load_info *info)
|
||||
/* This relies on module_mutex for list integrity. */
|
||||
module_bug_finalize(info->hdr, info->sechdrs, mod);
|
||||
|
||||
/* Set RO and NX regions */
|
||||
module_enable_ro(mod);
|
||||
module_enable_ro(mod, false);
|
||||
module_enable_nx(mod);
|
||||
|
||||
/* Mark state as coming so strong_try_module_get() ignores us,
|
||||
|
||||
Loading…
Reference in New Issue
Block a user