mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-28 20:02:17 +00:00
2abcc4b5a6
module_init_layout_section() choses whether the core module loader
considers a section as init or not. This affects the placement of the
exit section when module unloading is disabled. This code will never run,
so it can be free()d once the module has been initialised.
arm and arm64 need to count the number of PLTs they need before applying
relocations based on the section name. The init PLTs are stored separately
so they can be free()d. arm and arm64 both use within_module_init() to
decide which list of PLTs to use when applying the relocation.
Because within_module_init()'s behaviour changes when module unloading
is disabled, both architecture would need to take this into account when
counting the PLTs.
Today neither architecture does this, meaning when module unloading is
disabled there are insufficient PLTs in the init section to load some
modules, resulting in warnings:
| WARNING: CPU: 2 PID: 51 at arch/arm64/kernel/module-plts.c:99 module_emit_plt_entry+0x184/0x1cc
| Modules linked in: crct10dif_common
| CPU: 2 PID: 51 Comm: modprobe Not tainted 6.5.0-rc4-yocto-standard-dirty #15208
| Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
| pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : module_emit_plt_entry+0x184/0x1cc
| lr : module_emit_plt_entry+0x94/0x1cc
| sp : ffffffc0803bba60
[...]
| Call trace:
| module_emit_plt_entry+0x184/0x1cc
| apply_relocate_add+0x2bc/0x8e4
| load_module+0xe34/0x1bd4
| init_module_from_file+0x84/0xc0
| __arm64_sys_finit_module+0x1b8/0x27c
| invoke_syscall.constprop.0+0x5c/0x104
| do_el0_svc+0x58/0x160
| el0_svc+0x38/0x110
| el0t_64_sync_handler+0xc0/0xc4
| el0t_64_sync+0x190/0x194
Instead of duplicating module_init_layout_section()s logic, expose it.
Reported-by: Adam Johnston <adam.johnston@arm.com>
Fixes: 055f23b74b ("module: check for exit sections in layout_sections() instead of module_init_section()")
Cc: stable@vger.kernel.org
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
132 lines
4.1 KiB
C
132 lines
4.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _LINUX_MODULELOADER_H
|
|
#define _LINUX_MODULELOADER_H
|
|
/* The stuff needed for archs to support modules. */
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/elf.h>
|
|
|
|
/* These may be implemented by architectures that need to hook into the
|
|
* module loader code. Architectures that don't need to do anything special
|
|
* can just rely on the 'weak' default hooks defined in kernel/module.c.
|
|
* Note, however, that at least one of apply_relocate or apply_relocate_add
|
|
* must be implemented by each architecture.
|
|
*/
|
|
|
|
/* arch may override to do additional checking of ELF header architecture */
|
|
bool module_elf_check_arch(Elf_Ehdr *hdr);
|
|
|
|
/* Adjust arch-specific sections. Return 0 on success. */
|
|
int module_frob_arch_sections(Elf_Ehdr *hdr,
|
|
Elf_Shdr *sechdrs,
|
|
char *secstrings,
|
|
struct module *mod);
|
|
|
|
/* Additional bytes needed by arch in front of individual sections */
|
|
unsigned int arch_mod_section_prepend(struct module *mod, unsigned int section);
|
|
|
|
/* Allocator used for allocating struct module, core sections and init
|
|
sections. Returns NULL on failure. */
|
|
void *module_alloc(unsigned long size);
|
|
|
|
/* Free memory returned from module_alloc. */
|
|
void module_memfree(void *module_region);
|
|
|
|
/* Determines if the section name is an init section (that is only used during
|
|
* module loading).
|
|
*/
|
|
bool module_init_section(const char *name);
|
|
|
|
/* Determines if the section name is an exit section (that is only used during
|
|
* module unloading)
|
|
*/
|
|
bool module_exit_section(const char *name);
|
|
|
|
/* Describes whether within_module_init() will consider this an init section
|
|
* or not. This behaviour changes with CONFIG_MODULE_UNLOAD.
|
|
*/
|
|
bool module_init_layout_section(const char *sname);
|
|
|
|
/*
|
|
* Apply the given relocation to the (simplified) ELF. Return -error
|
|
* or 0.
|
|
*/
|
|
#ifdef CONFIG_MODULES_USE_ELF_REL
|
|
int apply_relocate(Elf_Shdr *sechdrs,
|
|
const char *strtab,
|
|
unsigned int symindex,
|
|
unsigned int relsec,
|
|
struct module *mod);
|
|
#else
|
|
static inline int apply_relocate(Elf_Shdr *sechdrs,
|
|
const char *strtab,
|
|
unsigned int symindex,
|
|
unsigned int relsec,
|
|
struct module *me)
|
|
{
|
|
printk(KERN_ERR "module %s: REL relocation unsupported\n",
|
|
module_name(me));
|
|
return -ENOEXEC;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Apply the given add relocation to the (simplified) ELF. Return
|
|
* -error or 0
|
|
*/
|
|
#ifdef CONFIG_MODULES_USE_ELF_RELA
|
|
int apply_relocate_add(Elf_Shdr *sechdrs,
|
|
const char *strtab,
|
|
unsigned int symindex,
|
|
unsigned int relsec,
|
|
struct module *mod);
|
|
#ifdef CONFIG_LIVEPATCH
|
|
/*
|
|
* Some architectures (namely x86_64 and ppc64) perform sanity checks when
|
|
* applying relocations. If a patched module gets unloaded and then later
|
|
* reloaded (and re-patched), klp re-applies relocations to the replacement
|
|
* function(s). Any leftover relocations from the previous loading of the
|
|
* patched module might trigger the sanity checks.
|
|
*
|
|
* To prevent that, when unloading a patched module, clear out any relocations
|
|
* that might trigger arch-specific sanity checks on a future module reload.
|
|
*/
|
|
void clear_relocate_add(Elf_Shdr *sechdrs,
|
|
const char *strtab,
|
|
unsigned int symindex,
|
|
unsigned int relsec,
|
|
struct module *me);
|
|
#endif
|
|
#else
|
|
static inline int apply_relocate_add(Elf_Shdr *sechdrs,
|
|
const char *strtab,
|
|
unsigned int symindex,
|
|
unsigned int relsec,
|
|
struct module *me)
|
|
{
|
|
printk(KERN_ERR "module %s: REL relocation unsupported\n",
|
|
module_name(me));
|
|
return -ENOEXEC;
|
|
}
|
|
#endif
|
|
|
|
/* Any final processing of module before access. Return -error or 0. */
|
|
int module_finalize(const Elf_Ehdr *hdr,
|
|
const Elf_Shdr *sechdrs,
|
|
struct module *mod);
|
|
|
|
/* Any cleanup needed when module leaves. */
|
|
void module_arch_cleanup(struct module *mod);
|
|
|
|
/* Any cleanup before freeing mod->module_init */
|
|
void module_arch_freeing_init(struct module *mod);
|
|
|
|
#if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \
|
|
!defined(CONFIG_KASAN_VMALLOC)
|
|
#include <linux/kasan.h>
|
|
#define MODULE_ALIGN (PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT)
|
|
#else
|
|
#define MODULE_ALIGN PAGE_SIZE
|
|
#endif
|
|
|
|
#endif
|