[mirror_ubuntu-hirsute-kernel.git] / arch / x86 / kernel / module.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*  Kernel module help for x86.
    Copyright (C) 2001 Rusty Russell.

*/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/moduleloader.h>
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/kasan.h>
#include <linux/bug.h>
#include <linux/mm.h>
#include <linux/gfp.h>
#include <linux/jump_label.h>
#include <linux/random.h>

#include <asm/text-patching.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/setup.h>
#include <asm/unwind.h>

#if 0
#define DEBUGP(fmt, ...)				\
	printk(KERN_DEBUG fmt, ##__VA_ARGS__)
#else
#define DEBUGP(fmt, ...)				\
do {							\
	if (0)						\
		printk(KERN_DEBUG fmt, ##__VA_ARGS__);	\
} while (0)
#endif

#ifdef CONFIG_RANDOMIZE_BASE
static unsigned long module_load_offset;

/* Mutex protects the module_load_offset. */
static DEFINE_MUTEX(module_kaslr_mutex);

static unsigned long int get_module_load_offset(void)
{
	if (kaslr_enabled()) {
		mutex_lock(&module_kaslr_mutex);
		/*
		 * Calculate the module_load_offset the first time this
		 * code is called. Once calculated it stays the same until
		 * reboot.
		 */
		if (module_load_offset == 0)
			module_load_offset =
				(get_random_int() % 1024 + 1) * PAGE_SIZE;
		mutex_unlock(&module_kaslr_mutex);
	}
	return module_load_offset;
}
#else
static unsigned long int get_module_load_offset(void)
{
	return 0;
}
#endif

void *module_alloc(unsigned long size)
{
	void *p;

	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, 0, NUMA_NO_NODE,
				    __builtin_return_address(0));
	if (p && (kasan_module_alloc(p, size) < 0)) {
		vfree(p);
		return NULL;
	}

	return p;
}

#ifdef CONFIG_X86_32
int apply_relocate(Elf32_Shdr *sechdrs,
		   const char *strtab,
		   unsigned int symindex,
		   unsigned int relsec,
		   struct module *me)
{
	unsigned int i;
	Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
	Elf32_Sym *sym;
	uint32_t *location;

	DEBUGP("Applying relocate section %u to %u\n",
	       relsec, sechdrs[relsec].sh_info);
	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
		/* This is where to make the change */
		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
			+ rel[i].r_offset;
		/* This is the symbol it is referring to.  Note that all
		   undefined symbols have been resolved.  */
		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
			+ ELF32_R_SYM(rel[i].r_info);

		switch (ELF32_R_TYPE(rel[i].r_info)) {
		case R_386_32:
			/* We add the value into the location given */
			*location += sym->st_value;
			break;
		case R_386_PC32:
			/* Add the value, subtract its position */
			*location += sym->st_value - (uint32_t)location;
			break;
		default:
			pr_err("%s: Unknown relocation: %u\n",
			       me->name, ELF32_R_TYPE(rel[i].r_info));
			return -ENOEXEC;
		}
	}
	return 0;
}
#else /*X86_64*/
int apply_relocate_add(Elf64_Shdr *sechdrs,
		   const char *strtab,
		   unsigned int symindex,
		   unsigned int relsec,
		   struct module *me)
{
	unsigned int i;
	Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
	Elf64_Sym *sym;
	void *loc;
	u64 val;

	DEBUGP("Applying relocate section %u to %u\n",
	       relsec, sechdrs[relsec].sh_info);
	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
		/* This is where to make the change */
		loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
			+ rel[i].r_offset;

		/* This is the symbol it is referring to.  Note that all
		   undefined symbols have been resolved.  */
		sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
			+ ELF64_R_SYM(rel[i].r_info);

		DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
		       (int)ELF64_R_TYPE(rel[i].r_info),
		       sym->st_value, rel[i].r_addend, (u64)loc);

		val = sym->st_value + rel[i].r_addend;

		switch (ELF64_R_TYPE(rel[i].r_info)) {
		case R_X86_64_NONE:
			break;
		case R_X86_64_64:
			if (*(u64 *)loc != 0)
				goto invalid_relocation;
			*(u64 *)loc = val;
			break;
		case R_X86_64_32:
			if (*(u32 *)loc != 0)
				goto invalid_relocation;
			*(u32 *)loc = val;
			if (val != *(u32 *)loc)
				goto overflow;
			break;
		case R_X86_64_32S:
			if (*(s32 *)loc != 0)
				goto invalid_relocation;
			*(s32 *)loc = val;
			if ((s64)val != *(s32 *)loc)
				goto overflow;
			break;
		case R_X86_64_PC32:
		case R_X86_64_PLT32:
			if (*(u32 *)loc != 0)
				goto invalid_relocation;
			val -= (u64)loc;
			*(u32 *)loc = val;
#if 0
			if ((s64)val != *(s32 *)loc)
				goto overflow;
#endif
			break;
		case R_X86_64_PC64:
			if (*(u64 *)loc != 0)
				goto invalid_relocation;
			val -= (u64)loc;
			*(u64 *)loc = val;
			break;
		default:
			pr_err("%s: Unknown rela relocation: %llu\n",
			       me->name, ELF64_R_TYPE(rel[i].r_info));
			return -ENOEXEC;
		}
	}
	return 0;

invalid_relocation:
	pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
	       (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
	return -ENOEXEC;

overflow:
	pr_err("overflow in relocation type %d val %Lx\n",
	       (int)ELF64_R_TYPE(rel[i].r_info), val);
	pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
	       me->name);
	return -ENOEXEC;
}
#endif

int module_finalize(const Elf_Ehdr *hdr,
		    const Elf_Shdr *sechdrs,
		    struct module *me)
{
	const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
		*para = NULL, *orc = NULL, *orc_ip = NULL;
	char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;

	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
		if (!strcmp(".text", secstrings + s->sh_name))
			text = s;
		if (!strcmp(".altinstructions", secstrings + s->sh_name))
			alt = s;
		if (!strcmp(".smp_locks", secstrings + s->sh_name))
			locks = s;
		if (!strcmp(".parainstructions", secstrings + s->sh_name))
			para = s;
		if (!strcmp(".orc_unwind", secstrings + s->sh_name))
			orc = s;
		if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
			orc_ip = s;
	}

	if (alt) {
		/* patch .altinstructions */
		void *aseg = (void *)alt->sh_addr;
		apply_alternatives(aseg, aseg + alt->sh_size);
	}
	if (locks && text) {
		void *lseg = (void *)locks->sh_addr;
		void *tseg = (void *)text->sh_addr;
		alternatives_smp_module_add(me, me->name,
					    lseg, lseg + locks->sh_size,
					    tseg, tseg + text->sh_size);
	}

	if (para) {
		void *pseg = (void *)para->sh_addr;
		apply_paravirt(pseg, pseg + para->sh_size);
	}

	/* make jump label nops */
	jump_label_apply_nops(me);

	if (orc && orc_ip)
		unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
				   (void *)orc->sh_addr, orc->sh_size);

	return 0;
}

void module_arch_cleanup(struct module *mod)
{
	alternatives_smp_module_del(mod);
}
Commit	Line	Data
1a59d1b8	1	// SPDX-License-Identifier: GPL-2.0-or-later
2d5bf28f AW	2	/* Kernel module help for x86.
	3	Copyright (C) 2001 Rusty Russell.
	4
2d5bf28f	5	*/
c767a54b JP	6
	7	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	8
2d5bf28f AW	9	#include <linux/moduleloader.h>
	10	#include <linux/elf.h>
	11	#include <linux/vmalloc.h>
	12	#include <linux/fs.h>
	13	#include <linux/string.h>
	14	#include <linux/kernel.h>
bebf56a1	15	#include <linux/kasan.h>
2d5bf28f AW	16	#include <linux/bug.h>
2d5bf28f AW	17	#include <linux/mm.h>
5a0e3ad6	18	#include <linux/gfp.h>
d430d3d7	19	#include <linux/jump_label.h>
e2b32e67	20	#include <linux/random.h>
2d5bf28f	21
35de5b06	22	#include <asm/text-patching.h>
2d5bf28f AW	23	#include <asm/page.h>
2d5bf28f AW	24	#include <asm/pgtable.h>
78cac48c	25	#include <asm/setup.h>
ee9f8fce	26	#include <asm/unwind.h>
2d5bf28f AW	27
2d5bf28f AW	28	#if 0
c767a54b JP	29	#define DEBUGP(fmt, ...) \
c767a54b JP	30	printk(KERN_DEBUG fmt, ##__VA_ARGS__)
2d5bf28f	31	#else
c767a54b JP	32	#define DEBUGP(fmt, ...) \
	33	do { \
	34	if (0) \
	35	printk(KERN_DEBUG fmt, ##__VA_ARGS__); \
	36	} while (0)
2d5bf28f AW	37	#endif
2d5bf28f AW	38
e2b32e67 KC	39	#ifdef CONFIG_RANDOMIZE_BASE
e2b32e67 KC	40	static unsigned long module_load_offset;
e2b32e67	41
9dd721c6 KC	42	/* Mutex protects the module_load_offset. */
	43	static DEFINE_MUTEX(module_kaslr_mutex);
	44
e2b32e67 KC	45	static unsigned long int get_module_load_offset(void)
e2b32e67 KC	46	{
78cac48c	47	if (kaslr_enabled()) {
9dd721c6	48	mutex_lock(&module_kaslr_mutex);
e2b32e67 KC	49	/*
	50	* Calculate the module_load_offset the first time this
	51	* code is called. Once calculated it stays the same until
	52	* reboot.
	53	*/
	54	if (module_load_offset == 0)
	55	module_load_offset =
	56	(get_random_int() % 1024 + 1) * PAGE_SIZE;
9dd721c6	57	mutex_unlock(&module_kaslr_mutex);
e2b32e67 KC	58	}
	59	return module_load_offset;
	60	}
	61	#else
	62	static unsigned long int get_module_load_offset(void)
	63	{
	64	return 0;
	65	}
	66	#endif
	67
0fdc83b9 AW	68	void *module_alloc(unsigned long size)
0fdc83b9 AW	69	{
bebf56a1 AR	70	void *p;
bebf56a1 AR	71
d0a21265	72	if (PAGE_ALIGN(size) > MODULES_LEN)
0fdc83b9	73	return NULL;
bebf56a1 AR	74
bebf56a1 AR	75	p = __vmalloc_node_range(size, MODULE_ALIGN,
e2b32e67	76	MODULES_VADDR + get_module_load_offset(),
19809c2d	77	MODULES_END, GFP_KERNEL,
f2c65fb3	78	PAGE_KERNEL, 0, NUMA_NO_NODE,
e2b32e67	79	__builtin_return_address(0));
bebf56a1 AR	80	if (p && (kasan_module_alloc(p, size) < 0)) {
	81	vfree(p);
	82	return NULL;
	83	}
	84
	85	return p;
0fdc83b9	86	}
0fdc83b9	87
0fdc83b9 AW	88	#ifdef CONFIG_X86_32
	89	int apply_relocate(Elf32_Shdr *sechdrs,
	90	const char *strtab,
	91	unsigned int symindex,
	92	unsigned int relsec,
	93	struct module *me)
	94	{
	95	unsigned int i;
	96	Elf32_Rel rel = (void )sechdrs[relsec].sh_addr;
	97	Elf32_Sym *sym;
	98	uint32_t *location;
	99
c767a54b JP	100	DEBUGP("Applying relocate section %u to %u\n",
c767a54b JP	101	relsec, sechdrs[relsec].sh_info);
0fdc83b9 AW	102	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
	103	/* This is where to make the change */
	104	location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
	105	+ rel[i].r_offset;
	106	/* This is the symbol it is referring to. Note that all
	107	undefined symbols have been resolved. */
	108	sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
	109	+ ELF32_R_SYM(rel[i].r_info);
	110
	111	switch (ELF32_R_TYPE(rel[i].r_info)) {
	112	case R_386_32:
	113	/* We add the value into the location given */
	114	*location += sym->st_value;
	115	break;
	116	case R_386_PC32:
2e76c283	117	/* Add the value, subtract its position */
0fdc83b9 AW	118	*location += sym->st_value - (uint32_t)location;
	119	break;
	120	default:
c767a54b	121	pr_err("%s: Unknown relocation: %u\n",
0fdc83b9 AW	122	me->name, ELF32_R_TYPE(rel[i].r_info));
	123	return -ENOEXEC;
	124	}
	125	}
	126	return 0;
	127	}
0fdc83b9 AW	128	#else /X86_64/
	129	int apply_relocate_add(Elf64_Shdr *sechdrs,
	130	const char *strtab,
	131	unsigned int symindex,
	132	unsigned int relsec,
	133	struct module *me)
	134	{
	135	unsigned int i;
	136	Elf64_Rela rel = (void )sechdrs[relsec].sh_addr;
	137	Elf64_Sym *sym;
	138	void *loc;
	139	u64 val;
	140
c767a54b JP	141	DEBUGP("Applying relocate section %u to %u\n",
c767a54b JP	142	relsec, sechdrs[relsec].sh_info);
0fdc83b9 AW	143	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
	144	/* This is where to make the change */
	145	loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
	146	+ rel[i].r_offset;
	147
	148	/* This is the symbol it is referring to. Note that all
	149	undefined symbols have been resolved. */
	150	sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
	151	+ ELF64_R_SYM(rel[i].r_info);
	152
	153	DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
c767a54b JP	154	(int)ELF64_R_TYPE(rel[i].r_info),
c767a54b JP	155	sym->st_value, rel[i].r_addend, (u64)loc);
0fdc83b9 AW	156
	157	val = sym->st_value + rel[i].r_addend;
	158
	159	switch (ELF64_R_TYPE(rel[i].r_info)) {
	160	case R_X86_64_NONE:
	161	break;
	162	case R_X86_64_64:
eda9cec4 JP	163	if ((u64 )loc != 0)
eda9cec4 JP	164	goto invalid_relocation;
0fdc83b9 AW	165	(u64 )loc = val;
	166	break;
	167	case R_X86_64_32:
eda9cec4 JP	168	if ((u32 )loc != 0)
eda9cec4 JP	169	goto invalid_relocation;
0fdc83b9 AW	170	(u32 )loc = val;
	171	if (val != (u32 )loc)
	172	goto overflow;
	173	break;
	174	case R_X86_64_32S:
eda9cec4 JP	175	if ((s32 )loc != 0)
eda9cec4 JP	176	goto invalid_relocation;
0fdc83b9 AW	177	(s32 )loc = val;
	178	if ((s64)val != (s32 )loc)
	179	goto overflow;
	180	break;
	181	case R_X86_64_PC32:
b21ebf2f	182	case R_X86_64_PLT32:
eda9cec4 JP	183	if ((u32 )loc != 0)
eda9cec4 JP	184	goto invalid_relocation;
0fdc83b9 AW	185	val -= (u64)loc;
	186	(u32 )loc = val;
	187	#if 0
	188	if ((s64)val != (s32 )loc)
	189	goto overflow;
	190	#endif
	191	break;
b40a142b AB	192	case R_X86_64_PC64:
	193	if ((u64 )loc != 0)
	194	goto invalid_relocation;
	195	val -= (u64)loc;
	196	(u64 )loc = val;
	197	break;
0fdc83b9	198	default:
c767a54b	199	pr_err("%s: Unknown rela relocation: %llu\n",
0fdc83b9 AW	200	me->name, ELF64_R_TYPE(rel[i].r_info));
	201	return -ENOEXEC;
	202	}
	203	}
	204	return 0;
	205
eda9cec4 JP	206	invalid_relocation:
	207	pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
	208	(int)ELF64_R_TYPE(rel[i].r_info), loc, val);
	209	return -ENOEXEC;
	210
0fdc83b9	211	overflow:
c767a54b	212	pr_err("overflow in relocation type %d val %Lx\n",
0fdc83b9	213	(int)ELF64_R_TYPE(rel[i].r_info), val);
c767a54b	214	pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
0fdc83b9 AW	215	me->name);
	216	return -ENOEXEC;
	217	}
0fdc83b9 AW	218	#endif
0fdc83b9 AW	219
2d5bf28f AW	220	int module_finalize(const Elf_Ehdr *hdr,
	221	const Elf_Shdr *sechdrs,
	222	struct module *me)
	223	{
	224	const Elf_Shdr s, text = NULL, alt = NULL, locks = NULL,
ee9f8fce	225	para = NULL, orc = NULL, *orc_ip = NULL;
2d5bf28f AW	226	char secstrings = (void )hdr + sechdrs[hdr->e_shstrndx].sh_offset;
	227
	228	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
	229	if (!strcmp(".text", secstrings + s->sh_name))
	230	text = s;
	231	if (!strcmp(".altinstructions", secstrings + s->sh_name))
	232	alt = s;
	233	if (!strcmp(".smp_locks", secstrings + s->sh_name))
	234	locks = s;
	235	if (!strcmp(".parainstructions", secstrings + s->sh_name))
	236	para = s;
ee9f8fce JP	237	if (!strcmp(".orc_unwind", secstrings + s->sh_name))
	238	orc = s;
	239	if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
	240	orc_ip = s;
2d5bf28f AW	241	}
	242
	243	if (alt) {
	244	/* patch .altinstructions */
	245	void aseg = (void )alt->sh_addr;
	246	apply_alternatives(aseg, aseg + alt->sh_size);
	247	}
	248	if (locks && text) {
	249	void lseg = (void )locks->sh_addr;
	250	void tseg = (void )text->sh_addr;
	251	alternatives_smp_module_add(me, me->name,
	252	lseg, lseg + locks->sh_size,
	253	tseg, tseg + text->sh_size);
	254	}
	255
	256	if (para) {
	257	void pseg = (void )para->sh_addr;
	258	apply_paravirt(pseg, pseg + para->sh_size);
	259	}
	260
d9f5ab7b JB	261	/* make jump label nops */
	262	jump_label_apply_nops(me);
	263
ee9f8fce JP	264	if (orc && orc_ip)
	265	unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
	266	(void *)orc->sh_addr, orc->sh_size);
	267
5336377d	268	return 0;
2d5bf28f AW	269	}
	270
	271	void module_arch_cleanup(struct module *mod)
	272	{
	273	alternatives_smp_module_del(mod);
2d5bf28f	274	}