xref: /linux/arch/s390/kernel/machine_kexec_file.c (revision 79790b6818e96c58fe2bffee1b418c16e64e7b80)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * s390 code for kexec_file_load system call
4  *
5  * Copyright IBM Corp. 2018
6  *
7  * Author(s): Philipp Rudo <prudo@linux.vnet.ibm.com>
8  */
9 
10 #define pr_fmt(fmt)	"kexec: " fmt
11 
12 #include <linux/elf.h>
13 #include <linux/errno.h>
14 #include <linux/kexec.h>
15 #include <linux/module_signature.h>
16 #include <linux/verification.h>
17 #include <linux/vmalloc.h>
18 #include <asm/boot_data.h>
19 #include <asm/ipl.h>
20 #include <asm/setup.h>
21 
22 const struct kexec_file_ops * const kexec_file_loaders[] = {
23 	&s390_kexec_elf_ops,
24 	&s390_kexec_image_ops,
25 	NULL,
26 };
27 
28 #ifdef CONFIG_KEXEC_SIG
s390_verify_sig(const char * kernel,unsigned long kernel_len)29 int s390_verify_sig(const char *kernel, unsigned long kernel_len)
30 {
31 	const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1;
32 	struct module_signature *ms;
33 	unsigned long sig_len;
34 	int ret;
35 
36 	/* Skip signature verification when not secure IPLed. */
37 	if (!ipl_secure_flag)
38 		return 0;
39 
40 	if (marker_len > kernel_len)
41 		return -EKEYREJECTED;
42 
43 	if (memcmp(kernel + kernel_len - marker_len, MODULE_SIG_STRING,
44 		   marker_len))
45 		return -EKEYREJECTED;
46 	kernel_len -= marker_len;
47 
48 	ms = (void *)kernel + kernel_len - sizeof(*ms);
49 	kernel_len -= sizeof(*ms);
50 
51 	sig_len = be32_to_cpu(ms->sig_len);
52 	if (sig_len >= kernel_len)
53 		return -EKEYREJECTED;
54 	kernel_len -= sig_len;
55 
56 	if (ms->id_type != PKEY_ID_PKCS7)
57 		return -EKEYREJECTED;
58 
59 	if (ms->algo != 0 ||
60 	    ms->hash != 0 ||
61 	    ms->signer_len != 0 ||
62 	    ms->key_id_len != 0 ||
63 	    ms->__pad[0] != 0 ||
64 	    ms->__pad[1] != 0 ||
65 	    ms->__pad[2] != 0) {
66 		return -EBADMSG;
67 	}
68 
69 	ret = verify_pkcs7_signature(kernel, kernel_len,
70 				     kernel + kernel_len, sig_len,
71 				     VERIFY_USE_SECONDARY_KEYRING,
72 				     VERIFYING_MODULE_SIGNATURE,
73 				     NULL, NULL);
74 	if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING))
75 		ret = verify_pkcs7_signature(kernel, kernel_len,
76 					     kernel + kernel_len, sig_len,
77 					     VERIFY_USE_PLATFORM_KEYRING,
78 					     VERIFYING_MODULE_SIGNATURE,
79 					     NULL, NULL);
80 	return ret;
81 }
82 #endif /* CONFIG_KEXEC_SIG */
83 
kexec_file_update_purgatory(struct kimage * image,struct s390_load_data * data)84 static int kexec_file_update_purgatory(struct kimage *image,
85 				       struct s390_load_data *data)
86 {
87 	u64 entry, type;
88 	int ret;
89 
90 	if (image->type == KEXEC_TYPE_CRASH) {
91 		entry = STARTUP_KDUMP_OFFSET;
92 		type = KEXEC_TYPE_CRASH;
93 	} else {
94 		entry = STARTUP_NORMAL_OFFSET;
95 		type = KEXEC_TYPE_DEFAULT;
96 	}
97 
98 	ret = kexec_purgatory_get_set_symbol(image, "kernel_entry", &entry,
99 					     sizeof(entry), false);
100 	if (ret)
101 		return ret;
102 
103 	ret = kexec_purgatory_get_set_symbol(image, "kernel_type", &type,
104 					     sizeof(type), false);
105 	if (ret)
106 		return ret;
107 
108 #ifdef CONFIG_CRASH_DUMP
109 	if (image->type == KEXEC_TYPE_CRASH) {
110 		u64 crash_size;
111 
112 		ret = kexec_purgatory_get_set_symbol(image, "crash_start",
113 						     &crashk_res.start,
114 						     sizeof(crashk_res.start),
115 						     false);
116 		if (ret)
117 			return ret;
118 
119 		crash_size = crashk_res.end - crashk_res.start + 1;
120 		ret = kexec_purgatory_get_set_symbol(image, "crash_size",
121 						     &crash_size,
122 						     sizeof(crash_size),
123 						     false);
124 	}
125 #endif
126 	return ret;
127 }
128 
kexec_file_add_purgatory(struct kimage * image,struct s390_load_data * data)129 static int kexec_file_add_purgatory(struct kimage *image,
130 				    struct s390_load_data *data)
131 {
132 	struct kexec_buf buf;
133 	int ret;
134 
135 	buf.image = image;
136 
137 	data->memsz = ALIGN(data->memsz, PAGE_SIZE);
138 	buf.mem = data->memsz;
139 #ifdef CONFIG_CRASH_DUMP
140 	if (image->type == KEXEC_TYPE_CRASH)
141 		buf.mem += crashk_res.start;
142 #endif
143 
144 	ret = kexec_load_purgatory(image, &buf);
145 	if (ret)
146 		return ret;
147 	data->memsz += buf.memsz;
148 
149 	return kexec_file_update_purgatory(image, data);
150 }
151 
kexec_file_add_initrd(struct kimage * image,struct s390_load_data * data)152 static int kexec_file_add_initrd(struct kimage *image,
153 				 struct s390_load_data *data)
154 {
155 	struct kexec_buf buf;
156 	int ret;
157 
158 	buf.image = image;
159 
160 	buf.buffer = image->initrd_buf;
161 	buf.bufsz = image->initrd_buf_len;
162 
163 	data->memsz = ALIGN(data->memsz, PAGE_SIZE);
164 	buf.mem = data->memsz;
165 #ifdef CONFIG_CRASH_DUMP
166 	if (image->type == KEXEC_TYPE_CRASH)
167 		buf.mem += crashk_res.start;
168 #endif
169 	buf.memsz = buf.bufsz;
170 
171 	data->parm->initrd_start = data->memsz;
172 	data->parm->initrd_size = buf.memsz;
173 	data->memsz += buf.memsz;
174 
175 	ret = kexec_add_buffer(&buf);
176 	if (ret)
177 		return ret;
178 
179 	return ipl_report_add_component(data->report, &buf, 0, 0);
180 }
181 
kexec_file_add_ipl_report(struct kimage * image,struct s390_load_data * data)182 static int kexec_file_add_ipl_report(struct kimage *image,
183 				     struct s390_load_data *data)
184 {
185 	__u32 *lc_ipl_parmblock_ptr;
186 	unsigned int len, ncerts;
187 	struct kexec_buf buf;
188 	unsigned long addr;
189 	void *ptr, *end;
190 	int ret;
191 
192 	buf.image = image;
193 
194 	data->memsz = ALIGN(data->memsz, PAGE_SIZE);
195 	buf.mem = data->memsz;
196 
197 	ptr = __va(ipl_cert_list_addr);
198 	end = ptr + ipl_cert_list_size;
199 	ncerts = 0;
200 	while (ptr < end) {
201 		ncerts++;
202 		len = *(unsigned int *)ptr;
203 		ptr += sizeof(len);
204 		ptr += len;
205 	}
206 
207 	addr = data->memsz + data->report->size;
208 	addr += ncerts * sizeof(struct ipl_rb_certificate_entry);
209 	ptr = __va(ipl_cert_list_addr);
210 	while (ptr < end) {
211 		len = *(unsigned int *)ptr;
212 		ptr += sizeof(len);
213 		ipl_report_add_certificate(data->report, ptr, addr, len);
214 		addr += len;
215 		ptr += len;
216 	}
217 
218 	ret = -ENOMEM;
219 	buf.buffer = ipl_report_finish(data->report);
220 	if (!buf.buffer)
221 		goto out;
222 	buf.bufsz = data->report->size;
223 	buf.memsz = buf.bufsz;
224 	image->arch.ipl_buf = buf.buffer;
225 
226 	data->memsz += buf.memsz;
227 
228 	lc_ipl_parmblock_ptr =
229 		data->kernel_buf + offsetof(struct lowcore, ipl_parmblock_ptr);
230 	*lc_ipl_parmblock_ptr = (__u32)buf.mem;
231 
232 #ifdef CONFIG_CRASH_DUMP
233 	if (image->type == KEXEC_TYPE_CRASH)
234 		buf.mem += crashk_res.start;
235 #endif
236 
237 	ret = kexec_add_buffer(&buf);
238 out:
239 	return ret;
240 }
241 
kexec_file_add_components(struct kimage * image,int (* add_kernel)(struct kimage * image,struct s390_load_data * data))242 void *kexec_file_add_components(struct kimage *image,
243 				int (*add_kernel)(struct kimage *image,
244 						  struct s390_load_data *data))
245 {
246 	unsigned long max_command_line_size = LEGACY_COMMAND_LINE_SIZE;
247 	struct s390_load_data data = {0};
248 	unsigned long minsize;
249 	int ret;
250 
251 	data.report = ipl_report_init(&ipl_block);
252 	if (IS_ERR(data.report))
253 		return data.report;
254 
255 	ret = add_kernel(image, &data);
256 	if (ret)
257 		goto out;
258 
259 	ret = -EINVAL;
260 	minsize = PARMAREA + offsetof(struct parmarea, command_line);
261 	if (image->kernel_buf_len < minsize)
262 		goto out;
263 
264 	if (data.parm->max_command_line_size)
265 		max_command_line_size = data.parm->max_command_line_size;
266 
267 	if (minsize + max_command_line_size < minsize)
268 		goto out;
269 
270 	if (image->kernel_buf_len < minsize + max_command_line_size)
271 		goto out;
272 
273 	if (image->cmdline_buf_len >= max_command_line_size)
274 		goto out;
275 
276 	memcpy(data.parm->command_line, image->cmdline_buf,
277 	       image->cmdline_buf_len);
278 
279 #ifdef CONFIG_CRASH_DUMP
280 	if (image->type == KEXEC_TYPE_CRASH) {
281 		data.parm->oldmem_base = crashk_res.start;
282 		data.parm->oldmem_size = crashk_res.end - crashk_res.start + 1;
283 	}
284 #endif
285 
286 	if (image->initrd_buf) {
287 		ret = kexec_file_add_initrd(image, &data);
288 		if (ret)
289 			goto out;
290 	}
291 
292 	ret = kexec_file_add_purgatory(image, &data);
293 	if (ret)
294 		goto out;
295 
296 	if (data.kernel_mem == 0) {
297 		unsigned long restart_psw =  0x0008000080000000UL;
298 		restart_psw += image->start;
299 		memcpy(data.kernel_buf, &restart_psw, sizeof(restart_psw));
300 		image->start = 0;
301 	}
302 
303 	ret = kexec_file_add_ipl_report(image, &data);
304 out:
305 	ipl_report_free(data.report);
306 	return ERR_PTR(ret);
307 }
308 
arch_kexec_apply_relocations_add(struct purgatory_info * pi,Elf_Shdr * section,const Elf_Shdr * relsec,const Elf_Shdr * symtab)309 int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
310 				     Elf_Shdr *section,
311 				     const Elf_Shdr *relsec,
312 				     const Elf_Shdr *symtab)
313 {
314 	const char *strtab, *name, *shstrtab;
315 	const Elf_Shdr *sechdrs;
316 	Elf_Rela *relas;
317 	int i, r_type;
318 	int ret;
319 
320 	/* String & section header string table */
321 	sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
322 	strtab = (char *)pi->ehdr + sechdrs[symtab->sh_link].sh_offset;
323 	shstrtab = (char *)pi->ehdr + sechdrs[pi->ehdr->e_shstrndx].sh_offset;
324 
325 	relas = (void *)pi->ehdr + relsec->sh_offset;
326 
327 	for (i = 0; i < relsec->sh_size / sizeof(*relas); i++) {
328 		const Elf_Sym *sym;	/* symbol to relocate */
329 		unsigned long addr;	/* final location after relocation */
330 		unsigned long val;	/* relocated symbol value */
331 		void *loc;		/* tmp location to modify */
332 
333 		sym = (void *)pi->ehdr + symtab->sh_offset;
334 		sym += ELF64_R_SYM(relas[i].r_info);
335 
336 		if (sym->st_name)
337 			name = strtab + sym->st_name;
338 		else
339 			name = shstrtab + sechdrs[sym->st_shndx].sh_name;
340 
341 		if (sym->st_shndx == SHN_UNDEF) {
342 			pr_err("Undefined symbol: %s\n", name);
343 			return -ENOEXEC;
344 		}
345 
346 		if (sym->st_shndx == SHN_COMMON) {
347 			pr_err("symbol '%s' in common section\n", name);
348 			return -ENOEXEC;
349 		}
350 
351 		if (sym->st_shndx >= pi->ehdr->e_shnum &&
352 		    sym->st_shndx != SHN_ABS) {
353 			pr_err("Invalid section %d for symbol %s\n",
354 			       sym->st_shndx, name);
355 			return -ENOEXEC;
356 		}
357 
358 		loc = pi->purgatory_buf;
359 		loc += section->sh_offset;
360 		loc += relas[i].r_offset;
361 
362 		val = sym->st_value;
363 		if (sym->st_shndx != SHN_ABS)
364 			val += pi->sechdrs[sym->st_shndx].sh_addr;
365 		val += relas[i].r_addend;
366 
367 		addr = section->sh_addr + relas[i].r_offset;
368 
369 		r_type = ELF64_R_TYPE(relas[i].r_info);
370 
371 		if (r_type == R_390_PLT32DBL)
372 			r_type = R_390_PC32DBL;
373 
374 		ret = arch_kexec_do_relocs(r_type, loc, val, addr);
375 		if (ret) {
376 			pr_err("Unknown rela relocation: %d\n", r_type);
377 			return -ENOEXEC;
378 		}
379 	}
380 	return 0;
381 }
382 
arch_kimage_file_post_load_cleanup(struct kimage * image)383 int arch_kimage_file_post_load_cleanup(struct kimage *image)
384 {
385 	vfree(image->arch.ipl_buf);
386 	image->arch.ipl_buf = NULL;
387 
388 	return kexec_image_post_load_cleanup_default(image);
389 }
390