1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Copyright 2021 Google LLC. |
4 | */ |
5 | |
6 | #include <linux/init.h> |
7 | #include <linux/highmem.h> |
8 | #include <linux/kobject.h> |
9 | #include <linux/mm.h> |
10 | #include <linux/module.h> |
11 | #include <linux/slab.h> |
12 | #include <linux/sysfs.h> |
13 | #include <linux/vmalloc.h> |
14 | |
15 | #include "internal.h" |
16 | |
17 | static int module_extend_max_pages(struct load_info *info, unsigned int extent) |
18 | { |
19 | struct page **new_pages; |
20 | |
21 | new_pages = kvmalloc_array(n: info->max_pages + extent, |
22 | size: sizeof(info->pages), GFP_KERNEL); |
23 | if (!new_pages) |
24 | return -ENOMEM; |
25 | |
26 | memcpy(new_pages, info->pages, info->max_pages * sizeof(info->pages)); |
27 | kvfree(addr: info->pages); |
28 | info->pages = new_pages; |
29 | info->max_pages += extent; |
30 | |
31 | return 0; |
32 | } |
33 | |
34 | static struct page *module_get_next_page(struct load_info *info) |
35 | { |
36 | struct page *page; |
37 | int error; |
38 | |
39 | if (info->max_pages == info->used_pages) { |
40 | error = module_extend_max_pages(info, extent: info->used_pages); |
41 | if (error) |
42 | return ERR_PTR(error); |
43 | } |
44 | |
45 | page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM); |
46 | if (!page) |
47 | return ERR_PTR(error: -ENOMEM); |
48 | |
49 | info->pages[info->used_pages++] = page; |
50 | return page; |
51 | } |
52 | |
53 | #if defined(CONFIG_MODULE_COMPRESS_GZIP) |
54 | #include <linux/zlib.h> |
55 | #define MODULE_COMPRESSION gzip |
56 | #define MODULE_DECOMPRESS_FN module_gzip_decompress |
57 | |
58 | /* |
59 | * Calculate length of the header which consists of signature, header |
60 | * flags, time stamp and operating system ID (10 bytes total), plus |
61 | * an optional filename. |
62 | */ |
63 | static size_t module_gzip_header_len(const u8 *buf, size_t size) |
64 | { |
65 | const u8 signature[] = { 0x1f, 0x8b, 0x08 }; |
66 | size_t len = 10; |
67 | |
68 | if (size < len || memcmp(buf, signature, sizeof(signature))) |
69 | return 0; |
70 | |
71 | if (buf[3] & 0x08) { |
72 | do { |
73 | /* |
74 | * If we can't find the end of the file name we must |
75 | * be dealing with a corrupted file. |
76 | */ |
77 | if (len == size) |
78 | return 0; |
79 | } while (buf[len++] != '\0'); |
80 | } |
81 | |
82 | return len; |
83 | } |
84 | |
85 | static ssize_t module_gzip_decompress(struct load_info *info, |
86 | const void *buf, size_t size) |
87 | { |
88 | struct z_stream_s s = { 0 }; |
89 | size_t new_size = 0; |
90 | size_t gzip_hdr_len; |
91 | ssize_t retval; |
92 | int rc; |
93 | |
94 | gzip_hdr_len = module_gzip_header_len(buf, size); |
95 | if (!gzip_hdr_len) { |
96 | pr_err("not a gzip compressed module\n" ); |
97 | return -EINVAL; |
98 | } |
99 | |
100 | s.next_in = buf + gzip_hdr_len; |
101 | s.avail_in = size - gzip_hdr_len; |
102 | |
103 | s.workspace = kvmalloc(zlib_inflate_workspacesize(), GFP_KERNEL); |
104 | if (!s.workspace) |
105 | return -ENOMEM; |
106 | |
107 | rc = zlib_inflateInit2(&s, -MAX_WBITS); |
108 | if (rc != Z_OK) { |
109 | pr_err("failed to initialize decompressor: %d\n" , rc); |
110 | retval = -EINVAL; |
111 | goto out; |
112 | } |
113 | |
114 | do { |
115 | struct page *page = module_get_next_page(info); |
116 | |
117 | if (IS_ERR(page)) { |
118 | retval = PTR_ERR(page); |
119 | goto out_inflate_end; |
120 | } |
121 | |
122 | s.next_out = kmap_local_page(page); |
123 | s.avail_out = PAGE_SIZE; |
124 | rc = zlib_inflate(&s, 0); |
125 | kunmap_local(s.next_out); |
126 | |
127 | new_size += PAGE_SIZE - s.avail_out; |
128 | } while (rc == Z_OK); |
129 | |
130 | if (rc != Z_STREAM_END) { |
131 | pr_err("decompression failed with status %d\n" , rc); |
132 | retval = -EINVAL; |
133 | goto out_inflate_end; |
134 | } |
135 | |
136 | retval = new_size; |
137 | |
138 | out_inflate_end: |
139 | zlib_inflateEnd(&s); |
140 | out: |
141 | kvfree(s.workspace); |
142 | return retval; |
143 | } |
144 | #elif defined(CONFIG_MODULE_COMPRESS_XZ) |
145 | #include <linux/xz.h> |
146 | #define MODULE_COMPRESSION xz |
147 | #define MODULE_DECOMPRESS_FN module_xz_decompress |
148 | |
149 | static ssize_t module_xz_decompress(struct load_info *info, |
150 | const void *buf, size_t size) |
151 | { |
152 | static const u8 signature[] = { 0xfd, '7', 'z', 'X', 'Z', 0 }; |
153 | struct xz_dec *xz_dec; |
154 | struct xz_buf xz_buf; |
155 | enum xz_ret xz_ret; |
156 | size_t new_size = 0; |
157 | ssize_t retval; |
158 | |
159 | if (size < sizeof(signature) || |
160 | memcmp(buf, signature, sizeof(signature))) { |
161 | pr_err("not an xz compressed module\n" ); |
162 | return -EINVAL; |
163 | } |
164 | |
165 | xz_dec = xz_dec_init(XZ_DYNALLOC, (u32)-1); |
166 | if (!xz_dec) |
167 | return -ENOMEM; |
168 | |
169 | xz_buf.in_size = size; |
170 | xz_buf.in = buf; |
171 | xz_buf.in_pos = 0; |
172 | |
173 | do { |
174 | struct page *page = module_get_next_page(info); |
175 | |
176 | if (IS_ERR(page)) { |
177 | retval = PTR_ERR(page); |
178 | goto out; |
179 | } |
180 | |
181 | xz_buf.out = kmap_local_page(page); |
182 | xz_buf.out_pos = 0; |
183 | xz_buf.out_size = PAGE_SIZE; |
184 | xz_ret = xz_dec_run(xz_dec, &xz_buf); |
185 | kunmap_local(xz_buf.out); |
186 | |
187 | new_size += xz_buf.out_pos; |
188 | } while (xz_buf.out_pos == PAGE_SIZE && xz_ret == XZ_OK); |
189 | |
190 | if (xz_ret != XZ_STREAM_END) { |
191 | pr_err("decompression failed with status %d\n" , xz_ret); |
192 | retval = -EINVAL; |
193 | goto out; |
194 | } |
195 | |
196 | retval = new_size; |
197 | |
198 | out: |
199 | xz_dec_end(xz_dec); |
200 | return retval; |
201 | } |
202 | #elif defined(CONFIG_MODULE_COMPRESS_ZSTD) |
203 | #include <linux/zstd.h> |
204 | #define MODULE_COMPRESSION zstd |
205 | #define MODULE_DECOMPRESS_FN module_zstd_decompress |
206 | |
207 | static ssize_t module_zstd_decompress(struct load_info *info, |
208 | const void *buf, size_t size) |
209 | { |
210 | static const u8 signature[] = { 0x28, 0xb5, 0x2f, 0xfd }; |
211 | ZSTD_outBuffer zstd_dec; |
212 | ZSTD_inBuffer zstd_buf; |
213 | zstd_frame_header header; |
214 | size_t wksp_size; |
215 | void *wksp = NULL; |
216 | ZSTD_DStream *dstream; |
217 | size_t ret; |
218 | size_t new_size = 0; |
219 | int retval; |
220 | |
221 | if (size < sizeof(signature) || |
222 | memcmp(buf, signature, sizeof(signature))) { |
223 | pr_err("not a zstd compressed module\n" ); |
224 | return -EINVAL; |
225 | } |
226 | |
227 | zstd_buf.src = buf; |
228 | zstd_buf.pos = 0; |
229 | zstd_buf.size = size; |
230 | |
231 | ret = zstd_get_frame_header(&header, zstd_buf.src, zstd_buf.size); |
232 | if (ret != 0) { |
233 | pr_err("ZSTD-compressed data has an incomplete frame header\n" ); |
234 | retval = -EINVAL; |
235 | goto out; |
236 | } |
237 | if (header.windowSize > (1 << ZSTD_WINDOWLOG_MAX)) { |
238 | pr_err("ZSTD-compressed data has too large a window size\n" ); |
239 | retval = -EINVAL; |
240 | goto out; |
241 | } |
242 | |
243 | wksp_size = zstd_dstream_workspace_bound(header.windowSize); |
244 | wksp = kvmalloc(wksp_size, GFP_KERNEL); |
245 | if (!wksp) { |
246 | retval = -ENOMEM; |
247 | goto out; |
248 | } |
249 | |
250 | dstream = zstd_init_dstream(header.windowSize, wksp, wksp_size); |
251 | if (!dstream) { |
252 | pr_err("Can't initialize ZSTD stream\n" ); |
253 | retval = -ENOMEM; |
254 | goto out; |
255 | } |
256 | |
257 | do { |
258 | struct page *page = module_get_next_page(info); |
259 | |
260 | if (IS_ERR(page)) { |
261 | retval = PTR_ERR(page); |
262 | goto out; |
263 | } |
264 | |
265 | zstd_dec.dst = kmap_local_page(page); |
266 | zstd_dec.pos = 0; |
267 | zstd_dec.size = PAGE_SIZE; |
268 | |
269 | ret = zstd_decompress_stream(dstream, &zstd_dec, &zstd_buf); |
270 | kunmap_local(zstd_dec.dst); |
271 | retval = zstd_get_error_code(ret); |
272 | if (retval) |
273 | break; |
274 | |
275 | new_size += zstd_dec.pos; |
276 | } while (zstd_dec.pos == PAGE_SIZE && ret != 0); |
277 | |
278 | if (retval) { |
279 | pr_err("ZSTD-decompression failed with status %d\n" , retval); |
280 | retval = -EINVAL; |
281 | goto out; |
282 | } |
283 | |
284 | retval = new_size; |
285 | |
286 | out: |
287 | kvfree(wksp); |
288 | return retval; |
289 | } |
290 | #else |
291 | #error "Unexpected configuration for CONFIG_MODULE_DECOMPRESS" |
292 | #endif |
293 | |
294 | int module_decompress(struct load_info *info, const void *buf, size_t size) |
295 | { |
296 | unsigned int n_pages; |
297 | ssize_t data_size; |
298 | int error; |
299 | |
300 | #if defined(CONFIG_MODULE_STATS) |
301 | info->compressed_len = size; |
302 | #endif |
303 | |
304 | /* |
305 | * Start with number of pages twice as big as needed for |
306 | * compressed data. |
307 | */ |
308 | n_pages = DIV_ROUND_UP(size, PAGE_SIZE) * 2; |
309 | error = module_extend_max_pages(info, extent: n_pages); |
310 | |
311 | data_size = MODULE_DECOMPRESS_FN(info, buf, size); |
312 | if (data_size < 0) { |
313 | error = data_size; |
314 | goto err; |
315 | } |
316 | |
317 | info->hdr = vmap(pages: info->pages, count: info->used_pages, VM_MAP, PAGE_KERNEL); |
318 | if (!info->hdr) { |
319 | error = -ENOMEM; |
320 | goto err; |
321 | } |
322 | |
323 | info->len = data_size; |
324 | return 0; |
325 | |
326 | err: |
327 | module_decompress_cleanup(info); |
328 | return error; |
329 | } |
330 | |
331 | void module_decompress_cleanup(struct load_info *info) |
332 | { |
333 | int i; |
334 | |
335 | if (info->hdr) |
336 | vunmap(addr: info->hdr); |
337 | |
338 | for (i = 0; i < info->used_pages; i++) |
339 | __free_page(info->pages[i]); |
340 | |
341 | kvfree(addr: info->pages); |
342 | |
343 | info->pages = NULL; |
344 | info->max_pages = info->used_pages = 0; |
345 | } |
346 | |
347 | #ifdef CONFIG_SYSFS |
348 | static ssize_t compression_show(struct kobject *kobj, |
349 | struct kobj_attribute *attr, char *buf) |
350 | { |
351 | return sysfs_emit(buf, __stringify(MODULE_COMPRESSION) "\n" ); |
352 | } |
353 | |
354 | static struct kobj_attribute module_compression_attr = __ATTR_RO(compression); |
355 | |
356 | static int __init module_decompress_sysfs_init(void) |
357 | { |
358 | int error; |
359 | |
360 | error = sysfs_create_file(kobj: &module_kset->kobj, |
361 | attr: &module_compression_attr.attr); |
362 | if (error) |
363 | pr_warn("Failed to create 'compression' attribute" ); |
364 | |
365 | return 0; |
366 | } |
367 | late_initcall(module_decompress_sysfs_init); |
368 | #endif |
369 | |