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b1ae6dc4 DT |
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 | ||
cfc1d277 | 15 | #include "internal.h" |
b1ae6dc4 DT |
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(info->max_pages + extent, | |
22 | 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(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, 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(-ENOMEM); | |
48 | ||
49 | info->pages[info->used_pages++] = page; | |
50 | return page; | |
51 | } | |
52 | ||
53 | #ifdef 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 = kmalloc(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) { | |
285ac8dc | 109 | pr_err("failed to initialize decompressor: %d\n", rc); |
b1ae6dc4 DT |
110 | retval = -EINVAL; |
111 | goto out; | |
112 | } | |
113 | ||
114 | do { | |
115 | struct page *page = module_get_next_page(info); | |
5aff4dfd | 116 | |
45af1d7a ML |
117 | if (IS_ERR(page)) { |
118 | retval = PTR_ERR(page); | |
b1ae6dc4 DT |
119 | goto out_inflate_end; |
120 | } | |
121 | ||
554694ba | 122 | s.next_out = kmap_local_page(page); |
b1ae6dc4 DT |
123 | s.avail_out = PAGE_SIZE; |
124 | rc = zlib_inflate(&s, 0); | |
554694ba | 125 | kunmap_local(s.next_out); |
b1ae6dc4 DT |
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 | kfree(s.workspace); | |
142 | return retval; | |
143 | } | |
144 | #elif 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); | |
5aff4dfd | 175 | |
45af1d7a ML |
176 | if (IS_ERR(page)) { |
177 | retval = PTR_ERR(page); | |
b1ae6dc4 DT |
178 | goto out; |
179 | } | |
180 | ||
554694ba | 181 | xz_buf.out = kmap_local_page(page); |
b1ae6dc4 DT |
182 | xz_buf.out_pos = 0; |
183 | xz_buf.out_size = PAGE_SIZE; | |
184 | xz_ret = xz_dec_run(xz_dec, &xz_buf); | |
554694ba | 185 | kunmap_local(xz_buf.out); |
b1ae6dc4 DT |
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 | #else | |
203 | #error "Unexpected configuration for CONFIG_MODULE_DECOMPRESS" | |
204 | #endif | |
205 | ||
206 | int module_decompress(struct load_info *info, const void *buf, size_t size) | |
207 | { | |
208 | unsigned int n_pages; | |
209 | ssize_t data_size; | |
210 | int error; | |
211 | ||
212 | /* | |
213 | * Start with number of pages twice as big as needed for | |
214 | * compressed data. | |
215 | */ | |
216 | n_pages = DIV_ROUND_UP(size, PAGE_SIZE) * 2; | |
217 | error = module_extend_max_pages(info, n_pages); | |
218 | ||
219 | data_size = MODULE_DECOMPRESS_FN(info, buf, size); | |
220 | if (data_size < 0) { | |
221 | error = data_size; | |
222 | goto err; | |
223 | } | |
224 | ||
225 | info->hdr = vmap(info->pages, info->used_pages, VM_MAP, PAGE_KERNEL); | |
226 | if (!info->hdr) { | |
227 | error = -ENOMEM; | |
228 | goto err; | |
229 | } | |
230 | ||
231 | info->len = data_size; | |
232 | return 0; | |
233 | ||
234 | err: | |
235 | module_decompress_cleanup(info); | |
236 | return error; | |
237 | } | |
238 | ||
239 | void module_decompress_cleanup(struct load_info *info) | |
240 | { | |
241 | int i; | |
242 | ||
243 | if (info->hdr) | |
244 | vunmap(info->hdr); | |
245 | ||
246 | for (i = 0; i < info->used_pages; i++) | |
247 | __free_page(info->pages[i]); | |
248 | ||
249 | kvfree(info->pages); | |
250 | ||
251 | info->pages = NULL; | |
252 | info->max_pages = info->used_pages = 0; | |
253 | } | |
254 | ||
a8e8f851 | 255 | #ifdef CONFIG_SYSFS |
b1ae6dc4 DT |
256 | static ssize_t compression_show(struct kobject *kobj, |
257 | struct kobj_attribute *attr, char *buf) | |
258 | { | |
77d6354b | 259 | return sysfs_emit(buf, __stringify(MODULE_COMPRESSION) "\n"); |
b1ae6dc4 | 260 | } |
5aff4dfd | 261 | |
b1ae6dc4 DT |
262 | static struct kobj_attribute module_compression_attr = __ATTR_RO(compression); |
263 | ||
264 | static int __init module_decompress_sysfs_init(void) | |
265 | { | |
266 | int error; | |
267 | ||
268 | error = sysfs_create_file(&module_kset->kobj, | |
269 | &module_compression_attr.attr); | |
270 | if (error) | |
271 | pr_warn("Failed to create 'compression' attribute"); | |
272 | ||
273 | return 0; | |
274 | } | |
275 | late_initcall(module_decompress_sysfs_init); | |
a8e8f851 | 276 | #endif |