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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * fs/proc/kcore.c kernel ELF core dumper | |
3 | * | |
4 | * Modelled on fs/exec.c:aout_core_dump() | |
5 | * Jeremy Fitzhardinge <jeremy@sw.oz.au> | |
6 | * ELF version written by David Howells <David.Howells@nexor.co.uk> | |
7 | * Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com> | |
8 | * Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com> | |
9 | * Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com> | |
10 | */ | |
11 | ||
1da177e4 LT |
12 | #include <linux/mm.h> |
13 | #include <linux/proc_fs.h> | |
14 | #include <linux/user.h> | |
16f7e0fe | 15 | #include <linux/capability.h> |
1da177e4 LT |
16 | #include <linux/elf.h> |
17 | #include <linux/elfcore.h> | |
18 | #include <linux/vmalloc.h> | |
19 | #include <linux/highmem.h> | |
20 | #include <linux/init.h> | |
21 | #include <asm/uaccess.h> | |
22 | #include <asm/io.h> | |
2ef43ec7 | 23 | #include <linux/list.h> |
1da177e4 | 24 | |
36027604 | 25 | #define CORE_STR "CORE" |
1da177e4 | 26 | |
79885b22 EI |
27 | #ifndef ELF_CORE_EFLAGS |
28 | #define ELF_CORE_EFLAGS 0 | |
29 | #endif | |
30 | ||
97ce5d6d AD |
31 | static struct proc_dir_entry *proc_root_kcore; |
32 | ||
1da177e4 LT |
33 | static int open_kcore(struct inode * inode, struct file * filp) |
34 | { | |
35 | return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; | |
36 | } | |
37 | ||
38 | static ssize_t read_kcore(struct file *, char __user *, size_t, loff_t *); | |
39 | ||
97ce5d6d | 40 | static const struct file_operations proc_kcore_operations = { |
1da177e4 LT |
41 | .read = read_kcore, |
42 | .open = open_kcore, | |
43 | }; | |
44 | ||
45 | #ifndef kc_vaddr_to_offset | |
46 | #define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET) | |
47 | #endif | |
48 | #ifndef kc_offset_to_vaddr | |
49 | #define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET) | |
50 | #endif | |
51 | ||
1da177e4 LT |
52 | /* An ELF note in memory */ |
53 | struct memelfnote | |
54 | { | |
55 | const char *name; | |
56 | int type; | |
57 | unsigned int datasz; | |
58 | void *data; | |
59 | }; | |
60 | ||
2ef43ec7 | 61 | static LIST_HEAD(kclist_head); |
1da177e4 LT |
62 | static DEFINE_RWLOCK(kclist_lock); |
63 | ||
64 | void | |
c30bb2a2 | 65 | kclist_add(struct kcore_list *new, void *addr, size_t size, int type) |
1da177e4 LT |
66 | { |
67 | new->addr = (unsigned long)addr; | |
68 | new->size = size; | |
c30bb2a2 | 69 | new->type = type; |
1da177e4 LT |
70 | |
71 | write_lock(&kclist_lock); | |
2ef43ec7 | 72 | list_add_tail(&new->list, &kclist_head); |
1da177e4 LT |
73 | write_unlock(&kclist_lock); |
74 | } | |
75 | ||
76 | static size_t get_kcore_size(int *nphdr, size_t *elf_buflen) | |
77 | { | |
78 | size_t try, size; | |
79 | struct kcore_list *m; | |
80 | ||
81 | *nphdr = 1; /* PT_NOTE */ | |
82 | size = 0; | |
83 | ||
2ef43ec7 | 84 | list_for_each_entry(m, &kclist_head, list) { |
1da177e4 LT |
85 | try = kc_vaddr_to_offset((size_t)m->addr + m->size); |
86 | if (try > size) | |
87 | size = try; | |
88 | *nphdr = *nphdr + 1; | |
89 | } | |
90 | *elf_buflen = sizeof(struct elfhdr) + | |
91 | (*nphdr + 2)*sizeof(struct elf_phdr) + | |
36027604 MD |
92 | 3 * ((sizeof(struct elf_note)) + |
93 | roundup(sizeof(CORE_STR), 4)) + | |
94 | roundup(sizeof(struct elf_prstatus), 4) + | |
95 | roundup(sizeof(struct elf_prpsinfo), 4) + | |
96 | roundup(sizeof(struct task_struct), 4); | |
1da177e4 LT |
97 | *elf_buflen = PAGE_ALIGN(*elf_buflen); |
98 | return size + *elf_buflen; | |
99 | } | |
100 | ||
101 | ||
102 | /*****************************************************************************/ | |
103 | /* | |
104 | * determine size of ELF note | |
105 | */ | |
106 | static int notesize(struct memelfnote *en) | |
107 | { | |
108 | int sz; | |
109 | ||
110 | sz = sizeof(struct elf_note); | |
632dd205 | 111 | sz += roundup((strlen(en->name) + 1), 4); |
1da177e4 LT |
112 | sz += roundup(en->datasz, 4); |
113 | ||
114 | return sz; | |
115 | } /* end notesize() */ | |
116 | ||
117 | /*****************************************************************************/ | |
118 | /* | |
119 | * store a note in the header buffer | |
120 | */ | |
121 | static char *storenote(struct memelfnote *men, char *bufp) | |
122 | { | |
123 | struct elf_note en; | |
124 | ||
125 | #define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0) | |
126 | ||
632dd205 | 127 | en.n_namesz = strlen(men->name) + 1; |
1da177e4 LT |
128 | en.n_descsz = men->datasz; |
129 | en.n_type = men->type; | |
130 | ||
131 | DUMP_WRITE(&en, sizeof(en)); | |
132 | DUMP_WRITE(men->name, en.n_namesz); | |
133 | ||
134 | /* XXX - cast from long long to long to avoid need for libgcc.a */ | |
135 | bufp = (char*) roundup((unsigned long)bufp,4); | |
136 | DUMP_WRITE(men->data, men->datasz); | |
137 | bufp = (char*) roundup((unsigned long)bufp,4); | |
138 | ||
139 | #undef DUMP_WRITE | |
140 | ||
141 | return bufp; | |
142 | } /* end storenote() */ | |
143 | ||
144 | /* | |
145 | * store an ELF coredump header in the supplied buffer | |
146 | * nphdr is the number of elf_phdr to insert | |
147 | */ | |
148 | static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff) | |
149 | { | |
150 | struct elf_prstatus prstatus; /* NT_PRSTATUS */ | |
151 | struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */ | |
152 | struct elf_phdr *nhdr, *phdr; | |
153 | struct elfhdr *elf; | |
154 | struct memelfnote notes[3]; | |
155 | off_t offset = 0; | |
156 | struct kcore_list *m; | |
157 | ||
158 | /* setup ELF header */ | |
159 | elf = (struct elfhdr *) bufp; | |
160 | bufp += sizeof(struct elfhdr); | |
161 | offset += sizeof(struct elfhdr); | |
162 | memcpy(elf->e_ident, ELFMAG, SELFMAG); | |
163 | elf->e_ident[EI_CLASS] = ELF_CLASS; | |
164 | elf->e_ident[EI_DATA] = ELF_DATA; | |
165 | elf->e_ident[EI_VERSION]= EV_CURRENT; | |
166 | elf->e_ident[EI_OSABI] = ELF_OSABI; | |
167 | memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD); | |
168 | elf->e_type = ET_CORE; | |
169 | elf->e_machine = ELF_ARCH; | |
170 | elf->e_version = EV_CURRENT; | |
171 | elf->e_entry = 0; | |
172 | elf->e_phoff = sizeof(struct elfhdr); | |
173 | elf->e_shoff = 0; | |
79885b22 | 174 | elf->e_flags = ELF_CORE_EFLAGS; |
1da177e4 LT |
175 | elf->e_ehsize = sizeof(struct elfhdr); |
176 | elf->e_phentsize= sizeof(struct elf_phdr); | |
177 | elf->e_phnum = nphdr; | |
178 | elf->e_shentsize= 0; | |
179 | elf->e_shnum = 0; | |
180 | elf->e_shstrndx = 0; | |
181 | ||
182 | /* setup ELF PT_NOTE program header */ | |
183 | nhdr = (struct elf_phdr *) bufp; | |
184 | bufp += sizeof(struct elf_phdr); | |
185 | offset += sizeof(struct elf_phdr); | |
186 | nhdr->p_type = PT_NOTE; | |
187 | nhdr->p_offset = 0; | |
188 | nhdr->p_vaddr = 0; | |
189 | nhdr->p_paddr = 0; | |
190 | nhdr->p_filesz = 0; | |
191 | nhdr->p_memsz = 0; | |
192 | nhdr->p_flags = 0; | |
193 | nhdr->p_align = 0; | |
194 | ||
195 | /* setup ELF PT_LOAD program header for every area */ | |
2ef43ec7 | 196 | list_for_each_entry(m, &kclist_head, list) { |
1da177e4 LT |
197 | phdr = (struct elf_phdr *) bufp; |
198 | bufp += sizeof(struct elf_phdr); | |
199 | offset += sizeof(struct elf_phdr); | |
200 | ||
201 | phdr->p_type = PT_LOAD; | |
202 | phdr->p_flags = PF_R|PF_W|PF_X; | |
203 | phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff; | |
204 | phdr->p_vaddr = (size_t)m->addr; | |
205 | phdr->p_paddr = 0; | |
206 | phdr->p_filesz = phdr->p_memsz = m->size; | |
207 | phdr->p_align = PAGE_SIZE; | |
208 | } | |
209 | ||
210 | /* | |
211 | * Set up the notes in similar form to SVR4 core dumps made | |
212 | * with info from their /proc. | |
213 | */ | |
214 | nhdr->p_offset = offset; | |
215 | ||
216 | /* set up the process status */ | |
36027604 | 217 | notes[0].name = CORE_STR; |
1da177e4 LT |
218 | notes[0].type = NT_PRSTATUS; |
219 | notes[0].datasz = sizeof(struct elf_prstatus); | |
220 | notes[0].data = &prstatus; | |
221 | ||
222 | memset(&prstatus, 0, sizeof(struct elf_prstatus)); | |
223 | ||
224 | nhdr->p_filesz = notesize(¬es[0]); | |
225 | bufp = storenote(¬es[0], bufp); | |
226 | ||
227 | /* set up the process info */ | |
36027604 | 228 | notes[1].name = CORE_STR; |
1da177e4 LT |
229 | notes[1].type = NT_PRPSINFO; |
230 | notes[1].datasz = sizeof(struct elf_prpsinfo); | |
231 | notes[1].data = &prpsinfo; | |
232 | ||
233 | memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo)); | |
234 | prpsinfo.pr_state = 0; | |
235 | prpsinfo.pr_sname = 'R'; | |
236 | prpsinfo.pr_zomb = 0; | |
237 | ||
238 | strcpy(prpsinfo.pr_fname, "vmlinux"); | |
239 | strncpy(prpsinfo.pr_psargs, saved_command_line, ELF_PRARGSZ); | |
240 | ||
241 | nhdr->p_filesz += notesize(¬es[1]); | |
242 | bufp = storenote(¬es[1], bufp); | |
243 | ||
244 | /* set up the task structure */ | |
36027604 | 245 | notes[2].name = CORE_STR; |
1da177e4 LT |
246 | notes[2].type = NT_TASKSTRUCT; |
247 | notes[2].datasz = sizeof(struct task_struct); | |
248 | notes[2].data = current; | |
249 | ||
250 | nhdr->p_filesz += notesize(¬es[2]); | |
251 | bufp = storenote(¬es[2], bufp); | |
252 | ||
253 | } /* end elf_kcore_store_hdr() */ | |
254 | ||
255 | /*****************************************************************************/ | |
256 | /* | |
257 | * read from the ELF header and then kernel memory | |
258 | */ | |
259 | static ssize_t | |
260 | read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) | |
261 | { | |
262 | ssize_t acc = 0; | |
263 | size_t size, tsz; | |
264 | size_t elf_buflen; | |
265 | int nphdr; | |
266 | unsigned long start; | |
267 | ||
268 | read_lock(&kclist_lock); | |
269 | proc_root_kcore->size = size = get_kcore_size(&nphdr, &elf_buflen); | |
270 | if (buflen == 0 || *fpos >= size) { | |
271 | read_unlock(&kclist_lock); | |
272 | return 0; | |
273 | } | |
274 | ||
275 | /* trim buflen to not go beyond EOF */ | |
276 | if (buflen > size - *fpos) | |
277 | buflen = size - *fpos; | |
278 | ||
279 | /* construct an ELF core header if we'll need some of it */ | |
280 | if (*fpos < elf_buflen) { | |
281 | char * elf_buf; | |
282 | ||
283 | tsz = elf_buflen - *fpos; | |
284 | if (buflen < tsz) | |
285 | tsz = buflen; | |
f8314dc6 | 286 | elf_buf = kzalloc(elf_buflen, GFP_ATOMIC); |
1da177e4 LT |
287 | if (!elf_buf) { |
288 | read_unlock(&kclist_lock); | |
289 | return -ENOMEM; | |
290 | } | |
1da177e4 LT |
291 | elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen); |
292 | read_unlock(&kclist_lock); | |
293 | if (copy_to_user(buffer, elf_buf + *fpos, tsz)) { | |
294 | kfree(elf_buf); | |
295 | return -EFAULT; | |
296 | } | |
297 | kfree(elf_buf); | |
298 | buflen -= tsz; | |
299 | *fpos += tsz; | |
300 | buffer += tsz; | |
301 | acc += tsz; | |
302 | ||
303 | /* leave now if filled buffer already */ | |
304 | if (buflen == 0) | |
305 | return acc; | |
306 | } else | |
307 | read_unlock(&kclist_lock); | |
308 | ||
309 | /* | |
310 | * Check to see if our file offset matches with any of | |
311 | * the addresses in the elf_phdr on our list. | |
312 | */ | |
313 | start = kc_offset_to_vaddr(*fpos - elf_buflen); | |
314 | if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen) | |
315 | tsz = buflen; | |
316 | ||
317 | while (buflen) { | |
318 | struct kcore_list *m; | |
319 | ||
320 | read_lock(&kclist_lock); | |
2ef43ec7 | 321 | list_for_each_entry(m, &kclist_head, list) { |
1da177e4 LT |
322 | if (start >= m->addr && start < (m->addr+m->size)) |
323 | break; | |
324 | } | |
325 | read_unlock(&kclist_lock); | |
326 | ||
327 | if (m == NULL) { | |
328 | if (clear_user(buffer, tsz)) | |
329 | return -EFAULT; | |
9e2779fa | 330 | } else if (is_vmalloc_addr((void *)start)) { |
1da177e4 | 331 | char * elf_buf; |
1da177e4 | 332 | |
f8314dc6 | 333 | elf_buf = kzalloc(tsz, GFP_KERNEL); |
1da177e4 LT |
334 | if (!elf_buf) |
335 | return -ENOMEM; | |
73d7c33e KH |
336 | vread(elf_buf, (char *)start, tsz); |
337 | /* we have to zero-fill user buffer even if no read */ | |
1da177e4 LT |
338 | if (copy_to_user(buffer, elf_buf, tsz)) { |
339 | kfree(elf_buf); | |
340 | return -EFAULT; | |
341 | } | |
342 | kfree(elf_buf); | |
343 | } else { | |
344 | if (kern_addr_valid(start)) { | |
345 | unsigned long n; | |
346 | ||
347 | n = copy_to_user(buffer, (char *)start, tsz); | |
348 | /* | |
349 | * We cannot distingush between fault on source | |
350 | * and fault on destination. When this happens | |
351 | * we clear too and hope it will trigger the | |
352 | * EFAULT again. | |
353 | */ | |
354 | if (n) { | |
355 | if (clear_user(buffer + tsz - n, | |
0635170b | 356 | n)) |
1da177e4 LT |
357 | return -EFAULT; |
358 | } | |
359 | } else { | |
360 | if (clear_user(buffer, tsz)) | |
361 | return -EFAULT; | |
362 | } | |
363 | } | |
364 | buflen -= tsz; | |
365 | *fpos += tsz; | |
366 | buffer += tsz; | |
367 | acc += tsz; | |
368 | start += tsz; | |
369 | tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen); | |
370 | } | |
371 | ||
372 | return acc; | |
373 | } | |
97ce5d6d | 374 | |
a0614da8 KH |
375 | static struct kcore_list kcore_vmalloc; |
376 | ||
97ce5d6d AD |
377 | static int __init proc_kcore_init(void) |
378 | { | |
379 | proc_root_kcore = proc_create("kcore", S_IRUSR, NULL, &proc_kcore_operations); | |
a0614da8 KH |
380 | |
381 | kclist_add(&kcore_vmalloc, (void *)VMALLOC_START, | |
382 | VMALLOC_END - VMALLOC_START, KCORE_VMALLOC); | |
97ce5d6d AD |
383 | return 0; |
384 | } | |
385 | module_init(proc_kcore_init); |