| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | #include <crypto/hash.h> |
| 3 | #include <linux/export.h> |
| 4 | #include <linux/bvec.h> |
| 5 | #include <linux/fault-inject-usercopy.h> |
| 6 | #include <linux/uio.h> |
| 7 | #include <linux/pagemap.h> |
| 8 | #include <linux/slab.h> |
| 9 | #include <linux/vmalloc.h> |
| 10 | #include <linux/splice.h> |
| 11 | #include <linux/compat.h> |
| 12 | #include <net/checksum.h> |
| 13 | #include <linux/scatterlist.h> |
| 14 | #include <linux/instrumented.h> |
| 15 | |
| 16 | #define PIPE_PARANOIA /* for now */ |
| 17 | |
| 18 | #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ |
| 19 | size_t left; \ |
| 20 | size_t wanted = n; \ |
| 21 | __p = i->iov; \ |
| 22 | __v.iov_len = min(n, __p->iov_len - skip); \ |
| 23 | if (likely(__v.iov_len)) { \ |
| 24 | __v.iov_base = __p->iov_base + skip; \ |
| 25 | left = (STEP); \ |
| 26 | __v.iov_len -= left; \ |
| 27 | skip += __v.iov_len; \ |
| 28 | n -= __v.iov_len; \ |
| 29 | } else { \ |
| 30 | left = 0; \ |
| 31 | } \ |
| 32 | while (unlikely(!left && n)) { \ |
| 33 | __p++; \ |
| 34 | __v.iov_len = min(n, __p->iov_len); \ |
| 35 | if (unlikely(!__v.iov_len)) \ |
| 36 | continue; \ |
| 37 | __v.iov_base = __p->iov_base; \ |
| 38 | left = (STEP); \ |
| 39 | __v.iov_len -= left; \ |
| 40 | skip = __v.iov_len; \ |
| 41 | n -= __v.iov_len; \ |
| 42 | } \ |
| 43 | n = wanted - n; \ |
| 44 | } |
| 45 | |
| 46 | #define iterate_kvec(i, n, __v, __p, skip, STEP) { \ |
| 47 | size_t wanted = n; \ |
| 48 | __p = i->kvec; \ |
| 49 | __v.iov_len = min(n, __p->iov_len - skip); \ |
| 50 | if (likely(__v.iov_len)) { \ |
| 51 | __v.iov_base = __p->iov_base + skip; \ |
| 52 | (void)(STEP); \ |
| 53 | skip += __v.iov_len; \ |
| 54 | n -= __v.iov_len; \ |
| 55 | } \ |
| 56 | while (unlikely(n)) { \ |
| 57 | __p++; \ |
| 58 | __v.iov_len = min(n, __p->iov_len); \ |
| 59 | if (unlikely(!__v.iov_len)) \ |
| 60 | continue; \ |
| 61 | __v.iov_base = __p->iov_base; \ |
| 62 | (void)(STEP); \ |
| 63 | skip = __v.iov_len; \ |
| 64 | n -= __v.iov_len; \ |
| 65 | } \ |
| 66 | n = wanted; \ |
| 67 | } |
| 68 | |
| 69 | #define iterate_bvec(i, n, __v, __bi, skip, STEP) { \ |
| 70 | struct bvec_iter __start; \ |
| 71 | __start.bi_size = n; \ |
| 72 | __start.bi_bvec_done = skip; \ |
| 73 | __start.bi_idx = 0; \ |
| 74 | for_each_bvec(__v, i->bvec, __bi, __start) { \ |
| 75 | (void)(STEP); \ |
| 76 | } \ |
| 77 | } |
| 78 | |
| 79 | #define iterate_all_kinds(i, n, v, I, B, K) { \ |
| 80 | if (likely(n)) { \ |
| 81 | size_t skip = i->iov_offset; \ |
| 82 | if (unlikely(i->type & ITER_BVEC)) { \ |
| 83 | struct bio_vec v; \ |
| 84 | struct bvec_iter __bi; \ |
| 85 | iterate_bvec(i, n, v, __bi, skip, (B)) \ |
| 86 | } else if (unlikely(i->type & ITER_KVEC)) { \ |
| 87 | const struct kvec *kvec; \ |
| 88 | struct kvec v; \ |
| 89 | iterate_kvec(i, n, v, kvec, skip, (K)) \ |
| 90 | } else if (unlikely(i->type & ITER_DISCARD)) { \ |
| 91 | } else { \ |
| 92 | const struct iovec *iov; \ |
| 93 | struct iovec v; \ |
| 94 | iterate_iovec(i, n, v, iov, skip, (I)) \ |
| 95 | } \ |
| 96 | } \ |
| 97 | } |
| 98 | |
| 99 | #define iterate_and_advance(i, n, v, I, B, K) { \ |
| 100 | if (unlikely(i->count < n)) \ |
| 101 | n = i->count; \ |
| 102 | if (i->count) { \ |
| 103 | size_t skip = i->iov_offset; \ |
| 104 | if (unlikely(i->type & ITER_BVEC)) { \ |
| 105 | const struct bio_vec *bvec = i->bvec; \ |
| 106 | struct bio_vec v; \ |
| 107 | struct bvec_iter __bi; \ |
| 108 | iterate_bvec(i, n, v, __bi, skip, (B)) \ |
| 109 | i->bvec = __bvec_iter_bvec(i->bvec, __bi); \ |
| 110 | i->nr_segs -= i->bvec - bvec; \ |
| 111 | skip = __bi.bi_bvec_done; \ |
| 112 | } else if (unlikely(i->type & ITER_KVEC)) { \ |
| 113 | const struct kvec *kvec; \ |
| 114 | struct kvec v; \ |
| 115 | iterate_kvec(i, n, v, kvec, skip, (K)) \ |
| 116 | if (skip == kvec->iov_len) { \ |
| 117 | kvec++; \ |
| 118 | skip = 0; \ |
| 119 | } \ |
| 120 | i->nr_segs -= kvec - i->kvec; \ |
| 121 | i->kvec = kvec; \ |
| 122 | } else if (unlikely(i->type & ITER_DISCARD)) { \ |
| 123 | skip += n; \ |
| 124 | } else { \ |
| 125 | const struct iovec *iov; \ |
| 126 | struct iovec v; \ |
| 127 | iterate_iovec(i, n, v, iov, skip, (I)) \ |
| 128 | if (skip == iov->iov_len) { \ |
| 129 | iov++; \ |
| 130 | skip = 0; \ |
| 131 | } \ |
| 132 | i->nr_segs -= iov - i->iov; \ |
| 133 | i->iov = iov; \ |
| 134 | } \ |
| 135 | i->count -= n; \ |
| 136 | i->iov_offset = skip; \ |
| 137 | } \ |
| 138 | } |
| 139 | |
| 140 | static int copyout(void __user *to, const void *from, size_t n) |
| 141 | { |
| 142 | if (should_fail_usercopy()) |
| 143 | return n; |
| 144 | if (access_ok(to, n)) { |
| 145 | instrument_copy_to_user(to, from, n); |
| 146 | n = raw_copy_to_user(to, from, n); |
| 147 | } |
| 148 | return n; |
| 149 | } |
| 150 | |
| 151 | static int copyin(void *to, const void __user *from, size_t n) |
| 152 | { |
| 153 | if (should_fail_usercopy()) |
| 154 | return n; |
| 155 | if (access_ok(from, n)) { |
| 156 | instrument_copy_from_user(to, from, n); |
| 157 | n = raw_copy_from_user(to, from, n); |
| 158 | } |
| 159 | return n; |
| 160 | } |
| 161 | |
| 162 | static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, |
| 163 | struct iov_iter *i) |
| 164 | { |
| 165 | size_t skip, copy, left, wanted; |
| 166 | const struct iovec *iov; |
| 167 | char __user *buf; |
| 168 | void *kaddr, *from; |
| 169 | |
| 170 | if (unlikely(bytes > i->count)) |
| 171 | bytes = i->count; |
| 172 | |
| 173 | if (unlikely(!bytes)) |
| 174 | return 0; |
| 175 | |
| 176 | might_fault(); |
| 177 | wanted = bytes; |
| 178 | iov = i->iov; |
| 179 | skip = i->iov_offset; |
| 180 | buf = iov->iov_base + skip; |
| 181 | copy = min(bytes, iov->iov_len - skip); |
| 182 | |
| 183 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) { |
| 184 | kaddr = kmap_atomic(page); |
| 185 | from = kaddr + offset; |
| 186 | |
| 187 | /* first chunk, usually the only one */ |
| 188 | left = copyout(buf, from, copy); |
| 189 | copy -= left; |
| 190 | skip += copy; |
| 191 | from += copy; |
| 192 | bytes -= copy; |
| 193 | |
| 194 | while (unlikely(!left && bytes)) { |
| 195 | iov++; |
| 196 | buf = iov->iov_base; |
| 197 | copy = min(bytes, iov->iov_len); |
| 198 | left = copyout(buf, from, copy); |
| 199 | copy -= left; |
| 200 | skip = copy; |
| 201 | from += copy; |
| 202 | bytes -= copy; |
| 203 | } |
| 204 | if (likely(!bytes)) { |
| 205 | kunmap_atomic(kaddr); |
| 206 | goto done; |
| 207 | } |
| 208 | offset = from - kaddr; |
| 209 | buf += copy; |
| 210 | kunmap_atomic(kaddr); |
| 211 | copy = min(bytes, iov->iov_len - skip); |
| 212 | } |
| 213 | /* Too bad - revert to non-atomic kmap */ |
| 214 | |
| 215 | kaddr = kmap(page); |
| 216 | from = kaddr + offset; |
| 217 | left = copyout(buf, from, copy); |
| 218 | copy -= left; |
| 219 | skip += copy; |
| 220 | from += copy; |
| 221 | bytes -= copy; |
| 222 | while (unlikely(!left && bytes)) { |
| 223 | iov++; |
| 224 | buf = iov->iov_base; |
| 225 | copy = min(bytes, iov->iov_len); |
| 226 | left = copyout(buf, from, copy); |
| 227 | copy -= left; |
| 228 | skip = copy; |
| 229 | from += copy; |
| 230 | bytes -= copy; |
| 231 | } |
| 232 | kunmap(page); |
| 233 | |
| 234 | done: |
| 235 | if (skip == iov->iov_len) { |
| 236 | iov++; |
| 237 | skip = 0; |
| 238 | } |
| 239 | i->count -= wanted - bytes; |
| 240 | i->nr_segs -= iov - i->iov; |
| 241 | i->iov = iov; |
| 242 | i->iov_offset = skip; |
| 243 | return wanted - bytes; |
| 244 | } |
| 245 | |
| 246 | static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes, |
| 247 | struct iov_iter *i) |
| 248 | { |
| 249 | size_t skip, copy, left, wanted; |
| 250 | const struct iovec *iov; |
| 251 | char __user *buf; |
| 252 | void *kaddr, *to; |
| 253 | |
| 254 | if (unlikely(bytes > i->count)) |
| 255 | bytes = i->count; |
| 256 | |
| 257 | if (unlikely(!bytes)) |
| 258 | return 0; |
| 259 | |
| 260 | might_fault(); |
| 261 | wanted = bytes; |
| 262 | iov = i->iov; |
| 263 | skip = i->iov_offset; |
| 264 | buf = iov->iov_base + skip; |
| 265 | copy = min(bytes, iov->iov_len - skip); |
| 266 | |
| 267 | if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) { |
| 268 | kaddr = kmap_atomic(page); |
| 269 | to = kaddr + offset; |
| 270 | |
| 271 | /* first chunk, usually the only one */ |
| 272 | left = copyin(to, buf, copy); |
| 273 | copy -= left; |
| 274 | skip += copy; |
| 275 | to += copy; |
| 276 | bytes -= copy; |
| 277 | |
| 278 | while (unlikely(!left && bytes)) { |
| 279 | iov++; |
| 280 | buf = iov->iov_base; |
| 281 | copy = min(bytes, iov->iov_len); |
| 282 | left = copyin(to, buf, copy); |
| 283 | copy -= left; |
| 284 | skip = copy; |
| 285 | to += copy; |
| 286 | bytes -= copy; |
| 287 | } |
| 288 | if (likely(!bytes)) { |
| 289 | kunmap_atomic(kaddr); |
| 290 | goto done; |
| 291 | } |
| 292 | offset = to - kaddr; |
| 293 | buf += copy; |
| 294 | kunmap_atomic(kaddr); |
| 295 | copy = min(bytes, iov->iov_len - skip); |
| 296 | } |
| 297 | /* Too bad - revert to non-atomic kmap */ |
| 298 | |
| 299 | kaddr = kmap(page); |
| 300 | to = kaddr + offset; |
| 301 | left = copyin(to, buf, copy); |
| 302 | copy -= left; |
| 303 | skip += copy; |
| 304 | to += copy; |
| 305 | bytes -= copy; |
| 306 | while (unlikely(!left && bytes)) { |
| 307 | iov++; |
| 308 | buf = iov->iov_base; |
| 309 | copy = min(bytes, iov->iov_len); |
| 310 | left = copyin(to, buf, copy); |
| 311 | copy -= left; |
| 312 | skip = copy; |
| 313 | to += copy; |
| 314 | bytes -= copy; |
| 315 | } |
| 316 | kunmap(page); |
| 317 | |
| 318 | done: |
| 319 | if (skip == iov->iov_len) { |
| 320 | iov++; |
| 321 | skip = 0; |
| 322 | } |
| 323 | i->count -= wanted - bytes; |
| 324 | i->nr_segs -= iov - i->iov; |
| 325 | i->iov = iov; |
| 326 | i->iov_offset = skip; |
| 327 | return wanted - bytes; |
| 328 | } |
| 329 | |
| 330 | #ifdef PIPE_PARANOIA |
| 331 | static bool sanity(const struct iov_iter *i) |
| 332 | { |
| 333 | struct pipe_inode_info *pipe = i->pipe; |
| 334 | unsigned int p_head = pipe->head; |
| 335 | unsigned int p_tail = pipe->tail; |
| 336 | unsigned int p_mask = pipe->ring_size - 1; |
| 337 | unsigned int p_occupancy = pipe_occupancy(p_head, p_tail); |
| 338 | unsigned int i_head = i->head; |
| 339 | unsigned int idx; |
| 340 | |
| 341 | if (i->iov_offset) { |
| 342 | struct pipe_buffer *p; |
| 343 | if (unlikely(p_occupancy == 0)) |
| 344 | goto Bad; // pipe must be non-empty |
| 345 | if (unlikely(i_head != p_head - 1)) |
| 346 | goto Bad; // must be at the last buffer... |
| 347 | |
| 348 | p = &pipe->bufs[i_head & p_mask]; |
| 349 | if (unlikely(p->offset + p->len != i->iov_offset)) |
| 350 | goto Bad; // ... at the end of segment |
| 351 | } else { |
| 352 | if (i_head != p_head) |
| 353 | goto Bad; // must be right after the last buffer |
| 354 | } |
| 355 | return true; |
| 356 | Bad: |
| 357 | printk(KERN_ERR "idx = %d, offset = %zd\n", i_head, i->iov_offset); |
| 358 | printk(KERN_ERR "head = %d, tail = %d, buffers = %d\n", |
| 359 | p_head, p_tail, pipe->ring_size); |
| 360 | for (idx = 0; idx < pipe->ring_size; idx++) |
| 361 | printk(KERN_ERR "[%p %p %d %d]\n", |
| 362 | pipe->bufs[idx].ops, |
| 363 | pipe->bufs[idx].page, |
| 364 | pipe->bufs[idx].offset, |
| 365 | pipe->bufs[idx].len); |
| 366 | WARN_ON(1); |
| 367 | return false; |
| 368 | } |
| 369 | #else |
| 370 | #define sanity(i) true |
| 371 | #endif |
| 372 | |
| 373 | static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes, |
| 374 | struct iov_iter *i) |
| 375 | { |
| 376 | struct pipe_inode_info *pipe = i->pipe; |
| 377 | struct pipe_buffer *buf; |
| 378 | unsigned int p_tail = pipe->tail; |
| 379 | unsigned int p_mask = pipe->ring_size - 1; |
| 380 | unsigned int i_head = i->head; |
| 381 | size_t off; |
| 382 | |
| 383 | if (unlikely(bytes > i->count)) |
| 384 | bytes = i->count; |
| 385 | |
| 386 | if (unlikely(!bytes)) |
| 387 | return 0; |
| 388 | |
| 389 | if (!sanity(i)) |
| 390 | return 0; |
| 391 | |
| 392 | off = i->iov_offset; |
| 393 | buf = &pipe->bufs[i_head & p_mask]; |
| 394 | if (off) { |
| 395 | if (offset == off && buf->page == page) { |
| 396 | /* merge with the last one */ |
| 397 | buf->len += bytes; |
| 398 | i->iov_offset += bytes; |
| 399 | goto out; |
| 400 | } |
| 401 | i_head++; |
| 402 | buf = &pipe->bufs[i_head & p_mask]; |
| 403 | } |
| 404 | if (pipe_full(i_head, p_tail, pipe->max_usage)) |
| 405 | return 0; |
| 406 | |
| 407 | buf->ops = &page_cache_pipe_buf_ops; |
| 408 | get_page(page); |
| 409 | buf->page = page; |
| 410 | buf->offset = offset; |
| 411 | buf->len = bytes; |
| 412 | |
| 413 | pipe->head = i_head + 1; |
| 414 | i->iov_offset = offset + bytes; |
| 415 | i->head = i_head; |
| 416 | out: |
| 417 | i->count -= bytes; |
| 418 | return bytes; |
| 419 | } |
| 420 | |
| 421 | /* |
| 422 | * Fault in one or more iovecs of the given iov_iter, to a maximum length of |
| 423 | * bytes. For each iovec, fault in each page that constitutes the iovec. |
| 424 | * |
| 425 | * Return 0 on success, or non-zero if the memory could not be accessed (i.e. |
| 426 | * because it is an invalid address). |
| 427 | */ |
| 428 | int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) |
| 429 | { |
| 430 | size_t skip = i->iov_offset; |
| 431 | const struct iovec *iov; |
| 432 | int err; |
| 433 | struct iovec v; |
| 434 | |
| 435 | if (!(i->type & (ITER_BVEC|ITER_KVEC))) { |
| 436 | iterate_iovec(i, bytes, v, iov, skip, ({ |
| 437 | err = fault_in_pages_readable(v.iov_base, v.iov_len); |
| 438 | if (unlikely(err)) |
| 439 | return err; |
| 440 | 0;})) |
| 441 | } |
| 442 | return 0; |
| 443 | } |
| 444 | EXPORT_SYMBOL(iov_iter_fault_in_readable); |
| 445 | |
| 446 | void iov_iter_init(struct iov_iter *i, unsigned int direction, |
| 447 | const struct iovec *iov, unsigned long nr_segs, |
| 448 | size_t count) |
| 449 | { |
| 450 | WARN_ON(direction & ~(READ | WRITE)); |
| 451 | direction &= READ | WRITE; |
| 452 | |
| 453 | /* It will get better. Eventually... */ |
| 454 | if (uaccess_kernel()) { |
| 455 | i->type = ITER_KVEC | direction; |
| 456 | i->kvec = (struct kvec *)iov; |
| 457 | } else { |
| 458 | i->type = ITER_IOVEC | direction; |
| 459 | i->iov = iov; |
| 460 | } |
| 461 | i->nr_segs = nr_segs; |
| 462 | i->iov_offset = 0; |
| 463 | i->count = count; |
| 464 | } |
| 465 | EXPORT_SYMBOL(iov_iter_init); |
| 466 | |
| 467 | static void memzero_page(struct page *page, size_t offset, size_t len) |
| 468 | { |
| 469 | char *addr = kmap_atomic(page); |
| 470 | memset(addr + offset, 0, len); |
| 471 | kunmap_atomic(addr); |
| 472 | } |
| 473 | |
| 474 | static inline bool allocated(struct pipe_buffer *buf) |
| 475 | { |
| 476 | return buf->ops == &default_pipe_buf_ops; |
| 477 | } |
| 478 | |
| 479 | static inline void data_start(const struct iov_iter *i, |
| 480 | unsigned int *iter_headp, size_t *offp) |
| 481 | { |
| 482 | unsigned int p_mask = i->pipe->ring_size - 1; |
| 483 | unsigned int iter_head = i->head; |
| 484 | size_t off = i->iov_offset; |
| 485 | |
| 486 | if (off && (!allocated(&i->pipe->bufs[iter_head & p_mask]) || |
| 487 | off == PAGE_SIZE)) { |
| 488 | iter_head++; |
| 489 | off = 0; |
| 490 | } |
| 491 | *iter_headp = iter_head; |
| 492 | *offp = off; |
| 493 | } |
| 494 | |
| 495 | static size_t push_pipe(struct iov_iter *i, size_t size, |
| 496 | int *iter_headp, size_t *offp) |
| 497 | { |
| 498 | struct pipe_inode_info *pipe = i->pipe; |
| 499 | unsigned int p_tail = pipe->tail; |
| 500 | unsigned int p_mask = pipe->ring_size - 1; |
| 501 | unsigned int iter_head; |
| 502 | size_t off; |
| 503 | ssize_t left; |
| 504 | |
| 505 | if (unlikely(size > i->count)) |
| 506 | size = i->count; |
| 507 | if (unlikely(!size)) |
| 508 | return 0; |
| 509 | |
| 510 | left = size; |
| 511 | data_start(i, &iter_head, &off); |
| 512 | *iter_headp = iter_head; |
| 513 | *offp = off; |
| 514 | if (off) { |
| 515 | left -= PAGE_SIZE - off; |
| 516 | if (left <= 0) { |
| 517 | pipe->bufs[iter_head & p_mask].len += size; |
| 518 | return size; |
| 519 | } |
| 520 | pipe->bufs[iter_head & p_mask].len = PAGE_SIZE; |
| 521 | iter_head++; |
| 522 | } |
| 523 | while (!pipe_full(iter_head, p_tail, pipe->max_usage)) { |
| 524 | struct pipe_buffer *buf = &pipe->bufs[iter_head & p_mask]; |
| 525 | struct page *page = alloc_page(GFP_USER); |
| 526 | if (!page) |
| 527 | break; |
| 528 | |
| 529 | buf->ops = &default_pipe_buf_ops; |
| 530 | buf->page = page; |
| 531 | buf->offset = 0; |
| 532 | buf->len = min_t(ssize_t, left, PAGE_SIZE); |
| 533 | left -= buf->len; |
| 534 | iter_head++; |
| 535 | pipe->head = iter_head; |
| 536 | |
| 537 | if (left == 0) |
| 538 | return size; |
| 539 | } |
| 540 | return size - left; |
| 541 | } |
| 542 | |
| 543 | static size_t copy_pipe_to_iter(const void *addr, size_t bytes, |
| 544 | struct iov_iter *i) |
| 545 | { |
| 546 | struct pipe_inode_info *pipe = i->pipe; |
| 547 | unsigned int p_mask = pipe->ring_size - 1; |
| 548 | unsigned int i_head; |
| 549 | size_t n, off; |
| 550 | |
| 551 | if (!sanity(i)) |
| 552 | return 0; |
| 553 | |
| 554 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
| 555 | if (unlikely(!n)) |
| 556 | return 0; |
| 557 | do { |
| 558 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
| 559 | memcpy_to_page(pipe->bufs[i_head & p_mask].page, off, addr, chunk); |
| 560 | i->head = i_head; |
| 561 | i->iov_offset = off + chunk; |
| 562 | n -= chunk; |
| 563 | addr += chunk; |
| 564 | off = 0; |
| 565 | i_head++; |
| 566 | } while (n); |
| 567 | i->count -= bytes; |
| 568 | return bytes; |
| 569 | } |
| 570 | |
| 571 | static __wsum csum_and_memcpy(void *to, const void *from, size_t len, |
| 572 | __wsum sum, size_t off) |
| 573 | { |
| 574 | __wsum next = csum_partial_copy_nocheck(from, to, len); |
| 575 | return csum_block_add(sum, next, off); |
| 576 | } |
| 577 | |
| 578 | static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes, |
| 579 | struct csum_state *csstate, |
| 580 | struct iov_iter *i) |
| 581 | { |
| 582 | struct pipe_inode_info *pipe = i->pipe; |
| 583 | unsigned int p_mask = pipe->ring_size - 1; |
| 584 | __wsum sum = csstate->csum; |
| 585 | size_t off = csstate->off; |
| 586 | unsigned int i_head; |
| 587 | size_t n, r; |
| 588 | |
| 589 | if (!sanity(i)) |
| 590 | return 0; |
| 591 | |
| 592 | bytes = n = push_pipe(i, bytes, &i_head, &r); |
| 593 | if (unlikely(!n)) |
| 594 | return 0; |
| 595 | do { |
| 596 | size_t chunk = min_t(size_t, n, PAGE_SIZE - r); |
| 597 | char *p = kmap_atomic(pipe->bufs[i_head & p_mask].page); |
| 598 | sum = csum_and_memcpy(p + r, addr, chunk, sum, off); |
| 599 | kunmap_atomic(p); |
| 600 | i->head = i_head; |
| 601 | i->iov_offset = r + chunk; |
| 602 | n -= chunk; |
| 603 | off += chunk; |
| 604 | addr += chunk; |
| 605 | r = 0; |
| 606 | i_head++; |
| 607 | } while (n); |
| 608 | i->count -= bytes; |
| 609 | csstate->csum = sum; |
| 610 | csstate->off = off; |
| 611 | return bytes; |
| 612 | } |
| 613 | |
| 614 | size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
| 615 | { |
| 616 | const char *from = addr; |
| 617 | if (unlikely(iov_iter_is_pipe(i))) |
| 618 | return copy_pipe_to_iter(addr, bytes, i); |
| 619 | if (iter_is_iovec(i)) |
| 620 | might_fault(); |
| 621 | iterate_and_advance(i, bytes, v, |
| 622 | copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), |
| 623 | memcpy_to_page(v.bv_page, v.bv_offset, |
| 624 | (from += v.bv_len) - v.bv_len, v.bv_len), |
| 625 | memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len) |
| 626 | ) |
| 627 | |
| 628 | return bytes; |
| 629 | } |
| 630 | EXPORT_SYMBOL(_copy_to_iter); |
| 631 | |
| 632 | #ifdef CONFIG_ARCH_HAS_COPY_MC |
| 633 | static int copyout_mc(void __user *to, const void *from, size_t n) |
| 634 | { |
| 635 | if (access_ok(to, n)) { |
| 636 | instrument_copy_to_user(to, from, n); |
| 637 | n = copy_mc_to_user((__force void *) to, from, n); |
| 638 | } |
| 639 | return n; |
| 640 | } |
| 641 | |
| 642 | static unsigned long copy_mc_to_page(struct page *page, size_t offset, |
| 643 | const char *from, size_t len) |
| 644 | { |
| 645 | unsigned long ret; |
| 646 | char *to; |
| 647 | |
| 648 | to = kmap_atomic(page); |
| 649 | ret = copy_mc_to_kernel(to + offset, from, len); |
| 650 | kunmap_atomic(to); |
| 651 | |
| 652 | return ret; |
| 653 | } |
| 654 | |
| 655 | static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes, |
| 656 | struct iov_iter *i) |
| 657 | { |
| 658 | struct pipe_inode_info *pipe = i->pipe; |
| 659 | unsigned int p_mask = pipe->ring_size - 1; |
| 660 | unsigned int i_head; |
| 661 | size_t n, off, xfer = 0; |
| 662 | |
| 663 | if (!sanity(i)) |
| 664 | return 0; |
| 665 | |
| 666 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
| 667 | if (unlikely(!n)) |
| 668 | return 0; |
| 669 | do { |
| 670 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
| 671 | unsigned long rem; |
| 672 | |
| 673 | rem = copy_mc_to_page(pipe->bufs[i_head & p_mask].page, |
| 674 | off, addr, chunk); |
| 675 | i->head = i_head; |
| 676 | i->iov_offset = off + chunk - rem; |
| 677 | xfer += chunk - rem; |
| 678 | if (rem) |
| 679 | break; |
| 680 | n -= chunk; |
| 681 | addr += chunk; |
| 682 | off = 0; |
| 683 | i_head++; |
| 684 | } while (n); |
| 685 | i->count -= xfer; |
| 686 | return xfer; |
| 687 | } |
| 688 | |
| 689 | /** |
| 690 | * _copy_mc_to_iter - copy to iter with source memory error exception handling |
| 691 | * @addr: source kernel address |
| 692 | * @bytes: total transfer length |
| 693 | * @iter: destination iterator |
| 694 | * |
| 695 | * The pmem driver deploys this for the dax operation |
| 696 | * (dax_copy_to_iter()) for dax reads (bypass page-cache and the |
| 697 | * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes |
| 698 | * successfully copied. |
| 699 | * |
| 700 | * The main differences between this and typical _copy_to_iter(). |
| 701 | * |
| 702 | * * Typical tail/residue handling after a fault retries the copy |
| 703 | * byte-by-byte until the fault happens again. Re-triggering machine |
| 704 | * checks is potentially fatal so the implementation uses source |
| 705 | * alignment and poison alignment assumptions to avoid re-triggering |
| 706 | * hardware exceptions. |
| 707 | * |
| 708 | * * ITER_KVEC, ITER_PIPE, and ITER_BVEC can return short copies. |
| 709 | * Compare to copy_to_iter() where only ITER_IOVEC attempts might return |
| 710 | * a short copy. |
| 711 | */ |
| 712 | size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) |
| 713 | { |
| 714 | const char *from = addr; |
| 715 | unsigned long rem, curr_addr, s_addr = (unsigned long) addr; |
| 716 | |
| 717 | if (unlikely(iov_iter_is_pipe(i))) |
| 718 | return copy_mc_pipe_to_iter(addr, bytes, i); |
| 719 | if (iter_is_iovec(i)) |
| 720 | might_fault(); |
| 721 | iterate_and_advance(i, bytes, v, |
| 722 | copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len, |
| 723 | v.iov_len), |
| 724 | ({ |
| 725 | rem = copy_mc_to_page(v.bv_page, v.bv_offset, |
| 726 | (from += v.bv_len) - v.bv_len, v.bv_len); |
| 727 | if (rem) { |
| 728 | curr_addr = (unsigned long) from; |
| 729 | bytes = curr_addr - s_addr - rem; |
| 730 | return bytes; |
| 731 | } |
| 732 | }), |
| 733 | ({ |
| 734 | rem = copy_mc_to_kernel(v.iov_base, (from += v.iov_len) |
| 735 | - v.iov_len, v.iov_len); |
| 736 | if (rem) { |
| 737 | curr_addr = (unsigned long) from; |
| 738 | bytes = curr_addr - s_addr - rem; |
| 739 | return bytes; |
| 740 | } |
| 741 | }) |
| 742 | ) |
| 743 | |
| 744 | return bytes; |
| 745 | } |
| 746 | EXPORT_SYMBOL_GPL(_copy_mc_to_iter); |
| 747 | #endif /* CONFIG_ARCH_HAS_COPY_MC */ |
| 748 | |
| 749 | size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) |
| 750 | { |
| 751 | char *to = addr; |
| 752 | if (unlikely(iov_iter_is_pipe(i))) { |
| 753 | WARN_ON(1); |
| 754 | return 0; |
| 755 | } |
| 756 | if (iter_is_iovec(i)) |
| 757 | might_fault(); |
| 758 | iterate_and_advance(i, bytes, v, |
| 759 | copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
| 760 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, |
| 761 | v.bv_offset, v.bv_len), |
| 762 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) |
| 763 | ) |
| 764 | |
| 765 | return bytes; |
| 766 | } |
| 767 | EXPORT_SYMBOL(_copy_from_iter); |
| 768 | |
| 769 | bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i) |
| 770 | { |
| 771 | char *to = addr; |
| 772 | if (unlikely(iov_iter_is_pipe(i))) { |
| 773 | WARN_ON(1); |
| 774 | return false; |
| 775 | } |
| 776 | if (unlikely(i->count < bytes)) |
| 777 | return false; |
| 778 | |
| 779 | if (iter_is_iovec(i)) |
| 780 | might_fault(); |
| 781 | iterate_all_kinds(i, bytes, v, ({ |
| 782 | if (copyin((to += v.iov_len) - v.iov_len, |
| 783 | v.iov_base, v.iov_len)) |
| 784 | return false; |
| 785 | 0;}), |
| 786 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, |
| 787 | v.bv_offset, v.bv_len), |
| 788 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) |
| 789 | ) |
| 790 | |
| 791 | iov_iter_advance(i, bytes); |
| 792 | return true; |
| 793 | } |
| 794 | EXPORT_SYMBOL(_copy_from_iter_full); |
| 795 | |
| 796 | size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) |
| 797 | { |
| 798 | char *to = addr; |
| 799 | if (unlikely(iov_iter_is_pipe(i))) { |
| 800 | WARN_ON(1); |
| 801 | return 0; |
| 802 | } |
| 803 | iterate_and_advance(i, bytes, v, |
| 804 | __copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, |
| 805 | v.iov_base, v.iov_len), |
| 806 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, |
| 807 | v.bv_offset, v.bv_len), |
| 808 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) |
| 809 | ) |
| 810 | |
| 811 | return bytes; |
| 812 | } |
| 813 | EXPORT_SYMBOL(_copy_from_iter_nocache); |
| 814 | |
| 815 | #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE |
| 816 | /** |
| 817 | * _copy_from_iter_flushcache - write destination through cpu cache |
| 818 | * @addr: destination kernel address |
| 819 | * @bytes: total transfer length |
| 820 | * @iter: source iterator |
| 821 | * |
| 822 | * The pmem driver arranges for filesystem-dax to use this facility via |
| 823 | * dax_copy_from_iter() for ensuring that writes to persistent memory |
| 824 | * are flushed through the CPU cache. It is differentiated from |
| 825 | * _copy_from_iter_nocache() in that guarantees all data is flushed for |
| 826 | * all iterator types. The _copy_from_iter_nocache() only attempts to |
| 827 | * bypass the cache for the ITER_IOVEC case, and on some archs may use |
| 828 | * instructions that strand dirty-data in the cache. |
| 829 | */ |
| 830 | size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) |
| 831 | { |
| 832 | char *to = addr; |
| 833 | if (unlikely(iov_iter_is_pipe(i))) { |
| 834 | WARN_ON(1); |
| 835 | return 0; |
| 836 | } |
| 837 | iterate_and_advance(i, bytes, v, |
| 838 | __copy_from_user_flushcache((to += v.iov_len) - v.iov_len, |
| 839 | v.iov_base, v.iov_len), |
| 840 | memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page, |
| 841 | v.bv_offset, v.bv_len), |
| 842 | memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base, |
| 843 | v.iov_len) |
| 844 | ) |
| 845 | |
| 846 | return bytes; |
| 847 | } |
| 848 | EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache); |
| 849 | #endif |
| 850 | |
| 851 | bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i) |
| 852 | { |
| 853 | char *to = addr; |
| 854 | if (unlikely(iov_iter_is_pipe(i))) { |
| 855 | WARN_ON(1); |
| 856 | return false; |
| 857 | } |
| 858 | if (unlikely(i->count < bytes)) |
| 859 | return false; |
| 860 | iterate_all_kinds(i, bytes, v, ({ |
| 861 | if (__copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len, |
| 862 | v.iov_base, v.iov_len)) |
| 863 | return false; |
| 864 | 0;}), |
| 865 | memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page, |
| 866 | v.bv_offset, v.bv_len), |
| 867 | memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) |
| 868 | ) |
| 869 | |
| 870 | iov_iter_advance(i, bytes); |
| 871 | return true; |
| 872 | } |
| 873 | EXPORT_SYMBOL(_copy_from_iter_full_nocache); |
| 874 | |
| 875 | static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) |
| 876 | { |
| 877 | struct page *head; |
| 878 | size_t v = n + offset; |
| 879 | |
| 880 | /* |
| 881 | * The general case needs to access the page order in order |
| 882 | * to compute the page size. |
| 883 | * However, we mostly deal with order-0 pages and thus can |
| 884 | * avoid a possible cache line miss for requests that fit all |
| 885 | * page orders. |
| 886 | */ |
| 887 | if (n <= v && v <= PAGE_SIZE) |
| 888 | return true; |
| 889 | |
| 890 | head = compound_head(page); |
| 891 | v += (page - head) << PAGE_SHIFT; |
| 892 | |
| 893 | if (likely(n <= v && v <= (page_size(head)))) |
| 894 | return true; |
| 895 | WARN_ON(1); |
| 896 | return false; |
| 897 | } |
| 898 | |
| 899 | size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, |
| 900 | struct iov_iter *i) |
| 901 | { |
| 902 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
| 903 | return 0; |
| 904 | if (i->type & (ITER_BVEC|ITER_KVEC)) { |
| 905 | void *kaddr = kmap_atomic(page); |
| 906 | size_t wanted = copy_to_iter(kaddr + offset, bytes, i); |
| 907 | kunmap_atomic(kaddr); |
| 908 | return wanted; |
| 909 | } else if (unlikely(iov_iter_is_discard(i))) |
| 910 | return bytes; |
| 911 | else if (likely(!iov_iter_is_pipe(i))) |
| 912 | return copy_page_to_iter_iovec(page, offset, bytes, i); |
| 913 | else |
| 914 | return copy_page_to_iter_pipe(page, offset, bytes, i); |
| 915 | } |
| 916 | EXPORT_SYMBOL(copy_page_to_iter); |
| 917 | |
| 918 | size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, |
| 919 | struct iov_iter *i) |
| 920 | { |
| 921 | if (unlikely(!page_copy_sane(page, offset, bytes))) |
| 922 | return 0; |
| 923 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
| 924 | WARN_ON(1); |
| 925 | return 0; |
| 926 | } |
| 927 | if (i->type & (ITER_BVEC|ITER_KVEC)) { |
| 928 | void *kaddr = kmap_atomic(page); |
| 929 | size_t wanted = _copy_from_iter(kaddr + offset, bytes, i); |
| 930 | kunmap_atomic(kaddr); |
| 931 | return wanted; |
| 932 | } else |
| 933 | return copy_page_from_iter_iovec(page, offset, bytes, i); |
| 934 | } |
| 935 | EXPORT_SYMBOL(copy_page_from_iter); |
| 936 | |
| 937 | static size_t pipe_zero(size_t bytes, struct iov_iter *i) |
| 938 | { |
| 939 | struct pipe_inode_info *pipe = i->pipe; |
| 940 | unsigned int p_mask = pipe->ring_size - 1; |
| 941 | unsigned int i_head; |
| 942 | size_t n, off; |
| 943 | |
| 944 | if (!sanity(i)) |
| 945 | return 0; |
| 946 | |
| 947 | bytes = n = push_pipe(i, bytes, &i_head, &off); |
| 948 | if (unlikely(!n)) |
| 949 | return 0; |
| 950 | |
| 951 | do { |
| 952 | size_t chunk = min_t(size_t, n, PAGE_SIZE - off); |
| 953 | memzero_page(pipe->bufs[i_head & p_mask].page, off, chunk); |
| 954 | i->head = i_head; |
| 955 | i->iov_offset = off + chunk; |
| 956 | n -= chunk; |
| 957 | off = 0; |
| 958 | i_head++; |
| 959 | } while (n); |
| 960 | i->count -= bytes; |
| 961 | return bytes; |
| 962 | } |
| 963 | |
| 964 | size_t iov_iter_zero(size_t bytes, struct iov_iter *i) |
| 965 | { |
| 966 | if (unlikely(iov_iter_is_pipe(i))) |
| 967 | return pipe_zero(bytes, i); |
| 968 | iterate_and_advance(i, bytes, v, |
| 969 | clear_user(v.iov_base, v.iov_len), |
| 970 | memzero_page(v.bv_page, v.bv_offset, v.bv_len), |
| 971 | memset(v.iov_base, 0, v.iov_len) |
| 972 | ) |
| 973 | |
| 974 | return bytes; |
| 975 | } |
| 976 | EXPORT_SYMBOL(iov_iter_zero); |
| 977 | |
| 978 | size_t iov_iter_copy_from_user_atomic(struct page *page, |
| 979 | struct iov_iter *i, unsigned long offset, size_t bytes) |
| 980 | { |
| 981 | char *kaddr = kmap_atomic(page), *p = kaddr + offset; |
| 982 | if (unlikely(!page_copy_sane(page, offset, bytes))) { |
| 983 | kunmap_atomic(kaddr); |
| 984 | return 0; |
| 985 | } |
| 986 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
| 987 | kunmap_atomic(kaddr); |
| 988 | WARN_ON(1); |
| 989 | return 0; |
| 990 | } |
| 991 | iterate_all_kinds(i, bytes, v, |
| 992 | copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), |
| 993 | memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, |
| 994 | v.bv_offset, v.bv_len), |
| 995 | memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) |
| 996 | ) |
| 997 | kunmap_atomic(kaddr); |
| 998 | return bytes; |
| 999 | } |
| 1000 | EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); |
| 1001 | |
| 1002 | static inline void pipe_truncate(struct iov_iter *i) |
| 1003 | { |
| 1004 | struct pipe_inode_info *pipe = i->pipe; |
| 1005 | unsigned int p_tail = pipe->tail; |
| 1006 | unsigned int p_head = pipe->head; |
| 1007 | unsigned int p_mask = pipe->ring_size - 1; |
| 1008 | |
| 1009 | if (!pipe_empty(p_head, p_tail)) { |
| 1010 | struct pipe_buffer *buf; |
| 1011 | unsigned int i_head = i->head; |
| 1012 | size_t off = i->iov_offset; |
| 1013 | |
| 1014 | if (off) { |
| 1015 | buf = &pipe->bufs[i_head & p_mask]; |
| 1016 | buf->len = off - buf->offset; |
| 1017 | i_head++; |
| 1018 | } |
| 1019 | while (p_head != i_head) { |
| 1020 | p_head--; |
| 1021 | pipe_buf_release(pipe, &pipe->bufs[p_head & p_mask]); |
| 1022 | } |
| 1023 | |
| 1024 | pipe->head = p_head; |
| 1025 | } |
| 1026 | } |
| 1027 | |
| 1028 | static void pipe_advance(struct iov_iter *i, size_t size) |
| 1029 | { |
| 1030 | struct pipe_inode_info *pipe = i->pipe; |
| 1031 | if (unlikely(i->count < size)) |
| 1032 | size = i->count; |
| 1033 | if (size) { |
| 1034 | struct pipe_buffer *buf; |
| 1035 | unsigned int p_mask = pipe->ring_size - 1; |
| 1036 | unsigned int i_head = i->head; |
| 1037 | size_t off = i->iov_offset, left = size; |
| 1038 | |
| 1039 | if (off) /* make it relative to the beginning of buffer */ |
| 1040 | left += off - pipe->bufs[i_head & p_mask].offset; |
| 1041 | while (1) { |
| 1042 | buf = &pipe->bufs[i_head & p_mask]; |
| 1043 | if (left <= buf->len) |
| 1044 | break; |
| 1045 | left -= buf->len; |
| 1046 | i_head++; |
| 1047 | } |
| 1048 | i->head = i_head; |
| 1049 | i->iov_offset = buf->offset + left; |
| 1050 | } |
| 1051 | i->count -= size; |
| 1052 | /* ... and discard everything past that point */ |
| 1053 | pipe_truncate(i); |
| 1054 | } |
| 1055 | |
| 1056 | static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) |
| 1057 | { |
| 1058 | struct bvec_iter bi; |
| 1059 | |
| 1060 | bi.bi_size = i->count; |
| 1061 | bi.bi_bvec_done = i->iov_offset; |
| 1062 | bi.bi_idx = 0; |
| 1063 | bvec_iter_advance(i->bvec, &bi, size); |
| 1064 | |
| 1065 | i->bvec += bi.bi_idx; |
| 1066 | i->nr_segs -= bi.bi_idx; |
| 1067 | i->count = bi.bi_size; |
| 1068 | i->iov_offset = bi.bi_bvec_done; |
| 1069 | } |
| 1070 | |
| 1071 | void iov_iter_advance(struct iov_iter *i, size_t size) |
| 1072 | { |
| 1073 | if (unlikely(iov_iter_is_pipe(i))) { |
| 1074 | pipe_advance(i, size); |
| 1075 | return; |
| 1076 | } |
| 1077 | if (unlikely(iov_iter_is_discard(i))) { |
| 1078 | i->count -= size; |
| 1079 | return; |
| 1080 | } |
| 1081 | if (iov_iter_is_bvec(i)) { |
| 1082 | iov_iter_bvec_advance(i, size); |
| 1083 | return; |
| 1084 | } |
| 1085 | iterate_and_advance(i, size, v, 0, 0, 0) |
| 1086 | } |
| 1087 | EXPORT_SYMBOL(iov_iter_advance); |
| 1088 | |
| 1089 | void iov_iter_revert(struct iov_iter *i, size_t unroll) |
| 1090 | { |
| 1091 | if (!unroll) |
| 1092 | return; |
| 1093 | if (WARN_ON(unroll > MAX_RW_COUNT)) |
| 1094 | return; |
| 1095 | i->count += unroll; |
| 1096 | if (unlikely(iov_iter_is_pipe(i))) { |
| 1097 | struct pipe_inode_info *pipe = i->pipe; |
| 1098 | unsigned int p_mask = pipe->ring_size - 1; |
| 1099 | unsigned int i_head = i->head; |
| 1100 | size_t off = i->iov_offset; |
| 1101 | while (1) { |
| 1102 | struct pipe_buffer *b = &pipe->bufs[i_head & p_mask]; |
| 1103 | size_t n = off - b->offset; |
| 1104 | if (unroll < n) { |
| 1105 | off -= unroll; |
| 1106 | break; |
| 1107 | } |
| 1108 | unroll -= n; |
| 1109 | if (!unroll && i_head == i->start_head) { |
| 1110 | off = 0; |
| 1111 | break; |
| 1112 | } |
| 1113 | i_head--; |
| 1114 | b = &pipe->bufs[i_head & p_mask]; |
| 1115 | off = b->offset + b->len; |
| 1116 | } |
| 1117 | i->iov_offset = off; |
| 1118 | i->head = i_head; |
| 1119 | pipe_truncate(i); |
| 1120 | return; |
| 1121 | } |
| 1122 | if (unlikely(iov_iter_is_discard(i))) |
| 1123 | return; |
| 1124 | if (unroll <= i->iov_offset) { |
| 1125 | i->iov_offset -= unroll; |
| 1126 | return; |
| 1127 | } |
| 1128 | unroll -= i->iov_offset; |
| 1129 | if (iov_iter_is_bvec(i)) { |
| 1130 | const struct bio_vec *bvec = i->bvec; |
| 1131 | while (1) { |
| 1132 | size_t n = (--bvec)->bv_len; |
| 1133 | i->nr_segs++; |
| 1134 | if (unroll <= n) { |
| 1135 | i->bvec = bvec; |
| 1136 | i->iov_offset = n - unroll; |
| 1137 | return; |
| 1138 | } |
| 1139 | unroll -= n; |
| 1140 | } |
| 1141 | } else { /* same logics for iovec and kvec */ |
| 1142 | const struct iovec *iov = i->iov; |
| 1143 | while (1) { |
| 1144 | size_t n = (--iov)->iov_len; |
| 1145 | i->nr_segs++; |
| 1146 | if (unroll <= n) { |
| 1147 | i->iov = iov; |
| 1148 | i->iov_offset = n - unroll; |
| 1149 | return; |
| 1150 | } |
| 1151 | unroll -= n; |
| 1152 | } |
| 1153 | } |
| 1154 | } |
| 1155 | EXPORT_SYMBOL(iov_iter_revert); |
| 1156 | |
| 1157 | /* |
| 1158 | * Return the count of just the current iov_iter segment. |
| 1159 | */ |
| 1160 | size_t iov_iter_single_seg_count(const struct iov_iter *i) |
| 1161 | { |
| 1162 | if (unlikely(iov_iter_is_pipe(i))) |
| 1163 | return i->count; // it is a silly place, anyway |
| 1164 | if (i->nr_segs == 1) |
| 1165 | return i->count; |
| 1166 | if (unlikely(iov_iter_is_discard(i))) |
| 1167 | return i->count; |
| 1168 | else if (iov_iter_is_bvec(i)) |
| 1169 | return min(i->count, i->bvec->bv_len - i->iov_offset); |
| 1170 | else |
| 1171 | return min(i->count, i->iov->iov_len - i->iov_offset); |
| 1172 | } |
| 1173 | EXPORT_SYMBOL(iov_iter_single_seg_count); |
| 1174 | |
| 1175 | void iov_iter_kvec(struct iov_iter *i, unsigned int direction, |
| 1176 | const struct kvec *kvec, unsigned long nr_segs, |
| 1177 | size_t count) |
| 1178 | { |
| 1179 | WARN_ON(direction & ~(READ | WRITE)); |
| 1180 | i->type = ITER_KVEC | (direction & (READ | WRITE)); |
| 1181 | i->kvec = kvec; |
| 1182 | i->nr_segs = nr_segs; |
| 1183 | i->iov_offset = 0; |
| 1184 | i->count = count; |
| 1185 | } |
| 1186 | EXPORT_SYMBOL(iov_iter_kvec); |
| 1187 | |
| 1188 | void iov_iter_bvec(struct iov_iter *i, unsigned int direction, |
| 1189 | const struct bio_vec *bvec, unsigned long nr_segs, |
| 1190 | size_t count) |
| 1191 | { |
| 1192 | WARN_ON(direction & ~(READ | WRITE)); |
| 1193 | i->type = ITER_BVEC | (direction & (READ | WRITE)); |
| 1194 | i->bvec = bvec; |
| 1195 | i->nr_segs = nr_segs; |
| 1196 | i->iov_offset = 0; |
| 1197 | i->count = count; |
| 1198 | } |
| 1199 | EXPORT_SYMBOL(iov_iter_bvec); |
| 1200 | |
| 1201 | void iov_iter_pipe(struct iov_iter *i, unsigned int direction, |
| 1202 | struct pipe_inode_info *pipe, |
| 1203 | size_t count) |
| 1204 | { |
| 1205 | BUG_ON(direction != READ); |
| 1206 | WARN_ON(pipe_full(pipe->head, pipe->tail, pipe->ring_size)); |
| 1207 | i->type = ITER_PIPE | READ; |
| 1208 | i->pipe = pipe; |
| 1209 | i->head = pipe->head; |
| 1210 | i->iov_offset = 0; |
| 1211 | i->count = count; |
| 1212 | i->start_head = i->head; |
| 1213 | } |
| 1214 | EXPORT_SYMBOL(iov_iter_pipe); |
| 1215 | |
| 1216 | /** |
| 1217 | * iov_iter_discard - Initialise an I/O iterator that discards data |
| 1218 | * @i: The iterator to initialise. |
| 1219 | * @direction: The direction of the transfer. |
| 1220 | * @count: The size of the I/O buffer in bytes. |
| 1221 | * |
| 1222 | * Set up an I/O iterator that just discards everything that's written to it. |
| 1223 | * It's only available as a READ iterator. |
| 1224 | */ |
| 1225 | void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) |
| 1226 | { |
| 1227 | BUG_ON(direction != READ); |
| 1228 | i->type = ITER_DISCARD | READ; |
| 1229 | i->count = count; |
| 1230 | i->iov_offset = 0; |
| 1231 | } |
| 1232 | EXPORT_SYMBOL(iov_iter_discard); |
| 1233 | |
| 1234 | unsigned long iov_iter_alignment(const struct iov_iter *i) |
| 1235 | { |
| 1236 | unsigned long res = 0; |
| 1237 | size_t size = i->count; |
| 1238 | |
| 1239 | if (unlikely(iov_iter_is_pipe(i))) { |
| 1240 | unsigned int p_mask = i->pipe->ring_size - 1; |
| 1241 | |
| 1242 | if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) |
| 1243 | return size | i->iov_offset; |
| 1244 | return size; |
| 1245 | } |
| 1246 | iterate_all_kinds(i, size, v, |
| 1247 | (res |= (unsigned long)v.iov_base | v.iov_len, 0), |
| 1248 | res |= v.bv_offset | v.bv_len, |
| 1249 | res |= (unsigned long)v.iov_base | v.iov_len |
| 1250 | ) |
| 1251 | return res; |
| 1252 | } |
| 1253 | EXPORT_SYMBOL(iov_iter_alignment); |
| 1254 | |
| 1255 | unsigned long iov_iter_gap_alignment(const struct iov_iter *i) |
| 1256 | { |
| 1257 | unsigned long res = 0; |
| 1258 | size_t size = i->count; |
| 1259 | |
| 1260 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
| 1261 | WARN_ON(1); |
| 1262 | return ~0U; |
| 1263 | } |
| 1264 | |
| 1265 | iterate_all_kinds(i, size, v, |
| 1266 | (res |= (!res ? 0 : (unsigned long)v.iov_base) | |
| 1267 | (size != v.iov_len ? size : 0), 0), |
| 1268 | (res |= (!res ? 0 : (unsigned long)v.bv_offset) | |
| 1269 | (size != v.bv_len ? size : 0)), |
| 1270 | (res |= (!res ? 0 : (unsigned long)v.iov_base) | |
| 1271 | (size != v.iov_len ? size : 0)) |
| 1272 | ); |
| 1273 | return res; |
| 1274 | } |
| 1275 | EXPORT_SYMBOL(iov_iter_gap_alignment); |
| 1276 | |
| 1277 | static inline ssize_t __pipe_get_pages(struct iov_iter *i, |
| 1278 | size_t maxsize, |
| 1279 | struct page **pages, |
| 1280 | int iter_head, |
| 1281 | size_t *start) |
| 1282 | { |
| 1283 | struct pipe_inode_info *pipe = i->pipe; |
| 1284 | unsigned int p_mask = pipe->ring_size - 1; |
| 1285 | ssize_t n = push_pipe(i, maxsize, &iter_head, start); |
| 1286 | if (!n) |
| 1287 | return -EFAULT; |
| 1288 | |
| 1289 | maxsize = n; |
| 1290 | n += *start; |
| 1291 | while (n > 0) { |
| 1292 | get_page(*pages++ = pipe->bufs[iter_head & p_mask].page); |
| 1293 | iter_head++; |
| 1294 | n -= PAGE_SIZE; |
| 1295 | } |
| 1296 | |
| 1297 | return maxsize; |
| 1298 | } |
| 1299 | |
| 1300 | static ssize_t pipe_get_pages(struct iov_iter *i, |
| 1301 | struct page **pages, size_t maxsize, unsigned maxpages, |
| 1302 | size_t *start) |
| 1303 | { |
| 1304 | unsigned int iter_head, npages; |
| 1305 | size_t capacity; |
| 1306 | |
| 1307 | if (!maxsize) |
| 1308 | return 0; |
| 1309 | |
| 1310 | if (!sanity(i)) |
| 1311 | return -EFAULT; |
| 1312 | |
| 1313 | data_start(i, &iter_head, start); |
| 1314 | /* Amount of free space: some of this one + all after this one */ |
| 1315 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); |
| 1316 | capacity = min(npages, maxpages) * PAGE_SIZE - *start; |
| 1317 | |
| 1318 | return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start); |
| 1319 | } |
| 1320 | |
| 1321 | ssize_t iov_iter_get_pages(struct iov_iter *i, |
| 1322 | struct page **pages, size_t maxsize, unsigned maxpages, |
| 1323 | size_t *start) |
| 1324 | { |
| 1325 | if (maxsize > i->count) |
| 1326 | maxsize = i->count; |
| 1327 | |
| 1328 | if (unlikely(iov_iter_is_pipe(i))) |
| 1329 | return pipe_get_pages(i, pages, maxsize, maxpages, start); |
| 1330 | if (unlikely(iov_iter_is_discard(i))) |
| 1331 | return -EFAULT; |
| 1332 | |
| 1333 | iterate_all_kinds(i, maxsize, v, ({ |
| 1334 | unsigned long addr = (unsigned long)v.iov_base; |
| 1335 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); |
| 1336 | int n; |
| 1337 | int res; |
| 1338 | |
| 1339 | if (len > maxpages * PAGE_SIZE) |
| 1340 | len = maxpages * PAGE_SIZE; |
| 1341 | addr &= ~(PAGE_SIZE - 1); |
| 1342 | n = DIV_ROUND_UP(len, PAGE_SIZE); |
| 1343 | res = get_user_pages_fast(addr, n, |
| 1344 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, |
| 1345 | pages); |
| 1346 | if (unlikely(res < 0)) |
| 1347 | return res; |
| 1348 | return (res == n ? len : res * PAGE_SIZE) - *start; |
| 1349 | 0;}),({ |
| 1350 | /* can't be more than PAGE_SIZE */ |
| 1351 | *start = v.bv_offset; |
| 1352 | get_page(*pages = v.bv_page); |
| 1353 | return v.bv_len; |
| 1354 | }),({ |
| 1355 | return -EFAULT; |
| 1356 | }) |
| 1357 | ) |
| 1358 | return 0; |
| 1359 | } |
| 1360 | EXPORT_SYMBOL(iov_iter_get_pages); |
| 1361 | |
| 1362 | static struct page **get_pages_array(size_t n) |
| 1363 | { |
| 1364 | return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL); |
| 1365 | } |
| 1366 | |
| 1367 | static ssize_t pipe_get_pages_alloc(struct iov_iter *i, |
| 1368 | struct page ***pages, size_t maxsize, |
| 1369 | size_t *start) |
| 1370 | { |
| 1371 | struct page **p; |
| 1372 | unsigned int iter_head, npages; |
| 1373 | ssize_t n; |
| 1374 | |
| 1375 | if (!maxsize) |
| 1376 | return 0; |
| 1377 | |
| 1378 | if (!sanity(i)) |
| 1379 | return -EFAULT; |
| 1380 | |
| 1381 | data_start(i, &iter_head, start); |
| 1382 | /* Amount of free space: some of this one + all after this one */ |
| 1383 | npages = pipe_space_for_user(iter_head, i->pipe->tail, i->pipe); |
| 1384 | n = npages * PAGE_SIZE - *start; |
| 1385 | if (maxsize > n) |
| 1386 | maxsize = n; |
| 1387 | else |
| 1388 | npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); |
| 1389 | p = get_pages_array(npages); |
| 1390 | if (!p) |
| 1391 | return -ENOMEM; |
| 1392 | n = __pipe_get_pages(i, maxsize, p, iter_head, start); |
| 1393 | if (n > 0) |
| 1394 | *pages = p; |
| 1395 | else |
| 1396 | kvfree(p); |
| 1397 | return n; |
| 1398 | } |
| 1399 | |
| 1400 | ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, |
| 1401 | struct page ***pages, size_t maxsize, |
| 1402 | size_t *start) |
| 1403 | { |
| 1404 | struct page **p; |
| 1405 | |
| 1406 | if (maxsize > i->count) |
| 1407 | maxsize = i->count; |
| 1408 | |
| 1409 | if (unlikely(iov_iter_is_pipe(i))) |
| 1410 | return pipe_get_pages_alloc(i, pages, maxsize, start); |
| 1411 | if (unlikely(iov_iter_is_discard(i))) |
| 1412 | return -EFAULT; |
| 1413 | |
| 1414 | iterate_all_kinds(i, maxsize, v, ({ |
| 1415 | unsigned long addr = (unsigned long)v.iov_base; |
| 1416 | size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1)); |
| 1417 | int n; |
| 1418 | int res; |
| 1419 | |
| 1420 | addr &= ~(PAGE_SIZE - 1); |
| 1421 | n = DIV_ROUND_UP(len, PAGE_SIZE); |
| 1422 | p = get_pages_array(n); |
| 1423 | if (!p) |
| 1424 | return -ENOMEM; |
| 1425 | res = get_user_pages_fast(addr, n, |
| 1426 | iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p); |
| 1427 | if (unlikely(res < 0)) { |
| 1428 | kvfree(p); |
| 1429 | return res; |
| 1430 | } |
| 1431 | *pages = p; |
| 1432 | return (res == n ? len : res * PAGE_SIZE) - *start; |
| 1433 | 0;}),({ |
| 1434 | /* can't be more than PAGE_SIZE */ |
| 1435 | *start = v.bv_offset; |
| 1436 | *pages = p = get_pages_array(1); |
| 1437 | if (!p) |
| 1438 | return -ENOMEM; |
| 1439 | get_page(*p = v.bv_page); |
| 1440 | return v.bv_len; |
| 1441 | }),({ |
| 1442 | return -EFAULT; |
| 1443 | }) |
| 1444 | ) |
| 1445 | return 0; |
| 1446 | } |
| 1447 | EXPORT_SYMBOL(iov_iter_get_pages_alloc); |
| 1448 | |
| 1449 | size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, |
| 1450 | struct iov_iter *i) |
| 1451 | { |
| 1452 | char *to = addr; |
| 1453 | __wsum sum, next; |
| 1454 | size_t off = 0; |
| 1455 | sum = *csum; |
| 1456 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
| 1457 | WARN_ON(1); |
| 1458 | return 0; |
| 1459 | } |
| 1460 | iterate_and_advance(i, bytes, v, ({ |
| 1461 | next = csum_and_copy_from_user(v.iov_base, |
| 1462 | (to += v.iov_len) - v.iov_len, |
| 1463 | v.iov_len); |
| 1464 | if (next) { |
| 1465 | sum = csum_block_add(sum, next, off); |
| 1466 | off += v.iov_len; |
| 1467 | } |
| 1468 | next ? 0 : v.iov_len; |
| 1469 | }), ({ |
| 1470 | char *p = kmap_atomic(v.bv_page); |
| 1471 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, |
| 1472 | p + v.bv_offset, v.bv_len, |
| 1473 | sum, off); |
| 1474 | kunmap_atomic(p); |
| 1475 | off += v.bv_len; |
| 1476 | }),({ |
| 1477 | sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, |
| 1478 | v.iov_base, v.iov_len, |
| 1479 | sum, off); |
| 1480 | off += v.iov_len; |
| 1481 | }) |
| 1482 | ) |
| 1483 | *csum = sum; |
| 1484 | return bytes; |
| 1485 | } |
| 1486 | EXPORT_SYMBOL(csum_and_copy_from_iter); |
| 1487 | |
| 1488 | bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, |
| 1489 | struct iov_iter *i) |
| 1490 | { |
| 1491 | char *to = addr; |
| 1492 | __wsum sum, next; |
| 1493 | size_t off = 0; |
| 1494 | sum = *csum; |
| 1495 | if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { |
| 1496 | WARN_ON(1); |
| 1497 | return false; |
| 1498 | } |
| 1499 | if (unlikely(i->count < bytes)) |
| 1500 | return false; |
| 1501 | iterate_all_kinds(i, bytes, v, ({ |
| 1502 | next = csum_and_copy_from_user(v.iov_base, |
| 1503 | (to += v.iov_len) - v.iov_len, |
| 1504 | v.iov_len); |
| 1505 | if (!next) |
| 1506 | return false; |
| 1507 | sum = csum_block_add(sum, next, off); |
| 1508 | off += v.iov_len; |
| 1509 | 0; |
| 1510 | }), ({ |
| 1511 | char *p = kmap_atomic(v.bv_page); |
| 1512 | sum = csum_and_memcpy((to += v.bv_len) - v.bv_len, |
| 1513 | p + v.bv_offset, v.bv_len, |
| 1514 | sum, off); |
| 1515 | kunmap_atomic(p); |
| 1516 | off += v.bv_len; |
| 1517 | }),({ |
| 1518 | sum = csum_and_memcpy((to += v.iov_len) - v.iov_len, |
| 1519 | v.iov_base, v.iov_len, |
| 1520 | sum, off); |
| 1521 | off += v.iov_len; |
| 1522 | }) |
| 1523 | ) |
| 1524 | *csum = sum; |
| 1525 | iov_iter_advance(i, bytes); |
| 1526 | return true; |
| 1527 | } |
| 1528 | EXPORT_SYMBOL(csum_and_copy_from_iter_full); |
| 1529 | |
| 1530 | size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, |
| 1531 | struct iov_iter *i) |
| 1532 | { |
| 1533 | struct csum_state *csstate = _csstate; |
| 1534 | const char *from = addr; |
| 1535 | __wsum sum, next; |
| 1536 | size_t off; |
| 1537 | |
| 1538 | if (unlikely(iov_iter_is_pipe(i))) |
| 1539 | return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i); |
| 1540 | |
| 1541 | sum = csstate->csum; |
| 1542 | off = csstate->off; |
| 1543 | if (unlikely(iov_iter_is_discard(i))) { |
| 1544 | WARN_ON(1); /* for now */ |
| 1545 | return 0; |
| 1546 | } |
| 1547 | iterate_and_advance(i, bytes, v, ({ |
| 1548 | next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len, |
| 1549 | v.iov_base, |
| 1550 | v.iov_len); |
| 1551 | if (next) { |
| 1552 | sum = csum_block_add(sum, next, off); |
| 1553 | off += v.iov_len; |
| 1554 | } |
| 1555 | next ? 0 : v.iov_len; |
| 1556 | }), ({ |
| 1557 | char *p = kmap_atomic(v.bv_page); |
| 1558 | sum = csum_and_memcpy(p + v.bv_offset, |
| 1559 | (from += v.bv_len) - v.bv_len, |
| 1560 | v.bv_len, sum, off); |
| 1561 | kunmap_atomic(p); |
| 1562 | off += v.bv_len; |
| 1563 | }),({ |
| 1564 | sum = csum_and_memcpy(v.iov_base, |
| 1565 | (from += v.iov_len) - v.iov_len, |
| 1566 | v.iov_len, sum, off); |
| 1567 | off += v.iov_len; |
| 1568 | }) |
| 1569 | ) |
| 1570 | csstate->csum = sum; |
| 1571 | csstate->off = off; |
| 1572 | return bytes; |
| 1573 | } |
| 1574 | EXPORT_SYMBOL(csum_and_copy_to_iter); |
| 1575 | |
| 1576 | size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, |
| 1577 | struct iov_iter *i) |
| 1578 | { |
| 1579 | #ifdef CONFIG_CRYPTO_HASH |
| 1580 | struct ahash_request *hash = hashp; |
| 1581 | struct scatterlist sg; |
| 1582 | size_t copied; |
| 1583 | |
| 1584 | copied = copy_to_iter(addr, bytes, i); |
| 1585 | sg_init_one(&sg, addr, copied); |
| 1586 | ahash_request_set_crypt(hash, &sg, NULL, copied); |
| 1587 | crypto_ahash_update(hash); |
| 1588 | return copied; |
| 1589 | #else |
| 1590 | return 0; |
| 1591 | #endif |
| 1592 | } |
| 1593 | EXPORT_SYMBOL(hash_and_copy_to_iter); |
| 1594 | |
| 1595 | int iov_iter_npages(const struct iov_iter *i, int maxpages) |
| 1596 | { |
| 1597 | size_t size = i->count; |
| 1598 | int npages = 0; |
| 1599 | |
| 1600 | if (!size) |
| 1601 | return 0; |
| 1602 | if (unlikely(iov_iter_is_discard(i))) |
| 1603 | return 0; |
| 1604 | |
| 1605 | if (unlikely(iov_iter_is_pipe(i))) { |
| 1606 | struct pipe_inode_info *pipe = i->pipe; |
| 1607 | unsigned int iter_head; |
| 1608 | size_t off; |
| 1609 | |
| 1610 | if (!sanity(i)) |
| 1611 | return 0; |
| 1612 | |
| 1613 | data_start(i, &iter_head, &off); |
| 1614 | /* some of this one + all after this one */ |
| 1615 | npages = pipe_space_for_user(iter_head, pipe->tail, pipe); |
| 1616 | if (npages >= maxpages) |
| 1617 | return maxpages; |
| 1618 | } else iterate_all_kinds(i, size, v, ({ |
| 1619 | unsigned long p = (unsigned long)v.iov_base; |
| 1620 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) |
| 1621 | - p / PAGE_SIZE; |
| 1622 | if (npages >= maxpages) |
| 1623 | return maxpages; |
| 1624 | 0;}),({ |
| 1625 | npages++; |
| 1626 | if (npages >= maxpages) |
| 1627 | return maxpages; |
| 1628 | }),({ |
| 1629 | unsigned long p = (unsigned long)v.iov_base; |
| 1630 | npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE) |
| 1631 | - p / PAGE_SIZE; |
| 1632 | if (npages >= maxpages) |
| 1633 | return maxpages; |
| 1634 | }) |
| 1635 | ) |
| 1636 | return npages; |
| 1637 | } |
| 1638 | EXPORT_SYMBOL(iov_iter_npages); |
| 1639 | |
| 1640 | const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) |
| 1641 | { |
| 1642 | *new = *old; |
| 1643 | if (unlikely(iov_iter_is_pipe(new))) { |
| 1644 | WARN_ON(1); |
| 1645 | return NULL; |
| 1646 | } |
| 1647 | if (unlikely(iov_iter_is_discard(new))) |
| 1648 | return NULL; |
| 1649 | if (iov_iter_is_bvec(new)) |
| 1650 | return new->bvec = kmemdup(new->bvec, |
| 1651 | new->nr_segs * sizeof(struct bio_vec), |
| 1652 | flags); |
| 1653 | else |
| 1654 | /* iovec and kvec have identical layout */ |
| 1655 | return new->iov = kmemdup(new->iov, |
| 1656 | new->nr_segs * sizeof(struct iovec), |
| 1657 | flags); |
| 1658 | } |
| 1659 | EXPORT_SYMBOL(dup_iter); |
| 1660 | |
| 1661 | static int copy_compat_iovec_from_user(struct iovec *iov, |
| 1662 | const struct iovec __user *uvec, unsigned long nr_segs) |
| 1663 | { |
| 1664 | const struct compat_iovec __user *uiov = |
| 1665 | (const struct compat_iovec __user *)uvec; |
| 1666 | int ret = -EFAULT, i; |
| 1667 | |
| 1668 | if (!user_access_begin(uiov, nr_segs * sizeof(*uiov))) |
| 1669 | return -EFAULT; |
| 1670 | |
| 1671 | for (i = 0; i < nr_segs; i++) { |
| 1672 | compat_uptr_t buf; |
| 1673 | compat_ssize_t len; |
| 1674 | |
| 1675 | unsafe_get_user(len, &uiov[i].iov_len, uaccess_end); |
| 1676 | unsafe_get_user(buf, &uiov[i].iov_base, uaccess_end); |
| 1677 | |
| 1678 | /* check for compat_size_t not fitting in compat_ssize_t .. */ |
| 1679 | if (len < 0) { |
| 1680 | ret = -EINVAL; |
| 1681 | goto uaccess_end; |
| 1682 | } |
| 1683 | iov[i].iov_base = compat_ptr(buf); |
| 1684 | iov[i].iov_len = len; |
| 1685 | } |
| 1686 | |
| 1687 | ret = 0; |
| 1688 | uaccess_end: |
| 1689 | user_access_end(); |
| 1690 | return ret; |
| 1691 | } |
| 1692 | |
| 1693 | static int copy_iovec_from_user(struct iovec *iov, |
| 1694 | const struct iovec __user *uvec, unsigned long nr_segs) |
| 1695 | { |
| 1696 | unsigned long seg; |
| 1697 | |
| 1698 | if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec))) |
| 1699 | return -EFAULT; |
| 1700 | for (seg = 0; seg < nr_segs; seg++) { |
| 1701 | if ((ssize_t)iov[seg].iov_len < 0) |
| 1702 | return -EINVAL; |
| 1703 | } |
| 1704 | |
| 1705 | return 0; |
| 1706 | } |
| 1707 | |
| 1708 | struct iovec *iovec_from_user(const struct iovec __user *uvec, |
| 1709 | unsigned long nr_segs, unsigned long fast_segs, |
| 1710 | struct iovec *fast_iov, bool compat) |
| 1711 | { |
| 1712 | struct iovec *iov = fast_iov; |
| 1713 | int ret; |
| 1714 | |
| 1715 | /* |
| 1716 | * SuS says "The readv() function *may* fail if the iovcnt argument was |
| 1717 | * less than or equal to 0, or greater than {IOV_MAX}. Linux has |
| 1718 | * traditionally returned zero for zero segments, so... |
| 1719 | */ |
| 1720 | if (nr_segs == 0) |
| 1721 | return iov; |
| 1722 | if (nr_segs > UIO_MAXIOV) |
| 1723 | return ERR_PTR(-EINVAL); |
| 1724 | if (nr_segs > fast_segs) { |
| 1725 | iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL); |
| 1726 | if (!iov) |
| 1727 | return ERR_PTR(-ENOMEM); |
| 1728 | } |
| 1729 | |
| 1730 | if (compat) |
| 1731 | ret = copy_compat_iovec_from_user(iov, uvec, nr_segs); |
| 1732 | else |
| 1733 | ret = copy_iovec_from_user(iov, uvec, nr_segs); |
| 1734 | if (ret) { |
| 1735 | if (iov != fast_iov) |
| 1736 | kfree(iov); |
| 1737 | return ERR_PTR(ret); |
| 1738 | } |
| 1739 | |
| 1740 | return iov; |
| 1741 | } |
| 1742 | |
| 1743 | ssize_t __import_iovec(int type, const struct iovec __user *uvec, |
| 1744 | unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, |
| 1745 | struct iov_iter *i, bool compat) |
| 1746 | { |
| 1747 | ssize_t total_len = 0; |
| 1748 | unsigned long seg; |
| 1749 | struct iovec *iov; |
| 1750 | |
| 1751 | iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat); |
| 1752 | if (IS_ERR(iov)) { |
| 1753 | *iovp = NULL; |
| 1754 | return PTR_ERR(iov); |
| 1755 | } |
| 1756 | |
| 1757 | /* |
| 1758 | * According to the Single Unix Specification we should return EINVAL if |
| 1759 | * an element length is < 0 when cast to ssize_t or if the total length |
| 1760 | * would overflow the ssize_t return value of the system call. |
| 1761 | * |
| 1762 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the |
| 1763 | * overflow case. |
| 1764 | */ |
| 1765 | for (seg = 0; seg < nr_segs; seg++) { |
| 1766 | ssize_t len = (ssize_t)iov[seg].iov_len; |
| 1767 | |
| 1768 | if (!access_ok(iov[seg].iov_base, len)) { |
| 1769 | if (iov != *iovp) |
| 1770 | kfree(iov); |
| 1771 | *iovp = NULL; |
| 1772 | return -EFAULT; |
| 1773 | } |
| 1774 | |
| 1775 | if (len > MAX_RW_COUNT - total_len) { |
| 1776 | len = MAX_RW_COUNT - total_len; |
| 1777 | iov[seg].iov_len = len; |
| 1778 | } |
| 1779 | total_len += len; |
| 1780 | } |
| 1781 | |
| 1782 | iov_iter_init(i, type, iov, nr_segs, total_len); |
| 1783 | if (iov == *iovp) |
| 1784 | *iovp = NULL; |
| 1785 | else |
| 1786 | *iovp = iov; |
| 1787 | return total_len; |
| 1788 | } |
| 1789 | |
| 1790 | /** |
| 1791 | * import_iovec() - Copy an array of &struct iovec from userspace |
| 1792 | * into the kernel, check that it is valid, and initialize a new |
| 1793 | * &struct iov_iter iterator to access it. |
| 1794 | * |
| 1795 | * @type: One of %READ or %WRITE. |
| 1796 | * @uvec: Pointer to the userspace array. |
| 1797 | * @nr_segs: Number of elements in userspace array. |
| 1798 | * @fast_segs: Number of elements in @iov. |
| 1799 | * @iovp: (input and output parameter) Pointer to pointer to (usually small |
| 1800 | * on-stack) kernel array. |
| 1801 | * @i: Pointer to iterator that will be initialized on success. |
| 1802 | * |
| 1803 | * If the array pointed to by *@iov is large enough to hold all @nr_segs, |
| 1804 | * then this function places %NULL in *@iov on return. Otherwise, a new |
| 1805 | * array will be allocated and the result placed in *@iov. This means that |
| 1806 | * the caller may call kfree() on *@iov regardless of whether the small |
| 1807 | * on-stack array was used or not (and regardless of whether this function |
| 1808 | * returns an error or not). |
| 1809 | * |
| 1810 | * Return: Negative error code on error, bytes imported on success |
| 1811 | */ |
| 1812 | ssize_t import_iovec(int type, const struct iovec __user *uvec, |
| 1813 | unsigned nr_segs, unsigned fast_segs, |
| 1814 | struct iovec **iovp, struct iov_iter *i) |
| 1815 | { |
| 1816 | return __import_iovec(type, uvec, nr_segs, fast_segs, iovp, i, |
| 1817 | in_compat_syscall()); |
| 1818 | } |
| 1819 | EXPORT_SYMBOL(import_iovec); |
| 1820 | |
| 1821 | int import_single_range(int rw, void __user *buf, size_t len, |
| 1822 | struct iovec *iov, struct iov_iter *i) |
| 1823 | { |
| 1824 | if (len > MAX_RW_COUNT) |
| 1825 | len = MAX_RW_COUNT; |
| 1826 | if (unlikely(!access_ok(buf, len))) |
| 1827 | return -EFAULT; |
| 1828 | |
| 1829 | iov->iov_base = buf; |
| 1830 | iov->iov_len = len; |
| 1831 | iov_iter_init(i, rw, iov, 1, len); |
| 1832 | return 0; |
| 1833 | } |
| 1834 | EXPORT_SYMBOL(import_single_range); |
| 1835 | |
| 1836 | int iov_iter_for_each_range(struct iov_iter *i, size_t bytes, |
| 1837 | int (*f)(struct kvec *vec, void *context), |
| 1838 | void *context) |
| 1839 | { |
| 1840 | struct kvec w; |
| 1841 | int err = -EINVAL; |
| 1842 | if (!bytes) |
| 1843 | return 0; |
| 1844 | |
| 1845 | iterate_all_kinds(i, bytes, v, -EINVAL, ({ |
| 1846 | w.iov_base = kmap(v.bv_page) + v.bv_offset; |
| 1847 | w.iov_len = v.bv_len; |
| 1848 | err = f(&w, context); |
| 1849 | kunmap(v.bv_page); |
| 1850 | err;}), ({ |
| 1851 | w = v; |
| 1852 | err = f(&w, context);}) |
| 1853 | ) |
| 1854 | return err; |
| 1855 | } |
| 1856 | EXPORT_SYMBOL(iov_iter_for_each_range); |