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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 | // SPDX-License-Identifier: GPL-2.0-only /* * V4L2 JPEG header parser helpers. * * Copyright (C) 2019 Pengutronix, Philipp Zabel <kernel@pengutronix.de> * * For reference, see JPEG ITU-T.81 (ISO/IEC 10918-1) [1] * * [1] https://www.w3.org/Graphics/JPEG/itu-t81.pdf */ #include <asm/unaligned.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/types.h> #include <media/v4l2-jpeg.h> MODULE_DESCRIPTION("V4L2 JPEG header parser helpers"); MODULE_AUTHOR("Philipp Zabel <kernel@pengutronix.de>"); MODULE_LICENSE("GPL"); /* Table B.1 - Marker code assignments */ #define SOF0 0xffc0 /* start of frame */ #define SOF1 0xffc1 #define SOF2 0xffc2 #define SOF3 0xffc3 #define SOF5 0xffc5 #define SOF7 0xffc7 #define JPG 0xffc8 /* extensions */ #define SOF9 0xffc9 #define SOF11 0xffcb #define SOF13 0xffcd #define SOF15 0xffcf #define DHT 0xffc4 /* huffman table */ #define DAC 0xffcc /* arithmetic coding conditioning */ #define RST0 0xffd0 /* restart */ #define RST7 0xffd7 #define SOI 0xffd8 /* start of image */ #define EOI 0xffd9 /* end of image */ #define SOS 0xffda /* start of stream */ #define DQT 0xffdb /* quantization table */ #define DNL 0xffdc /* number of lines */ #define DRI 0xffdd /* restart interval */ #define DHP 0xffde /* hierarchical progression */ #define EXP 0xffdf /* expand reference */ #define APP0 0xffe0 /* application data */ #define APP14 0xffee /* application data for colour encoding */ #define APP15 0xffef #define JPG0 0xfff0 /* extensions */ #define JPG13 0xfffd #define COM 0xfffe /* comment */ #define TEM 0xff01 /* temporary */ /** * struct jpeg_stream - JPEG byte stream * @curr: current position in stream * @end: end position, after last byte */ struct jpeg_stream { u8 *curr; u8 *end; }; /* returns a value that fits into u8, or negative error */ static int jpeg_get_byte(struct jpeg_stream *stream) { if (stream->curr >= stream->end) return -EINVAL; return *stream->curr++; } /* returns a value that fits into u16, or negative error */ static int jpeg_get_word_be(struct jpeg_stream *stream) { u16 word; if (stream->curr + sizeof(__be16) > stream->end) return -EINVAL; word = get_unaligned_be16(stream->curr); stream->curr += sizeof(__be16); return word; } static int jpeg_skip(struct jpeg_stream *stream, size_t len) { if (stream->curr + len > stream->end) return -EINVAL; stream->curr += len; return 0; } static int jpeg_next_marker(struct jpeg_stream *stream) { int byte; u16 marker = 0; while ((byte = jpeg_get_byte(stream)) >= 0) { marker = (marker << 8) | byte; /* skip stuffing bytes and REServed markers */ if (marker == TEM || (marker > 0xffbf && marker < 0xffff)) return marker; } return byte; } /* this does not advance the current position in the stream */ static int jpeg_reference_segment(struct jpeg_stream *stream, struct v4l2_jpeg_reference *segment) { u16 len; if (stream->curr + sizeof(__be16) > stream->end) return -EINVAL; len = get_unaligned_be16(stream->curr); if (stream->curr + len > stream->end) return -EINVAL; segment->start = stream->curr; segment->length = len; return 0; } static int v4l2_jpeg_decode_subsampling(u8 nf, u8 h_v) { if (nf == 1) return V4L2_JPEG_CHROMA_SUBSAMPLING_GRAY; /* no chroma subsampling for 4-component images */ if (nf == 4 && h_v != 0x11) return -EINVAL; switch (h_v) { case 0x11: return V4L2_JPEG_CHROMA_SUBSAMPLING_444; case 0x21: return V4L2_JPEG_CHROMA_SUBSAMPLING_422; case 0x22: return V4L2_JPEG_CHROMA_SUBSAMPLING_420; case 0x41: return V4L2_JPEG_CHROMA_SUBSAMPLING_411; default: return -EINVAL; } } static int jpeg_parse_frame_header(struct jpeg_stream *stream, u16 sof_marker, struct v4l2_jpeg_frame_header *frame_header) { int len = jpeg_get_word_be(stream); if (len < 0) return len; /* Lf = 8 + 3 * Nf, Nf >= 1 */ if (len < 8 + 3) return -EINVAL; if (frame_header) { /* Table B.2 - Frame header parameter sizes and values */ int p, y, x, nf; int i; p = jpeg_get_byte(stream); if (p < 0) return p; /* * Baseline DCT only supports 8-bit precision. * Extended sequential DCT also supports 12-bit precision. */ if (p != 8 && (p != 12 || sof_marker != SOF1)) return -EINVAL; y = jpeg_get_word_be(stream); if (y < 0) return y; if (y == 0) return -EINVAL; x = jpeg_get_word_be(stream); if (x < 0) return x; if (x == 0) return -EINVAL; nf = jpeg_get_byte(stream); if (nf < 0) return nf; /* * The spec allows 1 <= Nf <= 255, but we only support up to 4 * components. */ if (nf < 1 || nf > V4L2_JPEG_MAX_COMPONENTS) return -EINVAL; if (len != 8 + 3 * nf) return -EINVAL; frame_header->precision = p; frame_header->height = y; frame_header->width = x; frame_header->num_components = nf; for (i = 0; i < nf; i++) { struct v4l2_jpeg_frame_component_spec *component; int c, h_v, tq; c = jpeg_get_byte(stream); if (c < 0) return c; h_v = jpeg_get_byte(stream); if (h_v < 0) return h_v; if (i == 0) { int subs; subs = v4l2_jpeg_decode_subsampling(nf, h_v); if (subs < 0) return subs; frame_header->subsampling = subs; } else if (h_v != 0x11) { /* all chroma sampling factors must be 1 */ return -EINVAL; } tq = jpeg_get_byte(stream); if (tq < 0) return tq; component = &frame_header->component[i]; component->component_identifier = c; component->horizontal_sampling_factor = (h_v >> 4) & 0xf; component->vertical_sampling_factor = h_v & 0xf; component->quantization_table_selector = tq; } } else { return jpeg_skip(stream, len - 2); } return 0; } static int jpeg_parse_scan_header(struct jpeg_stream *stream, struct v4l2_jpeg_scan_header *scan_header) { size_t skip; int len = jpeg_get_word_be(stream); if (len < 0) return len; /* Ls = 8 + 3 * Ns, Ns >= 1 */ if (len < 6 + 2) return -EINVAL; if (scan_header) { int ns; int i; ns = jpeg_get_byte(stream); if (ns < 0) return ns; if (ns < 1 || ns > 4 || len != 6 + 2 * ns) return -EINVAL; scan_header->num_components = ns; for (i = 0; i < ns; i++) { struct v4l2_jpeg_scan_component_spec *component; int cs, td_ta; cs = jpeg_get_byte(stream); if (cs < 0) return cs; td_ta = jpeg_get_byte(stream); if (td_ta < 0) return td_ta; component = &scan_header->component[i]; component->component_selector = cs; component->dc_entropy_coding_table_selector = (td_ta >> 4) & 0xf; component->ac_entropy_coding_table_selector = td_ta & 0xf; } skip = 3; /* skip Ss, Se, Ah, and Al */ } else { skip = len - 2; } return jpeg_skip(stream, skip); } /* B.2.4.1 Quantization table-specification syntax */ static int jpeg_parse_quantization_tables(struct jpeg_stream *stream, u8 precision, struct v4l2_jpeg_reference *tables) { int len = jpeg_get_word_be(stream); if (len < 0) return len; /* Lq = 2 + n * 65 (for baseline DCT), n >= 1 */ if (len < 2 + 65) return -EINVAL; len -= 2; while (len >= 65) { u8 pq, tq, *qk; int ret; int pq_tq = jpeg_get_byte(stream); if (pq_tq < 0) return pq_tq; /* quantization table element precision */ pq = (pq_tq >> 4) & 0xf; /* * Only 8-bit Qk values for 8-bit sample precision. Extended * sequential DCT with 12-bit sample precision also supports * 16-bit Qk values. */ if (pq != 0 && (pq != 1 || precision != 12)) return -EINVAL; /* quantization table destination identifier */ tq = pq_tq & 0xf; if (tq > 3) return -EINVAL; /* quantization table element */ qk = stream->curr; ret = jpeg_skip(stream, pq ? 128 : 64); if (ret < 0) return -EINVAL; if (tables) { tables[tq].start = qk; tables[tq].length = pq ? 128 : 64; } len -= pq ? 129 : 65; } return 0; } /* B.2.4.2 Huffman table-specification syntax */ static int jpeg_parse_huffman_tables(struct jpeg_stream *stream, struct v4l2_jpeg_reference *tables) { int mt; int len = jpeg_get_word_be(stream); if (len < 0) return len; /* Table B.5 - Huffman table specification parameter sizes and values */ if (len < 2 + 17) return -EINVAL; for (len -= 2; len >= 17; len -= 17 + mt) { u8 tc, th, *table; int tc_th = jpeg_get_byte(stream); int i, ret; if (tc_th < 0) return tc_th; /* table class - 0 = DC, 1 = AC */ tc = (tc_th >> 4) & 0xf; if (tc > 1) return -EINVAL; /* huffman table destination identifier */ th = tc_th & 0xf; /* only two Huffman tables for baseline DCT */ if (th > 1) return -EINVAL; /* BITS - number of Huffman codes with length i */ table = stream->curr; mt = 0; for (i = 0; i < 16; i++) { int li; li = jpeg_get_byte(stream); if (li < 0) return li; mt += li; } /* HUFFVAL - values associated with each Huffman code */ ret = jpeg_skip(stream, mt); if (ret < 0) return ret; if (tables) { tables[(tc << 1) | th].start = table; tables[(tc << 1) | th].length = stream->curr - table; } } return jpeg_skip(stream, len - 2); } /* B.2.4.4 Restart interval definition syntax */ static int jpeg_parse_restart_interval(struct jpeg_stream *stream, u16 *restart_interval) { int len = jpeg_get_word_be(stream); int ri; if (len < 0) return len; if (len != 4) return -EINVAL; ri = jpeg_get_word_be(stream); if (ri < 0) return ri; *restart_interval = ri; return 0; } static int jpeg_skip_segment(struct jpeg_stream *stream) { int len = jpeg_get_word_be(stream); if (len < 0) return len; if (len < 2) return -EINVAL; return jpeg_skip(stream, len - 2); } /* Rec. ITU-T T.872 (06/2012) 6.5.3 */ static int jpeg_parse_app14_data(struct jpeg_stream *stream, enum v4l2_jpeg_app14_tf *tf) { int ret; int lp; int skip; lp = jpeg_get_word_be(stream); if (lp < 0) return lp; /* Check for "Adobe\0" in Ap1..6 */ if (stream->curr + 6 > stream->end || strncmp(stream->curr, "Adobe\0", 6)) return -EINVAL; /* get to Ap12 */ ret = jpeg_skip(stream, 11); if (ret < 0) return ret; ret = jpeg_get_byte(stream); if (ret < 0) return ret; *tf = ret; /* skip the rest of the segment, this ensures at least it is complete */ skip = lp - 2 - 11; return jpeg_skip(stream, skip); } /** * v4l2_jpeg_parse_header - locate marker segments and optionally parse headers * @buf: address of the JPEG buffer, should start with a SOI marker * @len: length of the JPEG buffer * @out: returns marker segment positions and optionally parsed headers * * The out->scan_header pointer must be initialized to NULL or point to a valid * v4l2_jpeg_scan_header structure. The out->huffman_tables and * out->quantization_tables pointers must be initialized to NULL or point to a * valid array of 4 v4l2_jpeg_reference structures each. * * Returns 0 or negative error if parsing failed. */ int v4l2_jpeg_parse_header(void *buf, size_t len, struct v4l2_jpeg_header *out) { struct jpeg_stream stream; int marker; int ret = 0; stream.curr = buf; stream.end = stream.curr + len; out->num_dht = 0; out->num_dqt = 0; /* the first bytes must be SOI, B.2.1 High-level syntax */ if (jpeg_get_word_be(&stream) != SOI) return -EINVAL; /* init value to signal if this marker is not present */ out->app14_tf = V4L2_JPEG_APP14_TF_UNKNOWN; /* loop through marker segments */ while ((marker = jpeg_next_marker(&stream)) >= 0) { switch (marker) { /* baseline DCT, extended sequential DCT */ case SOF0 ... SOF1: ret = jpeg_reference_segment(&stream, &out->sof); if (ret < 0) return ret; ret = jpeg_parse_frame_header(&stream, marker, &out->frame); break; /* progressive, lossless */ case SOF2 ... SOF3: /* differential coding */ case SOF5 ... SOF7: /* arithmetic coding */ case SOF9 ... SOF11: case SOF13 ... SOF15: case DAC: case TEM: return -EINVAL; case DHT: ret = jpeg_reference_segment(&stream, &out->dht[out->num_dht++ % 4]); if (ret < 0) return ret; if (!out->huffman_tables) { ret = jpeg_skip_segment(&stream); break; } ret = jpeg_parse_huffman_tables(&stream, out->huffman_tables); break; case DQT: ret = jpeg_reference_segment(&stream, &out->dqt[out->num_dqt++ % 4]); if (ret < 0) return ret; if (!out->quantization_tables) { ret = jpeg_skip_segment(&stream); break; } ret = jpeg_parse_quantization_tables(&stream, out->frame.precision, out->quantization_tables); break; case DRI: ret = jpeg_parse_restart_interval(&stream, &out->restart_interval); break; case APP14: ret = jpeg_parse_app14_data(&stream, &out->app14_tf); break; case SOS: ret = jpeg_reference_segment(&stream, &out->sos); if (ret < 0) return ret; ret = jpeg_parse_scan_header(&stream, out->scan); /* * stop parsing, the scan header marks the beginning of * the entropy coded segment */ out->ecs_offset = stream.curr - (u8 *)buf; return ret; /* markers without parameters */ case RST0 ... RST7: /* restart */ case SOI: /* start of image */ case EOI: /* end of image */ break; /* skip unknown or unsupported marker segments */ default: ret = jpeg_skip_segment(&stream); break; } if (ret < 0) return ret; } return marker; } EXPORT_SYMBOL_GPL(v4l2_jpeg_parse_header); /** * v4l2_jpeg_parse_frame_header - parse frame header * @buf: address of the frame header, after the SOF0 marker * @len: length of the frame header * @frame_header: returns the parsed frame header * * Returns 0 or negative error if parsing failed. */ int v4l2_jpeg_parse_frame_header(void *buf, size_t len, struct v4l2_jpeg_frame_header *frame_header) { struct jpeg_stream stream; stream.curr = buf; stream.end = stream.curr + len; return jpeg_parse_frame_header(&stream, SOF0, frame_header); } EXPORT_SYMBOL_GPL(v4l2_jpeg_parse_frame_header); /** * v4l2_jpeg_parse_scan_header - parse scan header * @buf: address of the scan header, after the SOS marker * @len: length of the scan header * @scan_header: returns the parsed scan header * * Returns 0 or negative error if parsing failed. */ int v4l2_jpeg_parse_scan_header(void *buf, size_t len, struct v4l2_jpeg_scan_header *scan_header) { struct jpeg_stream stream; stream.curr = buf; stream.end = stream.curr + len; return jpeg_parse_scan_header(&stream, scan_header); } EXPORT_SYMBOL_GPL(v4l2_jpeg_parse_scan_header); /** * v4l2_jpeg_parse_quantization_tables - parse quantization tables segment * @buf: address of the quantization table segment, after the DQT marker * @len: length of the quantization table segment * @precision: sample precision (P) in bits per component * @q_tables: returns four references into the buffer for the * four possible quantization table destinations * * Returns 0 or negative error if parsing failed. */ int v4l2_jpeg_parse_quantization_tables(void *buf, size_t len, u8 precision, struct v4l2_jpeg_reference *q_tables) { struct jpeg_stream stream; stream.curr = buf; stream.end = stream.curr + len; return jpeg_parse_quantization_tables(&stream, precision, q_tables); } EXPORT_SYMBOL_GPL(v4l2_jpeg_parse_quantization_tables); /** * v4l2_jpeg_parse_huffman_tables - parse huffman tables segment * @buf: address of the Huffman table segment, after the DHT marker * @len: length of the Huffman table segment * @huffman_tables: returns four references into the buffer for the * four possible Huffman table destinations, in * the order DC0, DC1, AC0, AC1 * * Returns 0 or negative error if parsing failed. */ int v4l2_jpeg_parse_huffman_tables(void *buf, size_t len, struct v4l2_jpeg_reference *huffman_tables) { struct jpeg_stream stream; stream.curr = buf; stream.end = stream.curr + len; return jpeg_parse_huffman_tables(&stream, huffman_tables); } EXPORT_SYMBOL_GPL(v4l2_jpeg_parse_huffman_tables); |