tree: https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git topic/midi20 head: 77700b81bd0e47d89d50eb4b3f2f323492f79998 commit: 46397622a3fa8372b8fda0f04b33d16923b03b1b [25/40] ALSA: seq: Add UMP support config: i386-randconfig-m021-20230525 (https://download.01.org/0day-ci/archive/20230526/202305261415.NY0vapZK-lkp@i...) compiler: gcc-11 (Debian 11.3.0-12) 11.3.0

If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot lkp@intel.com | Reported-by: Dan Carpenter error27@gmail.com | Closes: https://lore.kernel.org/r/202305261415.NY0vapZK-lkp@intel.com/

smatch warnings: sound/core/seq/seq_clientmgr.c:482 snd_seq_read() error: copy_to_user() '&cell->event' too small (28 vs 32)

vim +482 sound/core/seq/seq_clientmgr.c

c7e0b5bf9fff1b Takashi Iwai 2005-11-17 407 static ssize_t snd_seq_read(struct file *file, char __user *buf, size_t count, c7e0b5bf9fff1b Takashi Iwai 2005-11-17 408 loff_t *offset) ^1da177e4c3f41 Linus Torvalds 2005-04-16 409 { c7e0b5bf9fff1b Takashi Iwai 2005-11-17 410 struct snd_seq_client *client = file->private_data; c7e0b5bf9fff1b Takashi Iwai 2005-11-17 411 struct snd_seq_fifo *fifo; 46397622a3fa83 Takashi Iwai 2023-05-23 412 size_t aligned_size; ^1da177e4c3f41 Linus Torvalds 2005-04-16 413 int err; ^1da177e4c3f41 Linus Torvalds 2005-04-16 414 long result = 0; c7e0b5bf9fff1b Takashi Iwai 2005-11-17 415 struct snd_seq_event_cell *cell; ^1da177e4c3f41 Linus Torvalds 2005-04-16 416 ^1da177e4c3f41 Linus Torvalds 2005-04-16 417 if (!(snd_seq_file_flags(file) & SNDRV_SEQ_LFLG_INPUT)) ^1da177e4c3f41 Linus Torvalds 2005-04-16 418 return -ENXIO; ^1da177e4c3f41 Linus Torvalds 2005-04-16 419 96d4f267e40f95 Linus Torvalds 2019-01-03 420 if (!access_ok(buf, count)) ^1da177e4c3f41 Linus Torvalds 2005-04-16 421 return -EFAULT; ^1da177e4c3f41 Linus Torvalds 2005-04-16 422 ^1da177e4c3f41 Linus Torvalds 2005-04-16 423 /* check client structures are in place */ 7eaa943c8ed8e9 Takashi Iwai 2008-08-08 424 if (snd_BUG_ON(!client)) 7eaa943c8ed8e9 Takashi Iwai 2008-08-08 425 return -ENXIO; ^1da177e4c3f41 Linus Torvalds 2005-04-16 426 f9a6bb841f7370 Takashi Iwai 2021-06-08 427 if (!client->accept_input) f9a6bb841f7370 Takashi Iwai 2021-06-08 428 return -ENXIO; f9a6bb841f7370 Takashi Iwai 2021-06-08 429 fifo = client->data.user.fifo; f9a6bb841f7370 Takashi Iwai 2021-06-08 430 if (!fifo) ^1da177e4c3f41 Linus Torvalds 2005-04-16 431 return -ENXIO; ^1da177e4c3f41 Linus Torvalds 2005-04-16 432 ^1da177e4c3f41 Linus Torvalds 2005-04-16 433 if (atomic_read(&fifo->overflow) > 0) { ^1da177e4c3f41 Linus Torvalds 2005-04-16 434 /* buffer overflow is detected */ ^1da177e4c3f41 Linus Torvalds 2005-04-16 435 snd_seq_fifo_clear(fifo); ^1da177e4c3f41 Linus Torvalds 2005-04-16 436 /* return error code */ ^1da177e4c3f41 Linus Torvalds 2005-04-16 437 return -ENOSPC; ^1da177e4c3f41 Linus Torvalds 2005-04-16 438 } ^1da177e4c3f41 Linus Torvalds 2005-04-16 439 ^1da177e4c3f41 Linus Torvalds 2005-04-16 440 cell = NULL; ^1da177e4c3f41 Linus Torvalds 2005-04-16 441 err = 0; ^1da177e4c3f41 Linus Torvalds 2005-04-16 442 snd_seq_fifo_lock(fifo); ^1da177e4c3f41 Linus Torvalds 2005-04-16 443 46397622a3fa83 Takashi Iwai 2023-05-23 444 if (client->midi_version > 0) 46397622a3fa83 Takashi Iwai 2023-05-23 445 aligned_size = sizeof(struct snd_seq_ump_event); 46397622a3fa83 Takashi Iwai 2023-05-23 446 else 46397622a3fa83 Takashi Iwai 2023-05-23 447 aligned_size = sizeof(struct snd_seq_event); 46397622a3fa83 Takashi Iwai 2023-05-23 448 ^1da177e4c3f41 Linus Torvalds 2005-04-16 449 /* while data available in queue */ 46397622a3fa83 Takashi Iwai 2023-05-23 450 while (count >= aligned_size) { ^1da177e4c3f41 Linus Torvalds 2005-04-16 451 int nonblock; ^1da177e4c3f41 Linus Torvalds 2005-04-16 452 ^1da177e4c3f41 Linus Torvalds 2005-04-16 453 nonblock = (file->f_flags & O_NONBLOCK) || result > 0; f9a6bb841f7370 Takashi Iwai 2021-06-08 454 err = snd_seq_fifo_cell_out(fifo, &cell, nonblock); f9a6bb841f7370 Takashi Iwai 2021-06-08 455 if (err < 0) ^1da177e4c3f41 Linus Torvalds 2005-04-16 456 break; 46397622a3fa83 Takashi Iwai 2023-05-23 457 if (!event_is_compatible(client, &cell->event)) { 46397622a3fa83 Takashi Iwai 2023-05-23 458 snd_seq_cell_free(cell); 46397622a3fa83 Takashi Iwai 2023-05-23 459 cell = NULL; 46397622a3fa83 Takashi Iwai 2023-05-23 460 continue; 46397622a3fa83 Takashi Iwai 2023-05-23 461 } ^1da177e4c3f41 Linus Torvalds 2005-04-16 462 if (snd_seq_ev_is_variable(&cell->event)) {

Smatch isn't clever enough to know that if snd_seq_ev_is_variable() is false that means client->midi_version is zero.

46397622a3fa83 Takashi Iwai 2023-05-23 463 struct snd_seq_ump_event tmpev; 46397622a3fa83 Takashi Iwai 2023-05-23 464 46397622a3fa83 Takashi Iwai 2023-05-23 465 memcpy(&tmpev, &cell->event, aligned_size); ^1da177e4c3f41 Linus Torvalds 2005-04-16 466 tmpev.data.ext.len &= ~SNDRV_SEQ_EXT_MASK; 46397622a3fa83 Takashi Iwai 2023-05-23 467 if (copy_to_user(buf, &tmpev, aligned_size)) { ^1da177e4c3f41 Linus Torvalds 2005-04-16 468 err = -EFAULT; ^1da177e4c3f41 Linus Torvalds 2005-04-16 469 break; ^1da177e4c3f41 Linus Torvalds 2005-04-16 470 } 46397622a3fa83 Takashi Iwai 2023-05-23 471 count -= aligned_size; 46397622a3fa83 Takashi Iwai 2023-05-23 472 buf += aligned_size; 4d23359b7ec8b0 Clemens Ladisch 2005-09-05 473 err = snd_seq_expand_var_event(&cell->event, count, 4d23359b7ec8b0 Clemens Ladisch 2005-09-05 474 (char __force *)buf, 0, 46397622a3fa83 Takashi Iwai 2023-05-23 475 aligned_size); ^1da177e4c3f41 Linus Torvalds 2005-04-16 476 if (err < 0) ^1da177e4c3f41 Linus Torvalds 2005-04-16 477 break; ^1da177e4c3f41 Linus Torvalds 2005-04-16 478 result += err; ^1da177e4c3f41 Linus Torvalds 2005-04-16 479 count -= err; ^1da177e4c3f41 Linus Torvalds 2005-04-16 480 buf += err; ^1da177e4c3f41 Linus Torvalds 2005-04-16 481 } else { 46397622a3fa83 Takashi Iwai 2023-05-23 @482 if (copy_to_user(buf, &cell->event, aligned_size)) {

So smatch complains that this might be a read overflow.

^1da177e4c3f41 Linus Torvalds 2005-04-16 483 err = -EFAULT; ^1da177e4c3f41 Linus Torvalds 2005-04-16 484 break; ^1da177e4c3f41 Linus Torvalds 2005-04-16 485 } 46397622a3fa83 Takashi Iwai 2023-05-23 486 count -= aligned_size; 46397622a3fa83 Takashi Iwai 2023-05-23 487 buf += aligned_size; ^1da177e4c3f41 Linus Torvalds 2005-04-16 488 } ^1da177e4c3f41 Linus Torvalds 2005-04-16 489 snd_seq_cell_free(cell); ^1da177e4c3f41 Linus Torvalds 2005-04-16 490 cell = NULL; /* to be sure */ 46397622a3fa83 Takashi Iwai 2023-05-23 491 result += aligned_size; ^1da177e4c3f41 Linus Torvalds 2005-04-16 492 } ^1da177e4c3f41 Linus Torvalds 2005-04-16 493 ^1da177e4c3f41 Linus Torvalds 2005-04-16 494 if (err < 0) { ^1da177e4c3f41 Linus Torvalds 2005-04-16 495 if (cell) ^1da177e4c3f41 Linus Torvalds 2005-04-16 496 snd_seq_fifo_cell_putback(fifo, cell); ^1da177e4c3f41 Linus Torvalds 2005-04-16 497 if (err == -EAGAIN && result > 0) ^1da177e4c3f41 Linus Torvalds 2005-04-16 498 err = 0; ^1da177e4c3f41 Linus Torvalds 2005-04-16 499 } ^1da177e4c3f41 Linus Torvalds 2005-04-16 500 snd_seq_fifo_unlock(fifo); ^1da177e4c3f41 Linus Torvalds 2005-04-16 501 ^1da177e4c3f41 Linus Torvalds 2005-04-16 502 return (err < 0) ? err : result; ^1da177e4c3f41 Linus Torvalds 2005-04-16 503 }