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path: root/drivers/comedi/drivers.c
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12 dayscomedi: Fix use of uninitialized data in insn_rw_emulate_bits()Ian Abbott
commit e9cb26291d009243a4478a7ffb37b3a9175bfce9 upstream. For Comedi `INSN_READ` and `INSN_WRITE` instructions on "digital" subdevices (subdevice types `COMEDI_SUBD_DI`, `COMEDI_SUBD_DO`, and `COMEDI_SUBD_DIO`), it is common for the subdevice driver not to have `insn_read` and `insn_write` handler functions, but to have an `insn_bits` handler function for handling Comedi `INSN_BITS` instructions. In that case, the subdevice's `insn_read` and/or `insn_write` function handler pointers are set to point to the `insn_rw_emulate_bits()` function by `__comedi_device_postconfig()`. For `INSN_WRITE`, `insn_rw_emulate_bits()` currently assumes that the supplied `data[0]` value is a valid copy from user memory. It will at least exist because `do_insnlist_ioctl()` and `do_insn_ioctl()` in "comedi_fops.c" ensure at lease `MIN_SAMPLES` (16) elements are allocated. However, if `insn->n` is 0 (which is allowable for `INSN_READ` and `INSN_WRITE` instructions, then `data[0]` may contain uninitialized data, and certainly contains invalid data, possibly from a different instruction in the array of instructions handled by `do_insnlist_ioctl()`. This will result in an incorrect value being written to the digital output channel (or to the digital input/output channel if configured as an output), and may be reflected in the internal saved state of the channel. Fix it by returning 0 early if `insn->n` is 0, before reaching the code that accesses `data[0]`. Previously, the function always returned 1 on success, but it is supposed to be the number of data samples actually read or written up to `insn->n`, which is 0 in this case. Reported-by: syzbot+cb96ec476fb4914445c9@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=cb96ec476fb4914445c9 Fixes: ed9eccbe8970 ("Staging: add comedi core") Cc: stable@vger.kernel.org # 5.13+ Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Link: https://lore.kernel.org/r/20250707153355.82474-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
12 dayscomedi: Fix some signed shift left operationsIan Abbott
commit ab705c8c35e18652abc6239c07cf3441f03e2cda upstream. Correct some left shifts of the signed integer constant 1 by some unsigned number less than 32. Change the constant to 1U to avoid shifting a 1 into the sign bit. The corrected functions are comedi_dio_insn_config(), comedi_dio_update_state(), and __comedi_device_postconfig(). Fixes: e523c6c86232 ("staging: comedi: drivers: introduce comedi_dio_insn_config()") Fixes: 05e60b13a36b ("staging: comedi: drivers: introduce comedi_dio_update_state()") Fixes: 09567cb4373e ("staging: comedi: initialize subdevice s->io_bits in postconfig") Cc: stable@vger.kernel.org # 5.13+ Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Link: https://lore.kernel.org/r/20250707121555.65424-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-10-05comedi: comedi_8254: Replace comedi_8254_init() and comedi_8254_mm_init()Ian Abbott
`comedi_8254_init()` and `comedi_8254_mm_init()` return `NULL` on failure, but the failure is not necessarily due to lack of memory. Change them to return an `ERR_PTR` value on failure and rename the functions to make it obvious the API has changed. `comedi_8254_init()` has been replaced with `comedi_8254_io_alloc()`, and `comedi_8254_mm_init()` has been replaced with `comedi_8254_mm_alloc()`. Cc: Arnd Bergmann <arnd@kernel.org> Cc: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Link: https://lore.kernel.org/r/20230913170712.111719-4-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-19drivers: comedi: replace ternary operator with min()Guo Zhengkui
Fix the following coccicheck warning: drivers/comedi/drivers.c:857:12-13: WARNING opportunity for min(). min() macro is defined in include/linux/minmax.h. It avoids multiple evaluations of the arguments when non-constant and performs strict type-checking. Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Guo Zhengkui <guozhengkui@vivo.com> Link: https://lore.kernel.org/r/20220513071608.49047-1-guozhengkui@vivo.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-26comedi: Move the main COMEDI headersIan Abbott
Move the main COMEDI driver headers out of "drivers/comedi/" into new directory "include/linux/comedi/". These are "comedidev.h", "comedilib.h", "comedi_pci.h", "comedi_pcmcia.h", and "comedi_usb.h". Additionally, move the user-space API header "comedi.h" into "include/uapi/linux/" and add "WITH Linux-syscall-note" to its SPDX-License-Identifier. Update the "COMEDI DRIVERS" section of the MAINTAINERS file to account for these changes. Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Link: https://lore.kernel.org/r/20211117120604.117740-2-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-15staging: comedi: move out of staging directoryGreg Kroah-Hartman
The comedi code came into the kernel back in 2008, but traces its lifetime to much much earlier. It's been polished and buffed and there's really nothing preventing it from being part of the "real" portion of the kernel. So move it to drivers/comedi/ as it belongs there. Many thanks to the hundreds of developers who did the work to make this happen. Cc: Ian Abbott <abbotti@mev.co.uk> Cc: H Hartley Sweeten <hsweeten@visionengravers.com> Link: https://lore.kernel.org/r/YHauop4u3sP6lz8j@kroah.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>