CVE-2025-38480
published 2025-07-28CVE-2025-38480: In the Linux kernel, the following vulnerability has been resolved: comedi: Fix use of uninitialized data in insn_rw_emulate_bits() For Comedi `INSN_READ` and…
medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
In the Linux kernel, the following vulnerability has been resolved:
comedi: Fix use of uninitialized data in insn_rw_emulate_bits()
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.
Affected
38 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | debian_linux | — | — |
| debian | linux | < linux 6.1.147-1 (bookworm) | linux 6.1.147-1 (bookworm) |
| debian | linux-6.1 | < linux 6.1.147-1 (bookworm) | linux 6.1.147-1 (bookworm) |
| linux | linux | — | — |
| linux | linux | >= ed9eccbe8970f6eedc1b978c157caf1251a896d4 < 4c2981bf30401adfcdbfece4ab6f411f7c5875a1 | 4c2981bf30401adfcdbfece4ab6f411f7c5875a1 |
| linux | linux | >= ed9eccbe8970f6eedc1b978c157caf1251a896d4 < 16256d7efcf7acc9f39abe21522c4c6b77f67c00 | 16256d7efcf7acc9f39abe21522c4c6b77f67c00 |
| linux | linux | >= ed9eccbe8970f6eedc1b978c157caf1251a896d4 < c53570e62b5b28bdb56bb563190227f8307817a5 | c53570e62b5b28bdb56bb563190227f8307817a5 |
| linux | linux | >= ed9eccbe8970f6eedc1b978c157caf1251a896d4 < 3050d197d6bc9ef128944a70210f42d2430b3000 | 3050d197d6bc9ef128944a70210f42d2430b3000 |
| linux | linux | >= ed9eccbe8970f6eedc1b978c157caf1251a896d4 < 10f9024a8c824a41827fff1fefefb314c98e2c88 | 10f9024a8c824a41827fff1fefefb314c98e2c88 |
| linux | linux | >= ed9eccbe8970f6eedc1b978c157caf1251a896d4 < 2af1e7d389c2619219171d23f5b96dbcbb7f9656 | 2af1e7d389c2619219171d23f5b96dbcbb7f9656 |
| linux | linux | >= ed9eccbe8970f6eedc1b978c157caf1251a896d4 < 3ab55ffaaf75d0c7b68e332c1cdcc1b0e0044870 | 3ab55ffaaf75d0c7b68e332c1cdcc1b0e0044870 |
| linux | linux | >= ed9eccbe8970f6eedc1b978c157caf1251a896d4 < e9cb26291d009243a4478a7ffb37b3a9175bfce9 | e9cb26291d009243a4478a7ffb37b3a9175bfce9 |
| linux | linux_kernel | — | — |
| linux | linux_kernel | >= 0 < 5.10.244-1 | 5.10.244-1 |
| linux | linux_kernel | >= 0 < 6.1.147-1 | 6.1.147-1 |
| linux | linux_kernel | >= 0 < 6.12.41-1 | 6.12.41-1 |
| linux | linux_kernel | >= 0 < 6.16.3-1 | 6.16.3-1 |
| linux | linux_kernel | >= 0 < 5.15.0-163.173 | 5.15.0-163.173 |
| linux | linux_kernel | >= 0 < 6.8.0-100.100 | 6.8.0-100.100 |
| linux | linux_kernel | >= 2.6.29 < 5.4.297 | 5.4.297 |
| linux | linux_kernel | >= 5.11 < 5.15.190 | 5.15.190 |
| linux | linux_kernel | >= 5.16 < 6.1.147 | 6.1.147 |
| linux | linux_kernel | >= 5.5 < 5.10.241 | 5.10.241 |
| linux | linux_kernel | >= 6.13 < 6.15.8 | 6.15.8 |
| linux | linux_kernel | >= 6.2 < 6.6.100 | 6.6.100 |
CVSS provenance
nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM