CVE-2025-38478 Information

Jul 29, 2025 cve

Description

In the Linux kernel the following vulnerability has been resolved:

comedi: Fix initialization of data for instructions that write to subdevice

Some Comedi subdevice instruction handlers are known to access instruction data elements beyond the first insn->n elements in some cases. The do_insn_ioctl() and do_insnlist_ioctl() functions allocate at least MIN_SAMPLES (16) data elements to deal with this but they do not initialize all of that. For Comedi instruction codes that write to the subdevice the first insn->n data elements are copied from user-space but the remaining elements are left uninitialized. That could be a problem if the subdevice instruction handler reads the uninitialized data. Ensure that the first MIN_SAMPLES elements are initialized before calling these instruction handlers filling the uncopied elements with 0. For do_insnlist_ioctl() the same data buffer elements are used for handling a list of instructions so ensure the first MIN_SAMPLES elements are initialized for each instruction that writes to the subdevice.

Reference

https://git.kernel.org/stable/c/46d8c744136ce2454aa4c35c138cc06817f92b8e https://git.kernel.org/stable/c/673ee92bd2d31055bca98a1d96b653f5284289c4 https://git.kernel.org/stable/c/c42116dc70af6664526f7aa82cf937824ab42649 https://git.kernel.org/stable/c/d3436638738ace8f101af7bdee2eae1bc38e9b29 https://git.kernel.org/stable/c/fe8713fb4e4e82a4f91910d9a41bf0613e69a0b9

CNNVD-202507-3455 (Published: 2025-07-28)

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