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strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. We expect both hi.data.modename and hi.data.drivername to be NUL-terminated based on its usage with sprintf: | sprintf(hi.data.modename, "%sclk,%smodem,fclk=%d,bps=%d%s", | bc->cfg.intclk ? "int" : "ext", | bc->cfg.extmodem ? "ext" : "int", bc->cfg.fclk, bc->cfg.bps, | bc->cfg.loopback ? ",loopback" : ""); Note that this data is copied out to userspace with: | if (copy_to_user(data, &hi, sizeof(hi))) ... however, the data was also copied FROM the user here: | if (copy_from_user(&hi, data, sizeof(hi))) Considering the above, a suitable replacement is strscpy_pad() as it guarantees NUL-termination on the destination buffer while also NUL-padding (which is good+wanted behavior when copying data to userspace). Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://github.com/KSPP/linux/issues/90 Signed-off-by: Justin Stitt <justinstitt@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://lore.kernel.org/r/20231016-strncpy-drivers-net-hamradio-baycom_epp-c-v2-1-39f72a72de30@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.