On Mon, Oct 16, 2023 at 12:42:22PM -0700, Kees Cook wrote: > On Mon, Oct 16, 2023 at 06:42:42PM +0000, Justin Stitt wrote: > > 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 > > Cc: [email protected] > > Signed-off-by: Justin Stitt <[email protected]> > > Thanks! > > Reviewed-by: Kees Cook <[email protected]>
Likewise, thanks. I prefer this over v1. Reviewed-by: Simon Horman <[email protected]>
