Messages in this thread | | | Date | Mon, 16 Oct 2023 08:47:53 +0300 | From | Dan Carpenter <> | Subject | Re: [PATCH] hamradio: replace deprecated strncpy with strscpy |
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On Sun, Oct 15, 2023 at 05:06:19PM +0200, Simon Horman wrote: > On Thu, Oct 12, 2023 at 09:33:32PM +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 but not necessarily NUL-padded which is evident by 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))) > > Thanks Justin, > > I see that too. > > Perhaps I am off the mark here, and perhaps it's out of scope for this > patch, but I do think it would be nicer if the kernel only sent > intended data to user-space, even if any unintended payload came > from user-space. >
It's kind of normal to pass user space data back to itself. We generally only worry about info leaks.
regards, dan carpenter
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