On Mon, Nov 02, 2020 at 12:43:01PM +0000, Lee Jones wrote: > On Mon, 02 Nov 2020, gre...@linuxfoundation.org wrote: > > > On Mon, Nov 02, 2020 at 11:49:03AM +0000, Lee Jones wrote: > > > On Mon, 02 Nov 2020, David Laight wrote: > > > > > > > From: Lee Jones > > > > > Sent: 02 November 2020 11:12 > > > > > > > > > > strncpy() may not provide a NUL terminator, which means that a 1-byte > > > > > leak would be possible *if* this was ever copied to userspace. Ensure > > > > > the buffer will always be NUL terminated by using the kernel's > > > > > strscpy() which a) uses the destination (instead of the source) size > > > > > as the bytes to copy and b) is *always* NUL terminated. > > > > > > > > > > Cc: Rodolfo Giometti <giome...@enneenne.com> > > > > > Cc: "Eurotech S.p.A" <i...@eurotech.it> > > > > > Reported-by: Geert Uytterhoeven <geert+rene...@glider.be> > > > > > Acked-by: Arnd Bergmann <a...@arndb.de> > > > > > Signed-off-by: Lee Jones <lee.jo...@linaro.org> > > > > > --- > > > > > drivers/misc/c2port/core.c | 2 +- > > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > > > diff --git a/drivers/misc/c2port/core.c b/drivers/misc/c2port/core.c > > > > > index 80d87e8a0bea9..b96444ec94c7e 100644 > > > > > --- a/drivers/misc/c2port/core.c > > > > > +++ b/drivers/misc/c2port/core.c > > > > > @@ -923,7 +923,7 @@ struct c2port_device *c2port_device_register(char > > > > > *name, > > > > > } > > > > > dev_set_drvdata(c2dev->dev, c2dev); > > > > > > > > > > - strncpy(c2dev->name, name, C2PORT_NAME_LEN - 1); > > > > > + strscpy(c2dev->name, name, sizeof(c2dev->name)); > > > > > > > > strscpy() doesn't zero fill so if the memory isn't zeroed > > > > and a 'blind' copy to user of the structure is done > > > > then more data is leaked. > > > > > > > > strscpy() may be better, but rational isn't right. > > > > > > The original patch zeroed the data too, but I was asked to remove that > > > part [0]. In your opinion, should it be reinstated? > > > > > > [0] https://lore.kernel.org/patchwork/patch/1272290/ > > > > Just keep the kzalloc() part of the patch, this portion makes no sense > > to me. > > Can do. > > > But if you REALLY want to get it correct, call dev_set_name() > > instead please, as that is what it is there for. > > The line above isn't setting the 'struct device' name. It looks as > though 'struct c2port' has it's own member, also called 'name'. As to > how they differ, I'm not currently aware. Nor do I wish to mess > around with the semantics all that much. > > Going with suggestion #1.
As the "device" already has a name, I suggest just getting rid of this name field anyway, no need for duplicates. thanks, greg k-h
