lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <123F9651-9469-4F2B-ADC1-12293C9EA7FE@kernel.org> Date: Mon, 16 Oct 2023 10:03:57 -0700 From: Kees Cook <kees@...nel.org> To: Dan Carpenter <dan.carpenter@...aro.org>, Simon Horman <horms@...nel.org> CC: Justin Stitt <justinstitt@...gle.com>, Thomas Sailer <t.sailer@...mni.ethz.ch>, "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, linux-hams@...r.kernel.org, netdev@...r.kernel.org, linux-kernel@...r.kernel.org, linux-hardening@...r.kernel.org Subject: Re: [PATCH] hamradio: replace deprecated strncpy with strscpy On October 16, 2023 10:01:20 AM PDT, Kees Cook <kees@...nel.org> wrote: > > >On October 15, 2023 10:47:53 PM PDT, Dan Carpenter <dan.carpenter@...aro.org> wrote: >>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. > >True but since this used to zero the rest of the buffet, let's just keep that behavior and use strscpy_pad(). I'm calling all byte arrays a "buffet" from now on. ;) -- Kees Cook
Powered by blists - more mailing lists