From: Kees Cook <keescook@chromium.org>
To: laniel_francis@privacyrequired.com
Cc: Jakub Kicinski <kuba@kernel.org>,
linux-hardening@vger.kernel.org, davem@davemloft.net
Subject: Re: [RFC][PATCH v2 2/3] Modify return value of nla_strlcpy to match that of strscpy.
Date: Mon, 19 Oct 2020 16:01:27 -0700 [thread overview]
Message-ID: <202010191559.3AC2C3F97@keescook> (raw)
In-Reply-To: <20201019094355.4f6f3826@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
On Mon, Oct 19, 2020 at 09:43:55AM -0700, Jakub Kicinski wrote:
> On Mon, 19 Oct 2020 17:23:30 +0200 laniel_francis@privacyrequired.com
> wrote:
> > -size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
> > +ssize_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
> > {
> > + size_t len;
> > + ssize_t ret;
> > size_t srclen = nla_len(nla);
> > char *src = nla_data(nla);
>
> Sort local variables long to short.
Specifically, "reverse christmas tree":
size_t srclen = nla_len(nla);
char *src = nla_data(nla);
size_t len;
ssize_t ret;
> > diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
> > index 41a55c6cbeb8..f0bf64393cbf 100644
> > --- a/net/sched/cls_api.c
> > +++ b/net/sched/cls_api.c
> > @@ -223,7 +223,7 @@ static inline u32 tcf_auto_prio(struct tcf_proto *tp)
> > static bool tcf_proto_check_kind(struct nlattr *kind, char *name)
> > {
> > if (kind)
> > - return nla_strlcpy(name, kind, IFNAMSIZ) >= IFNAMSIZ;
> > + return nla_strlcpy(name, kind, IFNAMSIZ) > 0;
>
> Bug.
>
> > memset(name, 0, IFNAMSIZ);
> > return false;
> > }
Have you been able to exercise the changed code paths? (I would have
expected this to immediately fail, for example.)
--
Kees Cook
next prev parent reply other threads:[~2020-10-19 23:01 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-16 12:52 [RFC][PATCH v1] Fix and rename nla_strlcpy to nla_strcpy laniel_francis
2020-10-16 12:52 ` [PATCH v1 1/3] Fix unefficient call to memset before memcpu in nla_strlcpy laniel_francis
2020-10-16 23:19 ` Kees Cook
2020-10-17 8:50 ` Francis Laniel
2020-10-16 23:29 ` Jann Horn
2020-10-17 8:50 ` Francis Laniel
2020-10-16 12:52 ` [PATCH v1 2/3] Modify return value of nla_strlcpy to match that of strscpy laniel_francis
2020-10-16 23:23 ` Kees Cook
2020-10-17 8:53 ` Francis Laniel
2020-10-17 0:41 ` Jann Horn
2020-10-17 8:56 ` Francis Laniel
2020-10-16 12:52 ` [PATCH v1 3/3] Rename nla_strlcpy to nla_strcpy laniel_francis
2020-10-16 23:18 ` Kees Cook
2020-10-19 15:23 ` [RFC][PATCH v2 0/3] Fix inefficiences and rename nla_strlcpy laniel_francis
2020-10-19 15:23 ` [RFC][PATCH v2 1/3] Fix unefficient call to memset before memcpu in nla_strlcpy laniel_francis
2020-10-19 15:23 ` [RFC][PATCH v2 2/3] Modify return value of nla_strlcpy to match that of strscpy laniel_francis
2020-10-19 16:43 ` Jakub Kicinski
2020-10-19 23:01 ` Kees Cook [this message]
2020-10-19 23:34 ` Jakub Kicinski
2020-10-20 10:28 ` Francis Laniel
2020-10-20 17:23 ` Kees Cook
2020-10-20 17:19 ` Kees Cook
2020-10-20 13:05 ` Francis Laniel
2020-10-20 10:17 ` Francis Laniel
2020-10-19 15:23 ` [RFC][PATCH v2 3/3] Rename nla_strlcpy to nla_strcpy laniel_francis
2020-10-19 16:45 ` [RFC][PATCH v2 0/3] Fix inefficiences and rename nla_strlcpy Jakub Kicinski
2020-10-19 22:58 ` Kees Cook
2020-10-19 23:34 ` Jakub Kicinski
2020-10-20 10:18 ` Francis Laniel
2020-10-19 23:03 ` Kees Cook
2020-10-20 13:06 ` Francis Laniel
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