Messages in this thread | | | Date | Thu, 17 Aug 2023 15:24:04 -0600 | Subject | Re: [PATCH 3/7] wifi: cfg80211: Annotate struct cfg80211_mbssid_elems with __counted_by | From | "Gustavo A. R. Silva" <> |
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On 8/17/23 15:15, Kees Cook wrote: > Prepare for the coming implementation by GCC and Clang of the __counted_by > attribute. Flexible array members annotated with __counted_by can have > their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS > (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family > functions). > > As found with Coccinelle[1], add __counted_by for struct cfg80211_mbssid_elems. > Additionally, since the element count member must be set before accessing > the annotated flexible array member, move its initialization earlier. > > [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci > > Cc: Johannes Berg <johannes@sipsolutions.net> > Cc: "David S. Miller" <davem@davemloft.net> > Cc: Eric Dumazet <edumazet@google.com> > Cc: Jakub Kicinski <kuba@kernel.org> > Cc: Paolo Abeni <pabeni@redhat.com> > Cc: linux-wireless@vger.kernel.org > Cc: netdev@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Thanks -- Gustavo
> --- > include/net/cfg80211.h | 2 +- > net/wireless/nl80211.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h > index eb73b5af5d04..5c7d091b3925 100644 > --- a/include/net/cfg80211.h > +++ b/include/net/cfg80211.h > @@ -1187,7 +1187,7 @@ struct cfg80211_mbssid_elems { > struct { > const u8 *data; > size_t len; > - } elem[]; > + } elem[] __counted_by(cnt); > }; > > /** > diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c > index 80633e815311..9ba4266368db 100644 > --- a/net/wireless/nl80211.c > +++ b/net/wireless/nl80211.c > @@ -5438,13 +5438,13 @@ nl80211_parse_mbssid_elems(struct wiphy *wiphy, struct nlattr *attrs) > elems = kzalloc(struct_size(elems, elem, num_elems), GFP_KERNEL); > if (!elems) > return ERR_PTR(-ENOMEM); > + elems->cnt = num_elems; > > nla_for_each_nested(nl_elems, attrs, rem_elems) { > elems->elem[i].data = nla_data(nl_elems); > elems->elem[i].len = nla_len(nl_elems); > i++; > } > - elems->cnt = num_elems; > return elems; > } >
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