Commit 7b6d7087 authored by Kees Cook's avatar Kees Cook Committed by Johannes Berg
Browse files

wifi: cfg80211: Annotate struct cfg80211_rnr_elems with __counted_by 

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_rnr_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: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarGustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: default avatarJeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20230817211531.4193219-5-keescook@chromium.org


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 342bc7c9

include/net/cfg80211.h

+1 −1
Original line number Diff line number Diff line
@@ -1204,7 +1204,7 @@ struct cfg80211_rnr_elems { 
	struct {

		const u8 *data;

		size_t len;

	} elem[];

	} elem[] __counted_by(cnt);

};



/**

net/wireless/nl80211.c

+1 −1
Original line number Diff line number Diff line
@@ -5470,13 +5470,13 @@ nl80211_parse_rnr_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;









}