From 7b6d7087031b69f0694cbef4485616c905664feb Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 17 Aug 2023 14:15:27 -0700 Subject: [PATCH] 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 Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: linux-wireless@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva Reviewed-by: Jeff Johnson Link: https://lore.kernel.org/r/20230817211531.4193219-5-keescook@chromium.org Signed-off-by: Johannes Berg --- 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 e9ca472..6efe216 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -1204,7 +1204,7 @@ struct cfg80211_rnr_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 9ba4266..0ffebf1 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -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; } -- 2.7.4