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_pmsr_request. 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@xxxxxxxxxxxxxxxx> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> Cc: Eric Dumazet <edumazet@xxxxxxxxxx> Cc: Jakub Kicinski <kuba@xxxxxxxxxx> Cc: Paolo Abeni <pabeni@xxxxxxxxxx> Cc: linux-wireless@xxxxxxxxxxxxxxx Cc: netdev@xxxxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- include/net/cfg80211.h | 2 +- net/wireless/pmsr.c | 3 +-- 2 files changed, 2 insertions(+), 3 deletions(-) diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h index 5c7d091b3925..e9ca4726a732 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -3948,7 +3948,7 @@ struct cfg80211_pmsr_request { struct list_head list; - struct cfg80211_pmsr_request_peer peers[]; + struct cfg80211_pmsr_request_peer peers[] __counted_by(n_peers); }; /** diff --git a/net/wireless/pmsr.c b/net/wireless/pmsr.c index 77000a264855..9611aa0bd051 100644 --- a/net/wireless/pmsr.c +++ b/net/wireless/pmsr.c @@ -291,6 +291,7 @@ int nl80211_pmsr_start(struct sk_buff *skb, struct genl_info *info) req = kzalloc(struct_size(req, peers, count), GFP_KERNEL); if (!req) return -ENOMEM; + req->n_peers = count; if (info->attrs[NL80211_ATTR_TIMEOUT]) req->timeout = nla_get_u32(info->attrs[NL80211_ATTR_TIMEOUT]); @@ -321,8 +322,6 @@ int nl80211_pmsr_start(struct sk_buff *skb, struct genl_info *info) goto out_err; idx++; } - - req->n_peers = count; req->cookie = cfg80211_assign_cookie(rdev); req->nl_portid = info->snd_portid; -- 2.34.1
