| Message ID | 20230817211531.4193219-3-keescook@chromium.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | wifi: cfg80211: Annotate with __counted_by | expand |
On 8/17/2023 2:15 PM, 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: Jeff Johnson <quic_jjohnson@quicinc.com>
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; }
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> --- include/net/cfg80211.h | 2 +- net/wireless/nl80211.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)