@@ -43,6 +43,10 @@ struct ieee80211_radiotap_header {
* @it_present: (first) present word
*/
__le32 it_present;
+ /**
+ * @it_optional: all remaining presence bitmaps
+ */
+ __le32 it_optional[];
} __packed;
/* version is always 0 */
@@ -359,7 +359,12 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
put_unaligned_le32(it_present_val, it_present);
- pos = (void *)(it_present + 1);
+ /* This references through an offset into it_optional[] rather
+ * than via it_present otherwise later uses of pos will cause
+ * the compiler to think we have walked past the end of the
+ * struct member.
+ */
+ pos = (void *)&rthdr->it_optional[it_present - rthdr->it_optional];
/* the order of the following fields is important */
@@ -115,10 +115,9 @@ int ieee80211_radiotap_iterator_init(
iterator->_max_length = get_unaligned_le16(&radiotap_header->it_len);
iterator->_arg_index = 0;
iterator->_bitmap_shifter = get_unaligned_le32(&radiotap_header->it_present);
- iterator->_arg = (uint8_t *)radiotap_header + sizeof(*radiotap_header);
+ iterator->_arg = (uint8_t *)radiotap_header->it_optional;
iterator->_reset_on_ext = 0;
- iterator->_next_bitmap = &radiotap_header->it_present;
- iterator->_next_bitmap++;
+ iterator->_next_bitmap = radiotap_header->it_optional;
iterator->_vns = vns;
iterator->current_namespace = &radiotap_ns;
iterator->is_radiotap_ns = 1;
In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memcpy(), memmove(), and memset(), avoid intentionally writing across neighboring fields. The it_present member of struct ieee80211_radiotap_header is treated as a flexible array (multiple u32s can be conditionally present). In order for memcpy() to reason (or really, not reason) about the size of operations against this struct, use of bytes beyond it_present need to be treated as part of the flexible array. Add a trailing flexible array and initialize its initial index via pointer arithmetic. Cc: Johannes Berg <johannes@sipsolutions.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: linux-wireless@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> --- include/net/ieee80211_radiotap.h | 4 ++++ net/mac80211/rx.c | 7 ++++++- net/wireless/radiotap.c | 5 ++--- 3 files changed, 12 insertions(+), 4 deletions(-)