Out-of-bounds read in Linux kernel wilc1000 P2P public action frames

In the Linux kernel, the following vulnerability has been resolved: wifi: wilc1000: fix out-of-bounds read in P2P public action frames wilc_wfi_p2p_rx() and mgmt_tx() start parsing a frame once ieee80211_is_public_action() returns true. That helper only verifies the frame is long enough for the action category field, that is offsetofend(struct ieee80211_mgmt, u.action.category), 25 bytes. Both functions then read the P2P public action header up to oui_subtype at offset 30 and pass "size - ie_offset" to cfg80211_find_vendor_ie(), where ie_offset is offsetof(struct ieee80211_mgmt, u) + sizeof(*d), i.e. 32. A public action frame of 25 to 31 bytes passes the check but is shorter than that 32 byte header, so oui_subtype can be read out of bounds, and because the length is unsigned, "size - ie_offset" underflows to a value close to 4 GiB. cfg80211_find_vendor_ie() takes an unsigned int length, so even the size_t subtraction in mgmt_tx() is truncated to the same value. It then walks far past the buffer searching for a vendor element until it reaches unmapped memory. In the receive path the frame arrives over the air and needs no association, so a nearby unauthenticated device can crash the host while it is in P2P listen. Reject frames shorter than the P2P public action header in both paths before dereferencing it.