Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:  wifi: mac80211: fix NULL pointer dereference in mesh_rx_csa_frame()  In mesh_rx_csa_frame(), elems->mesh_chansw_params_ie is dereferenced at lines 1638 and 1642 without a prior NULL check:      ifmsh->chsw_ttl = elems->mesh_chansw_params_ie->mesh_ttl;     ...     pre_value = le16_to_cpu(elems->mesh_chansw_params_ie->mesh_pre_value);  The mesh_matches_local() check above only validates the Mesh ID, Mesh Configuration, and Supported Rates IEs.  It does not verify the presence of the Mesh Channel Switch Parameters IE (element ID 118). When a received CSA action frame omits that IE, ieee802_11_parse_elems() leaves elems->mesh_chansw_params_ie as NULL, and the unconditional dereference causes a kernel NULL pointer dereference.  A remote mesh peer with an established peer link (PLINK_ESTAB) can trigger this by sending a crafted SPECTRUM_MGMT/CHL_SWITCH action frame that includes a matching Mesh ID and Mesh Configuration IE but omits the Mesh Channel Switch Parameters IE.  No authentication beyond the default open mesh peering is required.  Crash confirmed on kernel 6.17.0-5-generic via mac80211_hwsim:    BUG: kernel NULL pointer dereference, address: 0000000000000000   Oops: Oops: 0000 [#1] SMP NOPTI   RIP: 0010:ieee80211_mesh_rx_queued_mgmt+0x143/0x2a0 [mac80211]   CR2: 0000000000000000  Fix by adding a NULL check for mesh_chansw_params_ie after mesh_matches_local() returns, consistent with how other optional IEs are guarded throughout the mesh code.  The bug has been present since v3.13 (released 2014-01-19).