From: Masashi Honma Date: Fri, 29 May 2026 23:09:44 +0000 (+0900) Subject: wifi: mac80211: Use struct instead of macro for PREP frame X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a91c65cb99d1e03c8d8f0244258cbdd2d60faa86;p=thirdparty%2Flinux.git wifi: mac80211: Use struct instead of macro for PREP frame The existing PREP_IE_* macros access HWMP PREP frame fields via hardcoded byte offsets. When the AE (Address Extension) flag is set, an additional 6 bytes appear mid-frame, making the offset arithmetic error-prone. Introduce typed packed C structs to represent the PREP frame layout: - ieee80211_mesh_hwmp_prep_top: fixed fields before the optional AE address - ieee80211_mesh_hwmp_prep_bottom: fields after the optional AE address Add ieee80211_mesh_hwmp_prep_get_bottom() to locate the bottom struct correctly based on whether the AE flag is set. This preparatory refactoring is needed to fix a 2-byte overread of orig_addr in hwmp_prep_frame_process() when AE is enabled, which is addressed in a subsequent patch. Signed-off-by: Masashi Honma Link: https://patch.msgid.link/20260529230952.124754-2-masashi.honma@gmail.com Signed-off-by: Johannes Berg --- diff --git a/include/linux/ieee80211-mesh.h b/include/linux/ieee80211-mesh.h index bf4a544aed005..4ce4e47d6d018 100644 --- a/include/linux/ieee80211-mesh.h +++ b/include/linux/ieee80211-mesh.h @@ -53,6 +53,24 @@ struct ieee80211_mesh_hwmp_preq_bottom { struct ieee80211_mesh_hwmp_preq_target targets[]; } __packed; +struct ieee80211_mesh_hwmp_prep_top { + u8 flags; + u8 hopcount; + u8 ttl; + u8 target_addr[ETH_ALEN]; + __le32 target_sn; + + /* optional Target External Address */ + u8 variable[]; +} __packed; + +struct ieee80211_mesh_hwmp_prep_bottom { + __le32 lifetime; + __le32 metric; + u8 orig_addr[ETH_ALEN]; + __le32 orig_sn; +} __packed; + /* Mesh flags */ #define MESH_FLAGS_AE_A4 0x1 #define MESH_FLAGS_AE_A5_A6 0x2 @@ -269,4 +287,13 @@ ieee80211_mesh_hwmp_preq_get_bottom(const u8 *ie) ieee80211_mesh_preq_prep_ae_enabled(ie) ? ETH_ALEN : 0]; } +static inline struct ieee80211_mesh_hwmp_prep_bottom * +ieee80211_mesh_hwmp_prep_get_bottom(const u8 *ie) +{ + struct ieee80211_mesh_hwmp_prep_top *top = (void *)ie; + + return (void *)&top->variable[ + ieee80211_mesh_preq_prep_ae_enabled(ie) ? ETH_ALEN : 0]; +} + #endif /* LINUX_IEEE80211_MESH_H */ diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c index 1a6a22b185d9f..39b782370df0a 100644 --- a/net/mac80211/mesh_hwmp.c +++ b/net/mac80211/mesh_hwmp.c @@ -37,16 +37,6 @@ static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae) /* HWMP IE processing macros */ #define AE_F_SET(x) (*x & AE_F) -#define PREP_IE_FLAGS(x) (*(x)) -#define PREP_IE_HOPCOUNT(x) (*(x + 1)) -#define PREP_IE_TTL(x) (*(x + 2)) -#define PREP_IE_ORIG_ADDR(x) (AE_F_SET(x) ? x + 27 : x + 21) -#define PREP_IE_ORIG_SN(x) u32_field_get(x, 27, AE_F_SET(x)) -#define PREP_IE_LIFETIME(x) u32_field_get(x, 13, AE_F_SET(x)) -#define PREP_IE_METRIC(x) u32_field_get(x, 17, AE_F_SET(x)) -#define PREP_IE_TARGET_ADDR(x) (x + 3) -#define PREP_IE_TARGET_SN(x) u32_field_get(x, 9, 0) - #define PERR_IE_TTL(x) (*(x)) #define PERR_IE_TARGET_FLAGS(x) (*(x + 2)) #define PERR_IE_TARGET_ADDR(x) (x + 3) @@ -419,11 +409,16 @@ static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata, * so that we can easily use a single function to gather path * information from both PREQ and PREP frames. */ - orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie); - orig_sn = PREP_IE_TARGET_SN(hwmp_ie); - orig_lifetime = PREP_IE_LIFETIME(hwmp_ie); - orig_metric = PREP_IE_METRIC(hwmp_ie); - hopcount = PREP_IE_HOPCOUNT(hwmp_ie) + 1; + struct ieee80211_mesh_hwmp_prep_top *prep_elem_top = + (void *)hwmp_ie; + struct ieee80211_mesh_hwmp_prep_bottom *prep_elem_bottom = + ieee80211_mesh_hwmp_prep_get_bottom(hwmp_ie); + + orig_addr = prep_elem_top->target_addr; + orig_sn = le32_to_cpu(prep_elem_top->target_sn); + orig_lifetime = le32_to_cpu(prep_elem_bottom->lifetime); + orig_metric = le32_to_cpu(prep_elem_bottom->metric); + hopcount = prep_elem_top->hopcount + 1; break; default: rcu_read_unlock(); @@ -714,6 +709,9 @@ static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata, const u8 *prep_elem, u32 metric) { struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; + struct ieee80211_mesh_hwmp_prep_top *prep_elem_top = (void *)prep_elem; + struct ieee80211_mesh_hwmp_prep_bottom *prep_elem_bottom = + ieee80211_mesh_hwmp_prep_get_bottom(prep_elem); struct mesh_path *mpath; const u8 *target_addr, *orig_addr; u8 ttl, hopcount, flags; @@ -721,9 +719,9 @@ static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata, u32 target_sn, orig_sn, lifetime; mhwmp_dbg(sdata, "received PREP from %pM\n", - PREP_IE_TARGET_ADDR(prep_elem)); + prep_elem_top->target_addr); - orig_addr = PREP_IE_ORIG_ADDR(prep_elem); + orig_addr = prep_elem_bottom->orig_addr; if (ether_addr_equal(orig_addr, sdata->vif.addr)) /* destination, no forwarding required */ return; @@ -731,7 +729,7 @@ static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata, if (!ifmsh->mshcfg.dot11MeshForwarding) return; - ttl = PREP_IE_TTL(prep_elem); + ttl = prep_elem_top->ttl; if (ttl <= 1) { sdata->u.mesh.mshstats.dropped_frames_ttl++; return; @@ -750,12 +748,12 @@ static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata, memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN); spin_unlock_bh(&mpath->state_lock); --ttl; - flags = PREP_IE_FLAGS(prep_elem); - lifetime = PREP_IE_LIFETIME(prep_elem); - hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1; - target_addr = PREP_IE_TARGET_ADDR(prep_elem); - target_sn = PREP_IE_TARGET_SN(prep_elem); - orig_sn = PREP_IE_ORIG_SN(prep_elem); + flags = prep_elem_top->flags; + lifetime = le32_to_cpu(prep_elem_bottom->lifetime); + hopcount = prep_elem_top->hopcount + 1; + target_addr = prep_elem_top->target_addr; + target_sn = le32_to_cpu(prep_elem_top->target_sn); + orig_sn = le32_to_cpu(prep_elem_bottom->orig_sn); mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0, target_addr, target_sn, next_hop, hopcount,