From 7dd111e8ee10cc6816669eabcad3334447673236 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Thu, 25 Oct 2012 21:51:59 +0200 Subject: wireless: drop invalid mesh address extension frames The mesh header can have address extension by a 4th or a 5th and 6th address, but never both. Drop such frames in 802.11 -> 802.3 conversion along with any frames that have the wrong extension. Cc: stable@vger.kernel.org Reviewed-by: Javier Cardona Signed-off-by: Johannes Berg --- net/wireless/util.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'net/wireless/util.c') diff --git a/net/wireless/util.c b/net/wireless/util.c index ef35f4ef2aa..45a09de1ffe 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -312,18 +312,15 @@ EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb); static int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr) { int ae = meshhdr->flags & MESH_FLAGS_AE; - /* 7.1.3.5a.2 */ + /* 802.11-2012, 8.2.4.7.3 */ switch (ae) { + default: case 0: return 6; case MESH_FLAGS_AE_A4: return 12; case MESH_FLAGS_AE_A5_A6: return 18; - case (MESH_FLAGS_AE_A4 | MESH_FLAGS_AE_A5_A6): - return 24; - default: - return 6; } } @@ -373,6 +370,8 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr, /* make sure meshdr->flags is on the linear part */ if (!pskb_may_pull(skb, hdrlen + 1)) return -1; + if (meshdr->flags & MESH_FLAGS_AE_A4) + return -1; if (meshdr->flags & MESH_FLAGS_AE_A5_A6) { skb_copy_bits(skb, hdrlen + offsetof(struct ieee80211s_hdr, eaddr1), @@ -397,6 +396,8 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr, /* make sure meshdr->flags is on the linear part */ if (!pskb_may_pull(skb, hdrlen + 1)) return -1; + if (meshdr->flags & MESH_FLAGS_AE_A5_A6) + return -1; if (meshdr->flags & MESH_FLAGS_AE_A4) skb_copy_bits(skb, hdrlen + offsetof(struct ieee80211s_hdr, eaddr1), -- cgit v1.2.3-70-g09d2 From 9b395bc3be1cebf0144a127c7e67d56dbdac0930 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 26 Oct 2012 00:36:40 +0200 Subject: mac80211: verify that skb data is present A number of places in the mesh code don't check that the frame data is present and in the skb header when trying to access. Add those checks and the necessary pskb_may_pull() calls. This prevents accessing data that doesn't actually exist. To do this, export ieee80211_get_mesh_hdrlen() to be able to use it in mac80211. Cc: stable@vger.kernel.org Signed-off-by: Johannes Berg --- include/net/cfg80211.h | 9 +++++++++ net/mac80211/rx.c | 32 +++++++++++++++++++++++++++++++- net/wireless/util.c | 3 ++- 3 files changed, 42 insertions(+), 2 deletions(-) (limited to 'net/wireless/util.c') diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h index f8cd4cf3fad..7d5b6000378 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -2651,6 +2651,15 @@ unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb); */ unsigned int __attribute_const__ ieee80211_hdrlen(__le16 fc); +/** + * ieee80211_get_mesh_hdrlen - get mesh extension header length + * @meshhdr: the mesh extension header, only the flags field + * (first byte) will be accessed + * Returns the length of the extension header, which is always at + * least 6 bytes and at most 18 if address 5 and 6 are present. + */ +unsigned int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr); + /** * DOC: Data path helpers * diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 99cdee16e31..265a032dec4 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -531,6 +531,11 @@ ieee80211_rx_mesh_check(struct ieee80211_rx_data *rx) if (ieee80211_is_action(hdr->frame_control)) { u8 category; + + /* make sure category field is present */ + if (rx->skb->len < IEEE80211_MIN_ACTION_SIZE) + return RX_DROP_MONITOR; + mgmt = (struct ieee80211_mgmt *)hdr; category = mgmt->u.action.category; if (category != WLAN_CATEGORY_MESH_ACTION && @@ -1892,6 +1897,20 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx) hdr = (struct ieee80211_hdr *) skb->data; hdrlen = ieee80211_hdrlen(hdr->frame_control); + + /* make sure fixed part of mesh header is there, also checks skb len */ + if (!pskb_may_pull(rx->skb, hdrlen + 6)) + return RX_DROP_MONITOR; + + mesh_hdr = (struct ieee80211s_hdr *) (skb->data + hdrlen); + + /* make sure full mesh header is there, also checks skb len */ + if (!pskb_may_pull(rx->skb, + hdrlen + ieee80211_get_mesh_hdrlen(mesh_hdr))) + return RX_DROP_MONITOR; + + /* reload pointers */ + hdr = (struct ieee80211_hdr *) skb->data; mesh_hdr = (struct ieee80211s_hdr *) (skb->data + hdrlen); /* frame is in RMC, don't forward */ @@ -1915,9 +1934,12 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx) if (is_multicast_ether_addr(hdr->addr1)) { mpp_addr = hdr->addr3; proxied_addr = mesh_hdr->eaddr1; - } else { + } else if (mesh_hdr->flags & MESH_FLAGS_AE_A5_A6) { + /* has_a4 already checked in ieee80211_rx_mesh_check */ mpp_addr = hdr->addr4; proxied_addr = mesh_hdr->eaddr2; + } else { + return RX_DROP_MONITOR; } rcu_read_lock(); @@ -2354,6 +2376,10 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx) } break; case WLAN_CATEGORY_SELF_PROTECTED: + if (len < (IEEE80211_MIN_ACTION_SIZE + + sizeof(mgmt->u.action.u.self_prot.action_code))) + break; + switch (mgmt->u.action.u.self_prot.action_code) { case WLAN_SP_MESH_PEERING_OPEN: case WLAN_SP_MESH_PEERING_CLOSE: @@ -2372,6 +2398,10 @@ ieee80211_rx_h_action(struct ieee80211_rx_data *rx) } break; case WLAN_CATEGORY_MESH_ACTION: + if (len < (IEEE80211_MIN_ACTION_SIZE + + sizeof(mgmt->u.action.u.mesh_action.action_code))) + break; + if (!ieee80211_vif_is_mesh(&sdata->vif)) break; if (mesh_action_is_path_sel(mgmt) && diff --git a/net/wireless/util.c b/net/wireless/util.c index 45a09de1ffe..2762e832998 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -309,7 +309,7 @@ unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb) } EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb); -static int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr) +unsigned int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr) { int ae = meshhdr->flags & MESH_FLAGS_AE; /* 802.11-2012, 8.2.4.7.3 */ @@ -323,6 +323,7 @@ static int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr) return 18; } } +EXPORT_SYMBOL(ieee80211_get_mesh_hdrlen); int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr, enum nl80211_iftype iftype) -- cgit v1.2.3-70-g09d2