From d9e249704084982ac7581a560ffa284e11621d43 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Fri, 7 Oct 2022 14:56:11 +0200 Subject: wifi: cfg80211: fix ieee80211_data_to_8023_exthdr handling of small packets STP topology change notification packets only have a payload of 7 bytes, so they get dropped due to the skb->len < hdrlen + 8 check. Fix this by removing the extra 8 from the skb->len check and checking the return code on the skb_copy_bits calls. Fixes: 2d1c304cb2d5 ("cfg80211: add function for 802.3 conversion with separate output buffer") Reported-by: Chad Monroe Signed-off-by: Felix Fietkau Signed-off-by: Johannes Berg --- net/wireless/util.c | 40 +++++++++++++++++++++------------------- 1 file changed, 21 insertions(+), 19 deletions(-) (limited to 'net/wireless') diff --git a/net/wireless/util.c b/net/wireless/util.c index 01493568a21d..1f285b515028 100644 --- a/net/wireless/util.c +++ b/net/wireless/util.c @@ -559,7 +559,7 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr, return -1; hdrlen = ieee80211_hdrlen(hdr->frame_control) + data_offset; - if (skb->len < hdrlen + 8) + if (skb->len < hdrlen) return -1; /* convert IEEE 802.11 header + possible LLC headers into Ethernet @@ -574,8 +574,9 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr, memcpy(tmp.h_dest, ieee80211_get_DA(hdr), ETH_ALEN); memcpy(tmp.h_source, ieee80211_get_SA(hdr), ETH_ALEN); - if (iftype == NL80211_IFTYPE_MESH_POINT) - skb_copy_bits(skb, hdrlen, &mesh_flags, 1); + if (iftype == NL80211_IFTYPE_MESH_POINT && + skb_copy_bits(skb, hdrlen, &mesh_flags, 1) < 0) + return -1; mesh_flags &= MESH_FLAGS_AE; @@ -595,11 +596,12 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr, if (iftype == NL80211_IFTYPE_MESH_POINT) { if (mesh_flags == MESH_FLAGS_AE_A4) return -1; - if (mesh_flags == MESH_FLAGS_AE_A5_A6) { - skb_copy_bits(skb, hdrlen + - offsetof(struct ieee80211s_hdr, eaddr1), - tmp.h_dest, 2 * ETH_ALEN); - } + if (mesh_flags == MESH_FLAGS_AE_A5_A6 && + skb_copy_bits(skb, hdrlen + + offsetof(struct ieee80211s_hdr, eaddr1), + tmp.h_dest, 2 * ETH_ALEN) < 0) + return -1; + hdrlen += __ieee80211_get_mesh_hdrlen(mesh_flags); } break; @@ -613,10 +615,11 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr, if (iftype == NL80211_IFTYPE_MESH_POINT) { if (mesh_flags == MESH_FLAGS_AE_A5_A6) return -1; - if (mesh_flags == MESH_FLAGS_AE_A4) - skb_copy_bits(skb, hdrlen + - offsetof(struct ieee80211s_hdr, eaddr1), - tmp.h_source, ETH_ALEN); + if (mesh_flags == MESH_FLAGS_AE_A4 && + skb_copy_bits(skb, hdrlen + + offsetof(struct ieee80211s_hdr, eaddr1), + tmp.h_source, ETH_ALEN) < 0) + return -1; hdrlen += __ieee80211_get_mesh_hdrlen(mesh_flags); } break; @@ -628,16 +631,15 @@ int ieee80211_data_to_8023_exthdr(struct sk_buff *skb, struct ethhdr *ehdr, break; } - skb_copy_bits(skb, hdrlen, &payload, sizeof(payload)); - tmp.h_proto = payload.proto; - - if (likely((!is_amsdu && ether_addr_equal(payload.hdr, rfc1042_header) && - tmp.h_proto != htons(ETH_P_AARP) && - tmp.h_proto != htons(ETH_P_IPX)) || - ether_addr_equal(payload.hdr, bridge_tunnel_header))) { + if (likely(skb_copy_bits(skb, hdrlen, &payload, sizeof(payload)) == 0 && + ((!is_amsdu && ether_addr_equal(payload.hdr, rfc1042_header) && + payload.proto != htons(ETH_P_AARP) && + payload.proto != htons(ETH_P_IPX)) || + ether_addr_equal(payload.hdr, bridge_tunnel_header)))) { /* remove RFC1042 or Bridge-Tunnel encapsulation and * replace EtherType */ hdrlen += ETH_ALEN + 2; + tmp.h_proto = payload.proto; skb_postpull_rcsum(skb, &payload, ETH_ALEN + 2); } else { tmp.h_proto = htons(skb->len - hdrlen); -- cgit v1.2.3 From e3e6e1d16a4cf7b63159ec71774e822194071954 Mon Sep 17 00:00:00 2001 From: Hawkins Jiawei Date: Tue, 27 Sep 2022 07:34:59 +0800 Subject: wifi: wext: use flex array destination for memcpy() Syzkaller reports buffer overflow false positive as follows: ------------[ cut here ]------------ memcpy: detected field-spanning write (size 8) of single field "&compat_event->pointer" at net/wireless/wext-core.c:623 (size 4) WARNING: CPU: 0 PID: 3607 at net/wireless/wext-core.c:623 wireless_send_event+0xab5/0xca0 net/wireless/wext-core.c:623 Modules linked in: CPU: 1 PID: 3607 Comm: syz-executor659 Not tainted 6.0.0-rc6-next-20220921-syzkaller #0 [...] Call Trace: ioctl_standard_call+0x155/0x1f0 net/wireless/wext-core.c:1022 wireless_process_ioctl+0xc8/0x4c0 net/wireless/wext-core.c:955 wext_ioctl_dispatch net/wireless/wext-core.c:988 [inline] wext_ioctl_dispatch net/wireless/wext-core.c:976 [inline] wext_handle_ioctl+0x26b/0x280 net/wireless/wext-core.c:1049 sock_ioctl+0x285/0x640 net/socket.c:1220 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] Wireless events will be sent on the appropriate channels in wireless_send_event(). Different wireless events may have different payload structure and size, so kernel uses **len** and **cmd** field in struct __compat_iw_event as wireless event common LCP part, uses **pointer** as a label to mark the position of remaining different part. Yet the problem is that, **pointer** is a compat_caddr_t type, which may be smaller than the relative structure at the same position. So during wireless_send_event() tries to parse the wireless events payload, it may trigger the memcpy() run-time destination buffer bounds checking when the relative structure's data is copied to the position marked by **pointer**. This patch solves it by introducing flexible-array field **ptr_bytes**, to mark the position of the wireless events remaining part next to LCP part. What's more, this patch also adds **ptr_len** variable in wireless_send_event() to improve its maintainability. Reported-and-tested-by: syzbot+473754e5af963cf014cf@syzkaller.appspotmail.com Link: https://lore.kernel.org/all/00000000000070db2005e95a5984@google.com/ Suggested-by: Kees Cook Reviewed-by: Kees Cook Signed-off-by: Hawkins Jiawei Signed-off-by: Johannes Berg --- net/wireless/wext-core.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) (limited to 'net/wireless') diff --git a/net/wireless/wext-core.c b/net/wireless/wext-core.c index 76a80a41615b..fe8765c4075d 100644 --- a/net/wireless/wext-core.c +++ b/net/wireless/wext-core.c @@ -468,6 +468,7 @@ void wireless_send_event(struct net_device * dev, struct __compat_iw_event *compat_event; struct compat_iw_point compat_wrqu; struct sk_buff *compskb; + int ptr_len; #endif /* @@ -582,6 +583,9 @@ void wireless_send_event(struct net_device * dev, nlmsg_end(skb, nlh); #ifdef CONFIG_COMPAT hdr_len = compat_event_type_size[descr->header_type]; + + /* ptr_len is remaining size in event header apart from LCP */ + ptr_len = hdr_len - IW_EV_COMPAT_LCP_LEN; event_len = hdr_len + extra_len; compskb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); @@ -612,16 +616,15 @@ void wireless_send_event(struct net_device * dev, if (descr->header_type == IW_HEADER_TYPE_POINT) { compat_wrqu.length = wrqu->data.length; compat_wrqu.flags = wrqu->data.flags; - memcpy(&compat_event->pointer, - ((char *) &compat_wrqu) + IW_EV_COMPAT_POINT_OFF, - hdr_len - IW_EV_COMPAT_LCP_LEN); + memcpy(compat_event->ptr_bytes, + ((char *)&compat_wrqu) + IW_EV_COMPAT_POINT_OFF, + ptr_len); if (extra_len) - memcpy(((char *) compat_event) + hdr_len, - extra, extra_len); + memcpy(&compat_event->ptr_bytes[ptr_len], + extra, extra_len); } else { /* extra_len must be zero, so no if (extra) needed */ - memcpy(&compat_event->pointer, wrqu, - hdr_len - IW_EV_COMPAT_LCP_LEN); + memcpy(compat_event->ptr_bytes, wrqu, ptr_len); } nlmsg_end(compskb, nlh); -- cgit v1.2.3 From 10d5ea5a436da8d60cdb5845f454d595accdbce0 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 26 Sep 2022 19:29:23 -0700 Subject: wifi: nl80211: Split memcpy() of struct nl80211_wowlan_tcp_data_token flexible array To work around a misbehavior of the compiler's ability to see into composite flexible array structs (as detailed in the coming memcpy() hardening series[1]), split the memcpy() of the header and the payload so no false positive run-time overflow warning will be generated. [1] https://lore.kernel.org/linux-hardening/20220901065914.1417829-2-keescook@chromium.org/ Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva Signed-off-by: Johannes Berg --- net/wireless/nl80211.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'net/wireless') diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 8ff8b1c040f0..597c52236514 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -13265,7 +13265,9 @@ static int nl80211_parse_wowlan_tcp(struct cfg80211_registered_device *rdev, wake_mask_size); if (tok) { cfg->tokens_size = tokens_size; - memcpy(&cfg->payload_tok, tok, sizeof(*tok) + tokens_size); + cfg->payload_tok = *tok; + memcpy(cfg->payload_tok.token_stream, tok->token_stream, + tokens_size); } trig->tcp = cfg; -- cgit v1.2.3