From 2566866fc30965d915d0b52b5c3323b362619f0e Mon Sep 17 00:00:00 2001 From: Jérémy Jean Date: Tue, 15 Sep 2026 12:48:07 +0000 Subject: net: gue: reject invalid REMCSUM offsets MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The REMCSUM option carries an absolute checksum start and checksum field offset. gue_remcsum() passes them to skb_remcsum_process(), whose partial path stores offset - start in the u16 skb->csum_offset variable. If offset is less than start, this underflows. A forwarded packet can retain CHECKSUM_PARTIAL and reach a NETIF_F_HW_CSUM driver which trusts the metadata, leading skb_copy_and_csum_dev() to write two bytes about 64 KiB beyond the destination buffer. Reject reversed tuples in validate_gue_flags(), after the existing length validation, so all GUE parsers enforce the ordering in one place. Fixes: fe881ef11cf0 ("gue: Use checksum partial with remote checksum offload") Signed-off-by: Jérémy Jean Link: https://patch.msgid.link/20260915124806.2852293-2-Jeremy.Jean@oss.cyber.gouv.fr Signed-off-by: Jakub Kicinski --- include/net/gue.h | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) (limited to 'include/net') diff --git a/include/net/gue.h b/include/net/gue.h index caefd6da8693..d377155fd0b3 100644 --- a/include/net/gue.h +++ b/include/net/gue.h @@ -84,8 +84,9 @@ static inline size_t guehdr_priv_flags_len(__be32 flags) } /* Validate standard and private flags. Returns non-zero (meaning invalid) - * if there is an unknown standard or private flags, or the options length for - * the flags exceeds the options length specific in hlen of the GUE header. + * if there is an unknown standard or private flags, if the options length for + * the flags exceeds the options length specified in hlen of the GUE header, or + * if a private option contains invalid data. */ static inline int validate_gue_flags(struct guehdr *guehdr, size_t optlen) { @@ -103,8 +104,8 @@ static inline int validate_gue_flags(struct guehdr *guehdr, size_t optlen) /* Private flags are last four bytes accounted in * guehdr_flags_len */ - __be32 pflags = *(__be32 *)((void *)&guehdr[1] + - len - GUE_LEN_PRIV); + void *data = (void *)&guehdr[1] + len; + __be32 pflags = *(__be32 *)(data - GUE_LEN_PRIV); if (pflags & ~GUE_PFLAGS_ALL) return 1; @@ -112,6 +113,16 @@ static inline int validate_gue_flags(struct guehdr *guehdr, size_t optlen) len += guehdr_priv_flags_len(pflags); if (len > optlen) return 1; + + if (pflags & GUE_PFLAG_REMCSUM) { + __be16 *pd = data; + + /* The field offset pd[1] must not be less + * than the start pd[0]. + */ + if (ntohs(pd[1]) < ntohs(pd[0])) + return 1; + } } return 0; -- cgit v1.2.3 From be31fe6333f534155e6b408f1ef6d77974bb41aa Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Sun, 20 Sep 2026 19:14:32 +0000 Subject: ipv6: Fix dst leak for uncached routes. ip6_route_output_flags(), ip6_rt_put_flags(), and ip6_dst_check() detect an uncached route by list_empty(&rt->dst.rt_uncached), which replaced the static DST_NOCACHE flag check in commit a4c2fd7f7891 ("net: remove DST_NOCACHE flag"). When a device is unregistered, rt6_uncached_list_flush_dev() unlinks uncached routes tied to the device from rt6_uncached_list. Previously, they were moved to another list with list_move() (__list_del_entry() + list_add()), and since commit 98aa546af5e4 ("inet: remove (struct uncached_list)->quarantine"), the routes are just unlinked with list_del_init(). If list_del_init() runs concurrently, list_empty() evaluates to true; ip6_route_output_flags() calls dst_hold_safe() incorrectly and ip6_rt_put_flags() skips ip6_rt_put(), leaking dst, and thus dev tied via rt->from as well. The same race is partially fixed by commit 9a6f0c4d5796 ("dst: fix races in rt6_uncached_list_del() and rt_del_uncached_list()"). Let's check rt6->dst.rt_uncached_list instead. Note that IPv4 does not have the same issue. Fixes: 98aa546af5e4 ("inet: remove (struct uncached_list)->quarantine") Signed-off-by: Kuniyuki Iwashima Reviewed-by: Hangbin Liu Reviewed-by: Xuanqiang Luo Reviewed-by: Ido Schimmel Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260920191558.2990636-1-kuniyu@google.com Signed-off-by: Jakub Kicinski --- include/net/ip6_route.h | 4 ++-- net/ipv6/route.c | 7 ++++--- 2 files changed, 6 insertions(+), 5 deletions(-) (limited to 'include/net') diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index b9e8d2b759e9..0f9b7a260d25 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -101,12 +101,12 @@ static inline struct dst_entry *ip6_route_output(struct net *net, } /* Only conditionally release dst if flags indicates - * !RT6_LOOKUP_F_DST_NOREF or dst is in uncached_list. + * !RT6_LOOKUP_F_DST_NOREF or dst is uncached. */ static inline void ip6_rt_put_flags(struct rt6_info *rt, int flags) { if (!(flags & RT6_LOOKUP_F_DST_NOREF) || - !list_empty(&rt->dst.rt_uncached)) + rt->dst.rt_uncached_list) ip6_rt_put(rt); } diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 884d9ab0d50d..153ce16628c1 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -139,6 +139,7 @@ void rt6_uncached_list_add(struct rt6_info *rt) { struct uncached_list *ul = raw_cpu_ptr(&rt6_uncached_list); + /* Set once and never cleared: non-NULL marks an uncached route. */ rt->dst.rt_uncached_list = ul; spin_lock_bh(&ul->lock); @@ -2726,8 +2727,8 @@ struct dst_entry *ip6_route_output_flags(struct net *net, rcu_read_lock(); dst = ip6_route_output_flags_noref(net, sk, fl6, flags); rt6 = dst_rt6_info(dst); - /* For dst cached in uncached_list, refcnt is already taken. */ - if (list_empty(&rt6->dst.rt_uncached) && !dst_hold_safe(dst)) { + /* For an uncached dst, refcnt is already taken. */ + if (!rt6->dst.rt_uncached_list && !dst_hold_safe(dst)) { dst = &net->ipv6.ip6_null_entry->dst; dst_hold(dst); } @@ -2836,7 +2837,7 @@ INDIRECT_CALLABLE_SCOPE struct dst_entry *ip6_dst_check(struct dst_entry *dst, from = rcu_dereference(rt->from); if (from && (rt->rt6i_flags & RTF_PCPU || - unlikely(!list_empty(&rt->dst.rt_uncached)))) + unlikely(rt->dst.rt_uncached_list))) dst_ret = rt6_dst_from_check(rt, from, cookie); else dst_ret = rt6_check(rt, from, cookie); -- cgit v1.2.3 From dcab71a7011918f6fdba7adcec02d217dcb84b8d Mon Sep 17 00:00:00 2001 From: Luxiao Xu Date: Wed, 9 Sep 2026 13:19:24 +0800 Subject: nfc: fix use-after-free in nfc_get_local_general_bytes Commit 6709d4b7bc2e ("net: nfc: Fix use-after-free caused by nfc_llcp_find_local") attempted to fix a use-after-free (UAF) issue by invoking nfc_llcp_local_put(local) after accessing local->gb. However, if the reference count drops to zero, local is freed immediately, leading to a use-after-free when callers access the returned pointer. Alternative approaches using dynamic allocation (e.g. kmemdup) introduced memory leaks because callers consistently treat the returned pointer as borrowed memory. Fix this properly by refactoring nfc_llcp_general_bytes() and nfc_get_local_general_bytes() to accept a caller-provided output buffer (out_gb) and its maximum length (gb_max_len). The general bytes are safely copied into out_gb before calling nfc_llcp_local_put(local), ensuring safe lifetime management without ownership transfer complications. Update all callers across drivers (microread, pn533, pn544, st21nfca, digital_dep, and nci) to provide their own destination buffers and pass them to nfc_get_local_general_bytes(). Fixes: 6709d4b7bc2e ("net: nfc: Fix use-after-free caused by nfc_llcp_find_local") Cc: stable@vger.kernel.org Reported-by: Vega Assisted-by: LLM Signed-off-by: Luxiao Xu Signed-off-by: Ren Wei Reviewed-by: Simon Horman Link: https://patch.msgid.link/3cbaac3bee23f8ff3a3284ed32d347696eb1d208.1788841683.git.rakukuip@gmail.com Signed-off-by: David Heidelberg --- drivers/nfc/microread/microread.c | 6 +++--- drivers/nfc/pn533/pn533.c | 14 ++++++++------ drivers/nfc/pn533/pn533.h | 4 +++- drivers/nfc/pn544/pn544.c | 7 +++---- drivers/nfc/st21nfca/core.c | 8 ++++---- include/net/nfc/hci.h | 2 +- include/net/nfc/nfc.h | 3 ++- net/nfc/core.c | 15 +++++++-------- net/nfc/digital_dep.c | 8 ++++---- net/nfc/llcp_core.c | 17 +++++++++++++---- net/nfc/nci/core.c | 10 +++++----- net/nfc/nfc.h | 3 ++- 12 files changed, 55 insertions(+), 42 deletions(-) (limited to 'include/net') diff --git a/drivers/nfc/microread/microread.c b/drivers/nfc/microread/microread.c index dfa2490db545..2bfafa94e83d 100644 --- a/drivers/nfc/microread/microread.c +++ b/drivers/nfc/microread/microread.c @@ -251,9 +251,9 @@ static int microread_start_poll(struct nfc_hci_dev *hdev, param[1] |= (1 << 1); if ((im_protocols | tm_protocols) & NFC_PROTO_NFC_DEP_MASK) { - hdev->gb = nfc_get_local_general_bytes(hdev->ndev, - &hdev->gb_len); - if (hdev->gb == NULL || hdev->gb_len == 0) { + nfc_get_local_general_bytes(hdev->ndev, hdev->gb, + sizeof(hdev->gb), &hdev->gb_len); + if (hdev->gb_len == 0) { im_protocols &= ~NFC_PROTO_NFC_DEP_MASK; tm_protocols &= ~NFC_PROTO_NFC_DEP_MASK; } diff --git a/drivers/nfc/pn533/pn533.c b/drivers/nfc/pn533/pn533.c index f5a6a7c20d5a..b0133e51dce9 100644 --- a/drivers/nfc/pn533/pn533.c +++ b/drivers/nfc/pn533/pn533.c @@ -1357,10 +1357,11 @@ static int pn533_poll_dep(struct nfc_dev *nfc_dev) u8 *next, nfcid3[NFC_NFCID3_MAXSIZE]; u8 passive_data[PASSIVE_DATA_LEN] = {0x00, 0xff, 0xff, 0x00, 0x3}; - if (!dev->gb) { - dev->gb = nfc_get_local_general_bytes(nfc_dev, &dev->gb_len); - - if (!dev->gb || !dev->gb_len) { + if (!dev->gb_len) { + nfc_get_local_general_bytes(nfc_dev, dev->gb, + sizeof(dev->gb), + &dev->gb_len); + if (!dev->gb_len) { dev->poll_dep = 0; queue_work(dev->wq, &dev->rf_work); } @@ -1658,8 +1659,9 @@ static int pn533_start_poll(struct nfc_dev *nfc_dev, } if (tm_protocols) { - dev->gb = nfc_get_local_general_bytes(nfc_dev, &dev->gb_len); - if (dev->gb == NULL) + nfc_get_local_general_bytes(nfc_dev, dev->gb, + sizeof(dev->gb), &dev->gb_len); + if (dev->gb_len == 0) tm_protocols = 0; } diff --git a/drivers/nfc/pn533/pn533.h b/drivers/nfc/pn533/pn533.h index 09e35b8693f5..5ab668e05121 100644 --- a/drivers/nfc/pn533/pn533.h +++ b/drivers/nfc/pn533/pn533.h @@ -6,6 +6,8 @@ * Copyright (C) 2012-2013 Tieto Poland */ +#include + #define PN533_DEVICE_STD 0x1 #define PN533_DEVICE_PASORI 0x2 #define PN533_DEVICE_ACR122U 0x3 @@ -166,7 +168,7 @@ struct pn533 { struct timer_list listen_timer; int cancel_listen; - u8 *gb; + u8 gb[NFC_MAX_GT_LEN]; size_t gb_len; u8 tgt_available_prots; diff --git a/drivers/nfc/pn544/pn544.c b/drivers/nfc/pn544/pn544.c index 9d0a16ac465e..c4fa70e45c14 100644 --- a/drivers/nfc/pn544/pn544.c +++ b/drivers/nfc/pn544/pn544.c @@ -377,10 +377,9 @@ static int pn544_hci_start_poll(struct nfc_hci_dev *hdev, return r; if ((im_protocols | tm_protocols) & NFC_PROTO_NFC_DEP_MASK) { - hdev->gb = nfc_get_local_general_bytes(hdev->ndev, - &hdev->gb_len); - pr_debug("generate local bytes %p\n", hdev->gb); - if (hdev->gb == NULL || hdev->gb_len == 0) { + nfc_get_local_general_bytes(hdev->ndev, hdev->gb, + sizeof(hdev->gb), &hdev->gb_len); + if (hdev->gb_len == 0) { im_protocols &= ~NFC_PROTO_NFC_DEP_MASK; tm_protocols &= ~NFC_PROTO_NFC_DEP_MASK; } diff --git a/drivers/nfc/st21nfca/core.c b/drivers/nfc/st21nfca/core.c index fd39a05c9622..6bfeb8e7ed89 100644 --- a/drivers/nfc/st21nfca/core.c +++ b/drivers/nfc/st21nfca/core.c @@ -351,10 +351,10 @@ static int st21nfca_hci_start_poll(struct nfc_hci_dev *hdev, if (r < 0) return r; } else { - hdev->gb = nfc_get_local_general_bytes(hdev->ndev, - &hdev->gb_len); - - if (hdev->gb == NULL || hdev->gb_len == 0) { + nfc_get_local_general_bytes(hdev->ndev, hdev->gb, + sizeof(hdev->gb), + &hdev->gb_len); + if (hdev->gb_len == 0) { im_protocols &= ~NFC_PROTO_NFC_DEP_MASK; tm_protocols &= ~NFC_PROTO_NFC_DEP_MASK; } diff --git a/include/net/nfc/hci.h b/include/net/nfc/hci.h index 756c11084f65..86ed63e5d533 100644 --- a/include/net/nfc/hci.h +++ b/include/net/nfc/hci.h @@ -144,7 +144,7 @@ struct nfc_hci_dev { data_exchange_cb_t async_cb; void *async_cb_context; - u8 *gb; + u8 gb[NFC_MAX_GT_LEN]; size_t gb_len; unsigned long quirks; diff --git a/include/net/nfc/nfc.h b/include/net/nfc/nfc.h index c54df042db6b..bcafab5c53e5 100644 --- a/include/net/nfc/nfc.h +++ b/include/net/nfc/nfc.h @@ -273,7 +273,8 @@ struct sk_buff *nfc_alloc_recv_skb(unsigned int size, gfp_t gfp); int nfc_set_remote_general_bytes(struct nfc_dev *dev, const u8 *gt, u8 gt_len); -u8 *nfc_get_local_general_bytes(struct nfc_dev *dev, size_t *gb_len); +u8 *nfc_get_local_general_bytes(struct nfc_dev *dev, u8 *out_gb, + size_t gb_max_len, size_t *gb_len); int nfc_fw_download_done(struct nfc_dev *dev, const char *firmware_name, u32 result); diff --git a/net/nfc/core.c b/net/nfc/core.c index a92a6566e6a0..f521669293f0 100644 --- a/net/nfc/core.c +++ b/net/nfc/core.c @@ -279,10 +279,10 @@ static struct nfc_target *nfc_find_target(struct nfc_dev *dev, u32 target_idx) int nfc_dep_link_up(struct nfc_dev *dev, int target_index, u8 comm_mode) { - int rc = 0; - u8 *gb; - size_t gb_len; struct nfc_target *target; + u8 gb[NFC_MAX_GT_LEN]; + size_t gb_len = 0; + int rc = 0; pr_debug("dev_name=%s comm %d\n", dev_name(&dev->dev), comm_mode); @@ -301,7 +301,7 @@ int nfc_dep_link_up(struct nfc_dev *dev, int target_index, u8 comm_mode) goto error; } - gb = nfc_llcp_general_bytes(dev, &gb_len); + nfc_get_local_general_bytes(dev, gb, sizeof(gb), &gb_len); if (gb_len > NFC_MAX_GT_LEN) { rc = -EINVAL; goto error; @@ -644,11 +644,10 @@ int nfc_set_remote_general_bytes(struct nfc_dev *dev, const u8 *gb, u8 gb_len) } EXPORT_SYMBOL(nfc_set_remote_general_bytes); -u8 *nfc_get_local_general_bytes(struct nfc_dev *dev, size_t *gb_len) +u8 *nfc_get_local_general_bytes(struct nfc_dev *dev, u8 *out_gb, + size_t gb_max_len, size_t *gb_len) { - pr_debug("dev_name=%s\n", dev_name(&dev->dev)); - - return nfc_llcp_general_bytes(dev, gb_len); + return nfc_llcp_general_bytes(dev, out_gb, gb_max_len, gb_len); } EXPORT_SYMBOL(nfc_get_local_general_bytes); diff --git a/net/nfc/digital_dep.c b/net/nfc/digital_dep.c index 3982fa084737..968547c306a5 100644 --- a/net/nfc/digital_dep.c +++ b/net/nfc/digital_dep.c @@ -1490,14 +1490,14 @@ static int digital_tg_send_atr_res(struct nfc_digital_dev *ddev, struct digital_atr_req *atr_req) { struct digital_atr_res *atr_res; + u8 gb[NFC_MAX_GT_LEN]; struct sk_buff *skb; - u8 *gb, payload_bits; + u8 payload_bits; size_t gb_len; int rc; - gb = nfc_get_local_general_bytes(ddev->nfc_dev, &gb_len); - if (!gb) - gb_len = 0; + nfc_get_local_general_bytes(ddev->nfc_dev, gb, sizeof(gb), + &gb_len); skb = digital_skb_alloc(ddev, sizeof(struct digital_atr_res) + gb_len); if (!skb) diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c index 5017f6aa57a0..5ce3ce64baf2 100644 --- a/net/nfc/llcp_core.c +++ b/net/nfc/llcp_core.c @@ -652,23 +652,32 @@ out: return ret; } -u8 *nfc_llcp_general_bytes(struct nfc_dev *dev, size_t *general_bytes_len) +u8 *nfc_llcp_general_bytes(struct nfc_dev *dev, u8 *out_gb, size_t gb_max_len, + size_t *general_bytes_len) { struct nfc_llcp_local *local; + if (!out_gb || !general_bytes_len) + return NULL; + local = nfc_llcp_find_local(dev); - if (local == NULL) { + if (!local) { *general_bytes_len = 0; return NULL; } nfc_llcp_build_gb(local); - *general_bytes_len = local->gb_len; + if (local->gb_len) { + *general_bytes_len = min_t(size_t, local->gb_len, gb_max_len); + memcpy(out_gb, local->gb, *general_bytes_len); + } else { + *general_bytes_len = 0; + } nfc_llcp_local_put(local); - return local->gb; + return out_gb; } int nfc_llcp_set_remote_gb(struct nfc_dev *dev, const u8 *gb, u8 gb_len) diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c index 5f46c4b5720f..73e3a96470ac 100644 --- a/net/nfc/nci/core.c +++ b/net/nfc/nci/core.c @@ -780,15 +780,15 @@ static int nci_set_local_general_bytes(struct nfc_dev *nfc_dev) { struct nci_dev *ndev = nfc_get_drvdata(nfc_dev); struct nci_set_config_param param; + u8 gb[NFC_MAX_GT_LEN]; int rc; - param.val = nfc_get_local_general_bytes(nfc_dev, ¶m.len); - if ((param.val == NULL) || (param.len == 0)) + nfc_get_local_general_bytes(nfc_dev, gb, sizeof(gb), + ¶m.len); + if (param.len == 0) return 0; - if (param.len > NFC_MAX_GT_LEN) - return -EINVAL; - + param.val = gb; param.id = NCI_PN_ATR_REQ_GEN_BYTES; rc = nci_request(ndev, nci_set_config_req, ¶m, diff --git a/net/nfc/nfc.h b/net/nfc/nfc.h index 0b1e6466f4fb..82c5dfdad10e 100644 --- a/net/nfc/nfc.h +++ b/net/nfc/nfc.h @@ -49,7 +49,8 @@ void nfc_llcp_mac_is_up(struct nfc_dev *dev, u32 target_idx, int nfc_llcp_register_device(struct nfc_dev *dev); void nfc_llcp_unregister_device(struct nfc_dev *dev); int nfc_llcp_set_remote_gb(struct nfc_dev *dev, const u8 *gb, u8 gb_len); -u8 *nfc_llcp_general_bytes(struct nfc_dev *dev, size_t *general_bytes_len); +u8 *nfc_llcp_general_bytes(struct nfc_dev *dev, u8 *out_gb, size_t gb_max_len, + size_t *general_bytes_len); int nfc_llcp_data_received(struct nfc_dev *dev, struct sk_buff *skb); struct nfc_llcp_local *nfc_llcp_find_local(struct nfc_dev *dev); int nfc_llcp_local_put(struct nfc_llcp_local *local); -- cgit v1.2.3 From 87cd6b717e4069dca34e0866e57eaeb44d3b173e Mon Sep 17 00:00:00 2001 From: Yuya Kusakabe Date: Tue, 22 Sep 2026 05:49:56 +0900 Subject: net: ipv6: keep room for the mac header in dst_dev_overhead() The seg6, ioam6 and rpl lwtunnels size their skb_cow_head() request as the length they are about to push plus dst_dev_overhead(), then push the new headers and rebuild the mac header below them with skb_mac_header_rebuild(). That rebuild needs skb->mac_len of headroom, but dst_dev_overhead() leaves LL_RESERVED_SPACE() of the egress device, 16 bytes for plain Ethernet. Where the mac header is longer than that, as it is on ingress through a VLAN device with reorder_hdr off, the rebuild runs out of room: skb_set_mac_header(skb, -skb->mac_len) computes a negative offset, stores it unchecked in the u16 skb->mac_header, and the memmove that follows writes skb->mac_len bytes about 64 KB past skb->head. Forwarding plain ping6 traffic through such a device reproduces it on all five seg6 encapsulation modes and on the rpl and ioam6 inline paths; skb->mac_header comes back as 65534 on a 704-byte head. Return the larger of the two. The helper already returns skb->mac_len when it has no dst, so this only makes the other branch agree, and it covers every caller rather than each call site in turn. Fixes: 40475b63761a ("net: ipv6: seg6_iptunnel: mitigate 2-realloc issue") Fixes: dce525185bc9 ("net: ipv6: ioam6_iptunnel: mitigate 2-realloc issue") Fixes: 985ec6f5e623 ("net: ipv6: rpl_iptunnel: mitigate 2-realloc issue") Suggested-by: Andrea Mayer Signed-off-by: Yuya Kusakabe Reviewed-by: Justin Iurman Reviewed-by: Gabriel Goller Reviewed-by: Eric Dumazet Reviewed-by: Andrea Mayer Link: https://patch.msgid.link/20260922-seg6-maclen-headroom-v3-1-7b2f982ef79d@gmail.com Signed-off-by: Jakub Kicinski --- include/net/dst.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/net') diff --git a/include/net/dst.h b/include/net/dst.h index 307073eae7f8..dbedfe72e1fd 100644 --- a/include/net/dst.h +++ b/include/net/dst.h @@ -455,7 +455,8 @@ static inline unsigned int dst_dev_overhead(struct dst_entry *dst, struct sk_buff *skb) { if (likely(dst)) - return LL_RESERVED_SPACE(dst->dev); + return max_t(unsigned int, skb->mac_len, + LL_RESERVED_SPACE(dst->dev)); return skb->mac_len; } -- cgit v1.2.3 From 26b2bd70d22457556e2fa01cbf1192cb1a94d619 Mon Sep 17 00:00:00 2001 From: Ilya Maximets Date: Mon, 21 Sep 2026 16:55:43 +0200 Subject: net: openvswitch: conntrack: avoid modifying shared unconfirmed ct entry In a case where skb with an unconfirmed ct entry gets cloned, we may end up committing both but with different sets of extensions. The series of events: 1. The first clone wants to commit and runs the helpers wiring up the extension pointer into the expectation list. 2. Then it looses the confirmation keeping the entry unconfirmed. 3. Second clone now wants to commit labels and adds the new extension for that breaking the pointer in the expectation list causing UAF on the destruction path later. While this is possible to trigger, there should be no practical network pipeline where committing both clones without modifications into the same zone is needed. So, let's just reset the entry in case for some reason we got an skb with a shared one during commit. This doesn't affect any known use cases, but avoids any potential problems with sharing and modification of the unconfirmed ct entry. The fixes tag points to the introduction of helpers, since that's the main UAF trigger for the sharing. Fixes: cae3a2627520 ("openvswitch: Allow attaching helpers to ct action") Cc: stable@vger.kernel.org Reported-by: Axel Mierczuk Signed-off-by: Ilya Maximets Reviewed-by: Aaron Conole Link: https://patch.msgid.link/20260921145655.3167436-2-i.maximets@ovn.org Signed-off-by: Jakub Kicinski --- include/net/netfilter/nf_conntrack.h | 5 +++++ net/openvswitch/conntrack.c | 12 ++++++++++++ 2 files changed, 17 insertions(+) (limited to 'include/net') diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h index bc42dd0e10e6..c39425e54d87 100644 --- a/include/net/netfilter/nf_conntrack.h +++ b/include/net/netfilter/nf_conntrack.h @@ -185,6 +185,11 @@ static inline void nf_ct_put(struct nf_conn *ct) nf_ct_destroy(&ct->ct_general); } +static inline bool nf_ct_shared(const struct nf_conn *ct) +{ + return refcount_read(&ct->ct_general.use) > 1; +} + /* load module; enable/disable conntrack in this namespace */ int nf_ct_netns_get(struct net *net, u8 nfproto); void nf_ct_netns_put(struct net *net, u8 nfproto); diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c index 0f433688e17b..a733029c28dd 100644 --- a/net/openvswitch/conntrack.c +++ b/net/openvswitch/conntrack.c @@ -734,6 +734,18 @@ static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key, enum ip_conntrack_info ctinfo; struct nf_conn *ct; + /* If the ct entry is not confirmed and shared with some other skb, + * e.g., a cloned one, we can't just modify it with the commit as we + * must not modify the extension set. Reset. + */ + if (cached && info->commit) { + ct = nf_ct_get(skb, &ctinfo); + if (ct && !nf_ct_is_confirmed(ct) && nf_ct_shared(ct)) { + nf_reset_ct(skb); + cached = false; + } + } + if (!cached) { struct nf_hook_state state = { .hook = NF_INET_PRE_ROUTING, -- cgit v1.2.3 From fc6d80eb504458d6416b75a94188b268c95c6533 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Thu, 24 Sep 2026 11:44:12 -0400 Subject: tcp: prevent collapsing skbs across boundary in rtx queue tcp_write_collapse_fence() sets TCP_SKB_CB(skb)->eor = 1 on tcp_write_queue_tail(sk) to prevent skbs queued after a switch to device encryption from being collapsed into earlier skbs. The fence is a no-op if all earlier data has already been transmitted when the switch happens: sk->sk_write_queue is empty. The not yet acknowledged earlier skbs wait in sk->tcp_rtx_queue with eor 0. On a subsequent retransmit or SACK shift, tcp_retrans_try_collapse() or tcp_shift_skb_data() can then merge an skb queued after the switch into one queued before it. Both users of the fence are affected: - psp: devices only encrypt skbs with skb->decrypted set. The merged skb keeps decrypted = 0 from the earlier skb, so merged data sent after psp_sock_assoc_set_tx() is retransmitted in cleartext. - tls device offload: the merged skb straddles the start marker set in tls_set_device_offload(). The software fallback (fill_sg_in() returns -EINVAL) and the mlx5, nfp and funeth drivers cannot handle such an skb and drop it. Every retransmit rebuilds the same skb, so the connection stalls. Fix this in two places, for defense in depth: 1. Fall back to tcp_rtx_queue_tail(sk) in tcp_write_collapse_fence() when tcp_write_queue_tail(sk) is NULL. 2. Check !skb_cmp_decrypted(to, from) in tcp_skb_can_collapse(), as tcp_skb_can_collapse_rx() does on receive. skb_shift(), which both collapse paths call, already has a DEBUG_NET_WARN_ON_ONCE() for this condition. Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure") Cc: stable@vger.kernel.org Signed-off-by: Willem de Bruijn Reviewed-by: Eric Dumazet Reviewed-by: Daniel Zahka Link: https://patch.msgid.link/20260924154427.953800-1-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski --- include/net/tcp.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/net') diff --git a/include/net/tcp.h b/include/net/tcp.h index 436495ff2271..4416cdf9bf30 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1232,9 +1232,9 @@ static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb) static inline bool tcp_skb_can_collapse(const struct sk_buff *to, const struct sk_buff *from) { - /* skb_cmp_decrypted() not needed, use tcp_write_collapse_fence() */ return likely(tcp_skb_can_collapse_to(to) && mptcp_skb_can_collapse(to, from) && + !skb_cmp_decrypted(to, from) && skb_pure_zcopy_same(to, from) && skb_frags_readable(to) == skb_frags_readable(from)); } @@ -2327,7 +2327,7 @@ static inline void tcp_rtx_queue_unlink_and_free(struct sk_buff *skb, struct soc static inline void tcp_write_collapse_fence(struct sock *sk) { - struct sk_buff *skb = tcp_write_queue_tail(sk); + struct sk_buff *skb = tcp_write_queue_tail(sk) ?: tcp_rtx_queue_tail(sk); if (skb) TCP_SKB_CB(skb)->eor = 1; -- cgit v1.2.3