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[PATCH OLK-5.10] vhost/net: complete zerocopy ubufs only once
by Fanhua Li 26 Aug '26

26 Aug '26

From: Qing Ming <a0yami(a)mailbox.org> mainline inclusion from mainline-v7.2-rc1 commit 8f6898fe80794f2d7c3d38c1158c806e4074a1c4 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/17657 CVE: CVE-2026-74310 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- vhost-net initializes one ubuf_info per outstanding zerocopy TX descriptor and hands it to the backend socket. The networking stack may then clone a zerocopy skb before all skb references are released. For example, batman-adv fragmentation reaches skb_split(), which calls skb_zerocopy_clone() and increments the same ubuf_info refcount. vhost_zerocopy_complete() currently treats every ubuf callback as a completed vhost descriptor. It dereferences ubuf->ctx, writes the descriptor completion state, and drops the vhost_net_ubuf_ref even when the callback only releases a cloned skb reference. A backend reset can therefore wait for and free the vhost_net_ubuf_ref while another cloned skb still carries the same ubuf_info. A later completion then dereferences the freed ubufs pointer. KASAN reports the stale completion as: BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x1d7/0x1f0 BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x101/0x1f0 vhost_zerocopy_complete skb_copy_ubufs __dev_forward_skb2 veth_xmit The freed object was allocated from vhost_net_ioctl() while setting the backend and freed through kfree_rcu()/kvfree_rcu_bulk after backend removal, while delayed skb completion still reached vhost_zerocopy_complete(). Honor the generic ubuf_info refcount before touching vhost state, and run the vhost descriptor completion only for the final ubuf reference. This matches the msg_zerocopy_complete() ownership rule for cloned zerocopy skbs. Fixes: bab632d69ee4 ("vhost: vhost TX zero-copy support") Signed-off-by: Qing Ming <a0yami(a)mailbox.org> Signed-off-by: Michael S. Tsirkin <mst(a)redhat.com> Message-ID: <20260601104300.197210-1-a0yami(a)mailbox.org> Conflicts: drivers/vhost/net.c [Fanhua Li: context conflict] Signed-off-by: Fanhua Li <lifanhua5(a)huawei.com> --- drivers/vhost/net.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index f5503306457f3..8539281fb1ef1 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -383,12 +383,18 @@ static void vhost_zerocopy_signal_used(struct vhost_net *net, static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) { - struct vhost_net_ubuf_ref *ubufs = ubuf->ctx; - struct vhost_virtqueue *vq = ubufs->vq; + struct vhost_net_ubuf_ref *ubufs; + struct vhost_virtqueue *vq; int cnt; - rcu_read_lock_bh(); + /* Only the final cloned skb reference completes the vhost descriptor. */ + if (!refcount_dec_and_test(&ubuf->refcnt)) + return; + + ubufs = ubuf->ctx; + vq = ubufs->vq; + rcu_read_lock_bh(); /* set len to mark this desc buffers done DMA */ vq->heads[ubuf->desc].len = success ? VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; -- 2.43.0

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[PATCH openEuler-1.0-LTS] vhost/net: complete zerocopy ubufs only once
by Fanhua Li 26 Aug '26

26 Aug '26

From: Qing Ming <a0yami(a)mailbox.org> mianline inclusion from mianline-v7.2-rc1 commit 8f6898fe80794f2d7c3d38c1158c806e4074a1c4 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/17657 CVE: CVE-2026-74310 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- vhost-net initializes one ubuf_info per outstanding zerocopy TX descriptor and hands it to the backend socket. The networking stack may then clone a zerocopy skb before all skb references are released. For example, batman-adv fragmentation reaches skb_split(), which calls skb_zerocopy_clone() and increments the same ubuf_info refcount. vhost_zerocopy_complete() currently treats every ubuf callback as a completed vhost descriptor. It dereferences ubuf->ctx, writes the descriptor completion state, and drops the vhost_net_ubuf_ref even when the callback only releases a cloned skb reference. A backend reset can therefore wait for and free the vhost_net_ubuf_ref while another cloned skb still carries the same ubuf_info. A later completion then dereferences the freed ubufs pointer. KASAN reports the stale completion as: BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x1d7/0x1f0 BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x101/0x1f0 vhost_zerocopy_complete skb_copy_ubufs __dev_forward_skb2 veth_xmit The freed object was allocated from vhost_net_ioctl() while setting the backend and freed through kfree_rcu()/kvfree_rcu_bulk after backend removal, while delayed skb completion still reached vhost_zerocopy_complete(). Honor the generic ubuf_info refcount before touching vhost state, and run the vhost descriptor completion only for the final ubuf reference. This matches the msg_zerocopy_complete() ownership rule for cloned zerocopy skbs. Fixes: bab632d69ee4 ("vhost: vhost TX zero-copy support") Signed-off-by: Qing Ming <a0yami(a)mailbox.org> Signed-off-by: Michael S. Tsirkin <mst(a)redhat.com> Message-ID: <20260601104300.197210-1-a0yami(a)mailbox.org> Conflicts: drivers/vhost/net.c [Fanhua Li: context conflict] Signed-off-by: Fanhua Li <lifanhua5(a)huawei.com> --- drivers/vhost/net.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 4b9151474a245..121e4f80c08b6 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -371,12 +371,18 @@ static void vhost_zerocopy_signal_used(struct vhost_net *net, static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) { - struct vhost_net_ubuf_ref *ubufs = ubuf->ctx; - struct vhost_virtqueue *vq = ubufs->vq; + struct vhost_net_ubuf_ref *ubufs; + struct vhost_virtqueue *vq; int cnt; - rcu_read_lock_bh(); + /* Only the final cloned skb reference completes the vhost descriptor. */ + if (!refcount_dec_and_test(&ubuf->refcnt)) + return; + + ubufs = ubuf->ctx; + vq = ubufs->vq; + rcu_read_lock_bh(); /* set len to mark this desc buffers done DMA */ vq->heads[ubuf->desc].len = success ? VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; -- 2.43.0

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[PATCH openEuler-1.0-LTS] netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()
by superdcc97＠163.com 26 Aug '26

26 Aug '26

From: Jenny Guanni Qu <qguanni(a)gmail.com> mainline inclusion from mainline-v7.0-rc5 commit f173d0f4c0f689173f8cdac79991043a4a89bf66 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14095 CVE: CVE-2026-23455 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- In DecodeQ931(), the UserUserIE code path reads a 16-bit length from the packet, then decrements it by 1 to skip the protocol discriminator byte before passing it to DecodeH323_UserInformation(). If the encoded length is 0, the decrement wraps to -1, which is then passed as a large value to the decoder, leading to an out-of-bounds read. Add a check to ensure len is positive after the decrement. Fixes: 5e35941d9901 ("[NETFILTER]: Add H.323 conntrack/NAT helper") Reported-by: Klaudia Kloc <klaudia(a)vidocsecurity.com> Reported-by: Dawid Moczadło <dawid(a)vidocsecurity.com> Tested-by: Jenny Guanni Qu <qguanni(a)gmail.com> Signed-off-by: Jenny Guanni Qu <qguanni(a)gmail.com> Signed-off-by: Florian Westphal <fw(a)strlen.de> Signed-off-by: Dong Chenchen <dongchenchen2(a)huawei.com> --- net/netfilter/nf_conntrack_h323_asn1.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/netfilter/nf_conntrack_h323_asn1.c b/net/netfilter/nf_conntrack_h323_asn1.c index dbdce5a59493..c46357538aa3 100644 --- a/net/netfilter/nf_conntrack_h323_asn1.c +++ b/net/netfilter/nf_conntrack_h323_asn1.c @@ -925,6 +925,8 @@ int DecodeQ931(unsigned char *buf, size_t sz, Q931 *q931) break; p++; len--; + if (len <= 0) + break; return DecodeH323_UserInformation(buf, p, len, &q931->UUIE); } -- 2.43.0

2 1

[PATCH openEuler-1.0-LTS] ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()
by superdcc97＠163.com 26 Aug '26

26 Aug '26

From: Eric Dumazet <edumazet(a)google.com> mainline inclusion from mainline-v7.2-rc1 commit a5c0359f5cbc51a2e2b114d6041e0f3c73f903e9 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15907 CVE: CVE-2026-53221 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- In vti6_tnl_lookup(), when an exact match for a tunnel fails, the code falls back to searching for wildcard tunnels: - Tunnels matching the packet's local address, with any remote address wildcard remote). - Tunnels matching the packet's remote address, with any local address (wildcard local). However, vti6 stores all these different types of tunnels in the same hash table (ip6n->tnls_r_l) prone to hash collisions. The bug is that the fallback search loops in vti6_tnl_lookup() were missing checks to ensure that the candidate tunnel actually has a wildcard address. Fixes: fbe68ee87522 ("vti6: Add a lookup method for tunnels with wildcard endpoints.") Signed-off-by: Eric Dumazet <edumazet(a)google.com> Cc: Steffen Klassert <steffen.klassert(a)secunet.com> Reviewed-by: Nicolas Dichtel <nicolas.dichtel(a)6wind.com> Link: https://patch.msgid.link/20260608164613.933023-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> Signed-off-by: Dong Chenchen <dongchenchen2(a)huawei.com> --- net/ipv6/ip6_vti.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c index a64050e77588..a87b05b564a0 100644 --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -109,6 +109,7 @@ vti6_tnl_lookup(struct net *net, const struct in6_addr *remote, hash = HASH(&any, local); for_each_vti6_tunnel_rcu(ip6n->tnls_r_l[hash]) { if (ipv6_addr_equal(local, &t->parms.laddr) && + ipv6_addr_any(&t->parms.raddr) && (t->dev->flags & IFF_UP)) return t; } @@ -116,6 +117,7 @@ vti6_tnl_lookup(struct net *net, const struct in6_addr *remote, hash = HASH(remote, &any); for_each_vti6_tunnel_rcu(ip6n->tnls_r_l[hash]) { if (ipv6_addr_equal(remote, &t->parms.raddr) && + ipv6_addr_any(&t->parms.laddr) && (t->dev->flags & IFF_UP)) return t; } -- 2.43.0

1 0

[PATCH openEuler-1.0-LTS] ipv6: sit: reload inner IPv6 header after GSO offloads
by superdcc97＠163.com 26 Aug '26

26 Aug '26

From: Kyle Zeng <kylebot(a)openai.com> mainline inclusion from mainline-v7.2-rc1 commit f0e42f0c4337b1f220de1ddd63f47197c7dee4de category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15914 CVE: CVE-2026-53228 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- ipip6_tunnel_xmit() caches the inner IPv6 header pointer at function entry and continues using it after iptunnel_handle_offloads(). For GSO skbs, iptunnel_handle_offloads() calls skb_header_unclone(). When the skb header is cloned, skb_header_unclone() can call pskb_expand_head(), which may move the skb head. The pskb_expand_head() contract requires pointers into the skb header to be reloaded after the call. If the later skb_realloc_headroom() branch is not taken, SIT uses the stale iph6 pointer to read the inner hop limit and DS field. That can read from a freed skb head after the old head's remaining clone is released. Reload iph6 after the offload helper succeeds and before subsequent reads from the inner IPv6 header. Keep the existing reload after skb_realloc_headroom(), since that branch can also replace the skb. Fixes: 14909664e4e1 ("sit: Setup and TX path for sit/UDP foo-over-udp encapsulation") Signed-off-by: Kyle Zeng <kylebot(a)openai.com> Reviewed-by: Eric Dumazet <edumazet(a)google.com> Reported-by: syzbot+6eb9ca986d80f6f88cf9(a)syzkaller.appspotmail.com Link: https://patch.msgid.link/20260605073448.6524-1-kylebot@openai.com Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> Conflicts: net/ipv6/sit.c [context differs: fe8570186f10 use dst4_mtu() in ipip6_tunnel_xmit(), which is not backport] Signed-off-by: Dong Chenchen <dongchenchen2(a)huawei.com> --- net/ipv6/sit.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index 6799691f565c..0de46ad81f62 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -925,6 +925,7 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb, ip_rt_put(rt); goto tx_error; } + iph6 = ipv6_hdr(skb); if (df) { mtu = dst_mtu(&rt->dst) - t_hlen; -- 2.43.0

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[PATCH openEuler-1.0-LTS] netfilter: ip6t_eui64: reject invalid MAC header for all packets
by superdcc97＠163.com 26 Aug '26

26 Aug '26

From: Zhengchuan Liang <zcliangcn(a)gmail.com> mainline inclusion from mainline-v7.1-rc1 commit fdce0b3590f724540795b874b4c8850c90e6b0a8 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/14432 CVE: CVE-2026-31685 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- `eui64_mt6()` derives a modified EUI-64 from the Ethernet source address and compares it with the low 64 bits of the IPv6 source address. The existing guard only rejects an invalid MAC header when `par->fragoff != 0`. For packets with `par->fragoff == 0`, `eui64_mt6()` can still reach `eth_hdr(skb)` even when the MAC header is not valid. Fix this by removing the `par->fragoff != 0` condition so that packets with an invalid MAC header are rejected before accessing `eth_hdr(skb)`. Fixes: 1da177e4c3f41 ("Linux-2.6.12-rc2") Reported-by: Yifan Wu <yifanwucs(a)gmail.com> Reported-by: Juefei Pu <tomapufckgml(a)gmail.com> Co-developed-by: Yuan Tan <yuantan098(a)gmail.com> Signed-off-by: Yuan Tan <yuantan098(a)gmail.com> Suggested-by: Xin Liu <bird(a)lzu.edu.cn> Tested-by: Ren Wei <enjou1224z(a)gmail.com> Signed-off-by: Zhengchuan Liang <zcliangcn(a)gmail.com> Signed-off-by: Ren Wei <n05ec(a)lzu.edu.cn> Signed-off-by: Florian Westphal <fw(a)strlen.de> Signed-off-by: Dong Chenchen <dongchenchen2(a)huawei.com> --- net/ipv6/netfilter/ip6t_eui64.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/ipv6/netfilter/ip6t_eui64.c b/net/ipv6/netfilter/ip6t_eui64.c index aab0706908c5..cda3d43e527d 100644 --- a/net/ipv6/netfilter/ip6t_eui64.c +++ b/net/ipv6/netfilter/ip6t_eui64.c @@ -25,8 +25,7 @@ eui64_mt6(const struct sk_buff *skb, struct xt_action_param *par) unsigned char eui64[8]; if (!(skb_mac_header(skb) >= skb->head && - skb_mac_header(skb) + ETH_HLEN <= skb->data) && - par->fragoff != 0) { + skb_mac_header(skb) + ETH_HLEN <= skb->data)) { par->hotdrop = true; return false; } -- 2.43.0

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[PATCH OLK-6.6] tcp: clear sock_ops cb flags before force-closing a child socket
by JiangJieHua 26 Aug '26

26 Aug '26

From: Sechang Lim <rhkrqnwk98(a)gmail.com> mainline inclusion from mainline-v7.2-rc1 commit 990348e5bb457697c2f1f7f7b65154a3334d9d2b category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/17954 CVE: CVE-2026-74268 Reference:https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/… -------------------------------- A child socket inherits the listener's bpf_sock_ops_cb_flags via sk_clone_lock(). If its setup fails in tcp_v4_syn_recv_sock() / tcp_v6_syn_recv_sock(), the child is freed through put_and_exit, where inet_csk_prepare_forced_close() drops the socket lock and tcp_done() runs without it. If BPF_SOCK_OPS_STATE_CB_FLAG was inherited, tcp_done() -> tcp_set_state() calls tcp_call_bpf(), which expects the lock and trips sock_owned_by_me(): WARNING: include/net/sock.h:1799 at tcp_set_state+0x433/0x550 RIP: 0010:tcp_set_state+0x433/0x550 include/net/sock.h:1799 Call Trace: <IRQ> tcp_done+0xba/0x250 net/ipv4/tcp.c:5095 tcp_v4_syn_recv_sock+0x850/0xa50 net/ipv4/tcp_ipv4.c:1787 tcp_check_req+0xf30/0x1360 net/ipv4/tcp_minisocks.c:926 tcp_v4_rcv+0x1047/0x1b50 net/ipv4/tcp_ipv4.c:2164 </IRQ> The child is freed before it is ever established, so it should run no sock_ops callback. Clear its cb flags in inet_csk_prepare_for_destroy_sock(), the common point for the IPv4, IPv6 and chtls forced-close paths and for the MPTCP ->syn_recv_sock() failure path (dispose_child), which reaches tcp_done() on a child that was never established too. Suggested-by: Jiayuan Chen <jiayuan.chen(a)linux.dev> Fixes: d44874910a26 ("bpf: Add BPF_SOCK_OPS_STATE_CB") Signed-off-by: Sechang Lim <rhkrqnwk98(a)gmail.com> Reviewed-by: Jiayuan Chen <jiayuan.chen(a)linux.dev> Reviewed-by: Kuniyuki Iwashima <kuniyu(a)google.com> Reviewed-by: Eric Dumazet <edumazet(a)google.com> Link: https://patch.msgid.link/20260611092923.1895982-1-rhkrqnwk98@gmail.com Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> Conflicts: net/ipv4/inet_connection_sock.c [In OLK-6.6, inet_csk_prepare_for_destroy_sock() remains a static inline function in include/net/inet_connection_sock.h, while upstream already moved it into inet_connection_sock.c via commit 7051b54fb5aa (due to header dependency). This backport cherry-picks the inline-to-non-inline conversion (changing the definition in inet_connection_sock.h to a declaration), retains OLK-6.6's this_cpu_inc(*sk->sk_prot->orphan_count) implementation without pulling in the orphan_count refactoring, and adds a sk->sk_protocol == IPPROTO_TCP guard to isolate the DCCP path. Signed-off-by: JiangJieHua <jiangjiehua1(a)huawei.com> --- include/net/inet_connection_sock.h | 8 +------- include/net/tcp.h | 9 +++++++++ net/ipv4/inet_connection_sock.c | 9 +++++++++ 3 files changed, 19 insertions(+), 7 deletions(-) diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index 327ae14ca82b..c16f600e5c5c 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -303,14 +303,8 @@ reqsk_timeout(struct request_sock *req, unsigned long max_timeout) return (unsigned long)min_t(u64, timeout, max_timeout); } -static inline void inet_csk_prepare_for_destroy_sock(struct sock *sk) -{ - /* The below has to be done to allow calling inet_csk_destroy_sock */ - sock_set_flag(sk, SOCK_DEAD); - this_cpu_inc(*sk->sk_prot->orphan_count); -} - void inet_csk_destroy_sock(struct sock *sk); +void inet_csk_prepare_for_destroy_sock(struct sock *sk); void inet_csk_prepare_forced_close(struct sock *sk); /* diff --git a/include/net/tcp.h b/include/net/tcp.h index 8674996bd39c..e1a345d5a40b 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2515,6 +2515,11 @@ static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, return tcp_call_bpf(sk, op, 3, args); } +static inline void tcp_clear_sock_ops_cb_flags(struct sock *sk) +{ + tcp_sk(sk)->bpf_sock_ops_cb_flags = 0; +} + #else static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args) { @@ -2532,6 +2537,10 @@ static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2, return -EPERM; } +static inline void tcp_clear_sock_ops_cb_flags(struct sock *sk) +{ +} + #endif static inline u32 tcp_timeout_init(struct sock *sk) diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 9f1d17cd5eeb..b0844b7fa7fc 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -1240,6 +1240,15 @@ void inet_csk_destroy_sock(struct sock *sk) } EXPORT_SYMBOL(inet_csk_destroy_sock); +void inet_csk_prepare_for_destroy_sock(struct sock *sk) +{ + /* The below has to be done to allow calling inet_csk_destroy_sock */ + if (sk->sk_protocol == IPPROTO_TCP) + tcp_clear_sock_ops_cb_flags(sk); + sock_set_flag(sk, SOCK_DEAD); + tcp_orphan_count_inc(); +} + /* This function allows to force a closure of a socket after the call to * tcp/dccp_create_openreq_child(). */ -- 2.33.8

2 1

[PATCH OLK-6.6] perf/core: Fix group leader use-after-free after sibling detach
by Luo Gengkun 26 Aug '26

26 Aug '26

From: Aditya Chillara <aditya.chillara(a)oss.qualcomm.com> mainline inclusion from mainline-v7.2-rc6 commit 42c5ca1f0a288a52878bd72a5595b08261057438 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18309 CVE: CVE-2026-74637 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… ---------------------------------------------------------------------- perf_group_detach() handles leader and sibling detach differently. When the group leader is detached, all siblings are promoted to singleton events and their group_leader pointer is reset to themselves. When a sibling is detached, it is removed from the leader's sibling_list, but its group_leader pointer is left pointing at the old leader. That is harmless when the sibling is being closed and freed immediately, as in the DETACH_DEAD path. It is not safe when the sibling is detached but kept alive, such as during CPU hotplug with DETACH_GROUP. In that case the sibling is removed from the context, while its file descriptor can still keep it alive. A typical failing sequence is: - A group contains leader L and sibling S. - CPU hot-unplug detaches S with DETACH_GROUP, removing it from L->sibling_list but leaving S->group_leader == L. - L is later closed and freed. - A PERF_IOC_FLAG_GROUP ioctl on S follows S->group_leader and dereferences the freed leader. This was reproduced by running the perf event fuzzer, CPU hotplug, and a stress workload concurrently: Unable to handle kernel paging request at virtual address 006b6b6b6b6b6cdb CPU: 2 PID: 12489 Comm: perf_fuzzer 6.18.7 PREEMPT pc : perf_ioctl+0x34c/0xc68 x20: ffffff89a3fa2c70 x8 : 6b6b6b6b6b6b6b6b Code: 943c4a0e 340047a0 f9404a94 f9411e88 (f940b908) Call trace: perf_ioctl+0x34c/0xc68 (P) __arm64_sys_ioctl+0xa0/0xf4 invoke_syscall+0x58/0xe4 el0_svc_common+0xa8/0xdc do_el0_svc+0x1c/0x28 el0_svc+0x40/0xc0 el0t_64_sync_handler+0x68/0xdc el0t_64_sync+0x1c4/0x1c8 The fault happened in perf_ioctl(), where perf_event_for_each() follows the stale group_leader pointer and perf_event_for_each_child() then dereferences the freed leader's context. Fix the use-after-free by promoting the detached sibling to a singleton. Also fix __event_disable() cgroup accounting and event state change. Fixes: 8a49542c0554 ("perf_events: Fix races in group composition") Assisted-by: PatchWise:gpt-5.5 Signed-off-by: Aditya Chillara <aditya.chillara(a)oss.qualcomm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Reviewed-by: Dapeng Mi <dapeng1.mi(a)linux.intel.com> Cc: stable(a)vger.kernel.org Link: https://patch.msgid.link/20260807-fix-group-leader-uaf-v3-1-b0c2310c9a0d@os… Conflicts: kernel/events/core.c [Fix simple ctx diff.] Signed-off-by: Luo Gengkun <luogengkun2(a)huawei.com> --- kernel/events/core.c | 66 +++++++++++++++++++++++++------------------- 1 file changed, 37 insertions(+), 29 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 6916dc78b0e7..9a779ca76798 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2163,6 +2163,34 @@ static inline struct list_head *get_event_list(struct perf_event *event) &event->pmu_ctx->flexible_active; } +/* @sibling must already be unlinked from its old leader's sibling_list. */ +static void perf_promote_sibling_to_leader(struct perf_event *sibling, + struct perf_event_context *ctx, + int group_caps) +{ + /* + * Events that have PERF_EV_CAP_SIBLING require being part of + * a group and cannot exist on their own, schedule them out + * and move them into the ERROR state. Also see + * _perf_event_enable(), it will not be able to recover this + * ERROR state. + */ + if (sibling->event_caps & PERF_EV_CAP_SIBLING) + __event_disable(sibling, ctx, PERF_EVENT_STATE_ERROR); + + sibling->group_leader = sibling; + sibling->group_caps = group_caps; + + if (sibling->attach_state & PERF_ATTACH_CONTEXT) { + add_event_to_groups(sibling, ctx); + + if (sibling->state == PERF_EVENT_STATE_ACTIVE) + list_add_tail(&sibling->active_list, get_event_list(sibling)); + } + + perf_event__header_size(sibling); +} + static void perf_group_detach(struct perf_event *event) { struct perf_event *leader = event->group_leader; @@ -2186,8 +2214,9 @@ static void perf_group_detach(struct perf_event *event) */ if (leader != event) { list_del_init(&event->sibling_list); - event->group_leader->nr_siblings--; - event->group_leader->group_generation++; + leader->nr_siblings--; + leader->group_generation++; + perf_promote_sibling_to_leader(event, ctx, event->event_caps); goto out; } @@ -2197,32 +2226,14 @@ static void perf_group_detach(struct perf_event *event) * to whatever list we are on. */ list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) { - - /* - * Events that have PERF_EV_CAP_SIBLING require being part of - * a group and cannot exist on their own, schedule them out - * and move them into the ERROR state. Also see - * _perf_event_enable(), it will not be able to recover this - * ERROR state. - */ - if (sibling->event_caps & PERF_EV_CAP_SIBLING) - __event_disable(sibling, ctx, PERF_EVENT_STATE_ERROR); - - sibling->group_leader = sibling; list_del_init(&sibling->sibling_list); /* Inherit group flags from the previous leader */ - sibling->group_caps = event->group_caps; - - if (sibling->attach_state & PERF_ATTACH_CONTEXT) { - add_event_to_groups(sibling, event->ctx); - - if (sibling->state == PERF_EVENT_STATE_ACTIVE) - list_add_tail(&sibling->active_list, get_event_list(sibling)); - } + perf_promote_sibling_to_leader(sibling, ctx, event->group_caps); WARN_ON_ONCE(sibling->ctx != event->ctx); } + event->nr_siblings = 0; out: for_each_sibling_event(tmp, leader) @@ -2389,12 +2400,8 @@ __perf_remove_from_context(struct perf_event *event, if (flags & DETACH_DEAD) state = PERF_EVENT_STATE_DEAD; - event_sched_out(event, ctx); + __event_disable(event, ctx, state); - if (event->state > PERF_EVENT_STATE_OFF) - perf_cgroup_event_disable(event, ctx); - - perf_event_set_state(event, min(event->state, state)); if (flags & DETACH_GROUP) perf_group_detach(event); if (flags & DETACH_CHILD) @@ -2463,8 +2470,9 @@ static void __event_disable(struct perf_event *event, enum perf_event_state state) { event_sched_out(event, ctx); - perf_cgroup_event_disable(event, ctx); - perf_event_set_state(event, state); + if (event->state > PERF_EVENT_STATE_OFF) + perf_cgroup_event_disable(event, ctx); + perf_event_set_state(event, min(event->state, state)); } /* -- 2.34.1

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[PATCH OLK-6.6] tracing: Fix race between update_event_fields and, event_define_fields
by Tengda Wu 25 Aug '26

25 Aug '26

From: Michael Wu <michael(a)allwinnertech.com> stable inclusion from stable-v6.6.152 commit e5f1d301b4bdaa4206db251fdc691f623162b0a8 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18289 CVE: CVE-2026-74636 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit c3730b8373bb5059d735509b9e6a00d7eb337d7c upstream. The following sequence may leads race between event_define_fields() and update_event_fields(): CPU0 (loads module A) CPU1 (loads module B) =============================== =============================== load_module(A) load_module(B) notifier_call_chain notifier_call_chain trace_module_notify trace_module_notify mutex_lock(&event_mutex) trace_event_update_all() trace_module_add_events(A) down_write(&trace_event_sem) __register_event(call_A) __add_event_to_tracers(call_A) event_define_fields(call_A) for each f: list_for_each_entry(field, list_add(&f->link, &class->fields, link) &class->fields) field = class->fields->next; Where access to the class->fields is not protected by the event_mutex in trace_event_update_all(). This produces the following panic: Unable to handle kernel access ... at virtual address 0000000000000018 pc : update_event_fields+0xf8/0x368 Call trace: update_event_fields+0xf8/0x368 trace_event_update_all+0x7c/0x2b4 trace_module_notify+0x4c/0x1dc notifier_call_chain+0x84/0x168 blocking_notifier_call_chain_robust+0x64/0xd4 load_module+0x10c8/0x123c __arm64_sys_finit_module+0x230/0x31c Fix by taking event_mutex in trace_event_update_all() before trace_event_sem. Cc: stable(a)vger.kernel.org Fixes: b3bc8547d3be ("tracing: Have TRACE_DEFINE_ENUM affect trace event types as well") Link: https://patch.msgid.link/2e5730d2-c631-da41-3a3a-ae35bb4895f3@allwinnertech… Signed-off-by: Michael Wu <michael(a)allwinnertech.com> Signed-off-by: Steven Rostedt <rostedt(a)goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Conflicts: kernel/trace/trace_events.c [Context conflict] Signed-off-by: Tengda Wu <wutengda2(a)huawei.com> --- kernel/trace/trace_events.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index bea0ab4d8d73..7326cfafcc23 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -3035,6 +3035,7 @@ void trace_event_eval_update(struct trace_eval_map **map, int len) int last_i; int i; + mutex_lock(&event_mutex); down_write(&trace_event_sem); list_for_each_entry_safe(call, p, &ftrace_events, list) { /* events are usually grouped together with systems */ @@ -3068,6 +3069,7 @@ void trace_event_eval_update(struct trace_eval_map **map, int len) cond_resched(); } up_write(&trace_event_sem); + mutex_unlock(&event_mutex); } static struct trace_event_file * -- 2.34.1

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[PATCH OLK-6.6] eventfs: Fix use-after-free in eventfs_remove_rec()
by Tengda Wu 25 Aug '26

25 Aug '26

From: Shuangpeng Bai <shuangpeng.kernel(a)gmail.com> stable inclusion from stable-v6.6.152 commit b77581b25e213e83b79ce11eb30024e55ceeb3e9 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18299 CVE: CVE-2026-74606 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit fd73b691702170d37d66f4b0278530cea8ed419a upstream. eventfs_remove_rec() recursively removes the child at the current loop position. After the recursive call returns, list_for_each_entry() advances by reading list.next from the removed child. If free_ei() drops the final reference, release_ei() reuses the list/rcu union to queue an SRCU callback. The child may be freed before that read. The eventfs_mutex serializes list updates, but it does not keep the removed child alive or prevent the SRCU callback from running. Use list_for_each_entry_safe() to save the next sibling before recursively removing the current child. Cc: stable(a)vger.kernel.org Fixes: 43aa6f97c2d0 ("eventfs: Get rid of dentry pointers without refcounts") Link: https://patch.msgid.link/20260806022719.375354-1-shuangpeng.kernel@gmail.com Signed-off-by: Shuangpeng Bai <shuangpeng.kernel(a)gmail.com> Acked-by: Masami Hiramatsu (Google) <mhiramat(a)kernel.org> Signed-off-by: Steven Rostedt <rostedt(a)goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Tengda Wu <wutengda2(a)huawei.com> --- fs/tracefs/event_inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index 36257e1092d6..4ac459c7efc3 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -922,7 +922,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry */ static void eventfs_remove_rec(struct eventfs_inode *ei, int level) { - struct eventfs_inode *ei_child; + struct eventfs_inode *ei_child, *tmp; /* * Check recursion depth. It should never be greater than 3: @@ -935,7 +935,7 @@ static void eventfs_remove_rec(struct eventfs_inode *ei, int level) return; /* search for nested folders or files */ - list_for_each_entry(ei_child, &ei->children, list) + list_for_each_entry_safe(ei_child, tmp, &ei->children, list) eventfs_remove_rec(ei_child, level + 1); list_del_rcu(&ei->list); -- 2.34.1

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