Affected: Alpaquita:23: linux-lts, Alpaquita:25: linux-lts, Alpaquita:stream: linux-lts

In the Linux kernel, the following vulnerability has been resolved:

smb: client: Fix use-after-free of network namespace.

Recently, we got a customer report that CIFS triggers oops while reconnecting to a server. [0]

The workload runs on Kubernetes, and some pods mount CIFS servers in non-root network namespaces. The problem rarely happened, but it was always while the pod was dying.

The root cause is wrong reference counting for network namespace.

CIFS uses kernel sockets, which do not hold refcnt of the netns that the socket belongs to. That means CIFS must ensure the socket is always freed before its netns; otherwise, use-after-free happens.

The repro steps are roughly:

1. mount CIFS in a non-root netns 2. drop packets from the netns 3. destroy the netns 4. unmount CIFS

We can reproduce the issue quickly with the script [1] below and see the splat [2] if CONFIG_NET_NS_REFCNT_TRACKER is enabled.

When the socket is TCP, it is hard to guarantee the netns lifetime without holding refcnt due to async timers.

Let's hold netns refcnt for each socket as done for SMC in commit 9744d2bf1976 ("smc: Fix use-after-free in tcp_write_timer_handler().").

Note that we need to move put_net() from cifs_put_tcp_session() to clean_demultiplex_info(); otherwise, __sock_create() still could touch a freed netns while cifsd tries to reconnect from cifs_demultiplex_thread().

Also, maybe_get_net() cannot be put just before __sock_create() because the code is not under RCU and…

In the Linux kernel, the following vulnerability has been resolved:

smb: client: Fix use-after-free of network namespace.

Recently, we got a customer report that CIFS triggers oops while reconnecting to a server. [0]

The workload runs on Kubernetes, and some pods mount CIFS servers in non-root network namespaces. The problem rarely happened, but it was always while the pod was dying.

The root cause is wrong reference counting for network namespace.

CIFS uses kernel sockets, which do not hold refcnt of the netns that the socket belongs to. That means CIFS must ensure the socket is always freed before its netns; otherwise, use-after-free happens.

The repro steps are roughly:

1. mount CIFS in a non-root netns 2. drop packets from the netns 3. destroy the netns 4. unmount CIFS

We can reproduce the issue quickly with the script [1] below and see the splat [2] if CONFIG_NET_NS_REFCNT_TRACKER is enabled.

When the socket is TCP, it is hard to guarantee the netns lifetime without holding refcnt due to async timers.

Let's hold netns refcnt for each socket as done for SMC in commit 9744d2bf1976 ("smc: Fix use-after-free in tcp_write_timer_handler().").

Note that we need to move put_net() from cifs_put_tcp_session() to clean_demultiplex_info(); otherwise, __sock_create() still could touch a freed netns while cifsd tries to reconnect from cifs_demultiplex_thread().

Also, maybe_get_net() cannot be put just before __sock_create() because the code is not under RCU and…

Affected: openEuler:22.03-LTS-SP3: kernel

The Linux Kernel, the operating system core itself. Security Fix(es): In the Linux kernel, the following vulnerability has been resolved: smb: client: Fix use-after-free of network namespace. Recently, we got a customer report that CIFS triggers oops while reconnecting to a server. [0] The workload runs on Kubernetes, and some pods mount CIFS servers in non-root network namespaces. The problem rarely happened, but it was always while the pod was dying. The root cause is wrong reference counting for network namespace. CIFS uses kernel sockets, which do not hold refcnt of the netns that the socket belongs to. That means CIFS must ensure the socket is always freed before its netns; otherwise, use-after-free happens. The repro steps are roughly: 1. mount CIFS in a non-root netns 2. drop packets from the netns 3. destroy the netns 4. unmount CIFS We can reproduce the issue quickly with the script [1] below and see the splat [2] if CONFIG_NET_NS_REFCNT_TRACKER is enabled. When the socket is TCP, it is hard to guarantee the netns lifetime without holding refcnt due to async timers. Let's hold netns refcnt for each socket as done for SMC in commit 9744d2bf1976 ("smc: Fix use-after-free in tcp_write_timer_handler()."). Note that we need to move put_net() from cifs_put_tcp_session() to clean_demultiplex_info(); otherwise, __sock_create() still could touch a freed netns while cifsd tries to reconnect from cifs_demultiplex_thread(). Also, mayb…

kernel: xen-netfront: Fix NULL sring after live migration kernel: fscache: Fix oops due to race with cookie_lru and use_cookie kernel: tracing: Free buffers when a used dynamic event is removed kernel: net: tun: Fix use-after-free in tun_detach() kernel: hwmon: (ibmpex) Fix possible UAF when ibmpex_register_bmc() fails kernel: erofs/zmap.c: Fix incorrect offset calculation kernel: arm64/mm: fix incorrect file_map_count for non-leaf pmd/pud kernel: s390: avoid using global register for current_stack_pointer kernel: erofs: fix missing xas_retry() in fscache mode kernel: rpmsg: qcom_smd: Fix refcount leak in qcom_smd_parse_edge kernel: remoteproc: k3-r5: Fix refcount leak in k3_r5_cluster_of_init kernel: of: check previous kernel's ima-kexec-buffer against memory bounds kernel: coresight: Clear the connection field properly kernel: Linux kernel: Denial of Service in coresight: trbe kernel: rpmsg: char: Avoid double destroy of default endpoint kernel: coresight: cti: Fix hang in cti_disable_hw() kernel: lib/fonts: fix undefined behavior in bit shift for get_default_font kernel: Kernel: Denial of Service in pci_endpoint_test due to zero-length DMA mapping kernel: Linux kernel: Denial of Service in erofs due to memory leak kernel: erofs: fix missing unmap if z_erofs_get_extent_compressedlen() fails kernel: pipe: wakeup wr_wait after setting max_usage kernel: ntb: intel: Fix the NULL vs IS_ERR() bug for debugfs_create_dir() kernel: qed/qed_sriov: guard against NULL derefs from qed_…

Security update for the Linux Kernel

Affected: Ubuntu:Pro:14.04:LTS: linux-aws, Ubuntu:Pro:14.04:LTS: linux-azure, Ubuntu:Pro:14.04:LTS: linux-lts-xenial, Ubuntu:Pro:16.04:LTS: linux, Ubuntu:Pro:16.04:LTS: linux-aws, Ubuntu:Pro:16.04:LTS: linux-aws-hwe, Ubuntu:Pro:16.04:LTS: linux-azure, Ubuntu:Pro:16.04:LTS: linux-gcp, Ubuntu:Pro:16.04:LTS: linux-hwe, Ubuntu:16.04:LTS: linux-hwe-edge and 195 more

In the Linux kernel, the following vulnerability has been resolved: smb: client: Fix use-after-free of network namespace. Recently, we got a customer report that CIFS triggers oops while reconnecting to a server. [0] The workload runs on Kubernetes, and some pods mount CIFS servers in non-root network namespaces. The problem rarely happened, but it was always while the pod was dying. The root cause is wrong reference counting for network namespace. CIFS uses kernel sockets, which do not hold refcnt of the netns that the socket belongs to. That means CIFS must ensure the socket is always freed before its netns; otherwise, use-after-free happens. The repro steps are roughly: 1. mount CIFS in a non-root netns 2. drop packets from the netns 3. destroy the netns 4. unmount CIFS We can reproduce the issue quickly with the script [1] below and see the splat [2] if CONFIG_NET_NS_REFCNT_TRACKER is enabled. When the socket is TCP, it is hard to guarantee the netns lifetime without holding refcnt due to async timers. Let's hold netns refcnt for each socket as done for SMC in commit 9744d2bf1976 ("smc: Fix use-after-free in tcp_write_timer_handler()."). Note that we need to move put_net() from cifs_put_tcp_session() to clean_demultiplex_info(); otherwise, __sock_create() still could touch a freed netns while cifsd tries to reconnect from cifs_demultiplex_thread(). Also, maybe_get_net() cannot be put just before __sock_create() because the code is not under RCU and there is a…

Ein lokaler Angreifer kann mehrere Schwachstellen in Linux Kernel ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.