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

rxrpc: Fix locking in rxrpc's sendmsg

Fix three bugs in the rxrpc's sendmsg implementation:

(1) rxrpc_new_client_call() should release the socket lock when returning an error from rxrpc_get_call_slot().

(2) rxrpc_wait_for_tx_window_intr() will return without the call mutex held in the event that we're interrupted by a signal whilst waiting for tx space on the socket or relocking the call mutex afterwards.

Fix this by: (a) moving the unlock/lock of the call mutex up to rxrpc_send_data() such that the lock is not held around all of rxrpc_wait_for_tx_window*() and (b) indicating to higher callers whether we're return with the lock dropped. Note that this means recvmsg() will not block on this call whilst we're waiting.

(3) After dropping and regaining the call mutex, rxrpc_send_data() needs to go and recheck the state of the tx_pending buffer and the tx_total_len check in case we raced with another sendmsg() on the same call.

Thinking on this some more, it might make sense to have different locks for sendmsg() and recvmsg(). There's probably no need to make recvmsg() wait for sendmsg(). It does mean that recvmsg() can return MSG_EOR indicating that a call is dead before a sendmsg() to that call returns - but that can currently happen anyway.

Without fix (2), something like the following can be induced:

WARNING: bad unlock balance detected!…

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

rxrpc: Fix locking in rxrpc's sendmsg

Fix three bugs in the rxrpc's sendmsg implementation:

(1) rxrpc_new_client_call() should release the socket lock when returning an error from rxrpc_get_call_slot().

(2) rxrpc_wait_for_tx_window_intr() will return without the call mutex held in the event that we're interrupted by a signal whilst waiting for tx space on the socket or relocking the call mutex afterwards.

Fix this by: (a) moving the unlock/lock of the call mutex up to rxrpc_send_data() such that the lock is not held around all of rxrpc_wait_for_tx_window*() and (b) indicating to higher callers whether we're return with the lock dropped. Note that this means recvmsg() will not block on this call whilst we're waiting.

(3) After dropping and regaining the call mutex, rxrpc_send_data() needs to go and recheck the state of the tx_pending buffer and the tx_total_len check in case we raced with another sendmsg() on the same call.

Thinking on this some more, it might make sense to have different locks for sendmsg() and recvmsg(). There's probably no need to make recvmsg() wait for sendmsg(). It does mean that recvmsg() can return MSG_EOR indicating that a call is dead before a sendmsg() to that call returns - but that can currently happen anyway.

Without fix (2), something like the following can be induced:

WARNING: bad unlock balance detected!…

hw: cpu: AMD CPUs may transiently execute beyond unconditional direct branch kernel: ext4: kernel bug in ext4_write_inline_data_end() kernel: malicious data for FBIOPUT_VSCREENINFO ioctl may cause OOB write memory kernel: hwmon: (mlxreg-fan) Return non-zero value when fan current state is enforced from sysfs kernel: mlxsw: thermal: Fix out-of-bounds memory accesses kernel: mlxsw: spectrum: Protect driver from buggy firmware kernel: net: stmmac: fix tc flower deletion for VLAN priority Rx steering kernel: can: etas_es58x: es58x_rx_err_msg(): fix memory leak in error path kernel: possible race condition in drivers/tty/tty_buffers.c kernel: KVM: NULL pointer dereference in kvm_mmu_invpcid_gva kernel: use-after-free in free_pipe_info() could lead to privilege escalation kernel: KVM: nVMX: missing IBPB when exiting from nested guest can lead to Spectre v2 attacks kernel: netfilter: nf_conntrack_irc message handling issue kernel: race condition in xfrm_probe_algs can lead to OOB read/write kernel: out-of-bounds read in fib_nh_match of the file net/ipv4/fib_semantics.c kernel: race condition in hugetlb_no_page() in mm/hugetlb.c kernel: memory leak in ipv6_renew_options() kernel: data races around icsk->icsk_af_ops in do_ipv6_setsockopt kernel: data races around sk->sk_prot kernel: memory leak in l2cap_recv_acldata of the file net/bluetooth/l2cap_core.c kernel: denial of service in follow_page_pte in mm/gup.c due to poisoned pte entry kernel: use-after-free after failed devlink relo…

Affected: Ubuntu:Pro:14.04:LTS: linux-azure, 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, Ubuntu:Pro:16.04:LTS: linux-oracle, Ubuntu:Pro:18.04:LTS: linux, Ubuntu:Pro:18.04:LTS: linux-aws, Ubuntu:18.04:LTS: linux-aws-5.0 and 140 more

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix locking in rxrpc's sendmsg Fix three bugs in the rxrpc's sendmsg implementation: (1) rxrpc_new_client_call() should release the socket lock when returning an error from rxrpc_get_call_slot(). (2) rxrpc_wait_for_tx_window_intr() will return without the call mutex held in the event that we're interrupted by a signal whilst waiting for tx space on the socket or relocking the call mutex afterwards. Fix this by: (a) moving the unlock/lock of the call mutex up to rxrpc_send_data() such that the lock is not held around all of rxrpc_wait_for_tx_window*() and (b) indicating to higher callers whether we're return with the lock dropped. Note that this means recvmsg() will not block on this call whilst we're waiting. (3) After dropping and regaining the call mutex, rxrpc_send_data() needs to go and recheck the state of the tx_pending buffer and the tx_total_len check in case we raced with another sendmsg() on the same call. Thinking on this some more, it might make sense to have different locks for sendmsg() and recvmsg(). There's probably no need to make recvmsg() wait for sendmsg(). It does mean that recvmsg() can return MSG_EOR indicating that a call is dead before a sendmsg() to that call returns - but that can currently happen anyway. Without fix (2), something like the following can be induced: WARNING: bad unlock balance detected! 5.16.0-rc…

Ein lokaler Angreifer kann mehrere Schwachstellen in Linux Kernel ausnutzen, um einen Denial of Service Angriff durchzuführen.