Affected: Linux

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

bpf: Fix request_sock leak in sk lookup helpers

A customer reported a request_socket leak in a Calico cloud environment. We found that a BPF program was doing a socket lookup with takes a refcnt on the socket and that it was finding the request_socket but returning the parent LISTEN socket via sk_to_full_sk() without decrementing the child request socket 1st, resulting in request_sock slab object leak. This patch retains the existing behaviour of returning full socks to the caller but it also decrements the child request_socket if one is present before doing so to prevent the leak.

Thanks to Curtis Taylor for all the help in diagnosing and testing this. And thanks to Antoine Tenart for the reproducer and patch input.

v2 of this patch contains, refactor as per Daniel Borkmann's suggestions to validate RCU flags on the listen socket so that it balances with bpf_sk_release() and update comments as per Martin KaFai Lau's suggestion. One small change to Daniels suggestion, put "sk = sk2" under "if (sk2 != sk)" to avoid an extra instruction.

kernel: off-path attacker may inject data or terminate victim's TCP session kernel: race condition in VT_RESIZEX ioctl when vc_cons[i].d is already NULL leading to NULL pointer dereference kernel: use-after-free vulnerability in function sco_sock_sendmsg() kernel: memory leak for large arguments in video_usercopy function in drivers/media/v4l2-core/v4l2-ioctl.c kernel: mm/damon/dbgfs: protect targets destructions with kdamond_lock kernel: mm/hwpoison: clear MF_COUNT_INCREASED before retrying get_any_page() kernel: veth: ensure skb entering GRO are not cloned. kernel: inet: fully convert sk->sk_rx_dst to RCU rules kernel: NFSD: Fix READDIR buffer overflow kernel: cpufreq: CPPC: Fix potential memleak in cppc_cpufreq_cpu_init kernel: nvme-rdma: destroy cm id before destroy qp to avoid use after free kernel: regmap: Fix possible double-free in regcache_rbtree_exit() kernel: ethtool: do not perform operations on net devices being unregistered kernel: scsi: scsi_debug: Fix type in min_t to avoid stack OOB kernel: KVM: x86/mmu: Zap _all_ roots when unmapping gfn range in TDP MMU kernel: udmabuf: validate ubuf->pagecount kernel: drm/virtio: Ensure that objs is not NULL in virtio_gpu_array_put_free() kernel: smb2_ioctl_query_info NULL pointer dereference kernel: NULL pointer dereference in udf_expand_file_adinicbdue() during writeback kernel: swiotlb information leak with DMA_FROM_DEVICE kernel: uninitialized registers on stack in nft_do_chain can cause kernel pointer leakage to UM k…