CVE-2024-44991 — tcp: prevent concurrent execution of tcp_sk_exit_batch

Affected: Linux

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

tcp: prevent concurrent execution of tcp_sk_exit_batch

Its possible that two threads call tcp_sk_exit_batch() concurrently, once from the cleanup_net workqueue, once from a task that failed to clone a new netns. In the latter case, error unwinding calls the exit handlers in reverse order for the 'failed' netns.

tcp_sk_exit_batch() calls tcp_twsk_purge(). Problem is that since commit b099ce2602d8 ("net: Batch inet_twsk_purge"), this function picks up twsk in any dying netns, not just the one passed in via exit_batch list.

This means that the error unwind of setup_net() can "steal" and destroy timewait sockets belonging to the exiting netns.

This allows the netns exit worker to proceed to call

WARN_ON_ONCE(!refcount_dec_and_test(&net->ipv4.tcp_death_row.tw_refcount));

without the expected 1 -> 0 transition, which then splats.

At same time, error unwind path that is also running inet_twsk_purge() will splat as well:

WARNING: .. at lib/refcount.c:31 refcount_warn_saturate+0x1ed/0x210 ... refcount_dec include/linux/refcount.h:351 [inline] inet_twsk_kill+0x758/0x9c0 net/ipv4/inet_timewait_sock.c:70 inet_twsk_deschedule_put net/ipv4/inet_timewait_sock.c:221 inet_twsk_purge+0x725/0x890 net/ipv4/inet_timewait_sock.c:304 tcp_sk_exit_batch+0x1c/0x170 net/ipv4/tcp_ipv4.c:3522 ops_exit_list+0x128/0x180 net/core/net_namespace.c:178 setup_net+0x714/0xb40 net/core/net_namespace.c:375 copy_net_ns+0x2f0/0x67…

USN-7154-1 — linux, linux-aws, linux-aws-6.8, linux-gcp, linux-gcp-6.8, linux-gke, linux-ibm, linux-lowlatency, linux-lowlatency-hwe…

Affected: Ubuntu:22.04:LTS: linux-aws-6.8, Ubuntu:22.04:LTS: linux-gcp-6.8, Ubuntu:22.04:LTS: linux-lowlatency-hwe-6.8, Ubuntu:22.04:LTS: linux-oracle-6.8, Ubuntu:24.04:LTS: linux, Ubuntu:24.04:LTS: linux-aws, Ubuntu:24.04:LTS: linux-gcp, Ubuntu:24.04:LTS: linux-gke, Ubuntu:24.04:LTS: linux-ibm, Ubuntu:24.04:LTS: linux-lowlatency and 3 more

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - ARM64 architecture; - MIPS architecture; - PowerPC architecture; - RISC-V architecture; - S390 architecture; - User-Mode Linux (UML); - x86 architecture; - Block layer subsystem; - Android drivers; - ATM drivers; - Drivers core; - Ublk userspace block driver; - Bluetooth drivers; - Character device driver; - Hardware crypto device drivers; - Buffer Sharing and Synchronization framework; - DMA engine subsystem; - Qualcomm firmware drivers; - GPIO subsystem; - GPU drivers; - HID subsystem; - Hardware monitoring drivers; - I2C subsystem; - I3C subsystem; - IIO subsystem; - InfiniBand drivers; - Input Device core drivers; - Input Device (Miscellaneous) drivers; - IOMMU subsystem; - IRQ chip drivers; - LED subsystem; - Mailbox framework; - Multiple devices driver; - Media drivers; - Fastrpc Driver; - VMware VMCI Driver; - MMC subsystem; - Ethernet bonding driver; - Network drivers; - Mellanox network drivers; - Microsoft Azure Network Adapter (MANA) driver; - Near Field Communication (NFC) drivers; - NVME drivers; - Device tree and open firmware driver; - Parport drivers; - PCI subsystem; - Pin controllers subsystem; - x86 platform drivers; - Power supply drivers; - Remote Processor subsystem; - S/390…

Most recent entries from all

CVE-2024-44991 — tcp: prevent concurrent execution of tcp_sk_exit_batch

USN-7154-1 — linux, linux-aws, linux-aws-6.8, linux-gcp, linux-gcp-6.8, linux-gke, linux-ibm, linux-lowlatency, linux-lowlatency-hwe…