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CVE-2024-50154 — tcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().

Affected: Linux

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

tcp/dccp: Don't use timer_pending() in reqsk_queue_unlink().

Martin KaFai Lau reported use-after-free [0] in reqsk_timer_handler().

""" We are seeing a use-after-free from a bpf prog attached to trace_tcp_retransmit_synack. The program passes the req->sk to the bpf_sk_storage_get_tracing kernel helper which does check for null before using it. """

The commit 83fccfc3940c ("inet: fix potential deadlock in reqsk_queue_unlink()") added timer_pending() in reqsk_queue_unlink() not to call del_timer_sync() from reqsk_timer_handler(), but it introduced a small race window.

Before the timer is called, expire_timers() calls detach_timer(timer, true) to clear timer->entry.pprev and marks it as not pending.

If reqsk_queue_unlink() checks timer_pending() just after expire_timers() calls detach_timer(), TCP will miss del_timer_sync(); the reqsk timer will continue running and send multiple SYN+ACKs until it expires.

The reported UAF could happen if req->sk is close()d earlier than the timer expiration, which is 63s by default.

The scenario would be

1. inet_csk_complete_hashdance() calls inet_csk_reqsk_queue_drop(), but del_timer_sync() is missed

2. reqsk timer is executed and scheduled again

3. req->sk is accept()ed and reqsk_put() decrements rsk_refcnt, but reqsk timer still has another one, and inet_csk_accept() does not clear req->sk for non-TFO sockets

4. sk is close()d…

USN-7276-1 — linux, linux-lowlatency vulnerabilities

Affected: Ubuntu:24.10: linux, Ubuntu:24.10: linux-lowlatency

Attila Szász discovered that the HFS+ file system implementation in the Linux Kernel contained a heap overflow vulnerability. An attacker could use a specially crafted file system image that, when mounted, could cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2025-0927)

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: - ARM32 architecture; - ARM64 architecture; - PowerPC architecture; - RISC-V architecture; - S390 architecture; - SuperH RISC architecture; - User-Mode Linux (UML); - x86 architecture; - Block layer subsystem; - Cryptographic API; - Compute Acceleration Framework; - ACPI drivers; - Drivers core; - ATA over ethernet (AOE) driver; - RAM backed block device driver; - Network block device driver; - Ublk userspace block driver; - Compressed RAM block device driver; - Bluetooth drivers; - TPM device driver; - Clock framework and drivers; - Data acquisition framework and drivers; - CPU frequency scaling framework; - Hardware crypto device drivers; - CXL (Compute Express Link) drivers; - DAX dirext access to differentiated memory framework; - Buffer Sharing and Synchronization framework; - EDAC drivers; - FireWire subsystem; - ARM SCMI message protocol; - ARM SCPI message protocol; - EFI core; - Qualcomm firmware drivers; - GPIO subsystem;…