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CVE-2024-56658

Description

In the Linux kernel, the following vulnerability has been resolved:net: defer final 'struct net' free in netns dismantleIlya reported a slab-use-after-free in dst_destroy [1]Issue is in xfrm6_net_init() and xfrm4_net_init() :They copy xfrm[46]_dst_ops_template into net->xfrm.xfrm[46]_dst_ops.But net structure might be freed before all the dst callbacks arecalled. So when dst_destroy() calls later :if (dst->ops->destroy) dst->ops->destroy(dst);dst->ops points to the old net->xfrm.xfrm[46]_dst_ops, which has been freed.See a relevant issue fixed in :ac888d58869b ("net: do not delay dst_entries_add() in dst_release()")A fix is to queue the 'struct net' to be freed after oneanother cleanup_net() round (and existing rcu_barrier())[1]BUG: KASAN: slab-use-after-free in dst_destroy (net/core/dst.c:112)Read of size 8 at addr ffff8882137ccab0 by task swapper/37/0Dec 03 05:46:18 kernel:CPU: 37 UID: 0 PID: 0 Comm: swapper/37 Kdump: loaded Not tainted 6.12.0 #67Hardware name: Red Hat KVM/RHEL, BIOS 1.16.1-1.el9 04/01/2014Call Trace: dump_stack_lvl (lib/dump_stack.c:124)print_address_description.constprop.0 (mm/kasan/report.c:378)? dst_destroy (net/core/dst.c:112)print_report (mm/kasan/report.c:489)? dst_destroy (net/core/dst.c:112)? kasan_addr_to_slab (mm/kasan/common.c:37)kasan_report (mm/kasan/report.c:603)? dst_destroy (net/core/dst.c:112)? rcu_do_batch (kernel/rcu/tree.c:2567)dst_destroy (net/core/dst.c:112)rcu_do_batch (kernel/rcu/tree.c:2567)? __pfx_rcu_do_batch (kernel/rcu/tree.c:2491)? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4339 kernel/locking/lockdep.c:4406)rcu_core (kernel/rcu/tree.c:2825)handle_softirqs (kernel/softirq.c:554)__irq_exit_rcu (kernel/softirq.c:589 kernel/softirq.c:428 kernel/softirq.c:637)irq_exit_rcu (kernel/softirq.c:651)sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702)RIP: 0010:default_idle (./arch/x86/include/asm/irqflags.h:37 ./arch/x86/include/asm/irqflags.h:92 arch/x86/kernel/process.c:743)Code: 00 4d 29 c8 4c 01 c7 4c 29 c2 e9 6e ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 90 0f 00 2d c7 c9 27 00 fb f4 c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90RSP: 0018:ffff888100d2fe00 EFLAGS: 00000246RAX: 00000000001870ed RBX: 1ffff110201a5fc2 RCX: ffffffffb61a3e46RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffb3d4d123RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed11c7e1835dR10: ffff888e3f0c1aeb R11: 0000000000000000 R12: 0000000000000000R13: ffff888100d20000 R14: dffffc0000000000 R15: 0000000000000000? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:148)? cpuidle_idle_call (kernel/sched/idle.c:186)default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118)cpuidle_idle_call (kernel/sched/idle.c:186)? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168)? lock_release (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5848)? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59)do_idle (kernel/sched/idle.c:326)cpu_startup_entry (kernel/sched/idle.c:423 (discriminator 1))start_secondary (arch/x86/kernel/smpboot.c:202 arch/x86/kernel/smpboot.c:282)? __pfx_start_secondary (arch/x86/kernel/smpboot.c:232)? soft_restart_cpu (arch/x86/kernel/head_64.S:452)common_startup_64 (arch/x86/kernel/head_64.S:414) Dec 03 05:46:18 kernel:Allocated by task 12184:kasan_save_stack (mm/kasan/common.c:48)kasan_save_track (./arch/x86/include/asm/current.h:49 mm/kasan/common.c:60 mm/kasan/common.c:69)__kasan_slab_alloc (mm/kasan/common.c:319 mm/kasan/common.c:345)kmem_cache_alloc_noprof (mm/slub.c:4085 mm/slub.c:4134 mm/slub.c:4141)copy_net_ns (net/core/net_namespace.c:421 net/core/net_namespace.c:480)create_new_namespaces---truncated---

POC

Reference

No PoCs from references.

Github

- https://github.com/cku-heise/euvd-api-doc

- https://github.com/w4zu/Debian_security