CVE-2024-41096

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> PCI/MSI: Fix UAF in msi_capability_init<br /> <br /> KFENCE reports the following UAF:<br /> <br /> BUG: KFENCE: use-after-free read in __pci_enable_msi_range+0x2c0/0x488<br /> <br /> Use-after-free read at 0x0000000024629571 (in kfence-#12):<br /> __pci_enable_msi_range+0x2c0/0x488<br /> pci_alloc_irq_vectors_affinity+0xec/0x14c<br /> pci_alloc_irq_vectors+0x18/0x28<br /> <br /> kfence-#12: 0x0000000008614900-0x00000000e06c228d, size=104, cache=kmalloc-128<br /> <br /> allocated by task 81 on cpu 7 at 10.808142s:<br /> __kmem_cache_alloc_node+0x1f0/0x2bc<br /> kmalloc_trace+0x44/0x138<br /> msi_alloc_desc+0x3c/0x9c<br /> msi_domain_insert_msi_desc+0x30/0x78<br /> msi_setup_msi_desc+0x13c/0x184<br /> __pci_enable_msi_range+0x258/0x488<br /> pci_alloc_irq_vectors_affinity+0xec/0x14c<br /> pci_alloc_irq_vectors+0x18/0x28<br /> <br /> freed by task 81 on cpu 7 at 10.811436s:<br /> msi_domain_free_descs+0xd4/0x10c<br /> msi_domain_free_locked.part.0+0xc0/0x1d8<br /> msi_domain_alloc_irqs_all_locked+0xb4/0xbc<br /> pci_msi_setup_msi_irqs+0x30/0x4c<br /> __pci_enable_msi_range+0x2a8/0x488<br /> pci_alloc_irq_vectors_affinity+0xec/0x14c<br /> pci_alloc_irq_vectors+0x18/0x28<br /> <br /> Descriptor allocation done in:<br /> __pci_enable_msi_range<br /> msi_capability_init<br /> msi_setup_msi_desc<br /> msi_insert_msi_desc<br /> msi_domain_insert_msi_desc<br /> msi_alloc_desc<br /> ...<br /> <br /> Freed in case of failure in __msi_domain_alloc_locked()<br /> __pci_enable_msi_range<br /> msi_capability_init<br /> pci_msi_setup_msi_irqs<br /> msi_domain_alloc_irqs_all_locked<br /> msi_domain_alloc_locked<br /> __msi_domain_alloc_locked =&gt; fails<br /> msi_domain_free_locked<br /> ...<br /> <br /> That failure propagates back to pci_msi_setup_msi_irqs() in<br /> msi_capability_init() which accesses the descriptor for unmasking in the<br /> error exit path.<br /> <br /> Cure it by copying the descriptor and using the copy for the error exit path<br /> unmask operation.<br /> <br /> [ tglx: Massaged change log ]