A vulnerability classified as critical has been found in Linux Kernel up to 6.6.18/6.7.6. Affected is the function iommu_device_register. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: powerpc/pseries/iommu: DLPAR add doesn't completely initialize pci_controller When a PCI device is dynamically added, the kernel oopses with a NULL pointer dereference: BUG: Kernel NULL pointer dereference on read at 0x00000030 Faulting instruction address: 0xc0000000006bbe5c Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries Modules linked in: rpadlpar_io rpaphp rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs xsk_diag bonding nft_compat nf_tables nfnetlink rfkill binfmt_misc dm_multipath rpcrdma sunrpc rdma_ucm ib_srpt ib_isert iscsi_target_mod target_core_mod ib_umad ib_iser libiscsi scsi_transport_iscsi ib_ipoib rdma_cm iw_cm ib_cm mlx5_ib ib_uverbs ib_core pseries_rng drm drm_panel_orientation_quirks xfs libcrc32c mlx5_core mlxfw sd_mod t10_pi sg tls ibmvscsi ibmveth scsi_transport_srp vmx_crypto pseries_wdt psample dm_mirror dm_region_hash dm_log dm_mod fuse CPU: 17 PID: 2685 Comm: drmgr Not tainted 6.7.0-203405+ #66 Hardware name: IBM,9080-HEX POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_008) hv:phyp pSeries NIP: c0000000006bbe5c LR: c000000000a13e68 CTR: c0000000000579f8 REGS: c00000009924f240 TRAP: 0300 Not tainted (6.7.0-203405+) MSR: 8000000000009033 CR: 24002220 XER: 20040006 CFAR: c000000000a13e64 DAR: 0000000000000030 DSISR: 40000000 IRQMASK: 0 ... NIP sysfs_add_link_to_group+0x34/0x94 LR iommu_device_link+0x5c/0x118 Call Trace: iommu_init_device+0x26c/0x318 (unreliable) iommu_device_link+0x5c/0x118 iommu_init_device+0xa8/0x318 iommu_probe_device+0xc0/0x134 iommu_bus_notifier+0x44/0x104 notifier_call_chain+0xb8/0x19c blocking_notifier_call_chain+0x64/0x98 bus_notify+0x50/0x7c device_add+0x640/0x918 pci_device_add+0x23c/0x298 of_create_pci_dev+0x400/0x884 of_scan_pci_dev+0x124/0x1b0 __of_scan_bus+0x78/0x18c pcibios_scan_phb+0x2a4/0x3b0 init_phb_dynamic+0xb8/0x110 dlpar_add_slot+0x170/0x3b8 [rpadlpar_io] add_slot_store.part.0+0xb4/0x130 [rpadlpar_io] kobj_attr_store+0x2c/0x48 sysfs_kf_write+0x64/0x78 kernfs_fop_write_iter+0x1b0/0x290 vfs_write+0x350/0x4a0 ksys_write+0x84/0x140 system_call_exception+0x124/0x330 system_call_vectored_common+0x15c/0x2ec Commit a940904443e4 ("powerpc/iommu: Add iommu_ops to report capabilities and allow blocking domains") broke DLPAR add of PCI devices. The above added iommu_device structure to pci_controller. During system boot, PCI devices are discovered and this newly added iommu_device structure is initialized by a call to iommu_device_register(). During DLPAR add of a PCI device, a new pci_controller structure is allocated but there are no calls made to iommu_device_register() interface. Fix is to register the iommu device during DLPAR add as well.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2024-26738 since 02/19/2024. The exploitability is told to be difficult. There are known technical details, but no exploit is available.

Upgrading to version 6.6.19, 6.7.7 or 6.8 eliminates this vulnerability. Applying the patch b8315b2e25b4/46e36ebd5e00/a5c57fd2e9bd is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.6.0
• 6.6.1
• 6.6.2
• 6.6.3
• 6.6.4
• 6.6.5
• 6.6.6
• 6.6.7
• 6.6.8
• 6.6.9
• 6.6.10
• 6.6.11
• 6.6.12
• 6.6.13
• 6.6.14
• 6.6.15
• 6.6.16
• 6.6.17
• 6.6.18
• 6.7.0
• 6.7.1
• 6.7.2
• 6.7.3
• 6.7.4
• 6.7.5
• 6.7.6

License

• open-source

CPE 2.3info

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CPE 2.2info

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• 🔍
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