ghsa-44wr-9xpq-76v2
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
powerpc/pseries/iommu: IOMMU table is not initialized for kdump over SR-IOV
When kdump kernel tries to copy dump data over SR-IOV, LPAR panics due to NULL pointer exception:
Kernel attempted to read user page (0) - exploit attempt? (uid: 0)
BUG: Kernel NULL pointer dereference on read at 0x00000000
Faulting instruction address: 0xc000000020847ad4
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
Modules linked in: mlx5_core(+) vmx_crypto pseries_wdt papr_scm libnvdimm mlxfw tls psample sunrpc fuse overlay squashfs loop
CPU: 12 PID: 315 Comm: systemd-udevd Not tainted 6.4.0-Test102+ #12
Hardware name: IBM,9080-HEX POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_008) hv:phyp pSeries
NIP: c000000020847ad4 LR: c00000002083b2dc CTR: 00000000006cd18c
REGS: c000000029162ca0 TRAP: 0300 Not tainted (6.4.0-Test102+)
MSR: 800000000280b033
At the time of LPAR dump, before kexec hands over control to kdump kernel, DDWs (Dynamic DMA Windows) are scanned and added to the FDT. For the SR-IOV case, default DMA window "ibm,dma-window" is removed from the FDT and DDW added, for the device.
Now, kexec hands over control to the kdump kernel.
When the kdump kernel initializes, PCI busses are scanned and IOMMU group/tables created, in pci_dma_bus_setup_pSeriesLP(). For the SR-IOV case, there is no "ibm,dma-window". The original commit: b1fc44eaa9ba, fixes the path where memory is pre-mapped (direct mapped) to the DDW. When TCEs are direct mapped, there is no need to initialize IOMMU tables.
iommu_table_setparms_lpar() only considers "ibm,dma-window" property when initiallizing IOMMU table. In the scenario where TCEs are dynamically allocated for SR-IOV, newly created IOMMU table is not initialized. Later, when the device driver tries to enter TCEs for the SR-IOV device, NULL pointer execption is thrown from iommu_area_alloc().
The fix is to initialize the IOMMU table with DDW property stored in the FDT. There are 2 points to remember:
1. For the dedicated adapter, kdump kernel would encounter both
default and DDW in FDT. In this case, DDW property is used to
initialize the IOMMU table.
2. A DDW could be direct or dynamic mapped. kdump kernel would
initialize IOMMU table and mark the existing DDW as
"dynamic". This works fine since, at the time of table
initialization, iommu_table_clear() makes some space in the
DDW, for some predefined number of TCEs which are needed for
kdump to succeed.
{
"affected": [],
"aliases": [
"CVE-2024-26745"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-04-04T09:15:07Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/pseries/iommu: IOMMU table is not initialized for kdump over SR-IOV\n\nWhen kdump kernel tries to copy dump data over SR-IOV, LPAR panics due\nto NULL pointer exception:\n\n Kernel attempted to read user page (0) - exploit attempt? (uid: 0)\n BUG: Kernel NULL pointer dereference on read at 0x00000000\n Faulting instruction address: 0xc000000020847ad4\n Oops: Kernel access of bad area, sig: 11 [#1]\n LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries\n Modules linked in: mlx5_core(+) vmx_crypto pseries_wdt papr_scm libnvdimm mlxfw tls psample sunrpc fuse overlay squashfs loop\n CPU: 12 PID: 315 Comm: systemd-udevd Not tainted 6.4.0-Test102+ #12\n Hardware name: IBM,9080-HEX POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_008) hv:phyp pSeries\n NIP: c000000020847ad4 LR: c00000002083b2dc CTR: 00000000006cd18c\n REGS: c000000029162ca0 TRAP: 0300 Not tainted (6.4.0-Test102+)\n MSR: 800000000280b033 \u003cSF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE\u003e CR: 48288244 XER: 00000008\n CFAR: c00000002083b2d8 DAR: 0000000000000000 DSISR: 40000000 IRQMASK: 1\n ...\n NIP _find_next_zero_bit+0x24/0x110\n LR bitmap_find_next_zero_area_off+0x5c/0xe0\n Call Trace:\n dev_printk_emit+0x38/0x48 (unreliable)\n iommu_area_alloc+0xc4/0x180\n iommu_range_alloc+0x1e8/0x580\n iommu_alloc+0x60/0x130\n iommu_alloc_coherent+0x158/0x2b0\n dma_iommu_alloc_coherent+0x3c/0x50\n dma_alloc_attrs+0x170/0x1f0\n mlx5_cmd_init+0xc0/0x760 [mlx5_core]\n mlx5_function_setup+0xf0/0x510 [mlx5_core]\n mlx5_init_one+0x84/0x210 [mlx5_core]\n probe_one+0x118/0x2c0 [mlx5_core]\n local_pci_probe+0x68/0x110\n pci_call_probe+0x68/0x200\n pci_device_probe+0xbc/0x1a0\n really_probe+0x104/0x540\n __driver_probe_device+0xb4/0x230\n driver_probe_device+0x54/0x130\n __driver_attach+0x158/0x2b0\n bus_for_each_dev+0xa8/0x130\n driver_attach+0x34/0x50\n bus_add_driver+0x16c/0x300\n driver_register+0xa4/0x1b0\n __pci_register_driver+0x68/0x80\n mlx5_init+0xb8/0x100 [mlx5_core]\n do_one_initcall+0x60/0x300\n do_init_module+0x7c/0x2b0\n\nAt the time of LPAR dump, before kexec hands over control to kdump\nkernel, DDWs (Dynamic DMA Windows) are scanned and added to the FDT.\nFor the SR-IOV case, default DMA window \"ibm,dma-window\" is removed from\nthe FDT and DDW added, for the device.\n\nNow, kexec hands over control to the kdump kernel.\n\nWhen the kdump kernel initializes, PCI busses are scanned and IOMMU\ngroup/tables created, in pci_dma_bus_setup_pSeriesLP(). For the SR-IOV\ncase, there is no \"ibm,dma-window\". The original commit: b1fc44eaa9ba,\nfixes the path where memory is pre-mapped (direct mapped) to the DDW.\nWhen TCEs are direct mapped, there is no need to initialize IOMMU\ntables.\n\niommu_table_setparms_lpar() only considers \"ibm,dma-window\" property\nwhen initiallizing IOMMU table. In the scenario where TCEs are\ndynamically allocated for SR-IOV, newly created IOMMU table is not\ninitialized. Later, when the device driver tries to enter TCEs for the\nSR-IOV device, NULL pointer execption is thrown from iommu_area_alloc().\n\nThe fix is to initialize the IOMMU table with DDW property stored in the\nFDT. There are 2 points to remember:\n\n\t1. For the dedicated adapter, kdump kernel would encounter both\n\t default and DDW in FDT. In this case, DDW property is used to\n\t initialize the IOMMU table.\n\n\t2. A DDW could be direct or dynamic mapped. kdump kernel would\n\t initialize IOMMU table and mark the existing DDW as\n\t \"dynamic\". This works fine since, at the time of table\n\t initialization, iommu_table_clear() makes some space in the\n\t DDW, for some predefined number of TCEs which are needed for\n\t kdump to succeed.",
"id": "GHSA-44wr-9xpq-76v2",
"modified": "2024-10-31T21:31:44Z",
"published": "2024-04-04T09:30:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26745"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/09a3c1e46142199adcee372a420b024b4fc61051"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5da6d306f315344af1ca2eff4bd9b10b130f0c28"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7eb95e0af5c9c2e6fad50356eaf32d216d0e7bc3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d4d1e4b1513d975961de7bb4f75e450a92d65ebf"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
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