fkie_cve-2023-54137
Vulnerability from fkie_nvd
Published
2025-12-24 13:16
Modified
2025-12-24 13:16
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
vfio/type1: fix cap_migration information leak
Fix an information leak where an uninitialized hole in struct
vfio_iommu_type1_info_cap_migration on the stack is exposed to userspace.
The definition of struct vfio_iommu_type1_info_cap_migration contains a hole as
shown in this pahole(1) output:
struct vfio_iommu_type1_info_cap_migration {
struct vfio_info_cap_header header; /* 0 8 */
__u32 flags; /* 8 4 */
/* XXX 4 bytes hole, try to pack */
__u64 pgsize_bitmap; /* 16 8 */
__u64 max_dirty_bitmap_size; /* 24 8 */
/* size: 32, cachelines: 1, members: 4 */
/* sum members: 28, holes: 1, sum holes: 4 */
/* last cacheline: 32 bytes */
};
The cap_mig variable is filled in without initializing the hole:
static int vfio_iommu_migration_build_caps(struct vfio_iommu *iommu,
struct vfio_info_cap *caps)
{
struct vfio_iommu_type1_info_cap_migration cap_mig;
cap_mig.header.id = VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION;
cap_mig.header.version = 1;
cap_mig.flags = 0;
/* support minimum pgsize */
cap_mig.pgsize_bitmap = (size_t)1 << __ffs(iommu->pgsize_bitmap);
cap_mig.max_dirty_bitmap_size = DIRTY_BITMAP_SIZE_MAX;
return vfio_info_add_capability(caps, &cap_mig.header, sizeof(cap_mig));
}
The structure is then copied to a temporary location on the heap. At this point
it's already too late and ioctl(VFIO_IOMMU_GET_INFO) copies it to userspace
later:
int vfio_info_add_capability(struct vfio_info_cap *caps,
struct vfio_info_cap_header *cap, size_t size)
{
struct vfio_info_cap_header *header;
header = vfio_info_cap_add(caps, size, cap->id, cap->version);
if (IS_ERR(header))
return PTR_ERR(header);
memcpy(header + 1, cap + 1, size - sizeof(*header));
return 0;
}
This issue was found by code inspection.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvfio/type1: fix cap_migration information leak\n\nFix an information leak where an uninitialized hole in struct\nvfio_iommu_type1_info_cap_migration on the stack is exposed to userspace.\n\nThe definition of struct vfio_iommu_type1_info_cap_migration contains a hole as\nshown in this pahole(1) output:\n\n struct vfio_iommu_type1_info_cap_migration {\n struct vfio_info_cap_header header; /* 0 8 */\n __u32 flags; /* 8 4 */\n\n /* XXX 4 bytes hole, try to pack */\n\n __u64 pgsize_bitmap; /* 16 8 */\n __u64 max_dirty_bitmap_size; /* 24 8 */\n\n /* size: 32, cachelines: 1, members: 4 */\n /* sum members: 28, holes: 1, sum holes: 4 */\n /* last cacheline: 32 bytes */\n };\n\nThe cap_mig variable is filled in without initializing the hole:\n\n static int vfio_iommu_migration_build_caps(struct vfio_iommu *iommu,\n struct vfio_info_cap *caps)\n {\n struct vfio_iommu_type1_info_cap_migration cap_mig;\n\n cap_mig.header.id = VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION;\n cap_mig.header.version = 1;\n\n cap_mig.flags = 0;\n /* support minimum pgsize */\n cap_mig.pgsize_bitmap = (size_t)1 \u003c\u003c __ffs(iommu-\u003epgsize_bitmap);\n cap_mig.max_dirty_bitmap_size = DIRTY_BITMAP_SIZE_MAX;\n\n return vfio_info_add_capability(caps, \u0026cap_mig.header, sizeof(cap_mig));\n }\n\nThe structure is then copied to a temporary location on the heap. At this point\nit\u0027s already too late and ioctl(VFIO_IOMMU_GET_INFO) copies it to userspace\nlater:\n\n int vfio_info_add_capability(struct vfio_info_cap *caps,\n struct vfio_info_cap_header *cap, size_t size)\n {\n struct vfio_info_cap_header *header;\n\n header = vfio_info_cap_add(caps, size, cap-\u003eid, cap-\u003eversion);\n if (IS_ERR(header))\n return PTR_ERR(header);\n\n memcpy(header + 1, cap + 1, size - sizeof(*header));\n\n return 0;\n }\n\nThis issue was found by code inspection."
}
],
"id": "CVE-2023-54137",
"lastModified": "2025-12-24T13:16:15.693",
"metrics": {},
"published": "2025-12-24T13:16:15.693",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/13fd667db999bffb557c5de7adb3c14f1713dd51"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/1b5feb8497cdb5b9962db2700814bffbc030fb4a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ad83d83dd891244de0d07678b257dc976db7c132"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/cbac29a1caa49a34e131394e1f4d924a76d8b0c9"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/cd24e2a60af633f157d7e59c0a6dba64f131c0b1"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/f6f300ecc196d243c02adeb9ee0c62c677c24bfb"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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