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author | Stefan Hajnoczi <stefanha@redhat.com> | 2023-08-01 18:53:52 +0300 |
---|---|---|
committer | Alex Williamson <alex.williamson@redhat.com> | 2023-08-16 21:25:35 +0300 |
commit | cd24e2a60af633f157d7e59c0a6dba64f131c0b1 (patch) | |
tree | bf62d9abced6450271bd7cda6e5b46c765cddaca /drivers/vfio/pci/vfio_pci_core.c | |
parent | 6c092088fad4767420ed475de679942463f02707 (diff) | |
download | linux-cd24e2a60af633f157d7e59c0a6dba64f131c0b1.tar.xz |
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.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Fixes: ad721705d09c ("vfio iommu: Add migration capability to report supported features")
Link: https://lore.kernel.org/r/20230801155352.1391945-1-stefanha@redhat.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio/pci/vfio_pci_core.c')
0 files changed, 0 insertions, 0 deletions