vfio: Fix ksize arg while copying user struct in vfio_df_ioctl_bind_iommufd()

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commit 2f03f21fe7 upstream.

For the cases where user includes a non-zero value in 'token_uuid_ptr'
field of 'struct vfio_device_bind_iommufd', the copy_struct_from_user()
in vfio_df_ioctl_bind_iommufd() fails with -E2BIG. For the 'minsz' passed,
copy_struct_from_user() expects the newly introduced field to be zero-ed,
which would be incorrect in this case.

Fix this by passing the actual size of the kernel struct. If working
with a newer userspace, copy_struct_from_user() would copy the
'token_uuid_ptr' field, and if working with an old userspace, it would
zero out this field, thus still retaining backward compatibility.

Fixes: 86624ba3b5 ("vfio/pci: Do vf_token checks for VFIO_DEVICE_BIND_IOMMUFD")
Cc: stable@vger.kernel.org
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20251031170603.2260022-2-rananta@google.com
Signed-off-by: Alex Williamson <alex@shazbot.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Raghavendra Rao Ananta 2025-10-31 17:06:02 +00:00 • committed by Greg Kroah-Hartman

parent 8716a841d1

commit 479af0d9c6

1 changed files with 1 additions and 1 deletions

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drivers/vfio/device_cdev.c

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