Описание
In the Linux kernel, the following vulnerability has been resolved:
vdpa_sim_blk: reject out-of-range sector starts
vdpasim_blk_check_range() logs an invalid start sector but continues
validating the request. The subsequent unsigned capacity subtraction can
underflow and let an out-of-range buffer offset reach the data path.
The invalid offset is used by three request paths. VIRTIO_BLK_T_OUT
copies guest data to blk->buffer + offset through
vringh_iov_pull_iotlb(), causing an out-of-bounds write in
_copy_from_iter() or memcpy(). VIRTIO_BLK_T_IN copies from
blk->buffer + offset to the guest through vringh_iov_push_iotlb(),
causing an out-of-bounds read in _copy_to_iter().
VIRTIO_BLK_T_WRITE_ZEROES passes blk->buffer + offset to memset(),
causing an out-of-bounds write.
Reject starts at or beyond the capacity before the subtraction. Treat the
capacity boundary as invalid because the IN and OUT paths round byte counts
down to sectors for validation but later copy the original byte counts. A
sub-sector request at the capacity boundary would otherwise still access
past the end of the buffer.
I found this bug myself, though the patch was written with AI assistance.
A flaw was found in the Linux kernel's vDPA (vHost Data Path Acceleration) block simulator driver. Due to improper input validation, the driver logs out-of-range starting sector requests but fails to reject them, causing an arithmetic underflow and an invalid buffer offset. An attacker with access to the simulated device, such as a guest virtual machine, can submit a crafted storage request to trigger out-of-bounds memory reads and writes in the host kernel. This flaw may result in a system crash leading to a denial of service, information disclosure, or arbitrary code execution.
Меры по смягчению последствий
Prevent the vdpa_sim_blk kernel module from loading by adding a modprobe configuration entry:
- Disable loading of the module:
echo "install vdpa_sim_blk /bin/true" > /etc/modprobe.d/disable-vdpa_sim_blk.conf
- Unload the module if it is currently loaded:
modprobe -r vdpa_sim_blk
Caveat: Disabling this module prevents creating or operating simulated vDPA block devices. Warning: If the module is actively in use by virtual machines or system processes, it cannot be safely unloaded at runtime; a system restart is required for the configuration to take effect.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Affected | ||
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel | Affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 9 | kernel | Affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected |
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Дополнительная информация
Статус:
EPSS
7 High
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: vdpa_sim_blk: reject out-of-range sector starts vdpasim_blk_check_range() logs an invalid start sector but continues validating the request. The subsequent unsigned capacity subtraction can underflow and let an out-of-range buffer offset reach the data path. The invalid offset is used by three request paths. VIRTIO_BLK_T_OUT copies guest data to blk->buffer + offset through vringh_iov_pull_iotlb(), causing an out-of-bounds write in _copy_from_iter() or memcpy(). VIRTIO_BLK_T_IN copies from blk->buffer + offset to the guest through vringh_iov_push_iotlb(), causing an out-of-bounds read in _copy_to_iter(). VIRTIO_BLK_T_WRITE_ZEROES passes blk->buffer + offset to memset(), causing an out-of-bounds write. Reject starts at or beyond the capacity before the subtraction. Treat the capacity boundary as invalid because the IN and OUT paths round byte counts down to sectors for validation but later copy the original byte ...
In the Linux kernel, the following vulnerability has been resolved: vdpa_sim_blk: reject out-of-range sector starts vdpasim_blk_check_range() logs an invalid start sector but continues validating the request. The subsequent unsigned capacity subtraction can underflow and let an out-of-range buffer offset reach the data path. The invalid offset is used by three request paths. VIRTIO_BLK_T_OUT copies guest data to blk->buffer + offset through vringh_iov_pull_iotlb(), causing an out-of-bounds write in _copy_from_iter() or memcpy(). VIRTIO_BLK_T_IN copies from blk->buffer + offset to the guest through vringh_iov_push_iotlb(), causing an out-of-bounds read in _copy_to_iter(). VIRTIO_BLK_T_WRITE_ZEROES passes blk->buffer + offset to memset(), causing an out-of-bounds write. Reject starts at or beyond the capacity before the subtraction. Treat the capacity boundary as invalid because the IN and OUT paths round byte counts down to sectors for validation but later copy the original byte
In the Linux kernel, the following vulnerability has been resolved: v ...
In the Linux kernel, the following vulnerability has been resolved: vdpa_sim_blk: reject out-of-range sector starts vdpasim_blk_check_range() logs an invalid start sector but continues validating the request. The subsequent unsigned capacity subtraction can underflow and let an out-of-range buffer offset reach the data path. The invalid offset is used by three request paths. VIRTIO_BLK_T_OUT copies guest data to blk->buffer + offset through vringh_iov_pull_iotlb(), causing an out-of-bounds write in _copy_from_iter() or memcpy(). VIRTIO_BLK_T_IN copies from blk->buffer + offset to the guest through vringh_iov_push_iotlb(), causing an out-of-bounds read in _copy_to_iter(). VIRTIO_BLK_T_WRITE_ZEROES passes blk->buffer + offset to memset(), causing an out-of-bounds write. Reject starts at or beyond the capacity before the subtraction. Treat the capacity boundary as invalid because the IN and OUT paths round byte counts down to sectors for validation but later copy the original b...
EPSS
7 High
CVSS3