CVE-2024-50042: Out-of-bounds Read

In the Linux kernel, the following vulnerability has been resolved:

ice: Fix increasing MSI-X on VF

Increasing MSI-X value on a VF leads to invalid memory operations. This is caused by not reallocating some arrays.

Reproducer: modprobe ice echo 0 > /sys/bus/pci/devices/$PF_PCI/sriov_drivers_autoprobe echo 1 > /sys/bus/pci/devices/$PF_PCI/sriov_numvfs echo 17 > /sys/bus/pci/devices/$VF0_PCI/sriov_vf_msix_count

Default MSI-X is 16, so 17 and above triggers this issue.

KASAN reports:

BUG: KASAN: slab-out-of-bounds in ice_vsi_alloc_ring_stats+0x38d/0x4b0 [ice] Read of size 8 at addr ffff8888b937d180 by task bash/28433 (...)

Call Trace: (...) ? ice_vsi_alloc_ring_stats+0x38d/0x4b0 [ice] kasan_report+0xed/0x120 ? ice_vsi_alloc_ring_stats+0x38d/0x4b0 [ice] ice_vsi_alloc_ring_stats+0x38d/0x4b0 [ice] ice_vsi_cfg_def+0x3360/0x4770 [ice] ? mutex_unlock+0x83/0xd0 ? __pfx_ice_vsi_cfg_def+0x10/0x10 [ice] ? __pfx_ice_remove_vsi_lkup_fltr+0x10/0x10 [ice] ice_vsi_cfg+0x7f/0x3b0 [ice] ice_vf_reconfig_vsi+0x114/0x210 [ice] ice_sriov_set_msix_vec_count+0x3d0/0x960 [ice] sriov_vf_msix_count_store+0x21c/0x300 (...)

Allocated by task 28201: (...) ice_vsi_cfg_def+0x1c8e/0x4770 [ice] ice_vsi_cfg+0x7f/0x3b0 [ice] ice_vsi_setup+0x179/0xa30 [ice] ice_sriov_configure+0xcaa/0x1520 [ice] sriov_numvfs_store+0x212/0x390 (...)

To fix it, use ice_vsi_rebuild() instead of ice_vf_reconfig_vsi(). This causes the required arrays to be reallocated taking the new queue count into account (ice_vsi_realloc_stat_arrays()). Set req_txq and req_rxq before ice_vsi_rebuild(), so that realloc uses the newly set queue count.

Additionally, ice_vsi_rebuild() does not remove VSI filters (ice_fltr_remove_all()), so ice_vf_init_host_cfg() is no longer necessary.