CVE-2023-53659

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

iavf: Fix out-of-bounds when setting channels on remove

If we set channels greater during iavf_remove(), and waiting reset done would be timeout, then returned with error but changed num_active_queues directly, that will lead to OOB like the following logs. Because the num_active_queues is greater than tx/rx_rings[] allocated actually.

Reproducer:

[root@host ~]# cat repro.sh #!/bin/bash

pf_dbsf=0000:41:00.0 vf0_dbsf=0000:41:02.0 g_pids=()

function do_set_numvf() { echo 2 >/sys/bus/pci/devices/${pf_dbsf}/sriov_numvfs sleep $((RANDOM%3+1)) echo 0 >/sys/bus/pci/devices/${pf_dbsf}/sriov_numvfs sleep $((RANDOM%3+1)) }

function do_set_channel() { local nic=$(ls -1 –indicator-style=none /sys/bus/pci/devices/${vf0_dbsf}/net/) [ -z $nic ] && { sleep $((RANDOM%3)) ; return 1; } ifconfig $nic 192.168.18.5 netmask 255.255.255.0 ifconfig $nic up ethtool -L $nic combined 1 ethtool -L $nic combined 4 sleep $((RANDOM%3)) }

function on_exit() { local pid for pid in ${g_pids[@]}; do kill -0 $pid &>/dev/null && kill $pid &>/dev/null done g_pids=() }

trap on_exit; exit EXIT

while :; do do_set_numvf ; done & g_pids+=($!) while :; do do_set_channel ; done & g_pids+=($!)

wait

Result:

[ 3506.152887] iavf 0000:41:02.0: Removing device [ 3510.400799] ================================================================== [ 3510.400820] BUG: KASAN: slab-out-of-bounds in iavf_free_all_tx_resources+0x156/0x160 [iavf] [ 3510.400823] Read of size 8 at addr ffff88b6f9311008 by task repro.sh/55536 [ 3510.400823] [ 3510.400830] CPU: 101 PID: 55536 Comm: repro.sh Kdump: loaded Tainted: G O ——— -t - 4.18.0 #1 [ 3510.400832] Hardware name: Powerleader PR2008AL/H12DSi-N6, BIOS 2.0 04/09/2021 [ 3510.400835] Call Trace: [ 3510.400851] dump_stack+0x71/0xab [ 3510.400860] print_address_description+0x6b/0x290 [ 3510.400865] ? iavf_free_all_tx_resources+0x156/0x160 [iavf] [ 3510.400868] kasan_report+0x14a/0x2b0 [ 3510.400873] iavf_free_all_tx_resources+0x156/0x160 [iavf] [ 3510.400880] iavf_remove+0x2b6/0xc70 [iavf] [ 3510.400884] ? iavf_free_all_rx_resources+0x160/0x160 [iavf] [ 3510.400891] ? wait_woken+0x1d0/0x1d0 [ 3510.400895] ? notifier_call_chain+0xc1/0x130 [ 3510.400903] pci_device_remove+0xa8/0x1f0 [ 3510.400910] device_release_driver_internal+0x1c6/0x460 [ 3510.400916] pci_stop_bus_device+0x101/0x150 [ 3510.400919] pci_stop_and_remove_bus_device+0xe/0x20 [ 3510.400924] pci_iov_remove_virtfn+0x187/0x420 [ 3510.400927] ? pci_iov_add_virtfn+0xe10/0xe10 [ 3510.400929] ? pci_get_subsys+0x90/0x90 [ 3510.400932] sriov_disable+0xed/0x3e0 [ 3510.400936] ? bus_find_device+0x12d/0x1a0 [ 3510.400953] i40e_free_vfs+0x754/0x1210 [i40e] [ 3510.400966] ? i40e_reset_all_vfs+0x880/0x880 [i40e] [ 3510.400968] ? pci_get_device+0x7c/0x90 [ 3510.400970] ? pci_get_subsys+0x90/0x90 [ 3510.400982] ? pci_vfs_assigned.part.7+0x144/0x210 [ 3510.400987] ? __mutex_lock_slowpath+0x10/0x10 [ 3510.400996] i40e_pci_sriov_configure+0x1fa/0x2e0 [i40e] [ 3510.401001] sriov_numvfs_store+0x214/0x290 [ 3510.401005] ? sriov_totalvfs_show+0x30/0x30 [ 3510.401007] ? __mutex_lock_slowpath+0x10/0x10 [ 3510.401011] ? __check_object_size+0x15a/0x350 [ 3510.401018] kernfs_fop_write+0x280/0x3f0 [ 3510.401022] vfs_write+0x145/0x440 [ 3510.401025] ksys_write+0xab/0x160 [ 3510.401028] ? __ia32_sys_read+0xb0/0xb0 [ 3510.401031] ? fput_many+0x1a/0x120 [ 3510.401032] ? filp_close+0xf0/0x130 [ 3510.401038] do_syscall_64+0xa0/0x370 [ 3510.401041] ? page_fault+0x8/0x30 [ 3510.401043] entry_SYSCALL_64_after_hwframe+0x65/0xca [ 3510.401073] RIP: 0033:0x7f3a9bb842c0 [ 3510.401079] Code: 73 01 c3 48 8b 0d d8 cb 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 89 24 2d 00 00 75 10 b8 01 00 00 00 0f 05 <48> 3d —truncated—

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/540.html

References

• https://git.kernel.org/stable/c/0fb37ce6c01e17839e26d03222f0b44e6a3ed2b9
• https://git.kernel.org/stable/c/65ecebc9ac09427b2c65f271cd5e5bd536c3fe38
• https://git.kernel.org/stable/c/6e1d8f1332076a002e6d910d255aa5903d341c56
• https://git.kernel.org/stable/c/7c4bced3caa749ce468b0c5de711c98476b23a52
• https://git.kernel.org/stable/c/b92defe4e8ee86996c16417ad8c804cb4395fddd