CVE-2023-52611 wifi: rtw88: sdio: Honor the host max_req_size in the RX path

What is CVE-2023-52611?

CVE-2023-52611 is a medium-severity denial of service vulnerability in Linux kernel, published on 18 Mar 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

wifi: rtw88: sdio: Honor the host max_req_size in the RX path

Lukas reports skb_over_panic errors on his Banana Pi BPI-CM4 which comes with an Amlogic A311D (G12B) SoC and a RTL8822CS SDIO wifi/Bluetooth combo card. The error he observed is identical to what has been fixed in commit e967229ead0e ("wifi: rtw88: sdio: Check the HISR RX_REQUEST bit in rtw_sdio_rx_isr()") but that commit didn't fix Lukas' problem.

Lukas found that disabling or limiting RX aggregation works around the problem for some time (but does not fully fix it). In the following discussion a few key topics have been discussed which have an impact on this problem: - The Amlogic A311D (G12B) SoC has a hardware bug in the SDIO controller which prevents DMA transfers. Instead all transfers need to go through the controller SRAM which limits transfers to 1536 bytes - rtw88 chips don't split incoming (RX) packets, so if a big packet is received this is forwarded to the host in it's original form - rtw88 chips can do RX aggregation, meaning more multiple incoming packets can be pulled by the host from the card with one MMC/SDIO transfer. This Depends on settings in the REG_RXDMA_AGG_PG_TH register (BIT_RXDMA_AGG_PG_TH limits the number of packets that will be aggregated, BIT_DMA_AGG_TO_V1 configures a timeout for aggregation and BIT_EN_PRE_CALC makes the chip honor the limits more effectively)

Use multiple consecutive reads in rtw_sdio_read_port() and limit the number of bytes which are copied by the host from the card in one MMC/SDIO transfer. This allows receiving a buffer that's larger than the hosts max_req_size (number of bytes which can be transferred in one MMC/SDIO transfer). As a result of this the skb_over_panic error is gone as the rtw88 driver is now able to receive more than 1536 bytes from the card (either because the incoming packet is larger than that or because multiple packets have been aggregated).

In case of an receive errors (-EILSEQ has been observed by Lukas) we need to drain the remaining data from the card's buffer, otherwise the card will return corrupt data for the next rtw_sdio_read_port() call.

Which versions are affected by CVE-2023-52611?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2023-52611?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2023-52611 being exploited?

There is no known exploitation of CVE-2023-52611 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2023-52611, DEBIAN-CVE-2023-52611, GHSA-rw64-46h7-gmc8, UBUNTU-CVE-2023-52611.