CVE-2024-57843
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk10th percentile - higher than 10% of all known CVEs
Summary
In the Linux kernel, in the virtio-net driver, there is an overflow bug in virtnet_rq_alloc. When a frag is one page in size and the total size of the buffer plus virtnet_rq_dma exceeds one page, an overflow can occur, leading to system crashes or SCP failures.
Risk Assessment
The risk includes system crashes and data transmission issues (e.g., SCP errors), especially when sysctl net.core.high_order_alloc_disable is set to 1, which can affect the stability of virtual machines.
Recommendation
It is recommended to update the Linux kernel to a version containing the fix that reduces the buffer length when the frag size is insufficient to prevent overflow.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: virtio-net: fix overflow inside virtnet_rq_alloc When the frag just got a page, then may lead to regression on VM. Specially if the sysctl net.core.high_order_alloc_disable value is 1, then the frag always get a page when do refill. Which could see reliable crashes or scp failure (scp a file 100M in size to VM). The issue is that the virtnet_rq_dma takes up 16 bytes at the beginning of a new frag. When the frag size is larger than PAGE_SIZE, everything is fine. However, if the frag is only one page and the total size of the buffer and virtnet_rq_dma is larger than one page, an overflow may occur. The commit f9dac92ba908 ("virtio_ring: enable premapped mode whatever use_dma_api") introduced this problem. And we reverted some commits to fix this in last linux version. Now we try to enable it and fix this bug directly. Here, when the frag size is not enough, we reduce the buffer len to fix this problem.