CVSS 3.1
Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)
Атакува се
Време до експлоатация
Атакува се локално, без особени условия, с обикновен потребителски вход и без действие от потребителя.
Описание
Оригинално описание
In the Linux kernel, the following vulnerability has been resolved: spi: imx: fix slab corruption from undersized DMA bounce buffers Since commit faa8e404ad8e ("spi: imx: support dynamic burst length for ECSPI DMA mode"), the driver allocates its private DMA TX/RX buffers with kzalloc(dma_len), where dma_len is only rounded up to 4 bytes, but maps, syncs and unmaps them with DMA_CACHE_ALIGNED_LEN(dma_len), i.e. rounded up to the cache line size. As a result, the DMA API operates on memory beyond the end of the allocation. This was observed on a custom i.MX8MP platform with an mcp251xfd CAN controller under heavy RPMSG load, as a series of refcount_t warnings triggered from rpmsg_recv_done() in virtio_rpmsg_bus: refcount_t: addition on 0; use-after-free. refcount_t: underflow; use-after-free. refcount_t: saturated; leaking memory. Leading finally to an "Unable to handle kernel paging request" oops. Reproducing this problem took between 30 minutes and roughly 30 hours under the same workload. Hardware watchpoints on the refcount of a struct rpmsg_endpoint showed it was overwritten from 2 to 1 by __pi_memcpy_generic() in the irq/155-spi2.0 thread. Additionally it was found that a "normal" rpmsg_recv_done() took 11µs +/-2µs from its kref_get to kref_put. In the error case the same sequence took about 215µs +/-10µs. Based on this, an LLM was used to identify the size mismatch fixed here. Allocate the buffers with DMA_CACHE_ALIGNED_LEN(dma_len) so they cover the full mapped length, and use the same length for dma_sync_single_for_cpu() to stay consistent with map and unmap. With this patch applied, the same workload ran for more than 200 hours without the problem reproducing.
Засегнати продукти
- Linux Linux: faa8e404ad8e686cb98c51dc507fdcacfb8020ce преди 2777f6637da02da84c9c1ff92f413ce0f0995084; faa8e404ad8e686cb98c51dc507fdcacfb8020ce преди 59eb22641f0c526dd064390b11cff99ae87c2858
- Linux Linux: 7.0; преди 7.0; 7.2.13 до 7.2.*; от 7.3 нататък
История
- 28 октомври 2026 Публикувано