Memory Allocation Issue in Linux Kernel's NVMe PCI Implementation

CVE-2024-56756

What is CVE-2024-56756?

A memory allocation flaw in the NVMe PCI implementation of the Linux kernel has been identified. This vulnerability arises from the handling of the Host Memory Buffer (HMB) descriptor table, which is designed to accommodate the maximum number of descriptors for a device. However, due to a mismanagement in the __nvme_alloc_host_mem function, the allocation process may prematurely exit on memory allocation failure, resulting in fewer descriptors being utilized than intended. This discrepancy can lead to incorrect memory sizes being passed to the dma_free_coherent function. Although this issue was not prevalent in typical scenarios due to low descriptor counts, it potentially poses a risk in high-demand environments where accurate memory management is crucial.

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