CVE-2024-56712: 
Linux Kernel vulnerability analysis and mitigation

A memory leak vulnerability was discovered in the Linux kernel's udmabuf driver (CVE-2024-56712). The issue occurs in the export_udmabuf() function when dma_buf_fd() fails due to a full FD table, resulting in a created dma_buf owning the udmabuf without proper cleanup, leading to a memory leak with a dangling pointer. The vulnerability affects Linux kernel versions from 4.20 up to 6.12.7, including release candidates 6.13-rc1 through 6.13-rc3 (NVD).

The vulnerability stems from improper error handling in udmabuf_create() where the function tears down the udmabuf without addressing the containing dma_buf when dma_buf_fd() fails. This results in a dma_buf remaining in memory with a dangling pointer. The issue has been present since the introduction of udmabuf. The vulnerability has been assigned a CVSS v3.1 base score of 5.5 (Medium) with the vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H, indicating local access requirements and high availability impact (NVD).

The primary impact of this vulnerability is a memory leak in the Linux kernel. While the dangling pointer doesn't appear to cause immediate severe consequences beyond the memory leak, it could potentially lead to system resource exhaustion over time (Kernel Patch).

The vulnerability requires local access with low privileges to exploit. No known exploits in the wild have been reported at this time (NVD).

The vulnerability has been fixed by moving the dma_buf_fd() call out of export_udmabuf() to implement different error handling. The fix ensures proper cleanup of both the dmabuf and ubuf through udmabuf_ops.release when dma_buf_fd() fails (Kernel Patch).