CVE-2021-47104: 
Linux Kernel vulnerability analysis and mitigation

CVE-2021-47104 is a memory leak vulnerability discovered in the Linux kernel's InfiniBand QLogic (IB/qib) driver. The issue specifically affects the qib_user_sdma_queue_pkts() function where an incorrect goto label was used for error handling, resulting in a missed cleanup of packet allocation (CVE).

The vulnerability stems from a coding error in the qib_user_sdma_queue_pkts() function within the Linux kernel's IB/qib driver. The issue occurs when the wrong goto label ('free_pbc' instead of 'free_pkt') was used in the error case, which caused a failure to properly clean up the packet allocation. This was identified through Coverity scan with ID 1493352 as a "Resource leak" issue (Kernel Commit).

The vulnerability results in a memory leak in the Linux kernel's InfiniBand QLogic driver. When triggered, the system would fail to properly free allocated memory resources, potentially leading to resource exhaustion over time (CVE).

The vulnerability requires local access to the system and the ability to interact with the InfiniBand QLogic driver. No known exploits have been reported in the wild (Red Hat).

The issue has been fixed in the Linux kernel through a patch that corrects the goto label from 'free_pbc' to 'free_pkt' in the error handling code path. The fix was implemented in commit bee90911e0138c76ee67458ac0d58b38a3190f65 and has been backported to various stable kernel versions (Kernel Commit).