CVE-2021-4441: 
Linux Kernel vulnerability analysis and mitigation

CVE-2021-4441 is a vulnerability discovered in the Linux kernel's Zynq QSPI controller driver (spi-zynq-qspi). The vulnerability was identified through static analysis and involves a potential NULL pointer dereference in the zynqqspiexecmemop() function. The issue was discovered when kzalloc() was being directly used in memset() without proper NULL pointer checking (Kernel Git).

The vulnerability exists in the zynqqspiexecmemop() function where a memory allocation using kzalloc() is performed without checking for allocation failure before using the allocated memory in a memset() operation. This could lead to a NULL pointer dereference if the memory allocation fails. The bug was identified through differential checking that looks for inconsistent security operations between code paths (Kernel Git).

If exploited, this vulnerability could lead to a NULL pointer dereference in the Linux kernel's SPI subsystem, potentially causing a system crash or denial of service condition when interacting with the Zynq QSPI controller (Kernel Git).

The issue has been fixed by adding a proper NULL pointer check after the kzalloc() call and returning -ENOMEM if the allocation fails. The fix has been implemented and merged into the Linux kernel. Systems should be updated to include this security fix (Kernel Git).