In the Linux kernel, the following vulnerability has been resolved:
net: qlogic: qlcnic: Fix a NULL pointer dereference in qlcnic83xxadd_rings()
In qlcnic83xxaddrings(), the indirect function of ahw->hwops->allocmbxargs will be called to allocate memory for cmd.req.arg, and there is a dereference of it in qlcnic83xxaddrings(), which could lead to a NULL pointer dereference on failure of the indirect function like qlcnic83xxallocmbx_args().
Fix this bug by adding a check of allocmbxargs(), this patch imitates the logic of mbx_cmd()'s failure handling.
This bug was found by a static analyzer. The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs.
Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug.
Builds with CONFIG_QLCNIC=m show no new warnings, and our static analyzer no longer warns about this code.