Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
coresight: platform: defer connection counter increment until alloc succeeds
coresight_add_out_conn() increments nr_outconns before calling devm_krealloc_array() and again before devm_kmalloc(). If either allocation fails, the counter is already bumped while the corresponding array entry is NULL or uninitialized garbage.
coresight_add_in_conn() has the same problem with nr_inconns and devm_krealloc_array().
In both cases the probe returns -ENOMEM, which causes coresight_get_platform_data() to call coresight_release_platform_data() for cleanup. That function iterates up to nr_outconns (or nr_inconns) entries and dereferences each pointer unconditionally, hitting the NULL or garbage entry and panicking instead of failing gracefully.
Fix by moving the counter increments to after all allocations succeed, so the struct is always consistent on any error path.
Details
- Affected product:
- Debian 10 ELS
- Affected packages:
- linux @ 4.19.0