In the Linux kernel, the following vulnerability has been resolved:ftrace: Also allocate and copy hash for reading of filter filesCurrently the reader of set_ftrace_filter and set_ftrace_notrace just addsthe pointer to the global tracer hash to its iterator. Unlike the writerthat allocates a copy of the hash, the reader keeps the pointer to thefilter hashes. This is problematic because this pointer is static acrossfunction calls that release the locks that can update the global tracerhashes. This can cause UAF and similar bugs.Allocate and copy the hash for reading the filter files like it is donefor the writers. This not only fixes UAF bugs, but also makes the code abit simpler as it doesn't have to differentiate when to free theiterator's hash between writers and readers.
No PoCs from references.
- https://github.com/w4zu/Debian_security