In the Linux kernel, the following vulnerability has been resolved:
ipmi: fix refcount leak in i_ipmi_request()
When a caller provides a supplied_recv message to i_ipmi_request(),
the function increments the users nr_msgs reference count. If an
error occurs later, the out_err cleanup path only frees the recv_msg
if the function allocated it itself (i.e., !supplied_recv). In the
supplied_recv case the cleanup is skipped, leaving the reference count
elevated. The caller ipmi_request_supply_msgs() does not release the
supplied_recv on error, so the reference is permanently leaked.
Fix this by explicitly reverting the reference count operations when a supplied recv_msg with a valid user pointer is present in the error path: decrement nr_msgs and drop the users kref.
References
- https://git.kernel.org/stable/c/0fd23994ec8c5436d9f0b50848deb87ed933e6b3
- https://git.kernel.org/stable/c/9409e18ffe7378d202efe1cf69989df9f67b0369
- https://git.kernel.org/stable/c/a3f3859cecacb64f18fd446271ece9a3b3f2d4de
- https://git.kernel.org/stable/c/e2a3b77df6aef031455dd83ea8ed4344b7dca1f9
- https://git.kernel.org/stable/c/f5c5065963024390ddad51bd455d1adc710de575