There is a use-after-free vulnerability in the Linux Kernel which can be exploited to achieve local privilege escalation. To reach the vulnerability kernel configuration flag CONFIG_TLS or CONFIG_XFRM_ESPINTCP has to be configured, but the operation does not require any privilege.
There is a use-after-free bug of icsk_ulp_data of a struct inet_connection_sock.
When CONFIG_TLS is enabled, user can install a tls context (struct tls_context) on a connected tcp socket. The context is not cleared if this socket is disconnected and reused as a listener. If a new socket is created from the listener, the context is inherited and vulnerable.
The setsockopt TCP_ULP operation does not require any privilege.
We recommend upgrading past commit 2c02d41d71f90a5168391b6a5f2954112ba2307c
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Linux_kernel | Linux | 4.13.0 (including) | 4.14.303 (excluding) |
| Linux_kernel | Linux | 4.19 (including) | 4.19.270 (excluding) |
| Linux_kernel | Linux | 5.4 (including) | 5.4.229 (excluding) |
| Linux_kernel | Linux | 5.10 (including) | 5.10.163 (excluding) |
| Linux_kernel | Linux | 5.15 (including) | 5.15.88 (excluding) |
| Linux_kernel | Linux | 6.0 (including) | 6.0.19 (excluding) |
| Linux_kernel | Linux | 6.1 (including) | 6.1.5 (excluding) |
| Linux_kernel | Linux | 6.2-rc1 (including) | 6.2-rc1 (including) |
| Linux_kernel | Linux | 6.2-rc2 (including) | 6.2-rc2 (including) |
The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:
In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.