In the Linux kernel, the following vulnerability has been resolved:
net: Fix TOCTOU issue in sk_is_readable()
sk->sk_prot->sock_is_readable is a valid function pointer when sk resides in a sockmap. After the last sk_psock_put() (which usually happens when socket is removed from sockmap), sk->sk_prot gets restored and sk->sk_prot->sock_is_readable becomes NULL.
This makes sk_is_readable() racy, if the value of sk->sk_prot is reloaded after the initial check. Which in turn may lead to a null pointer dereference.
Ensure the function pointer does not turn NULL after the check.
| Software | From | Fixed in |
|---|---|---|
| linux / linux_kernel | 4.17 | 5.10.239 |
| linux / linux_kernel | 5.11 | 5.15.186 |
| linux / linux_kernel | 5.16 | 6.1.142 |
| linux / linux_kernel | 6.2 | 6.6.94 |
| linux / linux_kernel | 6.7 | 6.12.34 |
| linux / linux_kernel | 6.13 | 6.15.3 |
| linux / linux_kernel | 6.16-rc1 | 6.16-rc1.x |
| debian / debian_linux | 11.0 | 11.0.x |