CVE-2021-47496net/tls: Fix flipped sign in tls_err_abort() calls

Official description

In the Linux kernel, the following vulnerability has been resolved: net/tls: Fix flipped sign in tls_err_abort() calls sk->sk_err appears to expect a positive value, a convention that ktls doesn't always follow and that leads to memory corruption in other code. For instance, [kworker] tls_encrypt_done(..., err=<negative error from crypto request>) tls_err_abort(.., err) sk->sk_err = err; [task] splice_from_pipe_feed ... tls_sw_do_sendpage if (sk->sk_err) { ret = -sk->sk_err; // ret is positive splice_from_pipe_feed (continued) ret = actor(...) // ret is still positive and interpreted as bytes // written, resulting in underflow of buf->len and // sd->len, leading to huge buf->offset and bogus // addresses computed in later calls to actor() Fix all tls_err_abort() callers to pass a negative error code consistently and centralize the error-prone sign flip there, throwing in a warning to catch future misuse and uninlining the function so it really does only warn once.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/e0cfd5159f314d6b304d030363650b06a2299cbb
• https://git.kernel.org/stable/c/f3dec7e7ace38224f82cf83f0049159d067c2e19
• https://git.kernel.org/stable/c/e41473543f75f7dbc5d605007e6f883f1bd13b9a
• https://git.kernel.org/stable/c/da353fac65fede6b8b4cfe207f0d9408e3121105