CVE-2026-46024libceph: Prevent potential null-ptr-deref in ceph_handle_auth_reply()

Official description

In the Linux kernel, the following vulnerability has been resolved: libceph: Prevent potential null-ptr-deref in ceph_handle_auth_reply() If a message of type CEPH_MSG_AUTH_REPLY contains a zero value for both protocol and result, this is currently not treated as an error. In case of ac->negotiating == true and ac->protocol > 0, this leads to setting ac->protocol = 0 and ac->ops = NULL. Thereafter, the check for ac->protocol != protocol returns false, and init_protocol() is not called. Subsequently, ac->ops->handle_reply() is called, which leads to a null pointer dereference, because ac->ops is still NULL. This patch changes the check for ac->protocol != protocol to !ac->protocol, as this also includes the case when the protocol was set to zero in the message. This causes the message to be treated as containing a bad auth protocol.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/9ded62c302c0342efdb5eda3bf6e75720caad0df
• https://git.kernel.org/stable/c/f101271fcf55d7eacfefd610b51ec65f46ba8118
• https://git.kernel.org/stable/c/4b2738b93edad661178340239de657d876b73d3d
• https://git.kernel.org/stable/c/927e4bd5692f2a4901808822981fb2c8d4456548
• https://git.kernel.org/stable/c/016bc663657366d386993f63eb31072eb45a2b77
• https://git.kernel.org/stable/c/8f2be7285941a33a9f72579a23b96392f83c758e
• https://git.kernel.org/stable/c/5199c125d25aeae8615c4fc31652cc0fe624338e