🛡️ CVE-2026-46119 — kernel

libceph: Fix slab-out-of-bounds access in auth message processing

In the Linux kernel, the following vulnerability has been resolved:

libceph: Fix slab-out-of-bounds access in auth message processing

If a (potentially corrupted) message of type CEPH_MSG_AUTH_REPLY

contains a positive value in its result field, it is treated as an

error code by ceph_handle_auth_reply() and returned to

handle_auth_reply(). Thereafter, an attempt is made to send the

preallocated message of type CEPH_MSG_AUTH, where the returned value is

interpreted as the size of the front segment to send. If the result

value in the message is greater than the size of the memory buffer

allocated for the front segment, an out-of-bounds access occurs, and

the content of the memory region beyond this buffer is sent out.

This patch fixes the issue by treating only negative values in the

result field as errors. Positive values are therefore treated as success

in the same way as a zero value. Additionally, a BUG_ON is added to

__send_prepared_auth_request() comparing the len parameter to

front_alloc_len to prevent sending the message if it exceeds the bounds

of the allocation and to make it easier to catch any logic flaws leading

to this.