CVE-2026-68131rbd: Reset positive result codes to zero in object map update path

Official description

In the Linux kernel, the following vulnerability has been resolved: rbd: Reset positive result codes to zero in object map update path In a reply message to an RBD request, a positive result code indicates a data payload, which is not allowed for writes. While rbd_osd_req_callback() already resets a positive result code for writes to zero, rbd_object_map_callback() does not. This allows a corrupted reply to an object map update to trigger the rbd_assert(*result < 0) in __rbd_obj_handle_request(). This happens, because rbd_object_map_callback() calls rbd_obj_handle_request() -> __rbd_obj_handle_request() and passes this positive result code. From __rbd_obj_handle_request(), rbd_obj_advance_write() is called, which leaves the positive result code unchanged and returns true. Therefore, the if(done && *result) branch is executed in __rbd_obj_handle_request() and the assertion triggers. This patch fixes the issue by adjusting the logic in the rbd_object_map_callback() path. A positive result code for an object map update is now reset to zero (similar to rbd_osd_req_callback()), and the message is subsequently handled the same way as if the result code was zero from the beginning. Additionally, a WARN_ON_ONCE() is added for this case.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/cf1167292f606deaddac35ec384eba48f08a68d2
• https://git.kernel.org/stable/c/da926959bf791441ba06a80571708c3d0d3cc08f
• https://git.kernel.org/stable/c/6f33d9d539fb94e5a17589c2dfe271ff9bb64904
• https://git.kernel.org/stable/c/14995c4250f04b58bf6fc00e0e973a2e1b3cfb9b
• https://git.kernel.org/stable/c/2419aa74081007dc4d14ff5640659052dfdfd69a
• https://git.kernel.org/stable/c/34f2a2f32af570dfcc532ad70c080629ee1c32b0
• https://git.kernel.org/stable/c/b1a61366933224b3ad80975c4d01ac2cc6931ecf
• https://git.kernel.org/stable/c/a6c4250b81bd30beae94e1b7a4b26fa1193ad2e4