CyberRota Analysis
AI-GeneratedThe vulnerability in the Linux kernel affects the Distributed Replicated Block Device (DRBD) implementation, allowing a malicious peer to send a data reply with an out-of-range payload size, potentially leading to kernel memory corruption. This can occur when the payload length is manipulated to become negative, enabling an attacker to overwrite memory beyond allocated boundaries. Organizations using DRBD in their Linux environments, especially those with default configurations that do not enforce data integrity algorithms, should prioritize patching this vulnerability to mitigate the risk of exploitation.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: drbd: reject data replies with an out-of-range payload size recv_dless_read() receives a P_DATA_REPLY from a peer into the bio of an outstanding read request. The peer-supplied payload length reaches it as the signed int data_size, and two peer-controlled inputs can make it negative. With a negotiated data-integrity-alg the digest length is subtracted first, so a reply whose payload is smaller than the digest underflows data_size. With no integrity algorithm (the default) data_size is assigned from the unsigned h95/h100 wire length and drbdd() never bounds it for a payload-carrying command, so a length above INT_MAX casts it negative; this path needs no non-default feature. The bio receive loop then computes expect = min_t(int, data_size, bv_len), which is negative, and drbd_recv_all_warn(mapped, expect) receives with a size_t of SIZE_MAX into the first mapped page. The sibling receive path read_in_block() is not affected: it uses an unsigned size and rejects it against DRBD_MAX_BIO_SIZE before receiving. Reject a data reply whose size is negative after the optional digest subtraction, covering both triggers. Impact: a malicious or man-in-the-middle DRBD peer copies attacker-chosen bytes past a bio page in the receiver, corrupting kernel memory. A node that reads from its peer (a diskless node, or read-balancing to the peer) is exposed in the default configuration; data-integrity-alg is not required.