Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
Low
Attack Vector
Local
0

CVE-2024-56740

Disclosure Date: December 29, 2024
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

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

nfs/localio: must clear res.replen in nfs_local_read_done

Otherwise memory corruption can occur due to NFSv3 LOCALIO reads
leaving garbage in res.replen:

  • nfs3_read_done() copies that into server->read_hdrsize; from there
    nfs3_proc_read_setup() copies it to args.replen in new requests.
  • nfs3_xdr_enc_read3args() passes that to rpc_prepare_reply_pages()
    which includes it in hdrsize for xdr_init_pages, so that rq_rcv_buf
    contains a ridiculous len.
  • This is copied to rq_private_buf and xs_read_stream_request()
    eventually passes the kvec to sock_recvmsg() which receives incoming
    data into entirely the wrong place.

This is easily reproduced with NFSv3 LOCALIO that is servicing reads
when it is made to pivot back to using normal RPC. This switch back
to using normal NFSv3 with RPC can occur for a few reasons but this
issue was exposed with a test that stops and then restarts the NFSv3
server while LOCALIO is performing heavy read IO.

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CVSS V3 Severity and Metrics
Base Score:
7.8 High
Impact Score:
5.9
Exploitability Score:
1.8
Vector:
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector (AV):
Local
Attack Complexity (AC):
Low
Privileges Required (PR):
Low
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
High
Integrity (I):
High
Availability (A):
High

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