CVE-2026-89702
Description
In the Linux kernel, the following vulnerability has been resolved: nfsd: size fh_verify server sockaddr slot by xpt_locallen The nfsd_fh_verify and nfsd_fh_verify_err tracepoints declare the server sockaddr slot sized by xpt_remotelen but fill it from xpt_local using xpt_locallen: TP_STRUCT__entry( ... __sockaddr(server, rqstp->rq_xprt->xpt_remotelen) ... ) TP_fast_assign( ... __assign_sockaddr(server, &rqstp->rq_xprt->xpt_local, rqstp->rq_xprt->xpt_locallen); ... ) When xpt_locallen exceeds xpt_remotelen, __assign_sockaddr's memcpy writes past the reserved ring-buffer slot. In the reverse direction (xpt_locallen < xpt_remotelen) the slot is oversized and the unwritten tail leaks prior ring-buffer contents to trace consumers. The write-past-end case is reachable on NFS/UDP. svc_xprt_set_remote() is only called from svc_tcp_accept() (net/sunrpc/svcsock.c) and from the RDMA connect path; svc_create_socket() for UDP calls only svc_xprt_set_local(), so xpt_remotelen stays 0 for the xprt's lifetime. Every fh_verify trace for an NFSv2/v3-over-UDP request then copies 16 or 28 bytes from xpt_local into a zero-byte slot. The other NFSD tracepoints that record the server address (NFSD_TRACE_PROC_CALL_FIELDS, NFSD_TRACE_PROC_RES_FIELDS, SVC_RQST_ENDPOINT_FIELDS) already size the server slot by xpt_locallen; nfsd_fh_verify and nfsd_fh_verify_err were the only exceptions. Fix by sizing the server slot with xpt_locallen so the declared slot matches the copy length. The client slot and its assignment already agree on xpt_remotelen and are left untouched.
How to fix
- Linux Linux4c7569ad68fc8b86ca40c7e56ef21460c0344955, 50d9d581d2af80799125ee62617d37e9b6b476a7, 1c6a4d6c20fd42552ffc2c3dfaed2139c9477ee5, 95d064f9828a20ccca5ae90a17be3e2076f25272, 7ff8d6363cffff45654ea85e319f7c0c54226012, 719a10e3f5f868c3c4ac3cf3648c5775d12034bd, 71d068490098b1d23c63b2345e40675d3a1ca763, 5.15.224 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | dcbebc86850324fbe0a993ce352f0539cd98038a ≤ v < 4c7569ad68fc8b86ca40c7e56ef21460c0344955, 051382885552e12541cc0ebf82092be374a9ed2a ≤ v < 50d9d581d2af80799125ee62617d37e9b6b476a7, 051382885552e12541cc0ebf82092be374a9ed2a ≤ v < 1c6a4d6c20fd42552ffc2c3dfaed2139c9477ee5, 051382885552e12541cc0ebf82092be374a9ed2a ≤ v < 95d064f9828a20ccca5ae90a17be3e2076f25272, 051382885552e12541cc0ebf82092be374a9ed2a ≤ v < 7ff8d6363cffff45654ea85e319f7c0c54226012, 051382885552e12541cc0ebf82092be374a9ed2a ≤ v < 719a10e3f5f868c3c4ac3cf3648c5775d12034bd, 051382885552e12541cc0ebf82092be374a9ed2a ≤ v < 71d068490098b1d23c63b2345e40675d3a1ca763, 62980365d6e894234b29f44fb2bfad4f7f8bb824, 5.15.154 ≤ v < 5.15.224, 6.0 | 4c7569ad68fc8b86ca40c7e56ef21460c0344955, 50d9d581d2af80799125ee62617d37e9b6b476a7, 1c6a4d6c20fd42552ffc2c3dfaed2139c9477ee5, 95d064f9828a20ccca5ae90a17be3e2076f25272, 7ff8d6363cffff45654ea85e319f7c0c54226012, 719a10e3f5f868c3c4ac3cf3648c5775d12034bd, 71d068490098b1d23c63b2345e40675d3a1ca763, 5.15.224 |
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