From: Jeff Layton <jlayton@kernel.org> stable inclusion from stable-v6.6.157 commit 88bce7e326c368d7df15126ccac537e54bebd467 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18936 CVE: CVE-2026-89673 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 8b989aaec85e1293a871d602590c951fe44b8647 upstream. nfsd4_ff_encode_getdeviceinfo() computes the da_addr_body reservation as 16 + netid_len + addr_len, but the subsequent xdr_encode_opaque() calls emit 8 + round_up(netid_len, 4) + round_up(addr_len, 4) bytes. The mismatch means the declared da_addr_body length exceeds the actual encoded data by 2-8 bytes on every flexfile GETDEVICEINFO reply, leaking stale reply-page content to the client and mis-aligning the subsequent version list decode. Use xdr_align_size() for each string length to match what xdr_encode_opaque() actually writes. Fixes: efcae97fa425 ("NFSD: da_addr_body field missing in some GETDEVICEINFO replies") Cc: stable@vger.kernel.org Assisted-by: kres:claude-opus-4-6 Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://patch.msgid.link/20260527-pnfs-fixes-v1-1-784f39dc1eca@kernel.org Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Lu Jialin <lujialin4@huawei.com> --- fs/nfsd/flexfilelayoutxdr.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/nfsd/flexfilelayoutxdr.c b/fs/nfsd/flexfilelayoutxdr.c index b79608341de0..c05d1d3e2021 100644 --- a/fs/nfsd/flexfilelayoutxdr.c +++ b/fs/nfsd/flexfilelayoutxdr.c @@ -99,7 +99,8 @@ nfsd4_ff_encode_getdeviceinfo(struct xdr_stream *xdr, } /* len + padding for two strings */ - addr_len = 16 + da->netaddr.netid_len + da->netaddr.addr_len; + addr_len = 8 + xdr_align_size(da->netaddr.netid_len) + + xdr_align_size(da->netaddr.addr_len); ver_len = 20; len = 4 + ver_len + 4 + addr_len; -- 2.34.1