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DACL was encoded in a post-loop block that ran after the bitmap- iteration encoder had emitted higher-numbered attributes. When a client requested DACL together with any attribute numbered > 58 (e.g. FATTR4_XATTR_SUPPORT = 82), the DACL bytes landed after the higher-numbered attribute on the wire, violating RFC 8881 §3.3.7's attribute-number ordering and causing clients to decode garbage at the DACL slot. Add nfsd4_encode_fattr4_dacl(), register it at FATTR4_DACL in nfsd4_enc_fattr4_encode_ops[], and move the dacl pointer onto struct nfsd4_fattr_args so it flows through the dispatch path. Also gate the DACL fetch in nfsd4_encode_fattr4() on IS_NFSV4ACL so GETATTR/READDIR matches what supported_attrs advertises and what the SETATTR check in nfs4proc.c enforces; otherwise a client ignoring supported_attrs receives a flag=0 POSIX-translated fake DACL. This bug was discovered by customer using non-Linux NFSv4 client. (cherry picked from commit b92a9de)
Add note for future developers to not break our encoding here. (cherry picked from commit b1f0edc)
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anodos325
approved these changes
May 8, 2026
anodos325
approved these changes
May 8, 2026
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DACL was encoded in a post-loop block that ran after the bitmap- iteration encoder had emitted higher-numbered attributes. When a client requested DACL together with any attribute numbered > 58 (e.g. FATTR4_XATTR_SUPPORT = 82), the DACL bytes landed after the higher-numbered attribute on the wire, violating RFC 8881 §3.3.7's attribute-number ordering and causing clients to decode garbage at the DACL slot.
Add nfsd4_encode_fattr4_dacl(), register it at FATTR4_DACL in nfsd4_enc_fattr4_encode_ops[], and move the dacl pointer onto struct nfsd4_fattr_args so it flows through the dispatch path.
Also gate the DACL fetch in nfsd4_encode_fattr4() on IS_NFSV4ACL so GETATTR/READDIR matches what supported_attrs advertises and what the SETATTR check in nfs4proc.c enforces; otherwise a client ignoring supported_attrs receives a flag=0 POSIX-translated fake DACL.
This bug was discovered by customer using non-Linux NFSv4 client.
Original PR: #264