From: "J. Bruce Fields" We weren't actually checking for SHARE_ACCESS_WRITE, with the result that the owner could open a non-writeable file for write! Continue to allow DENY_WRITE only with write access. Thanks to Jim Rees for reporting the bug. Signed-off-by: J. Bruce Fields Signed-off-by: Neil Brown Signed-off-by: Andrew Morton --- fs/nfsd/nfs4proc.c | 4 +++- 1 files changed, 3 insertions(+), 1 deletion(-) diff -puN fs/nfsd/nfs4proc.c~knfsd-nfsd4-fix-open-permission-checking fs/nfsd/nfs4proc.c --- a/fs/nfsd/nfs4proc.c~knfsd-nfsd4-fix-open-permission-checking +++ a/fs/nfsd/nfs4proc.c @@ -78,8 +78,10 @@ do_open_permission(struct svc_rqst *rqst if (open->op_share_access & NFS4_SHARE_ACCESS_READ) accmode |= MAY_READ; - if (open->op_share_deny & NFS4_SHARE_ACCESS_WRITE) + if (open->op_share_access & NFS4_SHARE_ACCESS_WRITE) accmode |= (MAY_WRITE | MAY_TRUNC); + if (open->op_share_deny & NFS4_SHARE_DENY_WRITE) + accmode |= MAY_WRITE; status = fh_verify(rqstp, current_fh, S_IFREG, accmode); _