From: zhengbin zhengbin13@huawei.com
[ Upstream commit 255fbca65137e25b12bced18ec9a014dc77ecda0 ]
As the man(2) page for utime/utimes states, EPERM is returned when the second parameter of utime or utimes is not NULL, the caller's effective UID does not match the owner of the file, and the caller is not privileged.
However, in a NFS directory mounted from knfsd, it will return EACCES (from nfsd_setattr-> fh_verify->nfsd_permission). This patch fixes that.
Signed-off-by: zhengbin zhengbin13@huawei.com Signed-off-by: J. Bruce Fields bfields@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/vfs.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index f55527ef21e84..06d1f2edf2ec6 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -396,10 +396,23 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap, bool get_write_count; bool size_change = (iap->ia_valid & ATTR_SIZE);
- if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE)) + if (iap->ia_valid & ATTR_SIZE) { accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE; - if (iap->ia_valid & ATTR_SIZE) ftype = S_IFREG; + } + + /* + * If utimes(2) and friends are called with times not NULL, we should + * not set NFSD_MAY_WRITE bit. Otherwise fh_verify->nfsd_permission + * will return EACCESS, when the caller's effective UID does not match + * the owner of the file, and the caller is not privileged. In this + * situation, we should return EPERM(notify_change will return this). + */ + if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME)) { + accmode |= NFSD_MAY_OWNER_OVERRIDE; + if (!(iap->ia_valid & (ATTR_ATIME_SET | ATTR_MTIME_SET))) + accmode |= NFSD_MAY_WRITE; + }
/* Callers that do fh_verify should do the fh_want_write: */ get_write_count = !fhp->fh_dentry;