On Fri, Feb 21, 2020 at 11:51:04AM +0100, Pavel Machek wrote:
Hi!
With cross-server COPY we've introduced the possibility that the current or saved filehandle might not have fh_dentry/fh_export filled in, but we missed a place that assumed it was. I think this could be triggered by a compound like:
PUTFH(foreign filehandle) GETATTR SAVEFH COPY
First, check_if_stalefh_allowed sets no_verify on the first (PUTFH) op. Then op_func = nfsd4_putfh runs and leaves current_fh->fh_export NULL. need_wrongsec_check returns true, since this PUTFH has OP_IS_PUTFH_LIKE set and GETATTR does not have OP_HANDLES_WRONGSEC set.
We should probably also consider tightening the checks in check_if_stalefh_allowed and double-checking that we don't assume the filehandle is verified elsewhere in the compound. But I think this fixes the immediate issue.
Reported-by: Dan Carpenter dan.carpenter@oracle.com Fixes: 4e48f1cccab3 "NFSD: allow inter server COPY to have... "
AFAICT 4e48f1cccab3 "NFSD: allow inter server COPY to have... " is not part of 4.19 series, so this should not be needed in 4.19.
Not only 4e48f1cccab3 isn't in 4.19, it isn't in any tree! :)
Looks like an error in the patch, I'll drop this commit from everywhere.