From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "J. Bruce Fields" <bfields@redhat.com>,
Dan Carpenter <dan.carpenter@oracle.com>,
Sasha Levin <sashal@kernel.org>,
linux-nfs@vger.kernel.org
Subject: [PATCH AUTOSEL 4.9 002/141] nfsd4: avoid NULL deference on strange COPY compounds
Date: Fri, 14 Feb 2020 11:19:02 -0500 [thread overview]
Message-ID: <20200214162122.19794-2-sashal@kernel.org> (raw)
In-Reply-To: <20200214162122.19794-1-sashal@kernel.org>
From: "J. Bruce Fields" <bfields@redhat.com>
[ Upstream commit d781e3df710745fbbaee4eb07fd5b64331a1b175 ]
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... "
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/nfsd/nfs4proc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 66985a6a7047b..33537bbb70b36 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1800,7 +1800,8 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
if (opdesc->op_flags & OP_CLEAR_STATEID)
clear_current_stateid(cstate);
- if (need_wrongsec_check(rqstp))
+ if (current_fh->fh_export &&
+ need_wrongsec_check(rqstp))
op->status = check_nfsd_access(current_fh->fh_export, rqstp);
}
encode_op:
--
2.20.1
next parent reply other threads:[~2020-02-14 16:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200214162122.19794-1-sashal@kernel.org>
2020-02-14 16:19 ` Sasha Levin [this message]
2020-02-14 16:19 ` [PATCH AUTOSEL 4.9 021/141] nfs: NFS_SWAP should depend on SWAP Sasha Levin
2020-02-14 16:21 ` [PATCH AUTOSEL 4.9 140/141] NFSv4: try lease recovery on NFS4ERR_EXPIRED Sasha Levin
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