NFSD: verify the opened dentry after setting a delegation

Browse source

Between opening a file and setting a delegation on it, someone could
rename or unlink the dentry. If this happens, we do not want to grant a
delegation on the open.

On a CLAIM_NULL open, we're opening by filename, and we may (in the
non-create case) or may not (in the create case) be holding i_rwsem
when attempting to set a delegation.  The latter case allows a
race.

After getting a lease, redo the lookup of the file being opened and
validate that the resulting dentry matches the one in the open file
description.

To properly redo the lookup we need an rqst pointer to pass to
nfsd_lookup_dentry(), so make sure that is available.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

...

This commit is contained in:

Jeff Layton 2022-07-26 16:45:30 +10:00 • committed by Chuck Lever

parent bbf936edd5

commit 876c553cb4

3 changed files with 51 additions and 5 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

1

fs/nfsd/nfs4proc.c

View file

54

fs/nfsd/nfs4state.c

View file

1

fs/nfsd/xdr4.h

View file