redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

NFS: Handle a zero-length auth flavor list 

Some releases of Linux rpc.mountd (nfs-utils 1.1.4 and later) return an
empty auth flavor list if no sec= was specified for the export.  This is
notably broken server behavior.

The new auth flavor list checking added in a recent commit rejects this
case.  The OpenSolaris client does too.

The broken mountd implementation is already widely deployed.  To avoid
a behavioral regression, the kernel's mount client skips flavor checking
(ie reverts to the pre-2.6.32 behavior) if mountd returns an empty
flavor list.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
hifive-unleashed-5.1
Chuck Lever 2009-08-21 17:50:30 -04:00 committed by Trond Myklebust
parent 405d8f8b1d
commit 5eecfde615
1 changed files with 10 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
fs/nfs/super.c
View File

@ -1337,6 +1337,16 @@ static int nfs_walk_authlist(struct nfs_parsed_mount_data *args,
{
unsigned int i, j, server_authlist_len = *(request->auth_flav_len);
/*
* Certain releases of Linux's mountd return an empty
* flavor list. To prevent behavioral regression with
* these servers (ie. rejecting mounts that used to
* succeed), revert to pre-2.6.32 behavior (no checking)
* if the returned flavor list is empty.
*/
if (server_authlist_len == 0)
return 0;
/*
* We avoid sophisticated negotiating here, as there are
* plenty of cases where we can get it wrong, providing