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authorChuck Lever <chuck.lever@oracle.com>2017-08-10 16:41:31 -0400
committerTrond Myklebust <trond.myklebust@primarydata.com>2017-08-20 12:43:34 -0400
commit53a75f22e78a601321c2e1fd16266ecdae2f2309 (patch)
tree29e1691dc4353792cf2793934a817756da1bbe64 /fs/nfs/super.c
parentb79e87e070476e16b1d687e5ccc2da6db1a839dc (diff)
downloadlinux-53a75f22e78a601321c2e1fd16266ecdae2f2309.tar.bz2
NFS: Fix NFSv2 security settings
For a while now any NFSv2 mount where sec= is specified uses AUTH_NULL. If sec= is not specified, the mount uses AUTH_UNIX. Commit e68fd7c8071d ("mount: use sec= that was specified on the command line") attempted to address a very similar problem with NFSv3, and should have fixed this too, but it has a bug. The MNTv1 MNT procedure does not return a list of security flavors, so our client makes up a list containing just AUTH_NULL. This should enable nfs_verify_authflavors() to assign the sec= specified flavor, but instead, it incorrectly sets it to AUTH_NULL. I expect this would also be a problem for any NFSv3 server whose MNTv3 MNT procedure returned a security flavor list containing only AUTH_NULL. Fixes: e68fd7c8071d ("mount: use sec= that was specified on ... ") BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=310 Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs/super.c')
-rw-r--r--fs/nfs/super.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index d828ef88e7db..6b179af59b92 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -1691,8 +1691,8 @@ static int nfs_verify_authflavors(struct nfs_parsed_mount_data *args,
rpc_authflavor_t *server_authlist, unsigned int count)
{
rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
+ bool found_auth_null = false;
unsigned int i;
- int use_auth_null = false;
/*
* If the sec= mount option is used, the specified flavor or AUTH_NULL
@@ -1701,6 +1701,10 @@ static int nfs_verify_authflavors(struct nfs_parsed_mount_data *args,
* AUTH_NULL has a special meaning when it's in the server list - it
* means that the server will ignore the rpc creds, so any flavor
* can be used but still use the sec= that was specified.
+ *
+ * Note also that the MNT procedure in MNTv1 does not return a list
+ * of supported security flavors. In this case, nfs_mount() fabricates
+ * a security flavor list containing just AUTH_NULL.
*/
for (i = 0; i < count; i++) {
flavor = server_authlist[i];
@@ -1709,11 +1713,11 @@ static int nfs_verify_authflavors(struct nfs_parsed_mount_data *args,
goto out;
if (flavor == RPC_AUTH_NULL)
- use_auth_null = true;
+ found_auth_null = true;
}
- if (use_auth_null) {
- flavor = RPC_AUTH_NULL;
+ if (found_auth_null) {
+ flavor = args->auth_info.flavors[0];
goto out;
}