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SUNRPC handle EKEYEXPIRED in call_refreshresult

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Currently, when an RPCSEC_GSS context has expired or is non-existent
and the users (Kerberos) credentials have also expired or are non-existent,
the client receives the -EKEYEXPIRED error and tries to refresh the context
forever.  If an application is performing I/O, or other work against the share,
the application hangs, and the user is not prompted to refresh/establish their
credentials. This can result in a denial of service for other users.

Users are expected to manage their Kerberos credential lifetimes to mitigate
this issue.

Move the -EKEYEXPIRED handling into the RPC layer. Try tk_cred_retry number
of times to refresh the gss_context, and then return -EACCES to the application.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Andy Adamson
2012-11-27 10:34:19 -05:00
committed by Trond Myklebust
parent 620038f6d2
commit eb96d5c97b
6 changed files with 4 additions and 88 deletions
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43
fs/nfs/proc.c
View File

@@ -46,39 +46,6 @@
#define NFSDBG_FACILITY NFSDBG_PROC
/*
* wrapper to handle the -EKEYEXPIRED error message. This should generally
* only happen if using krb5 auth and a user's TGT expires. NFSv2 doesn't
* support the NFSERR_JUKEBOX error code, but we handle this situation in the
* same way that we handle that error with NFSv3.
*/
static int
nfs_rpc_wrapper(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
{
int res;
do {
res = rpc_call_sync(clnt, msg, flags);
if (res != -EKEYEXPIRED)
break;
freezable_schedule_timeout_killable(NFS_JUKEBOX_RETRY_TIME);
res = -ERESTARTSYS;
} while (!fatal_signal_pending(current));
return res;
}
#define rpc_call_sync(clnt, msg, flags) nfs_rpc_wrapper(clnt, msg, flags)
static int
nfs_async_handle_expired_key(struct rpc_task *task)
{
if (task->tk_status != -EKEYEXPIRED)
return 0;
task->tk_status = 0;
rpc_restart_call(task);
rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
return 1;
}
/*
* Bare-bones access to getattr: this is for nfs_read_super.
*/
@@ -364,8 +331,6 @@ static void nfs_proc_unlink_rpc_prepare(struct rpc_task *task, struct nfs_unlink
static int nfs_proc_unlink_done(struct rpc_task *task, struct inode *dir)
{
if (nfs_async_handle_expired_key(task))
return 0;
nfs_mark_for_revalidate(dir);
return 1;
}
@@ -385,8 +350,6 @@ static int
nfs_proc_rename_done(struct rpc_task *task, struct inode *old_dir,
struct inode *new_dir)
{
if (nfs_async_handle_expired_key(task))
return 0;
nfs_mark_for_revalidate(old_dir);
nfs_mark_for_revalidate(new_dir);
return 1;
@@ -642,9 +605,6 @@ static int nfs_read_done(struct rpc_task *task, struct nfs_read_data *data)
{
struct inode *inode = data->header->inode;
if (nfs_async_handle_expired_key(task))
return -EAGAIN;
nfs_invalidate_atime(inode);
if (task->tk_status >= 0) {
nfs_refresh_inode(inode, data->res.fattr);
@@ -671,9 +631,6 @@ static int nfs_write_done(struct rpc_task *task, struct nfs_write_data *data)
{
struct inode *inode = data->header->inode;
if (nfs_async_handle_expired_key(task))
return -EAGAIN;
if (task->tk_status >= 0)
nfs_post_op_update_inode_force_wcc(inode, data->res.fattr);
return 0;