2011-04-13 18:31:32

by Anna Schumaker

[permalink] [raw]
Subject: [PATCH 2/6] NFS: Fix infinite loop in gss_create_upcall()


There can be an infinite loop if gss_create_upcall() is called without
the userspace program running. To prevent this, we return -EACCES if
we notice that pipe_version hasn't changed (indicating that the pipe
has not been opened).

Signed-off-by: Bryan Schumaker <[email protected]>

---
fs/nfs/nfs4proc.c | 5 +++--
net/sunrpc/auth_gss/auth_gss.c | 8 +++++---
2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 9bf41ea..8a03ee0 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2224,8 +2224,9 @@ static int nfs4_proc_get_root(struct nfs_server *server, struct nfs_fh *fhandle,

for (i = 0; i < len; i++) {
status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
- if (status != -EPERM)
- break;
+ if (status == -EPERM || status == -EACCES)
+ continue;
+ break;
}
if (status == 0)
status = nfs4_server_capabilities(server, fhandle);
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index f3914d0..339ba64 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -520,7 +520,7 @@ gss_refresh_upcall(struct rpc_task *task)
warn_gssd();
task->tk_timeout = 15*HZ;
rpc_sleep_on(&pipe_version_rpc_waitqueue, task, NULL);
- return 0;
+ return -EAGAIN;
}
if (IS_ERR(gss_msg)) {
err = PTR_ERR(gss_msg);
@@ -563,10 +563,12 @@ retry:
if (PTR_ERR(gss_msg) == -EAGAIN) {
err = wait_event_interruptible_timeout(pipe_version_waitqueue,
pipe_version >= 0, 15*HZ);
+ if (pipe_version < 0) {
+ warn_gssd();
+ err = -EACCES;
+ }
if (err)
goto out;
- if (pipe_version < 0)
- warn_gssd();
goto retry;
}
if (IS_ERR(gss_msg)) {
--
1.7.4.4