From patchwork Wed Oct 12 14:32:18 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: NLM: Don't hang forever on NLM unlock requests - CVE-2011-2491 Date: Wed, 12 Oct 2011 04:32:18 -0000 From: Paolo Pisati X-Patchwork-Id: 119220 Message-Id: <1318429938-16867-4-git-send-email-paolo.pisati@canonical.com> To: kernel-team@lists.ubuntu.com From: Trond Myklebust NLM: Don't hang forever on NLM unlock requests If the NLM daemon is killed on the NFS server, we can currently end up hanging forever on an 'unlock' request, instead of aborting. Basically, if the rpcbind request fails, or the server keeps returning garbage, we really want to quit instead of retrying. Tested-by: Vasily Averin Signed-off-by: Trond Myklebust Cc: stable@kernel.org CVE-2011-2491 BugLink: http://bugs.launchpad.net/bugs/869237 (cherry picked from commit 0b760113a3a155269a3fba93a409c640031dd68f) Signed-off-by: Paolo Pisati --- fs/lockd/clntproc.c | 8 +++++++- include/linux/sunrpc/sched.h | 3 ++- net/sunrpc/clnt.c | 3 +++ net/sunrpc/sched.c | 1 + 4 files changed, 13 insertions(+), 2 deletions(-) diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c index adb45ec..e374050 100644 --- a/fs/lockd/clntproc.c +++ b/fs/lockd/clntproc.c @@ -708,7 +708,13 @@ static void nlmclnt_unlock_callback(struct rpc_task *task, void *data) if (task->tk_status < 0) { dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status); - goto retry_rebind; + switch (task->tk_status) { + case -EACCES: + case -EIO: + goto die; + default: + goto retry_rebind; + } } if (status == NLM_LCK_DENIED_GRACE_PERIOD) { rpc_delay(task, NLMCLNT_GRACE_WAIT); diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h index d81db80..86993a3 100644 --- a/include/linux/sunrpc/sched.h +++ b/include/linux/sunrpc/sched.h @@ -84,7 +84,8 @@ struct rpc_task { #endif unsigned char tk_priority : 2,/* Task priority */ tk_garb_retry : 2, - tk_cred_retry : 2; + tk_cred_retry : 2, + tk_rebind_retry : 2; }; #define tk_xprt tk_client->cl_xprt diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 35d046b..fe52109 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -1170,6 +1170,9 @@ call_bind_status(struct rpc_task *task) status = -EOPNOTSUPP; break; } + if (task->tk_rebind_retry == 0) + break; + task->tk_rebind_retry--; rpc_delay(task, 3*HZ); goto retry_timeout; case -ETIMEDOUT: diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c index 17c3e3a..11d8642 100644 --- a/net/sunrpc/sched.c +++ b/net/sunrpc/sched.c @@ -799,6 +799,7 @@ static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *ta /* Initialize retry counters */ task->tk_garb_retry = 2; task->tk_cred_retry = 2; + task->tk_rebind_retry = 2; task->tk_priority = task_setup_data->priority - RPC_PRIORITY_LOW; task->tk_owner = current->tgid;