From a0f6ed8ebe4f6d494ef70f67d4c0c153cbf59577 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Wed, 18 Sep 2013 11:16:03 -0400 Subject: RPCSEC_GSS: fix crash on destroying gss auth This fixes a regression since eb6dc19d8e72ce3a957af5511d20c0db0a8bd007 "RPCSEC_GSS: Share all credential caches on a per-transport basis" which could cause an occasional oops in the nfsd code (see below). The problem was that an auth was left referencing a client that had been freed. To avoid this we need to ensure that auths are shared only between descendants of a common client; the fact that a clone of an rpc_client takes a reference on its parent then ensures that the parent client will last as long as the auth. Also add a comment explaining what I think was the intention of this code. general protection fault: 0000 [#1] PREEMPT SMP Modules linked in: rpcsec_gss_krb5 nfsd auth_rpcgss oid_registry nfs_acl lockd sunrpc CPU: 3 PID: 4071 Comm: kworker/u8:2 Not tainted 3.11.0-rc2-00182-g025145f #1665 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Workqueue: nfsd4_callbacks nfsd4_do_callback_rpc [nfsd] task: ffff88003e206080 ti: ffff88003c384000 task.ti: ffff88003c384000 RIP: 0010:[] [] rpc_net_ns+0x53/0x70 [sunrpc] RSP: 0000:ffff88003c385ab8 EFLAGS: 00010246 RAX: 6b6b6b6b6b6b6b6b RBX: ffff88003af9a800 RCX: 0000000000000002 RDX: ffffffffa00001a5 RSI: 0000000000000001 RDI: ffffffff81e284e0 RBP: ffff88003c385ad8 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000015 R12: ffff88003c990840 R13: ffff88003c990878 R14: ffff88003c385ba8 R15: ffff88003e206080 FS: 0000000000000000(0000) GS:ffff88003fd80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00007fcdf737e000 CR3: 000000003ad2b000 CR4: 00000000000006e0 Stack: ffffffffa00001a5 0000000000000006 0000000000000006 ffff88003af9a800 ffff88003c385b08 ffffffffa00d52a4 ffff88003c385ba8 ffff88003c751bd8 ffff88003c751bc0 ffff88003e113600 ffff88003c385b18 ffffffffa00d530c Call Trace: [] ? rpc_net_ns+0x5/0x70 [sunrpc] [] __gss_pipe_release+0x54/0x90 [auth_rpcgss] [] gss_pipe_free+0x2c/0x30 [auth_rpcgss] [] gss_destroy+0x9b/0xf0 [auth_rpcgss] [] rpcauth_release+0x23/0x30 [sunrpc] [] rpc_release_client+0x51/0xb0 [sunrpc] [] rpc_shutdown_client+0xe5/0x170 [sunrpc] [] ? cpuacct_charge+0xa4/0xb0 [] ? cpuacct_charge+0x5/0xb0 [] nfsd4_process_cb_update.isra.17+0x2f/0x210 [nfsd] [] ? _raw_spin_unlock_irq+0x30/0x60 [] ? _raw_spin_unlock_irq+0x3b/0x60 [] ? process_one_work+0x15b/0x510 [] nfsd4_do_callback_rpc+0x8d/0xa0 [nfsd] [] process_one_work+0x1ce/0x510 [] ? process_one_work+0x15b/0x510 [] worker_thread+0x11b/0x370 [] ? manage_workers.isra.24+0x2b0/0x2b0 [] kthread+0xdb/0xe0 [] ? _raw_spin_unlock_irq+0x30/0x60 [] ? __init_kthread_worker+0x70/0x70 [] ret_from_fork+0x7c/0xb0 [] ? __init_kthread_worker+0x70/0x70 Code: a5 01 00 a0 31 d2 31 f6 48 c7 c7 e0 84 e2 81 e8 f4 91 0a e1 48 8b 43 60 48 c7 c2 a5 01 00 a0 be 01 00 00 00 48 c7 c7 e0 84 e2 81 <48> 8b 98 10 07 00 00 e8 91 8f 0a e1 e8 +3c 4e 07 e1 48 83 c4 18 RIP [] rpc_net_ns+0x53/0x70 [sunrpc] RSP Signed-off-by: J. Bruce Fields Signed-off-by: Trond Myklebust --- net/sunrpc/auth_gss/auth_gss.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c index fcac5d141717..084656671d6e 100644 --- a/net/sunrpc/auth_gss/auth_gss.c +++ b/net/sunrpc/auth_gss/auth_gss.c @@ -1075,6 +1075,15 @@ gss_destroy(struct rpc_auth *auth) kref_put(&gss_auth->kref, gss_free_callback); } +/* + * Auths may be shared between rpc clients that were cloned from a + * common client with the same xprt, if they also share the flavor and + * target_name. + * + * The auth is looked up from the oldest parent sharing the same + * cl_xprt, and the auth itself references only that common parent + * (which is guaranteed to last as long as any of its descendants). + */ static struct gss_auth * gss_auth_find_or_add_hashed(struct rpc_auth_create_args *args, struct rpc_clnt *clnt, @@ -1088,6 +1097,8 @@ gss_auth_find_or_add_hashed(struct rpc_auth_create_args *args, gss_auth, hash, hashval) { + if (gss_auth->client != clnt) + continue; if (gss_auth->rpc_auth.au_flavor != args->pseudoflavor) continue; if (gss_auth->target_name != args->target_name) { -- cgit v1.2.3