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authorJ. Bruce Fields <bfields@redhat.com>2013-09-18 11:16:03 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2013-09-18 10:18:44 -0500
commita0f6ed8ebe4f6d494ef70f67d4c0c153cbf59577 (patch)
treec41732e9849d08911aa5d581968185d1f1fa5e3b /net/sunrpc
parent272b98c6455f00884f0350f775c5342358ebb73f (diff)
downloadlinux-a0f6ed8ebe4f6d494ef70f67d4c0c153cbf59577.tar.gz
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:[<ffffffffa00001f3>] [<ffffffffa00001f3>] 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: [<ffffffffa00001a5>] ? rpc_net_ns+0x5/0x70 [sunrpc] [<ffffffffa00d52a4>] __gss_pipe_release+0x54/0x90 [auth_rpcgss] [<ffffffffa00d530c>] gss_pipe_free+0x2c/0x30 [auth_rpcgss] [<ffffffffa00d678b>] gss_destroy+0x9b/0xf0 [auth_rpcgss] [<ffffffffa000de63>] rpcauth_release+0x23/0x30 [sunrpc] [<ffffffffa0001e81>] rpc_release_client+0x51/0xb0 [sunrpc] [<ffffffffa00020d5>] rpc_shutdown_client+0xe5/0x170 [sunrpc] [<ffffffff81098a14>] ? cpuacct_charge+0xa4/0xb0 [<ffffffff81098975>] ? cpuacct_charge+0x5/0xb0 [<ffffffffa019556f>] nfsd4_process_cb_update.isra.17+0x2f/0x210 [nfsd] [<ffffffff819a4ac0>] ? _raw_spin_unlock_irq+0x30/0x60 [<ffffffff819a4acb>] ? _raw_spin_unlock_irq+0x3b/0x60 [<ffffffff810703ab>] ? process_one_work+0x15b/0x510 [<ffffffffa01957dd>] nfsd4_do_callback_rpc+0x8d/0xa0 [nfsd] [<ffffffff8107041e>] process_one_work+0x1ce/0x510 [<ffffffff810703ab>] ? process_one_work+0x15b/0x510 [<ffffffff810712ab>] worker_thread+0x11b/0x370 [<ffffffff81071190>] ? manage_workers.isra.24+0x2b0/0x2b0 [<ffffffff8107854b>] kthread+0xdb/0xe0 [<ffffffff819a4ac0>] ? _raw_spin_unlock_irq+0x30/0x60 [<ffffffff81078470>] ? __init_kthread_worker+0x70/0x70 [<ffffffff819ac7dc>] ret_from_fork+0x7c/0xb0 [<ffffffff81078470>] ? __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 [<ffffffffa00001f3>] rpc_net_ns+0x53/0x70 [sunrpc] RSP <ffff88003c385ab8> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'net/sunrpc')
-rw-r--r--net/sunrpc/auth_gss/auth_gss.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index fcac5d14171..084656671d6 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) {