From 9eb2ddb48ce3a7bd745c14a933112994647fa3cd Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sun, 16 Feb 2014 12:14:13 -0500 Subject: [PATCH] SUNRPC: Ensure that gss_auth isn't freed before its upcall messages Fix a race in which the RPC client is shutting down while the gss daemon is processing a downcall. If the RPC client manages to shut down before the gss daemon is done, then the struct gss_auth used in gss_release_msg() may have already been freed. Link: http://lkml.kernel.org/r/1392494917.71728.YahooMailNeo@web140002.mail.bf1.yahoo.com Reported-by: John Reported-by: Borislav Petkov Cc: stable@vger.kernel.org # 3.12+ Signed-off-by: Trond Myklebust --- net/sunrpc/auth_gss/auth_gss.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c index 44a61e8fda6f..1ba1fd114912 100644 --- a/net/sunrpc/auth_gss/auth_gss.c +++ b/net/sunrpc/auth_gss/auth_gss.c @@ -108,6 +108,7 @@ struct gss_auth { static DEFINE_SPINLOCK(pipe_version_lock); static struct rpc_wait_queue pipe_version_rpc_waitqueue; static DECLARE_WAIT_QUEUE_HEAD(pipe_version_waitqueue); +static void gss_put_auth(struct gss_auth *gss_auth); static void gss_free_ctx(struct gss_cl_ctx *); static const struct rpc_pipe_ops gss_upcall_ops_v0; @@ -320,6 +321,7 @@ gss_release_msg(struct gss_upcall_msg *gss_msg) if (gss_msg->ctx != NULL) gss_put_ctx(gss_msg->ctx); rpc_destroy_wait_queue(&gss_msg->rpc_waitqueue); + gss_put_auth(gss_msg->auth); kfree(gss_msg); } @@ -500,6 +502,7 @@ gss_alloc_msg(struct gss_auth *gss_auth, if (err) goto err_free_msg; }; + kref_get(&gss_auth->kref); return gss_msg; err_free_msg: kfree(gss_msg); @@ -1063,6 +1066,12 @@ gss_free_callback(struct kref *kref) gss_free(gss_auth); } +static void +gss_put_auth(struct gss_auth *gss_auth) +{ + kref_put(&gss_auth->kref, gss_free_callback); +} + static void gss_destroy(struct rpc_auth *auth) { @@ -1084,7 +1093,7 @@ gss_destroy(struct rpc_auth *auth) gss_auth->gss_pipe[1] = NULL; rpcauth_destroy_credcache(auth); - kref_put(&gss_auth->kref, gss_free_callback); + gss_put_auth(gss_auth); } /* @@ -1255,7 +1264,7 @@ gss_destroy_nullcred(struct rpc_cred *cred) call_rcu(&cred->cr_rcu, gss_free_cred_callback); if (ctx) gss_put_ctx(ctx); - kref_put(&gss_auth->kref, gss_free_callback); + gss_put_auth(gss_auth); } static void -- 2.20.1