From ac83228a7101e655ba5a7fa61ae10b058ada15db Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 24 Apr 2019 17:46:45 -0400 Subject: [PATCH] SUNRPC: Use namespace of listening daemon in the client AUTH_GSS upcall When the client needs to talk to rpc.gssd, we should ensure that the uid argument is encoded to match the user namespace of the daemon. Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker --- net/sunrpc/auth_gss/auth_gss.c | 60 +++++++++++++++++++++++++--------- 1 file changed, 44 insertions(+), 16 deletions(-) diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c index 5dc2aef2232a..b2cbc83d39c7 100644 --- a/net/sunrpc/auth_gss/auth_gss.c +++ b/net/sunrpc/auth_gss/auth_gss.c @@ -269,6 +269,7 @@ err: struct gss_upcall_msg { refcount_t count; kuid_t uid; + const char *service_name; struct rpc_pipe_msg msg; struct list_head list; struct gss_auth *auth; @@ -316,6 +317,7 @@ gss_release_msg(struct gss_upcall_msg *gss_msg) gss_put_ctx(gss_msg->ctx); rpc_destroy_wait_queue(&gss_msg->rpc_waitqueue); gss_put_auth(gss_msg->auth); + kfree_const(gss_msg->service_name); kfree(gss_msg); } @@ -410,10 +412,10 @@ gss_upcall_callback(struct rpc_task *task) gss_release_msg(gss_msg); } -static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg) +static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg, + const struct cred *cred) { - struct user_namespace *userns = gss_msg->auth->client->cl_cred ? - gss_msg->auth->client->cl_cred->user_ns : &init_user_ns; + struct user_namespace *userns = cred->user_ns; uid_t uid = from_kuid_munged(userns, gss_msg->uid); memcpy(gss_msg->databuf, &uid, sizeof(uid)); @@ -423,12 +425,24 @@ static void gss_encode_v0_msg(struct gss_upcall_msg *gss_msg) BUILD_BUG_ON(sizeof(uid) > sizeof(gss_msg->databuf)); } +static ssize_t +gss_v0_upcall(struct file *file, struct rpc_pipe_msg *msg, + char __user *buf, size_t buflen) +{ + struct gss_upcall_msg *gss_msg = container_of(msg, + struct gss_upcall_msg, + msg); + if (msg->copied == 0) + gss_encode_v0_msg(gss_msg, file->f_cred); + return rpc_pipe_generic_upcall(file, msg, buf, buflen); +} + static int gss_encode_v1_msg(struct gss_upcall_msg *gss_msg, const char *service_name, - const char *target_name) + const char *target_name, + const struct cred *cred) { - struct user_namespace *userns = gss_msg->auth->client->cl_cred ? - gss_msg->auth->client->cl_cred->user_ns : &init_user_ns; + struct user_namespace *userns = cred->user_ns; struct gss_api_mech *mech = gss_msg->auth->mech; char *p = gss_msg->databuf; size_t buflen = sizeof(gss_msg->databuf); @@ -496,6 +510,25 @@ out_overflow: return -ENOMEM; } +static ssize_t +gss_v1_upcall(struct file *file, struct rpc_pipe_msg *msg, + char __user *buf, size_t buflen) +{ + struct gss_upcall_msg *gss_msg = container_of(msg, + struct gss_upcall_msg, + msg); + int err; + if (msg->copied == 0) { + err = gss_encode_v1_msg(gss_msg, + gss_msg->service_name, + gss_msg->auth->target_name, + file->f_cred); + if (err) + return err; + } + return rpc_pipe_generic_upcall(file, msg, buf, buflen); +} + static struct gss_upcall_msg * gss_alloc_msg(struct gss_auth *gss_auth, kuid_t uid, const char *service_name) @@ -518,16 +551,11 @@ gss_alloc_msg(struct gss_auth *gss_auth, refcount_set(&gss_msg->count, 1); gss_msg->uid = uid; gss_msg->auth = gss_auth; - switch (vers) { - case 0: - gss_encode_v0_msg(gss_msg); - break; - default: - err = gss_encode_v1_msg(gss_msg, service_name, gss_auth->target_name); - if (err) + if (service_name) { + gss_msg->service_name = kstrdup_const(service_name, GFP_NOFS); + if (!gss_msg->service_name) goto err_put_pipe_version; } - kref_get(&gss_auth->kref); return gss_msg; err_put_pipe_version: put_pipe_version(gss_auth->net); @@ -2120,7 +2148,7 @@ static const struct rpc_credops gss_nullops = { }; static const struct rpc_pipe_ops gss_upcall_ops_v0 = { - .upcall = rpc_pipe_generic_upcall, + .upcall = gss_v0_upcall, .downcall = gss_pipe_downcall, .destroy_msg = gss_pipe_destroy_msg, .open_pipe = gss_pipe_open_v0, @@ -2128,7 +2156,7 @@ static const struct rpc_pipe_ops gss_upcall_ops_v0 = { }; static const struct rpc_pipe_ops gss_upcall_ops_v1 = { - .upcall = rpc_pipe_generic_upcall, + .upcall = gss_v1_upcall, .downcall = gss_pipe_downcall, .destroy_msg = gss_pipe_destroy_msg, .open_pipe = gss_pipe_open_v1,