rpc: implement server.manage-gids for group resolving on the bricks

The new volume option 'server.manage-gids' can be enabled in
environments where a user belongs to more than the current absolute
maximum of 93 groups. This option triggers the following behavior:

1. The AUTH_GLUSTERFS structure sent by GlusterFS clients (fuse, nfs or
   libgfapi) will contain only one (1) auxiliary group, instead of
   a full list. This reduces network usage and prevents problems in
   encoding the AUTH_GLUSTERFS structure which should fit in 400 bytes.
2. The single group in the RPC Calls received by the server is replaced
   by resolving the groups server-side. Permission checks and similar in
   lower xlators are applied against the full list of groups where the
   user belongs to, and not the single auxiliary group that the client
   sent.

Change-Id: I9e540de13e3022f8b63ff893ecba511129a47b91
BUG: 1053579
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Reviewed-on: http://review.gluster.org/7501
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Santosh Pradhan <spradhan@redhat.com>
Reviewed-by: Harshavardhana <harsha@harshavardhana.net>
Reviewed-by: Anand Avati <avati@redhat.com>

3 files changed, 154 insertions, 1 deletions

diff --git a/xlators/protocol/server/src/server-helpers.c b/xlators/protocol/server/src/server-helpers.c
index b349d7de1eb..9dcb55ce3aa 100644
--- a/xlators/protocol/server/src/server-helpers.c
+++ b/xlators/protocol/server/src/server-helpers.c
@@ -15,8 +15,117 @@
 
 #include "server.h"
 #include "server-helpers.h"
+#include "gidcache.h"
 
 #include <fnmatch.h>
+#include <pwd.h>
+#include <grp.h>
+
+/* based on nfs_fix_aux_groups() */
+int
+gid_resolve (server_conf_t *conf, call_stack_t *root)
+{
+        int               ret = 0;
+        struct passwd     mypw;
+        char              mystrs[1024];
+        struct passwd    *result;
+        gid_t             mygroups[GF_MAX_AUX_GROUPS];
+        gid_list_t        gl;
+        const gid_list_t *agl;
+        int               ngroups, i;
+
+        agl = gid_cache_lookup (&conf->gid_cache, root->uid, 0, 0);
+        if (agl) {
+                root->ngrps = agl->gl_count;
+                goto fill_groups;
+        }
+
+        ret = getpwuid_r (root->uid, &mypw, mystrs, sizeof(mystrs), &result);
+        if (ret != 0) {
+                gf_log("gid-cache", GF_LOG_ERROR, "getpwuid_r(%u) failed",
+                       root->uid);
+                return -1;
+        }
+
+        if (!result) {
+                gf_log ("gid-cache", GF_LOG_ERROR, "getpwuid_r(%u) found "
+                        "nothing", root->uid);
+                return -1;
+        }
+
+        gf_log ("gid-cache", GF_LOG_TRACE, "mapped %u => %s", root->uid,
+                result->pw_name);
+
+        ngroups = GF_MAX_AUX_GROUPS;
+        ret = getgrouplist (result->pw_name, root->gid, mygroups, &ngroups);
+        if (ret == -1) {
+                gf_log ("gid-cache", GF_LOG_ERROR, "could not map %s to group "
+                        "list (%d gids)", result->pw_name, root->ngrps);
+                return -1;
+        }
+        root->ngrps = (uint16_t) ngroups;
+
+fill_groups:
+        if (agl) {
+                /* the gl is not complete, we only use gl.gl_list later on */
+                gl.gl_list = agl->gl_list;
+        } else {
+                /* setup a full gid_list_t to add it to the gid_cache */
+                gl.gl_id = root->uid;
+                gl.gl_uid = root->uid;
+                gl.gl_gid = root->gid;
+                gl.gl_count = root->ngrps;
+
+                gl.gl_list = GF_MALLOC (root->ngrps * sizeof(gid_t),
+                                        gf_common_mt_groups_t);
+                if (gl.gl_list)
+                        memcpy (gl.gl_list, mygroups,
+                                sizeof(gid_t) * root->ngrps);
+                else
+                        return -1;
+        }
+
+        if (root->ngrps == 0) {
+                ret = 0;
+                goto out;
+        }
+
+        if (call_stack_alloc_groups (root, root->ngrps) != 0) {
+                ret = -1;
+                goto out;
+        }
+
+        /* finally fill the groups from the */
+        for (i = 0; i < root->ngrps; ++i)
+                root->groups[i] = gl.gl_list[i];
+
+out:
+        if (agl) {
+                gid_cache_release (&conf->gid_cache, agl);
+        } else {
+                if (gid_cache_add (&conf->gid_cache, &gl) != 1)
+                        GF_FREE (gl.gl_list);
+        }
+
+        return ret;
+}
+
+int
+server_resolve_groups (call_frame_t *frame, rpcsvc_request_t *req)
+{
+        xlator_t      *this = NULL;
+        server_conf_t *conf = NULL;
+
+        GF_VALIDATE_OR_GOTO ("server", frame, out);
+        GF_VALIDATE_OR_GOTO ("server", req, out);
+
+        this = req->trans->xl;
+        conf = this->private;
+
+        return gid_resolve (conf, frame->root);
+out:
+        return -1;
+}
 
 int
 server_decode_groups (call_frame_t *frame, rpcsvc_request_t *req)
@@ -379,7 +488,10 @@ get_frame_from_request (rpcsvc_request_t *req)
         frame->root->client   = client;
         frame->root->lk_owner = req->lk_owner;
 
-        server_decode_groups (frame, req);
+        if (priv->server_manage_gids)
+            server_resolve_groups (frame, req);
+        else
+            server_decode_groups (frame, req);
 
         frame->local = req;
 out:
diff --git a/xlators/protocol/server/src/server.c b/xlators/protocol/server/src/server.c
index 3d8e3d66d14..e551fd757a1 100644
--- a/xlators/protocol/server/src/server.c
+++ b/xlators/protocol/server/src/server.c
@@ -736,6 +736,17 @@ reconfigure (xlator_t *this, dict_t *options)
                 goto out;
         }
 
+        GF_OPTION_RECONF ("manage-gids", conf->server_manage_gids, options,
+                          bool, out);
+
+        GF_OPTION_RECONF ("gid-timeout", conf->gid_cache_timeout, options,
+                          int32, out);
+        if (gid_cache_reconf (&conf->gid_cache, conf->gid_cache_timeout) < 0) {
+                gf_log(this->name, GF_LOG_ERROR, "Failed to reconfigure group "
+                        "cache.");
+                goto out;
+        }
+
         rpc_conf = conf->rpc;
         if (!rpc_conf) {
                 gf_log (this->name, GF_LOG_ERROR, "No rpc_conf !!!!");
@@ -863,6 +874,19 @@ init (xlator_t *this)
                 goto out;
         }
 
+        ret = dict_get_str_boolean (this->options, "manage-gids", _gf_false);
+        if (ret == -1)
+                conf->server_manage_gids = _gf_false;
+        else
+                conf->server_manage_gids = ret;
+
+        GF_OPTION_INIT("gid-timeout", conf->gid_cache_timeout, int32, out);
+        if (gid_cache_init (&conf->gid_cache, conf->gid_cache_timeout) < 0) {
+                gf_log(this->name, GF_LOG_ERROR, "Failed to initialize "
+                        "group cache.");
+                goto out;
+        }
+
         /* RPC related */
         conf->rpc = rpcsvc_init (this, this->ctx, this->options, 0);
         if (conf->rpc == NULL) {
@@ -1141,5 +1165,17 @@ struct volume_options options[] = {
                          "requests from a client. 0 means no limit (can "
                          "potentially run out of memory)"
         },
+
+        { .key   = {"manage-gids"},
+          .type  = GF_OPTION_TYPE_BOOL,
+          .default_value = "off",
+          .description = "Resolve groups on the server-side."
+        },
+        { .key = {"gid-timeout"},
+          .type = GF_OPTION_TYPE_INT,
+          .default_value = "2",
+          .description = "Timeout in seconds for the cached groups to expire."
+        },
+
         { .key   = {NULL} },
 };
diff --git a/xlators/protocol/server/src/server.h b/xlators/protocol/server/src/server.h
index 4a1e10ca8b5..3e1feacb94b 100644
--- a/xlators/protocol/server/src/server.h
+++ b/xlators/protocol/server/src/server.h
@@ -22,6 +22,7 @@
 #include "glusterfs3.h"
 #include "timer.h"
 #include "client_t.h"
+#include "gidcache.h"
 
 #define DEFAULT_BLOCK_SIZE         4194304   /* 4MB */
 #define DEFAULT_VOLUME_FILE_PATH   CONFDIR "/glusterfs.vol"
@@ -58,6 +59,10 @@ struct server_conf {
         pthread_mutex_t         mutex;
         struct list_head        xprt_list;
         pthread_t               barrier_th;
+
+        gf_boolean_t            server_manage_gids; /* resolve gids on brick */
+        gid_cache_t             gid_cache;
+        int32_t                 gid_cache_timeout;
 };
 typedef struct server_conf server_conf_t;