From 8235de189845986a535d676b1fd2c894b9c02e52 Mon Sep 17 00:00:00 2001 From: Niels de Vos Date: Thu, 20 Mar 2014 18:13:49 +0100 Subject: rpc: warn and truncate grouplist if RPC/AUTH can not hold everything The GlusterFS protocol currently uses AUTH_GLUSTERFS_V2 in the RPC/AUTH header. This header contains the uid, gid and auxiliary groups of the user/process that accesses the Gluster Volume. The AUTH_GLUSTERFS_V2 structure allows up to 65535 auxiliary groups to be passed on. Unfortunately, the RPC/AUTH header is limited to 400 bytes by the RPC specification: http://tools.ietf.org/html/rfc5531#section-8.2 In order to not cause complete failures on the client-side when trying to encode a AUTH_GLUSTERFS_V2 that would result in more than 400 bytes, we can calculate the expected size of the other elements: 1 | pid 1 | uid 1 | gid 1 | groups_len XX | groups_val (GF_MAX_AUX_GROUPS=65535) 1 | lk_owner_len YY | lk_owner_val (GF_MAX_LOCK_OWNER_LEN=1024) ----+------------------------------------------- 5 | total xdr-units one XDR-unit is defined as BYTES_PER_XDR_UNIT = 4 bytes MAX_AUTH_BYTES = 400 is the maximum, this is 100 xdr-units. XX + YY can be 95 to fill the 100 xdr-units. Note that the on-wire protocol has tighter requirements than the internal structures. It is possible for xlators to use more groups and a bigger lk_owner than that can be sent by a GlusterFS-client. This change prevents overflows when allocating the RPC/AUTH header. Two new macros are introduced to calculate the number of groups that fit in the RPC/AUTH header, when taking the size of the lk_owner in account. In case the list of groups exceeds the maximum possible, only the first groups are passed over the RPC/GlusterFS protocol to the bricks. A warning is added to the logs, so that most system administrators will get informed. The reducing of the number of groups is not a new inventions. The RPC/AUTH header (AUTH_SYS or AUTH_UNIX) that NFS uses has a limit of 16 groups. Most, if not all, NFS-clients will reduce any bigger number of groups to 16. (nfs.server-aux-gids can be used to workaround the limit of 16 groups, but the Gluster NFS-server will be limited to a maximum of 93 groups, or fewer in case the lk_owner structure contains more items.) Change-Id: I8410e59d0fd246d601b54b961d3ae9cb5a858c10 BUG: 1053579 Signed-off-by: Niels de Vos Reviewed-on: http://review.gluster.org/7202 Tested-by: Gluster Build System Reviewed-by: Harshavardhana Reviewed-by: Santosh Pradhan Reviewed-by: Vijay Bellur --- rpc/rpc-lib/src/auth-glusterfs.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) (limited to 'rpc/rpc-lib/src/auth-glusterfs.c') diff --git a/rpc/rpc-lib/src/auth-glusterfs.c b/rpc/rpc-lib/src/auth-glusterfs.c index 7bafa82fb82..c3fc166b731 100644 --- a/rpc/rpc-lib/src/auth-glusterfs.c +++ b/rpc/rpc-lib/src/auth-glusterfs.c @@ -171,8 +171,10 @@ auth_glusterfs_v2_request_init (rpcsvc_request_t *req, void *priv) int auth_glusterfs_v2_authenticate (rpcsvc_request_t *req, void *priv) { struct auth_glusterfs_parms_v2 au = {0,}; - int ret = RPCSVC_AUTH_REJECT; - int i = 0; + int ret = RPCSVC_AUTH_REJECT; + int i = 0; + int max_groups = 0; + int max_lk_owner_len = 0; if (!req) return ret; @@ -191,17 +193,23 @@ int auth_glusterfs_v2_authenticate (rpcsvc_request_t *req, void *priv) req->lk_owner.len = au.lk_owner.lk_owner_len; req->auxgidcount = au.groups.groups_len; - if (req->auxgidcount > GF_MAX_AUX_GROUPS) { + /* the number of groups and size of lk_owner depend on each other */ + max_groups = GF_AUTH_GLUSTERFS_MAX_GROUPS (req->lk_owner.len); + max_lk_owner_len = GF_AUTH_GLUSTERFS_MAX_LKOWNER (req->auxgidcount); + + if (req->auxgidcount > max_groups) { gf_log ("", GF_LOG_WARNING, "more than max aux gids found (%d) , truncating it " "to %d and continuing", au.groups.groups_len, - GF_MAX_AUX_GROUPS); - req->auxgidcount = GF_MAX_AUX_GROUPS; + max_groups); + req->auxgidcount = max_groups; } - if (req->lk_owner.len > GF_MAX_LOCK_OWNER_LEN) { + if (req->lk_owner.len > max_lk_owner_len) { gf_log ("", GF_LOG_WARNING, - "lkowner field > 1k, failing authentication"); + "lkowner field to big (%d), depends on the number of " + "groups (%d), failing authentication", + req->lk_owner.len, req->auxgidcount); ret = RPCSVC_AUTH_REJECT; goto err; } -- cgit