From 2334f5b162e81d81673b59555baaf0a26189e603 Mon Sep 17 00:00:00 2001 From: Susant Palai Date: Mon, 8 Oct 2018 11:38:09 +0530 Subject: [PATCH 398/399] lock: Do not allow meta-lock count to be more than one In the current scheme of glusterfs where lock migration is experimental, (ideally) the rebalance process which is migrating the file should request for a metalock. Hence, the metalock count should not be more than one for an inode. In future, if there is a need for meta-lock from other clients, this patch can be reverted. Since pl_metalk is called as part of setxattr operation, any client process(non-rebalance) residing outside trusted network can exhaust memory of the server node by issuing setxattr repetitively on the metalock key. The current patch makes sure that more than one metalock cannot be granted on an inode. Fixes: CVE-2018-14660 Change-Id: I5a1dde0b24b0aedcfb29cc89dffc04ccc5a88bcb BUG: 1636308 Signed-off-by: Susant Palai Reviewed-on: https://code.engineering.redhat.com/gerrit/152041 Reviewed-by: Amar Tumballi Tested-by: Amar Tumballi Reviewed-by: Sunil Kumar Heggodu Gopala Acharya --- xlators/features/locks/src/posix.c | 36 +++++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) diff --git a/xlators/features/locks/src/posix.c b/xlators/features/locks/src/posix.c index 63f914c..c58e6ba 100644 --- a/xlators/features/locks/src/posix.c +++ b/xlators/features/locks/src/posix.c @@ -2938,6 +2938,40 @@ pl_metalk (call_frame_t *frame, xlator_t *this, inode_t *inode) goto out; } + /* Non rebalance process trying to do metalock */ + if (frame->root->pid != GF_CLIENT_PID_DEFRAG) { + ret = -1; + goto out; + } + + + /* Note: In the current scheme of glusterfs where lock migration is + * experimental, (ideally) the rebalance process which is migrating + * the file should request for a metalock. Hence, the metalock count + * should not be more than one for an inode. In future, if there is a + * need for meta-lock from other clients, the following block can be + * removed. + * + * Since pl_metalk is called as part of setxattr operation, any client + * process(non-rebalance) residing outside trusted network can exhaust + * memory of the server node by issuing setxattr repetitively on the + * metalock key. The following code makes sure that more than + * one metalock cannot be granted on an inode*/ + pthread_mutex_lock (&pl_inode->mutex); + { + if (pl_metalock_is_active(pl_inode)) { + gf_msg (this->name, GF_LOG_WARNING, EINVAL, 0, + "More than one meta-lock can not be granted on" + "the inode"); + ret = -1; + } + } + pthread_mutex_lock (&pl_inode->mutex); + + if (ret == -1) { + goto out; + } + if (frame->root->client) { ctx = pl_ctx_get (frame->root->client, this); if (!ctx) { @@ -3118,7 +3152,7 @@ pl_setxattr (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *dict, int flags, dict_t *xdata) { int op_ret = 0; - int op_errno = 0; + int op_errno = EINVAL; dict_t *xdata_rsp = NULL; PL_LOCAL_GET_REQUESTS (frame, this, xdata, NULL, loc, NULL); -- 1.8.3.1