In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
xprtrdma: Fix ep kref imbalance on ADDR_CHANGE<\/p>\n
rpcrdma_cm_event_handler() falls through to the disconnected: label
\non RDMA_CM_EVENT_ADDR_CHANGE and calls rpcrdma_ep_put() with no
\nmatching get when the event arrives before RDMA_CM_EVENT_ESTABLISHED.
\nThe kref then underflows during connect teardown and
\nrpcrdma_xprt_disconnect() operates on a freed ep.<\/p>\n
Reference counts across a normal connection lifecycle:<\/p>\n
rpcrdma_ep_create() kref_init ->1
\n rpcrdma_xprt_connect() ep_get ->2 (before post_recvs)
\n RDMA_CM_EVENT_ESTABLISHED ep_get ->3
\n RDMA_CM_EVENT_DISCONNECTED ep_put ->2
\n rpcrdma_xprt_drain() ep_put ->1
\n rpcrdma_xprt_disconnect() tail ep_put ->0 (ep_destroy)<\/p>\n
The connect-time get in rpcrdma_xprt_connect(), taken just before
\nrpcrdma_post_recvs() “while there are outstanding Receives,” is
\nbalanced by rpcrdma_xprt_drain. ADDR_CHANGE before ESTABLISHED has
\nno get to consume, so its put drops the count to 1 and the drain
\nput then frees the ep while rpcrdma_xprt_disconnect() still holds a
\npointer to it.<\/p>\n
Fix by dispatching on the prior re_connect_status via xchg(): for
\nprev == 0 (pre-ESTABLISHED) wake the connect waiter and return with
\nno put; for prev == 1 call rpcrdma_force_disconnect() and return.
\nThe case-1 arm relies on the subsequent RDMA_CM_EVENT_DISCONNECTED
\nevent — reliably delivered when rdma_disconnect() is called on a
\nstill-connected cm_id — to balance the ESTABLISHED get;
\nrpcrdma_xprt_drain() continues to balance only that connect-time
\nget. Any other prior value means teardown is already in flight.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
xprtrdma: Fix ep kref imbalance on ADDR_CHANGE<\/p>\n
rpcrdma_cm_event_handler() falls through to the disconnected: label
\non RDMA_CM_EVEN<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-7135","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/7135","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7135"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7135"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7135"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}