From c9acb42ef1904d15d0fb315061cefbe638f67f3a Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Fri, 19 Mar 2010 15:36:22 -0400 Subject: SUNRPC: Fix a use after free bug with the NFSv4.1 backchannel The ->release_request() callback was designed to allow the transport layer to do housekeeping after the RPC call is done. It cannot be used to free the request itself, and doing so leads to a use-after-free bug in xprt_release(). Signed-off-by: Trond Myklebust --- net/sunrpc/xprt.c | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) (limited to 'net/sunrpc/xprt.c') diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 469de292c23c..42f09ade0044 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -46,6 +46,7 @@ #include #include +#include #include "sunrpc.h" @@ -1032,21 +1033,16 @@ void xprt_release(struct rpc_task *task) if (req->rq_release_snd_buf) req->rq_release_snd_buf(req); - /* - * Early exit if this is a backchannel preallocated request. - * There is no need to have it added to the RPC slot list. - */ - if (is_bc_request) - return; - - memset(req, 0, sizeof(*req)); /* mark unused */ - dprintk("RPC: %5u release request %p\n", task->tk_pid, req); + if (likely(!is_bc_request)) { + memset(req, 0, sizeof(*req)); /* mark unused */ - spin_lock(&xprt->reserve_lock); - list_add(&req->rq_list, &xprt->free); - rpc_wake_up_next(&xprt->backlog); - spin_unlock(&xprt->reserve_lock); + spin_lock(&xprt->reserve_lock); + list_add(&req->rq_list, &xprt->free); + rpc_wake_up_next(&xprt->backlog); + spin_unlock(&xprt->reserve_lock); + } else + xprt_free_bc_request(req); } /** -- cgit v1.2.3