From: Chuck Lever Subject: Re: [PATCH 02/23] SUNRPC: Fix return type of svc_addr_len() Date: Tue, 24 Mar 2009 16:37:49 -0400 Message-ID: References: <20090319004024.32404.68289.stgit@ingres.1015granger.net> <20090319004535.32404.37120.stgit@ingres.1015granger.net> <20090324203206.GH19389@fieldses.org> Mime-Version: 1.0 (Apple Message framework v930.3) Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Cc: Trond Myklebust , Linux NFS Mailing List To: "J. Bruce Fields" , Tom Tucker Return-path: Received: from rcsinet12.oracle.com ([148.87.113.124]:54062 "EHLO rgminet12.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761048AbZCXUiK (ORCPT ); Tue, 24 Mar 2009 16:38:10 -0400 In-Reply-To: <20090324203206.GH19389@fieldses.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mar 24, 2009, at 4:32 PM, J. Bruce Fields wrote: > On Wed, Mar 18, 2009 at 08:45:36PM -0400, Chuck Lever wrote: >> The svc_addr_len() helper function can return a negative errno value, >> but its return type is size_t, which is unsigned. >> >> The RDMA transport code passes this return value directly to >> memset(), >> without checking first if it's negative. This could cause memset() >> to >> clobber a large piece of memory if svc_addr_len() has returned an >> error. > > I'd still like to understand when this can happen, to better > understand > how the error should be handled. > > Also: > >> >> Signed-off-by: Chuck Lever >> --- >> >> include/linux/sunrpc/svc_xprt.h | 3 ++- >> net/sunrpc/xprtrdma/svc_rdma_transport.c | 16 ++++++++++++++-- >> 2 files changed, 16 insertions(+), 3 deletions(-) >> >> diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/ >> svc_xprt.h >> index 0127dac..c2aa8cd 100644 >> --- a/include/linux/sunrpc/svc_xprt.h >> +++ b/include/linux/sunrpc/svc_xprt.h >> @@ -113,7 +113,7 @@ static inline unsigned short >> svc_addr_port(struct sockaddr *sa) >> return ret; >> } >> >> -static inline size_t svc_addr_len(struct sockaddr *sa) >> +static inline int svc_addr_len(const struct sockaddr *sa) >> { >> switch (sa->sa_family) { >> case AF_INET: >> @@ -121,6 +121,7 @@ static inline size_t svc_addr_len(struct >> sockaddr *sa) >> case AF_INET6: >> return sizeof(struct sockaddr_in6); >> } >> + >> return -EAFNOSUPPORT; >> } It's clearly a bug to return -EAFNOSUPPORT in a size_t. >> diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/ >> xprtrdma/svc_rdma_transport.c >> index 3d810e7..d1ec6f9 100644 >> --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c >> +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c >> @@ -546,6 +546,7 @@ static void handle_connect_req(struct >> rdma_cm_id *new_cma_id, size_t client_ird) >> struct svcxprt_rdma *listen_xprt = new_cma_id->context; >> struct svcxprt_rdma *newxprt; >> struct sockaddr *sa; >> + int len; >> >> /* Create a new transport */ >> newxprt = rdma_create_xprt(listen_xprt->sc_xprt.xpt_server, 0); >> @@ -563,9 +564,20 @@ static void handle_connect_req(struct >> rdma_cm_id *new_cma_id, size_t client_ird) >> >> /* Set the local and remote addresses in the transport */ >> sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.dst_addr; >> - svc_xprt_set_remote(&newxprt->sc_xprt, sa, svc_addr_len(sa)); >> + len = svc_addr_len(sa); >> + if (len < 0) { >> + dprintk("svcrdma: dst_addr has a bad address family\n"); >> + return; > > we're probably leaking something here. > > I don't want to fix this until it's understood well enough to fix it > correctly. Tom needs respond to this, but I think it would be safe to simply BUG() here. > --b. > >> + } >> + svc_xprt_set_remote(&newxprt->sc_xprt, sa, len); >> + >> sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.src_addr; >> - svc_xprt_set_local(&newxprt->sc_xprt, sa, svc_addr_len(sa)); >> + len = svc_addr_len(sa); >> + if (len < 0) { >> + dprintk("svcrdma: src_addr has a bad address family\n"); >> + return; >> + } >> + svc_xprt_set_local(&newxprt->sc_xprt, sa, len); >> >> /* >> * Enqueue the new transport on the accept queue of the listening -- Chuck Lever chuck[dot]lever[at]oracle[dot]com