Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:40002 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932130AbeCJPKL (ORCPT ); Sat, 10 Mar 2018 10:10:11 -0500 Subject: Re: [PATCH V2] clnt_dg_call: Change the memory allocation To: Libtirpc-devel Mailing List Cc: Linux NFS Mailing list References: <20180307140903.13278-1-steved@redhat.com> From: Steve Dickson Message-ID: Date: Sat, 10 Mar 2018 10:10:10 -0500 MIME-Version: 1.0 In-Reply-To: <20180307140903.13278-1-steved@redhat.com> Content-Type: text/plain; charset=utf-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On 03/07/2018 09:09 AM, Steve Dickson wrote: > Commit 2936f109590e add free()s on memory that > was allocated from the stack (via alloca()). > That type memory is automatically freed so > those added free()s was causing a double frees. > > It was suggested allocating memory from the > stack can be a bit troublesome. So this patch > changes the memory allocation from the stack > to the heap which also eliminates the double frees. > > Fixes: 2936f109590e ("clnt_dg_call: Fix a buffer overflow (CVE-2016-4429)") > BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1552163 > > Signed-off-by: Steve Dickson Committed... steved. > --- > src/clnt_dg.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/src/clnt_dg.c b/src/clnt_dg.c > index 884a2db..04a2aba 100644 > --- a/src/clnt_dg.c > +++ b/src/clnt_dg.c > @@ -430,7 +430,7 @@ get_reply: > struct sockaddr_in err_addr; > struct sockaddr_in *sin = (struct sockaddr_in *)&cu->cu_raddr; > struct iovec iov; > - char *cbuf = (char *) alloca (outlen + 256); > + char *cbuf = (char *) mem_alloc((outlen + 256)); > int ret; > > if (cbuf == NULL) > @@ -462,13 +462,13 @@ get_reply: > cmsg = CMSG_NXTHDR (&msg, cmsg)) > if (cmsg->cmsg_level == SOL_IP && cmsg->cmsg_type == IP_RECVERR) > { > - free(cbuf); > + mem_free(cbuf, (outlen + 256)); > e = (struct sock_extended_err *) CMSG_DATA(cmsg); > cu->cu_error.re_errno = e->ee_errno; > release_fd_lock(cu->cu_fd, mask); > return (cu->cu_error.re_status = RPC_CANTRECV); > } > - free(cbuf); > + mem_free(cbuf, (outlen + 256)); > } > #endif > >