linux-kernel - [PATCH] iw_cxgb4: Use memset_startat() for cpl_t5_pass_accept

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20211118202335.1285836-1-keescook@chromium.org>
Date:   Thu, 18 Nov 2021 12:23:35 -0800
From:   Kees Cook <keescook@...omium.org>
To:     Potnuri Bharat Teja <bharat@...lsio.com>
Cc:     Kees Cook <keescook@...omium.org>,
        Doug Ledford <dledford@...hat.com>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Raju Rangoju <rajur@...lsio.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, linux-kernel@...r.kernel.org,
        linux-rdma@...r.kernel.org, netdev@...r.kernel.org,
        linux-hardening@...r.kernel.org
Subject: [PATCH] iw_cxgb4: Use memset_startat() for cpl_t5_pass_accept_rpl

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memset(), avoid intentionally writing across
neighboring fields.

Use memset_startat() so memset() doesn't get confused about writing
beyond the destination member that is intended to be the starting point
of zeroing through the end of the struct. Additionally, since everything
appears to perform a roundup (including allocation), just change the
size of the struct itself and add a build-time check to validate the
expected size.

Signed-off-by: Kees Cook <keescook@...omium.org>
---
 drivers/infiniband/hw/cxgb4/cm.c            | 5 +++--
 drivers/net/ethernet/chelsio/cxgb4/t4_msg.h | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c
index 913f39ee4416..c16017f6e8db 100644
--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -2471,7 +2471,8 @@ static int accept_cr(struct c4iw_ep *ep, struct sk_buff *skb,
 	skb_get(skb);
 	rpl = cplhdr(skb);
 	if (!is_t4(adapter_type)) {
-		skb_trim(skb, roundup(sizeof(*rpl5), 16));
+		BUILD_BUG_ON(sizeof(*rpl5) != roundup(sizeof(*rpl5), 16));
+		skb_trim(skb, sizeof(*rpl5));
 		rpl5 = (void *)rpl;
 		INIT_TP_WR(rpl5, ep->hwtid);
 	} else {
@@ -2487,7 +2488,7 @@ static int accept_cr(struct c4iw_ep *ep, struct sk_buff *skb,
 		opt2 |= CONG_CNTRL_V(CONG_ALG_TAHOE);
 		opt2 |= T5_ISS_F;
 		rpl5 = (void *)rpl;
-		memset(&rpl5->iss, 0, roundup(sizeof(*rpl5)-sizeof(*rpl), 16));
+		memset_after(rpl5, 0, iss);
 		if (peer2peer)
 			isn += 4;
 		rpl5->iss = cpu_to_be32(isn);
diff --git a/drivers/net/ethernet/chelsio/cxgb4/t4_msg.h b/drivers/net/ethernet/chelsio/cxgb4/t4_msg.h
index fed5f93bf620..26433a62d7f0 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/t4_msg.h
+++ b/drivers/net/ethernet/chelsio/cxgb4/t4_msg.h
@@ -497,7 +497,7 @@ struct cpl_t5_pass_accept_rpl {
 	__be32 opt2;
 	__be64 opt0;
 	__be32 iss;
-	__be32 rsvd;
+	__be32 rsvd[3];
 };
 
 struct cpl_act_open_req {
-- 
2.30.2