linux-hardening - [PATCH] net: dccp: Use memset

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>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20211118203019.1286474-1-keescook@chromium.org>
Date:   Thu, 18 Nov 2021 12:30:19 -0800
From:   Kees Cook <keescook@...omium.org>
To:     "David S. Miller" <davem@...emloft.net>
Cc:     Kees Cook <keescook@...omium.org>,
        Jakub Kicinski <kuba@...nel.org>, linux-kernel@...r.kernel.org,
        dccp@...r.kernel.org, netdev@...r.kernel.org,
        linux-hardening@...r.kernel.org
Subject: [PATCH] net: dccp: Use memset_startat() for TP zeroing

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.

Signed-off-by: Kees Cook <keescook@...omium.org>
---
 net/dccp/trace.h | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net/dccp/trace.h b/net/dccp/trace.h
index 5062421beee9..5a43b3508c7f 100644
--- a/net/dccp/trace.h
+++ b/net/dccp/trace.h
@@ -60,9 +60,7 @@ TRACE_EVENT(dccp_probe,
 			__entry->tx_t_ipi = hc->tx_t_ipi;
 		} else {
 			__entry->tx_s = 0;
-			memset(&__entry->tx_rtt, 0, (void *)&__entry->tx_t_ipi -
-			       (void *)&__entry->tx_rtt +
-			       sizeof(__entry->tx_t_ipi));
+			memset_startat(__entry, 0, tx_rtt);
 		}
 	),
 
-- 
2.30.2