Thread (152 messages) 152 messages, 21 authors, 2021-08-13
STALE1783d
Revisions (2)
  1. v1 current
  2. v2 [diff vs current]

[PATCH 41/64] net: dccp: Use memset_after() for TP zeroing

From: Kees Cook <hidden>
Date: 2021-07-27 21:07:26
Also in: dri-devel, linux-hardening, linux-kbuild, linux-staging, linux-wireless, lkml, netdev
Subsystem: networking [general], the rest · Maintainers: "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

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

Use memset_after() 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 <redacted>
---
 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..3c2594da49fc 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_after(__entry, 0, tx_s);
 		}
 	),
 
-- 
2.30.2
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