On 1/13/23 2:19 AM, Hans Petter Selasky wrote:
The branch main has been updated by hselasky:
URL:
https://cgit.FreeBSD.org/src/commit/?id=e0d8add4af0be1d37ede9a16f46424dc08f0d95e
commit e0d8add4af0be1d37ede9a16f46424dc08f0d95e
Author: Hans Petter Selasky <hsela...@freebsd.org>
AuthorDate: 2022-11-28 22:56:16 +0000
Commit: Hans Petter Selasky <hsela...@freebsd.org>
CommitDate: 2023-01-13 10:18:19 +0000
tcp_lro: Fix for undefined behaviour.
Make sure the size of the raw[] array in the lro_address union is
correctly set at compile time, so that static code analysis tools
do not report undefined behaviour.
MFC after: 1 week
Sponsored by: NVIDIA Networking
---
sys/netinet/tcp_lro.h | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/sys/netinet/tcp_lro.h b/sys/netinet/tcp_lro.h
index 427657df47e7..e01e451c1e77 100644
--- a/sys/netinet/tcp_lro.h
+++ b/sys/netinet/tcp_lro.h
@@ -34,6 +34,8 @@
#define _TCP_LRO_H_
#include <sys/time.h>
+#include <sys/param.h>
param.h should always be the first header, and it also sorts before time.h.
+
#include <netinet/in.h>
#ifndef TCP_LRO_ENTRIES
@@ -65,8 +67,12 @@
struct inpcb;
+/* Precompute the LRO_RAW_ADDRESS_MAX value: */
+#define LRO_RAW_ADDRESS_MAX \
+ howmany(12 + 2 * sizeof(struct in6_addr), sizeof(u_long))
+
union lro_address {
- u_long raw[1];
+ u_long raw[LRO_RAW_ADDRESS_MAX];
In OFED this anti-pattern uses 'u_long raw[0]' which I think is probably at
least better than '[1]'. My worry is that LRO_RAW_ADDRESS_MAX is fairly
fragile and gross, though the static assertion at least catches if it is
wrong.
In general though for both OFED and this, I think is is actually cleaner to
remove the weird aliasing 'raw' member and just use a plain (u_long *)
cast. If you did that, you could revert this commit and have the simpler
definition of LRO_RAW_ADDRESS_MAX derived from the sizeof() the type.
--
John Baldwin
