memcpy() is allowed to make alignment assumptions based on the argument
type. We have to cast before using it to avoid misaligned reads:
lib/netdev-linux.c:6738:41: runtime error: load of misaligned address
0x51b000008db4 for type 'const struct rpl_rtnl_link_stats64 *',
which requires 8 byte alignment
0x51b000008db4: note: pointer points here
cc 00 17 00 01 00 00 00 00 00 00 00 01 00 00 00
^
0 0xad2d8 in get_stats_via_netlink lib/netdev-linux.c:6738:17
1 0x9dcce in netdev_linux_get_stats lib/netdev-linux.c:2293:13
2 0xee5b8 in netdev_get_stats lib/netdev.c:1722:16
3 0xc07ad in iface_refresh_stats vswitchd/bridge.c:2795:5
4 0xbf4fc in iface_create vswitchd/bridge.c:2274:5
5 0xbf4fc in bridge_add_ports__ vswitchd/bridge.c:1225:21
6 0x989fc in bridge_add_ports vswitchd/bridge.c:1236:5
7 0x989fc in bridge_reconfigure vswitchd/bridge.c:952:9
8 0x9102a in bridge_run vswitchd/bridge.c:3439:9
9 0xc8976 in main vswitchd/ovs-vswitchd.c:137:9
10 0x2a1c9 in __libc_start_call_main
11 0x2a28a in __libc_start_main
12 0xb3ff4 in _start (vswitchd/ovs-vswitchd+0x734ff4)
Reported by Clang 18 with UBsan on Ubuntu 24.04.
Fixes: c8c49a9db9f2 ("netdev-linux: Properly access 32-bit aligned
rtnl_link_stats64 structs.")
Signed-off-by: Ilya Maximets <[email protected]>
---
lib/netdev-linux.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index 765a07e35..0cd0850a3 100644
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -6735,7 +6735,8 @@ get_stats_via_netlink(const struct netdev *netdev_,
struct netdev_stats *stats)
struct rtnl_link_stats64 aligned_lstats;
if (!IS_PTR_ALIGNED(lstats)) {
- memcpy(&aligned_lstats, lstats, sizeof aligned_lstats);
+ memcpy(&aligned_lstats, (void *) lstats,
+ sizeof aligned_lstats);
lstats = &aligned_lstats;
}
netdev_stats_from_rtnl_link_stats64(stats, lstats);
--
2.46.0
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