Despite a proper NULL-termination after strncpy(..., ..., IFNAMSIZ - 1),
GCC8 still complains about *expected* string truncation:
xsk.c:330:2: error: 'strncpy' output may be truncated copying 15 bytes
from a string of length 15 [-Werror=stringop-truncation]
strncpy(ifr.ifr_name, xsk->ifname, IFNAMSIZ - 1);
This patch gets rid of the issue altogether by using memcpy instead.
There is no performance regression, as strncpy will still copy and fill
all of the bytes anyway.
Cc: Magnus Karlsson <magnus.karlsson@xxxxxxxxx>
Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
---
tools/lib/bpf/xsk.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
index 5007b5d4fd2c..65f5dd556f99 100644
--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c
@@ -327,7 +327,7 @@ static int xsk_get_max_queues(struct xsk_socket *xsk)
channels.cmd = ETHTOOL_GCHANNELS;
ifr.ifr_data = (void *)&channels;
- strncpy(ifr.ifr_name, xsk->ifname, IFNAMSIZ - 1);
+ memcpy(ifr.ifr_name, xsk->ifname, IFNAMSIZ - 1);
ifr.ifr_name[IFNAMSIZ - 1] = '\0';
err = ioctl(fd, SIOCETHTOOL, &ifr);
if (err && errno != EOPNOTSUPP) {
@@ -517,7 +517,7 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname,
err = -errno;
goto out_socket;
}
- strncpy(xsk->ifname, ifname, IFNAMSIZ - 1);
+ memcpy(xsk->ifname, ifname, IFNAMSIZ - 1);
xsk->ifname[IFNAMSIZ - 1] = '\0';
err = xsk_set_xdp_socket_config(&xsk->config, usr_config);
--
2.17.1
