From: Andrii Nakryiko andriin@fb.com
[ Upstream commit cb8ffde5694ae5fffb456eae932aac442aa3a207 ]
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.
v1->v2: - rebase against bpf tree.
Cc: Magnus Karlsson magnus.karlsson@intel.com Signed-off-by: Andrii Nakryiko andriin@fb.com Acked-by: Magnus Karlsson magnus.karlsson@intel.com Acked-by: Song Liu songliubraving@fb.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 8e03b65830da0..fa948c5445ecf 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -336,7 +336,7 @@ static int xsk_get_max_queues(struct xsk_socket *xsk) return -errno;
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) { @@ -561,7 +561,7 @@ 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);