From: Kuan-Wei Chiu <visitorckw@xxxxxxxxx> [ Upstream commit 4cdc0e4ce5e893bc92255f5f734d983012f2bc2e ] Replace shifts of '1' with '1U' in bitwise operations within __show_dev_tc_bpf() to prevent undefined behavior caused by shifting into the sign bit of a signed integer. By using '1U', the operations are explicitly performed on unsigned integers, avoiding potential integer overflow or sign-related issues. Signed-off-by: Kuan-Wei Chiu <visitorckw@xxxxxxxxx> Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Acked-by: Quentin Monnet <qmo@xxxxxxxxxx> Link: https://lore.kernel.org/bpf/20240908140009.3149781-1-visitorckw@xxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- tools/bpf/bpftool/net.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c index 66a8ce8ae0127..fd54ff436493f 100644 --- a/tools/bpf/bpftool/net.c +++ b/tools/bpf/bpftool/net.c @@ -480,9 +480,9 @@ static void __show_dev_tc_bpf(const struct ip_devname_ifindex *dev, if (prog_flags[i] || json_output) { NET_START_ARRAY("prog_flags", "%s "); for (j = 0; prog_flags[i] && j < 32; j++) { - if (!(prog_flags[i] & (1 << j))) + if (!(prog_flags[i] & (1U << j))) continue; - NET_DUMP_UINT_ONLY(1 << j); + NET_DUMP_UINT_ONLY(1U << j); } NET_END_ARRAY(""); } @@ -491,9 +491,9 @@ static void __show_dev_tc_bpf(const struct ip_devname_ifindex *dev, if (link_flags[i] || json_output) { NET_START_ARRAY("link_flags", "%s "); for (j = 0; link_flags[i] && j < 32; j++) { - if (!(link_flags[i] & (1 << j))) + if (!(link_flags[i] & (1U << j))) continue; - NET_DUMP_UINT_ONLY(1 << j); + NET_DUMP_UINT_ONLY(1U << j); } NET_END_ARRAY(""); } -- 2.43.0
