From a0f887bbdc525006f7662f4a83e240f2c46d3418 Mon Sep 17 00:00:00 2001
From: Kuan-Wei Chiu <visitorckw@gmail.com>
Date: Sun, 8 Sep 2024 22:00:09 +0800
Subject: [PATCH] bpftool: Fix undefined behavior caused by shifting into the sign bit
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@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <qmo@kernel.org>
Link: https://lore.kernel.org/bpf/20240908140009.3149781-1-visitorckw@gmail.com
---
src/net.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/src/net.c b/src/net.c
index 2a51f1c..3c50fc6 100644
--- a/src/net.c
+++ b/src/net.c
@@ -486,9 +486,9 @@ 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("");
}
@@ -497,9 +497,9 @@ 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("");
}