Patch "bpftool: Fix undefined behavior caused by shifting into the sign bit" has been added to the 6.11-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    bpftool: Fix undefined behavior caused by shifting into the sign bit

to the 6.11-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     bpftool-fix-undefined-behavior-caused-by-shifting-in.patch
and it can be found in the queue-6.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 39ab126b771091c734e8546a1d964e9ce72c26e5
Author: Kuan-Wei Chiu <visitorckw@xxxxxxxxx>
Date:   Sun Sep 8 22:00:09 2024 +0800

    bpftool: Fix undefined behavior caused by shifting into the sign bit
    
    [ 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>

diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c
index 968714b4c3d45..ad2ea6cf2db11 100644
--- a/tools/bpf/bpftool/net.c
+++ b/tools/bpf/bpftool/net.c
@@ -482,9 +482,9 @@ 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("");
 		}
@@ -493,9 +493,9 @@ 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("");
 			}