diff options
| author | Jakub Kicinski | 2026-02-17 11:41:50 -0800 |
|---|---|---|
| committer | Sasha Levin | 2026-03-04 07:20:20 -0500 |
| commit | 6b6b2fbd66d86f218dc345af57e5f333853d34f0 (patch) | |
| tree | c7b9326fb7fd61803a1427960f010727b416e605 /tools | |
| parent | db4636748c2250e569f96bcb32a53d786282262f (diff) | |
bpftool: Fix truncated netlink dumps
[ Upstream commit 3b39d73cc3379360a33eb583b17f21fe55e1288e ]
Netlink requires that the recv buffer used during dumps is at least
min(PAGE_SIZE, 8k) (see the man page). Otherwise the messages will
get truncated. Make sure bpftool follows this requirement, avoid
missing information on systems with large pages.
Acked-by: Quentin Monnet <qmo@kernel.org>
Fixes: 7084566a236f ("tools/bpftool: Remove libbpf_internal.h usage in bpftool")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20260217194150.734701-1-kuba@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/bpf/bpftool/net.c | 5 | ||||
| -rw-r--r-- | tools/lib/bpf/netlink.c | 4 |
2 files changed, 7 insertions, 2 deletions
diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c index c2ca82fc21e2..225d3678b4ed 100644 --- a/tools/bpf/bpftool/net.c +++ b/tools/bpf/bpftool/net.c @@ -150,7 +150,7 @@ static int netlink_recv(int sock, __u32 nl_pid, __u32 seq, bool multipart = true; struct nlmsgerr *err; struct nlmsghdr *nh; - char buf[4096]; + char buf[8192]; int len, ret; while (multipart) { @@ -195,6 +195,9 @@ static int netlink_recv(int sock, __u32 nl_pid, __u32 seq, return ret; } } + + if (len) + p_err("Invalid message or trailing data in Netlink response: %d bytes left", len); } ret = 0; done: diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c index 68a2def17175..6f16c4f7b3a4 100644 --- a/tools/lib/bpf/netlink.c +++ b/tools/lib/bpf/netlink.c @@ -143,7 +143,7 @@ static int libbpf_netlink_recv(int sock, __u32 nl_pid, int seq, struct nlmsghdr *nh; int len, ret; - ret = alloc_iov(&iov, 4096); + ret = alloc_iov(&iov, 8192); if (ret) goto done; @@ -212,6 +212,8 @@ start: } } } + if (len) + pr_warn("Invalid message or trailing data in Netlink response: %d bytes left\n", len); } ret = 0; done: |