From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E33FF39B970 for ; Sat, 28 Feb 2026 18:17:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772302642; cv=none; b=ssb4TQ8iTEcnEKsO6KLzHZjSr00Obcrn8Jx+SetdXlyvfI5+gmsMzwccOZmxsAFU4NZF0sw0FZo+EEG3puyHWsDoiWD8iwwd7tRSh5G8sGdOPDT1MD/yzvGFWYwsvRmumQyW1YfiRECje59t07vZZGjQEwO3HmROl2QoS3WY4V0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772302642; c=relaxed/simple; bh=KzBelGAVkTQu32eUhicHP8L3iEWU1w8czvHt4zYuzAw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QzmcFvhyxXnGZ2fTVuAXCoZWivZciOIXfRRxVYvaL3T7t1IgOdFp+cEvzlFt446ivjxHhf4mluOgPLByMzBqoK5mRN1fVNoY8048Sof9BYFzY3d66gBbriFoEbY649pbwnw/YGd6jdB62aeEbrCEx+/a1pu5D2AhSI9mFBPiGHk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Vq6x75RN; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Vq6x75RN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFD30C19425; Sat, 28 Feb 2026 18:17:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772302641; bh=KzBelGAVkTQu32eUhicHP8L3iEWU1w8czvHt4zYuzAw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Vq6x75RNVfHElhDM063JdSlKteoMm2lxHHM/923BRgkr91gQpzQNbzsjIQbBziwV0 nYrjEV8M0diwJ+7jdYGAE2O+03Raowue+PN3o4MYf7gLaw8GKrgYiqNz7V49Zwp4HZ RtxiIeVCPSd+/pxGJNu/n5KJ52OO7/iTfydAMoFyrbULx82DZYp8Cc6a03vMG6cmOz uRRAUsMr2eqmwTFKr7ImT+DqJqc5ggCLnl8UAvR8mn5pBBgR+cOrQ7xr2rtIs9SRE5 FOS3M67oyUbKjtfn6wdb/SsuorOLNLnK5useE7AC31wBqX635i7eH8voyxOY9sWMQD TpivH5t/A9e3Q== From: Sasha Levin To: patches@lists.linux.dev Cc: Jakub Kicinski , Quentin Monnet , Alexei Starovoitov , Sasha Levin Subject: [PATCH 5.15 163/164] bpftool: Fix truncated netlink dumps Date: Sat, 28 Feb 2026 13:15:02 -0500 Message-ID: <20260228181505.1600663-163-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228181505.1600663-1-sashal@kernel.org> References: <20260228181505.1600663-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Jakub Kicinski [ 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 Fixes: 7084566a236f ("tools/bpftool: Remove libbpf_internal.h usage in bpftool") Signed-off-by: Jakub Kicinski Link: https://lore.kernel.org/r/20260217194150.734701-1-kuba@kernel.org Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- tools/bpf/bpftool/net.c | 5 ++++- 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 18e5e5faa2aa2..ef7fe8dd50984 100644 --- a/tools/bpf/bpftool/net.c +++ b/tools/bpf/bpftool/net.c @@ -143,7 +143,7 @@ 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) { @@ -188,6 +188,9 @@ 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 fadde7d80a51c..00ba40b0a57e2 100644 --- a/tools/lib/bpf/netlink.c +++ b/tools/lib/bpf/netlink.c @@ -127,7 +127,7 @@ 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; @@ -196,6 +196,8 @@ static int libbpf_netlink_recv(int sock, __u32 nl_pid, int seq, } } } + if (len) + pr_warn("Invalid message or trailing data in Netlink response: %d bytes left\n", len); } ret = 0; done: -- 2.51.0