From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 DF288326D44; Tue, 21 Jul 2026 17:39:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784655598; cv=none; b=bywJ6CzxpMtTbeh5QtJiblqRH0y6IPE4fjE6q/ZGnALw4t8kvjpt2am16EEbWY5dYXIzVmvPFuOg63Yche2vf3SRaFB1Shih/gbNK8zEnNme5WDeT9dHJ/D99MqXfZO5eZRiuKIAKprudbngNnK3f1szeVbaecF44XQi6qDFlP4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784655598; c=relaxed/simple; bh=O1eUXmgxfhaKP5jA5jrtb62JMFRZgXRJ9VUi/DxWJ7k=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WkCiLpWrBg2oQdrAdLGZjOLXQ7FUkliOacMpJgnFHMi7FMd59F6T72Ji4mIIRWZ25CadCYYUuFEzdv4Y0yP8ssmH6KIHAZQPK/L1XzUH8RDeCu+oo1xxiEzwMlwIJaVWR0obE7zwcT9qUGwwsgA+bTGHOXwJlrN6P77nTcGGdcQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=cJXZDd6P; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="cJXZDd6P" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3C4231F000E9; Tue, 21 Jul 2026 17:39:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784655596; bh=JE5FqrGlowpkW/Q/sXLlt9qtjMTBloMqCnUph3Tv3Lc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cJXZDd6P+6LpPw0rsAWBqbnkQPqvLctWdhvk+AcGVCjKCvGe0dHw4d11mZp0HvQZ9 uLzD5Fr4azDnfNwnPlBoG6KgrtkZKgpX2pU34Ym2Q8Jke5Q4BW7/pL2jOrX2FgAbaZ fnSoFvbDych4VtVkEwo8w0tWktglKAzf3vzojgmE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Aaron Tomlin , Mykyta Yatsenko , Kumar Kartikeya Dwivedi , Sasha Levin Subject: [PATCH 6.18 0069/1611] libbpf: Report error when a negative kprobe offset is specified Date: Tue, 21 Jul 2026 17:03:05 +0200 Message-ID: <20260721152516.387913421@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152514.750365251@linuxfoundation.org> References: <20260721152514.750365251@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Aaron Tomlin [ Upstream commit ad35d8018669fd2eea76e3f74eb050fd3d2fb690 ] In attach_kprobe(), the parsing logic uses sscanf() to extract the target function name and offset from the section definition. Currently, if a user specifies a negative offset (e.g., SEC("kprobe/func+-100")), the input is not explicitly caught and reported as an error. This commit updates the logic to explicitly notify the user when a negative integer is provided. To facilitate this check, the offset variable is changed from unsigned long to long so that sscanf() can accurately capture a negative input for evaluation. If a negative offset is detected, the loader will now print an informative warning stating that the offset must be non-negative, and return -EINVAL. Additionally, free(func) is called in this new error path to prevent a memory leak, as the function name string is dynamically allocated by sscanf(). Fixes: e3f9bc35ea7e9 ("libbpf: Allow decimal offset for kprobes") Signed-off-by: Aaron Tomlin Acked-by: Mykyta Yatsenko Link: https://lore.kernel.org/bpf/20260419030944.1423642-1-atomlin@atomlin.com Signed-off-by: Kumar Kartikeya Dwivedi Signed-off-by: Sasha Levin --- tools/lib/bpf/libbpf.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 84b6fb47a2f79d..3baa6025ecba04 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -11826,7 +11826,7 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog, static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link) { DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts); - unsigned long offset = 0; + long offset = 0; const char *func_name; char *func; int n; @@ -11848,6 +11848,13 @@ static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf pr_warn("kprobe name is invalid: %s\n", func_name); return -EINVAL; } + + if (offset < 0) { + free(func); + pr_warn("kprobe offset must be a non-negative integer: %li\n", offset); + return -EINVAL; + } + if (opts.retprobe && offset != 0) { free(func); pr_warn("kretprobes do not support offset specification\n"); -- 2.53.0