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 6F14C2797A5; Mon, 5 May 2025 23:21:41 +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=1746487301; cv=none; b=ssuyKpztii+zZMVg1DlgYMM5+ObwTYN9Uu3doNTsblBSmmz/q7XhmYGCcI4Eovo0iP2NeYx5lE90VZnynW+APKW08lLjylKosNvwu3+L40rqO9mWBu4KQKjLXpUxDW/PsJdVoju87ypz+v7C2Qk4RIB/QRDX7OFrHEofLdrhBDY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746487301; c=relaxed/simple; bh=7wa+U1T31NJK/tUCaixLIQ5iCyGeLrmTTRl81nmcU0M=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=MLx1UJklsLrlh2sYN4cfy/8qPJjWwXUcuw/gvcuwrwIQqeZv1uxa9z4IXD48f9aWYSk7cWqS12UK8SJXHnbKpJlxsgTeaQSxxEBxKgzxnnHSF5GMZ9dTHjkBjyp42dvkccq5cYROc7z5ewPtGrQBiYMbETIKCzks4IaIXwUI9DA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ekPXbpMi; 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="ekPXbpMi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A690C4CEF1; Mon, 5 May 2025 23:21:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746487301; bh=7wa+U1T31NJK/tUCaixLIQ5iCyGeLrmTTRl81nmcU0M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ekPXbpMi+82v04am7vGk8qItbPRF0Jcm4WINAmZcTJLFqB9q/5vWl7Q6StWwB6OCV 9II1Fenrm7NZbtdiKWH3W9Z+//pwcRbBBDNu6HjZJMOIjscCmsPlg0+fWqY3tMWRPT zkK5FIZwoTT+2PMFaiz7Yl6rnAsUsB480DFJt1HQXBTmipD0saKqosxcMkc/mrd5JA F8KQuz19mXczOpllk2VuP6cHXwDXdSWOI3bwIT54SJCHmhL43uNtQXLS3f0AXTGb9T PSyWT2ur7MUgv/11M+EXPJt32uZygGfrlbevM230cdZo1i08jSumsAH4/uT22TwkPa wM4gYvLS2AEZA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Viktor Malik , Andrii Nakryiko , Quentin Monnet , Alexei Starovoitov , Sasha Levin , daniel@iogearbox.net, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 108/114] bpftool: Fix readlink usage in get_fd_type Date: Mon, 5 May 2025 19:18:11 -0400 Message-Id: <20250505231817.2697367-108-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250505231817.2697367-1-sashal@kernel.org> References: <20250505231817.2697367-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.10.237 Content-Transfer-Encoding: 8bit From: Viktor Malik [ Upstream commit 0053f7d39d491b6138d7c526876d13885cbb65f1 ] The `readlink(path, buf, sizeof(buf))` call reads at most sizeof(buf) bytes and *does not* append null-terminator to buf. With respect to that, fix two pieces in get_fd_type: 1. Change the truncation check to contain sizeof(buf) rather than sizeof(path). 2. Append null-terminator to buf. Reported by Coverity. Signed-off-by: Viktor Malik Signed-off-by: Andrii Nakryiko Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20250129071857.75182-1-vmalik@redhat.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- tools/bpf/bpftool/common.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c index eefa2b34e641a..33065b17900fa 100644 --- a/tools/bpf/bpftool/common.c +++ b/tools/bpf/bpftool/common.c @@ -311,10 +311,11 @@ int get_fd_type(int fd) p_err("can't read link type: %s", strerror(errno)); return -1; } - if (n == sizeof(path)) { + if (n == sizeof(buf)) { p_err("can't read link type: path too long!"); return -1; } + buf[n] = '\0'; if (strstr(buf, "bpf-map")) return BPF_OBJ_MAP; -- 2.39.5