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 46B4D378838; Fri, 4 Sep 2026 06:03:46 +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=1788501827; cv=none; b=uLHcGJlZj6NSrCgD2diI3lG+DFsDMMTw0bL/oihEtUnKx9ZC0cK/VvWSnpPzl5bYaPav9naLxWvUNTdv7TYKtQ3k+zjh6EDqKqv/GSRCiSX2Q4mi+DZZucbf0OB21Lz14NWn/F76B1LjxdQ12e3MKUJDicAz99jQyzEvu26O/gk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501827; c=relaxed/simple; bh=K/ddyJruXujSvdrTmFeYay/ltiqqEGtiwQICmB1uls4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JYxwOslMkrivWPq2cf3v9eFgFR/49f5tQWnAv0tLeY8CptmauV64Sl5XPUbzLrtK9Xg0fbQfVpH9CB5Wglt2/YcTOLNvcHPcD1UNaaxzOrkTGTYPrgUYl5m1iqcZI+0kiYH+Q1NH/uQEiB41A5tvNVfmtwk6Tuq5oBDFEK7ELrI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=JQOh6vsZ; 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="JQOh6vsZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F8C41F00A3D; Fri, 4 Sep 2026 06:03:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788501826; bh=hzf1FdkxNDoMlOLPFUO4ll1isd4//5P7btIYTYpuXR0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JQOh6vsZiAqDi0m2hjnY//HHxXyn9+W+P+kdN1ZbnC8uCe6mOcN3YZBQYFfPNFFgl N64A2K2DBkCa0SgAgOCOXgBI+/ETSQyzMHgS3h9wJKU0CsBAAC4sfJLWHn7xPaf2jF 2ygXyHbnZgDmqAYnWIy3yrtr83ej06rAE7QEcHOs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Bradley Morgan , Oleg Deomi , Andrew Morton , Balbir Singh Subject: [PATCH 6.18 547/552] taskstats: fix cpumask parsing cutting off the last character Date: Fri, 4 Sep 2026 07:01:44 +0200 Message-ID: <20260904045803.002082121@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045747.813364717@linuxfoundation.org> References: <20260904045747.813364717@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: Bradley Morgan commit 1f58a5335cdd14b3fb5f2a5d3763dee1f5cba1d3 upstream. parse() hands nla_strscpy() len as dstsize, and nla_strscpy() copies at most dstsize - 1 bytes. When the attr payload comes in without a trailing NUL, srclen == len >= dstsize and the last character of the cpumask string gets cut off. Register "0-15" and you are silently listening on "0-1", exit data for the rest never shows up. The bug only bites when the sender doesn't NUL terminate the payload; senders that include the NUL were always fine (srclen gets decremented for the trailing NUL, so srclen < dstsize). Thats probably why this survived 20 years. And the policy is NLA_STRING, not NLA_NUL_STRING, so a payload without the trailing NUL is legit input here. Skip the kmalloc/nla_strscpy dance entirely and use nla_strdup(), which already allocates srclen + 1 and terminates. The nla_len() bounds checks stay as they were. Link: https://lore.kernel.org/EC49FE41-7F5F-41E0-A07A-ABEB8ECA514D@grrlz.net Fixes: f9fd8914c1ac ("[PATCH] per-task delay accounting taskstats interface: control exit data through cpumasks") Signed-off-by: Bradley Morgan Reported-by: Oleg Deomi Closes: https://lore.kernel.org/CAByWkfZ6b1=3H9pwkz-dDQOs9cZaF-HYQ6b9Yb0=Hq2r1Vv_Pw@mail.gmail.com Reviewed-by: Andrew Morton Cc: Balbir Singh Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- kernel/taskstats.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/kernel/taskstats.c +++ b/kernel/taskstats.c @@ -368,10 +368,9 @@ static int parse(struct nlattr *na, stru return -E2BIG; if (len < 1) return -EINVAL; - data = kmalloc(len, GFP_KERNEL); + data = nla_strdup(na, GFP_KERNEL); if (!data) return -ENOMEM; - nla_strscpy(data, na, len); ret = cpulist_parse(data, mask); kfree(data); return ret;