From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.70.190.124 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794567913; b=v4Ki7xHwCZeO0OKmZhQrxvrPKTDZJ5hDgjyLJ0lt4g4RonVS0f22a9OwFG/rqV5VirUi hgqbNsu+wrUkIo+BcEIoUmDjp7PsrdhJARqJ4qDbz4jfDgY9Ss/eOFQ6ybajszUCp1Tze vvAPCFXDcBahTt1qEcP2+6aAHafLQlqW4YeYg7gXbco/V4/FT6B2285x91jyLRt9Q/xTx SAVxoEcHJQ19CFqFPdoGJv/7BvLvoRVuHwkW4DGP2OHTv+p/8NK6Z6yEr/libflFh/Jbz H/8pXJMH2H7DYaqut4GPYbAABpJMtePedhG7G1qK1tWJmXvLPxMeJsAEIcOv3gBgfmQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794567913; h=DMARC-Filter:DKIM-Signature:Received:Date:From:To:Cc:Subject: Message-ID:References:MIME-Version:Content-Type:Content-Disposition: In-Reply-To:X-Spam-Status:X-Spam-Checker-Version; bh=drqOGeCwG8bpqjI7Lmtgp303O9Fg7qLukmjnQwyfszk=; b=E03BsWU9s4RIQ/jsc09SV7oSQ0yg9hvwLVM6wHVPNH2NSc+1n2180GaFx7g/ZAimS5dh H7o9Xb1qTJ/+NKzfLoldW9CDsQKSYZ/j6Qn9aNUGV73Oo8fD4GkosD6cZlMHSB5BYvAb3 rNHl8rlp/VgmJ4WULkcBNi8ndpq+K++9yNo2NYtFk1r8aH3nJUHZJN85pL2QdlmscXN+A jgVibM0rL8wb95du9nBnYDo3Mm/MaKRCyeTeiKkjdYSdGZL0LWkzSmUap/wP6VpSCPoNc +IGVmjiBshkBB3IKVgpw8rXOt2+KdMx04qxd+2WfHg+1CR2DMlt8Dz3BdhS4Nl0j/KA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; dkim=pass header.d=netfilter.org header.i=@netfilter.org header.a=rsa-sha256 header.s=2025 header.b="fC3W/tiY"; arc=none smtp.remote-ip=217.70.190.124 Received: from mail.netfilter.org (mail.netfilter.org [217.70.190.124]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with UTF8SMTPS id 1BAB6606A8A2 for ; Fri, 13 Nov 2026 11:05:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 1BAB6606A8A2 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.a=rsa-sha256 header.s=2025 header.b=fC3W/tiY DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1794567910; bh=drqOGeCwG8bpqjI7Lmtgp303O9Fg7qLukmjnQwyfszk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fC3W/tiY52NFj0V7DjhkJ+yyp4IAEb23UYQspTcPq0/ss9jO7gwLmG08S7rGpVSfE BSqgwn+OrbnAc1u9h2+j4mBwNpf37N8TFrrzOJ7pAjzlI7ZMZ2ycz5GBG9uaVu5bIS 2414vWuzZfsIWhRTaQ5qxTuK2uCvkujz5P/SzPYSrji3ieOfX0feyo/XHhBlic9d/U SXAUClEi6X/IE7VhLEhcOAZele0lkuZZ8OG4iWhiSH1cp6AFLoGP02L5CyEUH7HFLB tPj6a1eakEvIMTeJrkvorbFh8g/iNGRSjhdhtsD/3ZftPNKwLJcSIOkyv44zMkkmUa c0RgMWsqWvmEw== Received: from netfilter.org (mail-agni [217.70.190.124]) by mail.netfilter.org (Postfix) with UTF8SMTPSA id A8FB960056; Fri, 13 Nov 2026 12:05:10 +0100 (CET) Date: Fri, 13 Nov 2026 12:05:08 +0100 From: Pablo Neira Ayuso To: Florian Stosse Cc: netfilter-devel@vger.kernel.org Subject: Re: [PATCH libmnl 5/5] callback: avoid signed overflow on INT_MIN error code Message-ID: References: <20261106191841.1645-1-florian.stosse@harvester.fr> <20261106191841.1645-6-florian.stosse@harvester.fr> X-Mailing-List: netfilter-devel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20261106191841.1645-6-florian.stosse@harvester.fr> On Fri, Nov 06, 2026 at 08:18:40PM +0100, Florian Stosse wrote: > mnl_cb_error() negates the error field of an NLMSG_ERROR message to get > a positive errno. For INT_MIN the negation overflows, which is undefined > behaviour. No errno has that value, so report the message as malformed > with EBADMSG instead. > > Co-Authored-By: Claude Opus 5.5 > Signed-off-by: Florian Stosse > --- > src/callback.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/src/callback.c b/src/callback.c > index 703ae80..660c90a 100644 > --- a/src/callback.c > +++ b/src/callback.c > @@ -8,6 +8,7 @@ > */ > > #include > +#include > #include > #include "internal.h" > > @@ -25,7 +26,9 @@ static int mnl_cb_error(const struct nlmsghdr *nlh, void *data) > return MNL_CB_ERROR; > } > /* Netlink subsystems returns the errno value with different signess */ > - if (err->error < 0) > + if (err->error == INT_MIN) > + errno = EBADMSG; This is most likely processing an errno from the kernel. IIRC, this is for historical reasons, I remember there was a very old bug in netlink. Probably this branch can just go away? > + else if (err->error < 0) > errno = -err->error; > else > errno = err->error; > -- > 2.56.0.windows.4 >