From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from plesk.hostmyservers.fr (plesk.hostmyservers.fr [45.145.164.37]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E7CCD1D79B3; Mon, 7 Apr 2025 14:17:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.145.164.37 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744035475; cv=none; b=DMbF5KpIdsQi0Re1/iIGX12SMexcyNy2hm9WviBBkb219ENN2EwnmI+IZ45n3ImBem5qBx9lOWEF82wfyEIdTA49WHScCCc/i0SXpKoFnI20RU3WBd2ybb8dlosX6V8O/K5BZEm5fvTj/Q2jFCLOo+0L5BYRKYYZNjVbjS+reEI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744035475; c=relaxed/simple; bh=ERmC0VihSwVE+kfQl3h22QpzW0EQ3aDUpCiKyvDOEq0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Eo+ekFPfD7+CvtQ4g6pdvhrspyhFzNklIKJmFw5X4onnfeusOy+DbU2i+pwYOimlYuihGmQQ80babPLnkS2maq4rLZ9t4E5m+JVTm3ADAwxQmSy1ZCc0mROwfVEe3GCLPHQqP/gxLULCYsW8OpnFXzF7u596LatdGWSDolFajgI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=arnaud-lcm.com; spf=pass smtp.mailfrom=arnaud-lcm.com; arc=none smtp.client-ip=45.145.164.37 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=arnaud-lcm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arnaud-lcm.com Received: from arnaudlcm-X570-UD.. (unknown [IPv6:2a01:e0a:3e8:c0d0:3b93:9152:d50e:6d45]) by plesk.hostmyservers.fr (Postfix) with ESMTPSA id D37DB28D8AF; Mon, 7 Apr 2025 14:17:51 +0000 (UTC) Authentication-Results: Plesk; spf=pass (sender IP is 2a01:e0a:3e8:c0d0:3b93:9152:d50e:6d45) smtp.mailfrom=contact@arnaud-lcm.com smtp.helo=arnaudlcm-X570-UD.. Received-SPF: pass (Plesk: connection is authenticated) From: Arnaud Lecomte To: syzbot+29fc8991b0ecb186cf40@syzkaller.appspotmail.com Cc: andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-ppp@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] Date: Mon, 7 Apr 2025 16:17:47 +0200 Message-ID: <20250407141747.92874-1-contact@arnaud-lcm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <67ae3912.050a0220.21dd3.0021.GAE@google.com> References: <67ae3912.050a0220.21dd3.0021.GAE@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-PPP-Message-ID: <174403547232.32667.4417870378199395325@Plesk> X-PPP-Vhost: arnaud-lcm.com Author: contact@arnaud-lcm.com #syz test diff --git a/drivers/net/ppp/ppp_synctty.c b/drivers/net/ppp/ppp_synctty.c index 644e99fc3623..520d895acc60 100644 --- a/drivers/net/ppp/ppp_synctty.c +++ b/drivers/net/ppp/ppp_synctty.c @@ -506,6 +506,11 @@ ppp_sync_txmunge(struct syncppp *ap, struct sk_buff *skb) unsigned char *data; int islcp; + /* Ensure we can safely access protocol field and LCP code */ + if (!skb || !pskb_may_pull(skb, 3)) { + kfree_skb(skb); + return NULL; + } data = skb->data; proto = get_unaligned_be16(data);