From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Thu, 02 Apr 2026 09:55:59 +0200 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1w8CuF-007m8X-2j for lore@lore.pengutronix.de; Thu, 02 Apr 2026 09:55:59 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1w8CuF-0006Z2-8C for lore@pengutronix.de; Thu, 02 Apr 2026 09:55:59 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:To:In-Reply-To: References:Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version: Subject:Date:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=8P3S0CDg9c1zp/vmos4NWlJ6sfRq54R8KioI7hFIbgM=; b=ggJb6Egt4X4+jAe/MK1mzcCQFU UKLjL/CEsd+mR/+FiPNmchbWIbupOQjt+l6ZZxM80672BYGMitXdvHQjkpzsqZ2j58Wkq3GFMkJxU 55xbVKVOSTWGCgT3gVPpYJ+IFsDFpglQFjqLCRtEGy+kwYN4w5pMQErbIn2vB4V5QxzNIU4XXPF3Y eh163aLWJbmiQq68n/48hB8kFj9tWZ9bzu8r/IkDcaRcsciDC4i7aw5k0WONjcMIhFAl8kEoRvk+w 7Jcnr7tcNdUK/BOT7N6a6/FPwDVJluG9m/BOYv1vAkHKI43uPpSn7SywKSJNkj+syikg1WQQzFVbG FsYteXww==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w8Ctr-0000000H7ft-2zzh; Thu, 02 Apr 2026 07:55:35 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w8Cto-0000000H7fA-3Zmh for barebox@lists.infradead.org; Thu, 02 Apr 2026 07:55:34 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1w8Ctf-0006Nv-E2; Thu, 02 Apr 2026 09:55:23 +0200 Received: from dude02.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::28]) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1w8Ctf-003L4i-0f; Thu, 02 Apr 2026 09:55:23 +0200 Received: from [::1] (helo=dude02.red.stw.pengutronix.de) by dude02.red.stw.pengutronix.de with esmtp (Exim 4.98.2) (envelope-from ) id 1w8Ctf-00000003RCj-0bY7; Thu, 02 Apr 2026 09:55:23 +0200 From: Sascha Hauer Date: Thu, 02 Apr 2026 09:55:23 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260402-net-nfs-buffer-overflows-v1-1-5dc46ef1da81@pengutronix.de> References: <20260402-net-nfs-buffer-overflows-v1-0-5dc46ef1da81@pengutronix.de> In-Reply-To: <20260402-net-nfs-buffer-overflows-v1-0-5dc46ef1da81@pengutronix.de> To: BAREBOX X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1775116523; l=2174; i=s.hauer@pengutronix.de; s=20230412; h=from:subject:message-id; bh=x2iJTIQRRShQtGZiR40jL5lkVW3A/0DSgbEQiTpk4tw=; b=G6GdsG18PVuX/yTMQq/h6xMPfpfRfCHC808e0bxcIqBoYGY6L00CJtE+dNaS9tHYGmB9LQ0og rTp3As+jXPVCJAtbDaVjewpj31NdjKINZ7CGpXSbqLNek9Mq6lVG7zs X-Developer-Key: i=s.hauer@pengutronix.de; a=ed25519; pk=4kuc9ocmECiBJKWxYgqyhtZOHj5AWi7+d0n/UjhkwTg= X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260402_005533_843785_AE1D2B1C X-CRM114-Status: GOOD ( 10.26 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Claude Opus 4.6 \(1M context\)" Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-5.2 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: [PATCH 1/2] fs: nfs: fix stack and packet buffer overflows from long NFS paths X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) nfs_mount_req() and nfs_umount_req() copy the NFS mount path into a stack-allocated uint32_t data[1024] buffer (4096 bytes) with only ~40 bytes of RPC header overhead. A mount path longer than ~4056 characters overflows the stack array. Additionally, rpc_req() copies the data array into the PKTSIZE (1536) packet buffer with only 1494 bytes available for UDP payload. After the 28-byte RPC call header, paths longer than ~1424 characters overflow the packet buffer. Fix by: - Adding a path length check in nfs_mount_req() and nfs_umount_req() against the stack buffer capacity before constructing the request - Adding a payload size check in rpc_req() before the memcpy to the packet buffer, protecting all RPC callers from overflows Signed-off-by: Sascha Hauer Co-Authored-By: Claude Opus 4.6 (1M context) --- fs/nfs.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/fs/nfs.c b/fs/nfs.c index 0b40c56ff3..edc15e0ce6 100644 --- a/fs/nfs.c +++ b/fs/nfs.c @@ -534,6 +534,13 @@ static struct packet *rpc_req(struct nfs_priv *npriv, int rpc_prog, pkt.vers = hton32(3); } + if (sizeof(pkt) + datalen * sizeof(uint32_t) > + PKTSIZE - ETHER_HDR_SIZE - sizeof(struct iphdr) - sizeof(struct udphdr)) { + dev_err(dev, "RPC request too large (%zu bytes)\n", + sizeof(pkt) + datalen * sizeof(uint32_t)); + return ERR_PTR(-EMSGSIZE); + } + memcpy(payload, &pkt, sizeof(pkt)); memcpy(payload + sizeof(pkt), data, datalen * sizeof(uint32_t)); @@ -786,6 +793,11 @@ static int nfs_mount_req(struct nfs_priv *npriv) pathlen = strlen(npriv->path); + if (pathlen > sizeof(data) - 11 * sizeof(uint32_t)) { + dev_err(dev, "path too long (%d bytes)\n", pathlen); + return -ENAMETOOLONG; + } + dev_dbg(dev, "%s: %s\n", __func__, npriv->path); p = &(data[0]); @@ -862,6 +874,8 @@ static void nfs_umount_req(struct nfs_priv *npriv) struct packet *nfs_packet; pathlen = strlen(npriv->path); + if (pathlen > sizeof(data) - 11 * sizeof(uint32_t)) + return; p = &(data[0]); p = rpc_add_credentials(p); -- 2.47.3