From patchwork Mon Nov 16 21:05:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Weinberger X-Patchwork-Id: 1401174 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.infradead.org (client-ip=2001:8b0:10b:1231::1; helo=merlin.infradead.org; envelope-from=linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=nod.at Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; secure) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=merlin.20170209 header.b=KJ6uA0uW; dkim-atps=neutral Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4CZhT95dW7z9sTL for ; Tue, 17 Nov 2020 08:06:37 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:To:From: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=w8C3UhVnOtCa20xw9Jslf0leqCVnjjpmFB9uT2MPEmU=; b=KJ6uA0uWtL6O4lengOrQKMqFZt Tz/7nyiGNOeXvb+ckIZTuEUrH9ZjbgDSEkym9ACDTGxMw884TnWAorlsadwimbP+E0lMXx1NY1BZi MtPicwGz1xLqg7HdzBQqN/1f+/O6DNZN8C1nqPil/mX2zYFrDtxwyVPXDFnIVjIvyt46OX+wp3AqF 7my+UWBSK/WsblfrTaS8tVj0N6hpK8xZ8H4kiPGPARGLzBH+1b5ci9n6e2JpQpuAtC27olv/hoM+q RlP15dvRCK37E2HiMXMUFJQ4KOvbXYlCyNHvBacbJ49AsxepCyS/P1EMPYjb+aWs9dO/U6UhIjDju +f/NPBgw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kelhB-0001Q5-1I; Mon, 16 Nov 2020 21:05:53 +0000 Received: from lilium.sigma-star.at ([109.75.188.150]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kelh9-0001Ox-Ce for linux-mtd@lists.infradead.org; Mon, 16 Nov 2020 21:05:52 +0000 Received: from localhost (localhost [127.0.0.1]) by lilium.sigma-star.at (Postfix) with ESMTP id 3BEF61816C728; Mon, 16 Nov 2020 22:05:47 +0100 (CET) Received: from lilium.sigma-star.at ([127.0.0.1]) by localhost (lilium.sigma-star.at [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id pj4MsuSeTHU4; Mon, 16 Nov 2020 22:05:46 +0100 (CET) Received: from lilium.sigma-star.at ([127.0.0.1]) by localhost (lilium.sigma-star.at [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id MinQ-477CHIm; Mon, 16 Nov 2020 22:05:46 +0100 (CET) From: Richard Weinberger To: linux-mtd@lists.infradead.org Subject: [PATCH] ubifs: wbuf: Don't leak kernel memory to flash Date: Mon, 16 Nov 2020 22:05:30 +0100 Message-Id: <20201116210530.26230-1-richard@nod.at> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201116_160551_543780_4E6BCBD6 X-CRM114-Status: GOOD ( 13.44 ) X-Spam-Score: 0.0 (/) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (0.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 T_SPF_PERMERROR SPF: test of record failed (permerror) 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Richard Weinberger , linux-kernel@vger.kernel.org, stable@vger.kernel.org Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org Write buffers use a kmalloc()'ed buffer, they can leak up to seven bytes of kernel memory to flash if writes are not aligned. So use ubifs_pad() to fill these gaps with padding bytes. This was never a problem while scanning because the scanner logic manually aligns node lengths and skips over these gaps. Cc: Fixes: 1e51764a3c2ac05a2 ("UBIFS: add new flash file system") Signed-off-by: Richard Weinberger Reviewed-by: Zhihao Cheng --- fs/ubifs/io.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/fs/ubifs/io.c b/fs/ubifs/io.c index 7e4bfaf2871f..eae9cf5a57b0 100644 --- a/fs/ubifs/io.c +++ b/fs/ubifs/io.c @@ -319,7 +319,7 @@ void ubifs_pad(const struct ubifs_info *c, void *buf, int pad) { uint32_t crc; - ubifs_assert(c, pad >= 0 && !(pad & 7)); + ubifs_assert(c, pad >= 0); if (pad >= UBIFS_PAD_NODE_SZ) { struct ubifs_ch *ch = buf; @@ -764,6 +764,10 @@ int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len) * write-buffer. */ memcpy(wbuf->buf + wbuf->used, buf, len); + if (aligned_len > len) { + ubifs_assert(c, aligned_len - len < 8); + ubifs_pad(c, wbuf->buf + wbuf->used + len, aligned_len - len); + } if (aligned_len == wbuf->avail) { dbg_io("flush jhead %s wbuf to LEB %d:%d", @@ -856,13 +860,18 @@ int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len) } spin_lock(&wbuf->lock); - if (aligned_len) + if (aligned_len) { /* * And now we have what's left and what does not take whole * max. write unit, so write it to the write-buffer and we are * done. */ memcpy(wbuf->buf, buf + written, len); + if (aligned_len > len) { + ubifs_assert(c, aligned_len - len < 8); + ubifs_pad(c, wbuf->buf + len, aligned_len - len); + } + } if (c->leb_size - wbuf->offs >= c->max_write_size) wbuf->size = c->max_write_size;