From patchwork Mon Jun 7 11:27:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Walle X-Patchwork-Id: 1488588 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=2607:7c80:54:e::133; helo=bombadil.infradead.org; envelope-from=linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org; receiver=) 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=bombadil.20210309 header.b=FOpoUFL6; dkim=fail reason="signature verification failed" (1024-bit key; secure) header.d=walle.cc header.i=@walle.cc header.a=rsa-sha256 header.s=mail2016061301 header.b=AboVC3dj; dkim-atps=neutral Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) (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 4FzB403t9hz9sWX for ; Mon, 7 Jun 2021 21:29:51 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=sLUtokwGitfJEiIIrdk9o+tNnvCFZqvf3xKRlgasTVs=; b=FOpoUFL6CelnHZ OO3yGsUNjJsquRqccD+nn8ZZPePk71JfKiZm1QlJ88YWbOUJoeYzi0N/AIdG6fmWuQfzhSmOSqUfa Eo5v3hWWdiWpiI+gqXIT2uqISck0POa8JBTDGi7if+RPGfVx2twnFSFQnfNLviBt/u0j6qRmNosdH ABiCbuZH4MgPub7c6q/Ibo5TsKf2wbvphKrOvbsfOn4NA7xjAmGjGi8BPqVfp5ZQrHyJUqzM7Ft19 h/ZcjaU/Lzss1hU3jbhtj5+DISpaDxSj2W0uELJ5CFepw2m3jKz8eW0HuRYdHv0dcTan/kAAAieTO 3TWg9h0n2+iFDLSoeLCg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqDRT-003M20-Pu; Mon, 07 Jun 2021 11:29:15 +0000 Received: from ssl.serverraum.org ([2a01:4f8:151:8464::1:2]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqDQ8-003LVl-NT for linux-mtd@lists.infradead.org; Mon, 07 Jun 2021 11:27:58 +0000 Received: from mwalle01.fritz.box (ip4d17858c.dynamic.kabel-deutschland.de [77.23.133.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by ssl.serverraum.org (Postfix) with ESMTPSA id 152B72224D; Mon, 7 Jun 2021 13:27:51 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2016061301; t=1623065271; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aPLr0bC6c5jU5r1OPXE3alwU7oqwB2zXRdHsI9UOrv8=; b=AboVC3dj7CIGi8nFLXtsf/q32kzUPsv48V3gRuSSqv2/RF1+2Gr+8+vdtMDW0r9Axiikcs 0rNmV2UjZtxk9lj/Z1jlz846NR2Q13LzcOno9fPAhmJz/J2fHlAjsftnB2ySQpVNlT7HsL R9U+kL3TvhncKlq9qi1Uk2dSYDtLAAo= From: Michael Walle To: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Tudor Ambarus , Michael Walle , Pratyush Yadav , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra Subject: [PATCH v6 3/4] mtd: spi-nor: otp: return -EROFS if region is read-only Date: Mon, 7 Jun 2021 13:27:43 +0200 Message-Id: <20210607112744.21587-4-michael@walle.cc> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210607112744.21587-1-michael@walle.cc> References: <20210607112744.21587-1-michael@walle.cc> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210607_042752_959547_FEC4447F X-CRM114-Status: GOOD ( 23.81 ) X-Spam-Score: -2.5 (--) X-Spam-Report: Spam detection software, running on the system "bombadil.infradead.org", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: SPI NOR flashes will just ignore program commands if the OTP region is locked. Thus, a user might not notice that the intended write didn't end up in the flash. Return -EROFS to the user in this case. [...] Content analysis details: (-2.5 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [2a01:4f8:151:8464:0:0:1:2 listed in] [list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org SPI NOR flashes will just ignore program commands if the OTP region is locked. Thus, a user might not notice that the intended write didn't end up in the flash. Return -EROFS to the user in this case. From what I can tell, chips/cfi_cmdset_0001.c also return this error code. One could optimize spi_nor_mtd_otp_range_is_locked() to read the status register only once and not for every OTP region, but for that we would need some more invasive changes. Given that this is one-time-programmable memory and the normal access mode is reading, we just live with the small overhead. By moving the code around a bit, we can just check the length before calling spi_nor_mtd_otp_range_is_locked() and avoid an underflow there if a len is 0. This way we don't need to take the lock either. We also skip the "*retlen = 0" assignment, mtdcore already takes care of that for us. Fixes: 069089acf88b ("mtd: spi-nor: add OTP support") Signed-off-by: Michael Walle Reviewed-by: Pratyush Yadav Reviewed-by: Tudor Ambarus --- drivers/mtd/spi-nor/otp.c | 41 ++++++++++++++++++++++++++++++++++++--- 1 file changed, 38 insertions(+), 3 deletions(-) diff --git a/drivers/mtd/spi-nor/otp.c b/drivers/mtd/spi-nor/otp.c index 3898ed67ba1c..89fe52e3851a 100644 --- a/drivers/mtd/spi-nor/otp.c +++ b/drivers/mtd/spi-nor/otp.c @@ -249,6 +249,29 @@ static int spi_nor_mtd_otp_info(struct mtd_info *mtd, size_t len, return ret; } +static int spi_nor_mtd_otp_range_is_locked(struct spi_nor *nor, loff_t ofs, + size_t len) +{ + const struct spi_nor_otp_ops *ops = nor->params->otp.ops; + unsigned int region; + int locked; + + /* + * If any of the affected OTP regions are locked the entire range is + * considered locked. + */ + for (region = spi_nor_otp_offset_to_region(nor, ofs); + region <= spi_nor_otp_offset_to_region(nor, ofs + len - 1); + region++) { + locked = ops->is_locked(nor, region); + /* take the branch it is locked or in case of an error */ + if (locked) + return locked; + } + + return 0; +} + static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs, size_t total_len, size_t *retlen, const u8 *buf, bool is_write) @@ -264,14 +287,26 @@ static int spi_nor_mtd_otp_read_write(struct mtd_info *mtd, loff_t ofs, if (ofs < 0 || ofs >= spi_nor_otp_size(nor)) return 0; + /* don't access beyond the end */ + total_len = min_t(size_t, total_len, spi_nor_otp_size(nor) - ofs); + + if (!total_len) + return 0; + ret = spi_nor_lock_and_prep(nor); if (ret) return ret; - /* don't access beyond the end */ - total_len = min_t(size_t, total_len, spi_nor_otp_size(nor) - ofs); + if (is_write) { + ret = spi_nor_mtd_otp_range_is_locked(nor, ofs, total_len); + if (ret < 0) { + goto out; + } else if (ret) { + ret = -EROFS; + goto out; + } + } - *retlen = 0; while (total_len) { /* * The OTP regions are mapped into a contiguous area starting