From patchwork Tue Feb 23 00:46:52 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bjorn Helgaas X-Patchwork-Id: 586612 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 9316A140B99 for ; Tue, 23 Feb 2016 11:46:57 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756379AbcBWAq4 (ORCPT ); Mon, 22 Feb 2016 19:46:56 -0500 Received: from mail.kernel.org ([198.145.29.136]:47940 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756509AbcBWAq4 (ORCPT ); Mon, 22 Feb 2016 19:46:56 -0500 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 4CFEB20270; Tue, 23 Feb 2016 00:46:55 +0000 (UTC) Received: from localhost (unknown [69.71.1.1]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 467812011D; Tue, 23 Feb 2016 00:46:54 +0000 (UTC) Subject: [PATCH v4 04/11] PCI: Determine actual VPD size on first access To: Hannes Reinecke From: Bjorn Helgaas Cc: linux-pci@vger.kernel.org, Jordan Hargrave , Babu Moger , Alexander Duyck Date: Mon, 22 Feb 2016 18:46:52 -0600 Message-ID: <20160223004652.10635.13976.stgit@bhelgaas-glaptop2.roam.corp.google.com> In-Reply-To: <20160223003444.10635.20204.stgit@bhelgaas-glaptop2.roam.corp.google.com> References: <20160223003444.10635.20204.stgit@bhelgaas-glaptop2.roam.corp.google.com> User-Agent: StGit/0.16 MIME-Version: 1.0 X-Spam-Status: No, score=0.6 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, NML_ADSP_CUSTOM_MED, UNPARSEABLE_RELAY, URIBL_SBL autolearn=no version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Hannes Reinecke PCI-2.2 VPD entries have a maximum size of 32k, but might actually be smaller than that. To figure out the actual size one has to read the VPD area until the 'end marker' is reached. Per spec, reading outside of the VPD space is "not allowed." In practice, it may cause simple read errors or even crash the card. To make matters worse not every PCI card implements this properly, leaving us with no 'end' marker or even completely invalid data. Try to determine the size of the VPD data when it's first accessed. If no valid data can be read an I/O error will be returned when reading or writing the sysfs attribute. As the amount of VPD data is unknown initially the size of the sysfs attribute will always be set to '0'. [bhelgaas: changelog, use 0/1 (not false/true) for bitfield, tweak pci_vpd_pci22_read() error checking] Signed-off-by: Hannes Reinecke Signed-off-by: Bjorn Helgaas Cc: Alexander Duyck --- drivers/pci/access.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++- drivers/pci/pci-sysfs.c | 2 + 2 files changed, 86 insertions(+), 3 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/pci/access.c b/drivers/pci/access.c index a7f0069..4850f06 100644 --- a/drivers/pci/access.c +++ b/drivers/pci/access.c @@ -285,8 +285,63 @@ struct pci_vpd_pci22 { u16 flag; u8 cap; u8 busy:1; + u8 valid:1; }; +/** + * pci_vpd_size - determine actual size of Vital Product Data + * @dev: pci device struct + * @old_size: current assumed size, also maximum allowed size + */ +static size_t pci_vpd_pci22_size(struct pci_dev *dev, size_t old_size) +{ + size_t off = 0; + unsigned char header[1+2]; /* 1 byte tag, 2 bytes length */ + + while (off < old_size && + pci_read_vpd(dev, off, 1, header) == 1) { + unsigned char tag; + + if (header[0] & PCI_VPD_LRDT) { + /* Large Resource Data Type Tag */ + tag = pci_vpd_lrdt_tag(header); + /* Only read length from known tag items */ + if ((tag == PCI_VPD_LTIN_ID_STRING) || + (tag == PCI_VPD_LTIN_RO_DATA) || + (tag == PCI_VPD_LTIN_RW_DATA)) { + if (pci_read_vpd(dev, off+1, 2, + &header[1]) != 2) { + dev_warn(&dev->dev, + "invalid large VPD tag %02x size at offset %zu", + tag, off + 1); + return 0; + } + off += PCI_VPD_LRDT_TAG_SIZE + + pci_vpd_lrdt_size(header); + } + } else { + /* Short Resource Data Type Tag */ + off += PCI_VPD_SRDT_TAG_SIZE + + pci_vpd_srdt_size(header); + tag = pci_vpd_srdt_tag(header); + } + + if (tag == PCI_VPD_STIN_END) /* End tag descriptor */ + return off; + + if ((tag != PCI_VPD_LTIN_ID_STRING) && + (tag != PCI_VPD_LTIN_RO_DATA) && + (tag != PCI_VPD_LTIN_RW_DATA)) { + dev_warn(&dev->dev, + "invalid %s VPD tag %02x at offset %zu", + (header[0] & PCI_VPD_LRDT) ? "large" : "short", + tag, off); + return 0; + } + } + return 0; +} + /* * Wait for last operation to complete. * This code has to spin since there is no other notification from the PCI @@ -337,9 +392,25 @@ static ssize_t pci_vpd_pci22_read(struct pci_dev *dev, loff_t pos, size_t count, loff_t end = pos + count; u8 *buf = arg; - if (pos < 0 || pos > vpd->base.len || end > vpd->base.len) + if (pos < 0) return -EINVAL; + if (!vpd->valid) { + vpd->valid = 1; + vpd->base.len = pci_vpd_pci22_size(dev, vpd->base.len); + } + + if (vpd->base.len == 0) + return -EIO; + + if (pos >= vpd->base.len) + return 0; + + if (end > vpd->base.len) { + end = vpd->base.len; + count = end - pos; + } + if (mutex_lock_killable(&vpd->lock)) return -EINTR; @@ -389,7 +460,18 @@ static ssize_t pci_vpd_pci22_write(struct pci_dev *dev, loff_t pos, size_t count loff_t end = pos + count; int ret = 0; - if (pos < 0 || (pos & 3) || (count & 3) || end > vpd->base.len) + if (pos < 0 || (pos & 3) || (count & 3)) + return -EINVAL; + + if (!vpd->valid) { + vpd->valid = 1; + vpd->base.len = pci_vpd_pci22_size(dev, vpd->base.len); + } + + if (vpd->base.len == 0) + return -EIO; + + if (end > vpd->base.len) return -EINVAL; if (mutex_lock_killable(&vpd->lock)) @@ -496,6 +578,7 @@ int pci_vpd_pci22_init(struct pci_dev *dev) mutex_init(&vpd->lock); vpd->cap = cap; vpd->busy = 0; + vpd->valid = 0; dev->vpd = &vpd->base; return 0; } diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index a730f54..ed39c09 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1323,7 +1323,7 @@ static int pci_create_capabilities_sysfs(struct pci_dev *dev) return -ENOMEM; sysfs_bin_attr_init(attr); - attr->size = dev->vpd->len; + attr->size = 0; attr->attr.name = "vpd"; attr->attr.mode = S_IRUSR | S_IWUSR; attr->read = read_vpd_attr;