From 6303049d16f0e69d0449c3c80d0e3695d4f02f94 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Thu, 15 Jul 2021 16:59:57 -0500 Subject: [PATCH] PCI/VPD: Reject resource tags with invalid size VPD is limited in size by the 15-bit VPD Address field in the VPD Capability. Each resource tag includes a length that determines the overall size of the resource. Reject any resources that would extend past the maximum VPD size. Signed-off-by: Bjorn Helgaas Reviewed-by: Hannes Reinecke --- drivers/pci/vpd.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c index 05e4df0a84d3..850deff0dd43 100644 --- a/drivers/pci/vpd.c +++ b/drivers/pci/vpd.c @@ -72,11 +72,11 @@ EXPORT_SYMBOL(pci_write_vpd); */ static size_t pci_vpd_size(struct pci_dev *dev, size_t old_size) { - size_t off = 0; - unsigned char header[1+2]; /* 1 byte tag, 2 bytes length */ + size_t off = 0, size; + unsigned char tag, header[1+2]; /* 1 byte tag, 2 bytes length */ while (off < old_size && pci_read_vpd(dev, off, 1, header) == 1) { - unsigned char tag; + size = 0; if (off == 0 && (header[0] == 0x00 || header[0] == 0xff)) goto error; @@ -94,8 +94,11 @@ static size_t pci_vpd_size(struct pci_dev *dev, size_t old_size) off + 1); return 0; } - off += PCI_VPD_LRDT_TAG_SIZE + - pci_vpd_lrdt_size(header); + size = pci_vpd_lrdt_size(header); + if (off + size > PCI_VPD_MAX_SIZE) + goto error; + + off += PCI_VPD_LRDT_TAG_SIZE + size; } else { pci_warn(dev, "invalid large VPD tag %02x at offset %zu\n", tag, off); @@ -103,9 +106,12 @@ static size_t pci_vpd_size(struct pci_dev *dev, size_t old_size) } } else { /* Short Resource Data Type Tag */ - off += PCI_VPD_SRDT_TAG_SIZE + - pci_vpd_srdt_size(header); tag = pci_vpd_srdt_tag(header); + size = pci_vpd_srdt_size(header); + if (off + size > PCI_VPD_MAX_SIZE) + goto error; + + off += PCI_VPD_SRDT_TAG_SIZE + size; if (tag == PCI_VPD_STIN_END) /* End tag descriptor */ return off; } @@ -113,8 +119,8 @@ static size_t pci_vpd_size(struct pci_dev *dev, size_t old_size) return 0; error: - pci_info(dev, "invalid VPD tag %#04x at offset %zu%s\n", - header[0], off, off == 0 ? + pci_info(dev, "invalid VPD tag %#04x (size %zu) at offset %zu%s\n", + header[0], size, off, off == 0 ? "; assume missing optional EEPROM" : ""); return 0; }