From: Ira Weiny <ira.weiny@xxxxxxxxx> The CDAT data is protected by a checksum and should be the proper length. Introduce cxl_cdat_valid() to validate the data. While at it check and store the sequence number. Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> --- Changes from V8 Move code to cxl/core/pci.c Changes from V6 Change name to cxl_cdat_valid() as this validates all the CDAT data not just the header Add error and debug prints Changes from V5 New patch, split out Update cdat_hdr_valid() Remove revision and cs field parsing There is no point in these Add seq check and debug print. --- drivers/cxl/cdat.h | 2 ++ drivers/cxl/core/pci.c | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+) diff --git a/drivers/cxl/cdat.h b/drivers/cxl/cdat.h index c6a48ab326bf..39eb561081f2 100644 --- a/drivers/cxl/cdat.h +++ b/drivers/cxl/cdat.h @@ -91,10 +91,12 @@ * * @table: cache of CDAT table * @length: length of cached CDAT table + * @seq: Last read Sequence number of the CDAT table */ struct cxl_cdat { void *table; size_t length; + u32 seq; }; #endif /* !__CXL_CDAT_H__ */ diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c index 84dc82f7dff0..cb70287e2984 100644 --- a/drivers/cxl/core/pci.c +++ b/drivers/cxl/core/pci.c @@ -531,6 +531,40 @@ static int cxl_cdat_get_length(struct device *dev, return rc; } +static bool cxl_cdat_valid(struct device *dev, struct cxl_cdat *cdat) +{ + u32 *table = cdat->table; + u8 *data8 = cdat->table; + u32 length, seq; + u8 check; + int i; + + length = FIELD_GET(CDAT_HEADER_DW0_LENGTH, table[0]); + if ((length < CDAT_HEADER_LENGTH_BYTES) || (length > cdat->length)) { + dev_err(dev, "CDAT Invalid length %u (%zu-%zu)\n", length, + CDAT_HEADER_LENGTH_BYTES, cdat->length); + return false; + } + + for (check = 0, i = 0; i < length; i++) + check += data8[i]; + + dev_dbg(dev, "CDAT length %u CS %u\n", length, check); + if (check != 0) { + dev_err(dev, "CDAT Invalid checksum %u\n", check); + return false; + } + + seq = FIELD_GET(CDAT_HEADER_DW3_SEQUENCE, table[3]); + /* Store the sequence for now. */ + if (cdat->seq != seq) { + dev_info(dev, "CDAT seq change %x -> %x\n", cdat->seq, seq); + cdat->seq = seq; + } + + return true; +} + static int cxl_cdat_read_table(struct device *dev, struct pci_doe_mb *cdat_mb, struct cxl_cdat *cdat) @@ -578,6 +612,8 @@ static int cxl_cdat_read_table(struct device *dev, } while (entry_handle != CXL_DOE_TABLE_ACCESS_LAST_ENTRY); + if (!rc && !cxl_cdat_valid(dev, cdat)) + return -EIO; return rc; } -- 2.35.1