From: Lukas Wunner <lukas@wunner.de>
Date: Sat, 11 Mar 2023 14:40:02 +0000 (+0100)
Subject: cxl/pci: Handle truncated CDAT header
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=34bafc747c54fb58c1908ec3116fa6137393e596;p=linux.git

cxl/pci: Handle truncated CDAT header

cxl_cdat_get_length() only checks whether the DOE response size is
sufficient for the Table Access response header (1 dword), but not the
succeeding CDAT header (1 dword length plus other fields).

It thus returns whatever uninitialized memory happens to be on the stack
if a truncated DOE response with only 1 dword was received.  Fix it.

Fixes: c97006046c79 ("cxl/port: Read CDAT table")
Reported-by: Ming Li <ming4.li@intel.com>
Tested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Ming Li <ming4.li@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: stable@vger.kernel.org # v6.0+
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: https://lore.kernel.org/r/000e69cd163461c8b1bc2cf4155b6e25402c29c7.1678543498.git.lukas@wunner.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---

diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index 49a99a84b6aa6..87da8c935185a 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -510,7 +510,7 @@ static int cxl_cdat_get_length(struct device *dev,
 		return rc;
 	}
 	wait_for_completion(&t.c);
-	if (t.task.rv < sizeof(__le32))
+	if (t.task.rv < 2 * sizeof(__le32))
 		return -EIO;
 
 	*length = le32_to_cpu(t.response_pl[1]);