If the length in the CDAT header is larger than the concatenation of the
header and all table entries, then the CDAT exposed to user space
contains trailing null bytes.
Not every consumer may be able to handle that. Per Postel's robustness
principle, "be liberal in what you accept" and silently reduce the
cached length to avoid exposing those null bytes.
Fixes: c97006046c79 ("cxl/port: Read CDAT table")
Tested-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v6.0+
---
Changes v2 -> v3:
* Newly added patch in v3
drivers/cxl/core/pci.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index a3fb6bd68d17..c37c41d7acb6 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -582,6 +582,9 @@ static int cxl_cdat_read_table(struct device *dev,
}
} while (entry_handle != CXL_DOE_TABLE_ACCESS_LAST_ENTRY);
+ /* Length in CDAT header may exceed concatenation of CDAT entries */
+ cdat->length -= length;
+
return 0;
}
--
2.39.1
