[PATCH 6.1 595/609] ptp: ocp: Fix board ID over-read

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ahmad Byagowi <[email protected]>

commit 6b69f2ef10cdb018c0b127a7cab88e590bbddba4 upstream.

The EEPROM board ID is a fixed 13-byte field and is not guaranteed to
contain a NUL terminator. Passing it directly to
devlink_info_version_fixed_put() treats it as a C string and may read
beyond the field.

Format at most OCP_BOARD_ID_LEN bytes into the existing local buffer
before reporting the ID. Use a precision limit because the snprintf()
output size alone does not bound the source string scan.

Fixes: 0cfcdd1ebcfe ("ptp: ocp: add nvmem interface for accessing eeprom")
Cc: [email protected]
Signed-off-by: Ahmad Byagowi <[email protected]>
Reviewed-by: Vadim Fedorenko <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/ptp/ptp_ocp.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/ptp/ptp_ocp.c
+++ b/drivers/ptp/ptp_ocp.c
@@ -1483,9 +1483,11 @@ ptp_ocp_devlink_info_get(struct devlink
 	if (err)
 		return err;
 
+	snprintf(buf, sizeof(buf), "%.*s", OCP_BOARD_ID_LEN,
+		 (const char *)bp->board_id);
 	err = devlink_info_version_fixed_put(req,
 			DEVLINK_INFO_VERSION_GENERIC_BOARD_ID,
-			bp->board_id);
+			buf);
 	if (err)
 		return err;