[U-Boot] [PATCH RESEND v6] usb: gadget: avoid variable name clipping in cb_getvar

[nicolas.le.bayon at st.com]

From: Nicolas Le Bayon <nlebayon at gmail.com>

Instead of using a fixed-size array to store variable name, preferring a
dynamic allocation treats correctly all variable name lengths.
Variable names are growing through releases and features. By this way, name
clipping is prevented.

Signed-off-by: Nicolas Le Bayon <nlebayon at gmail.com>
Reviewed-by: Marek Vasut <marex at denx.de>
Acked-by: Lukasz Majewski <lukma at denx.de>
---

Changes in v2:
 - instead of using a bigger fixed size, use malloc to fit with size needs
Changes in v3:
 - v2 was an error (intermediate version), so propose a complete one
Changes in v4:
 - be more explicit and detailed in label and description fields
 - remove intermediate variable only used one time
 - be more explicit in error message
 - fix indent issue
Changes in v5:
 - drop an unuseful error() call
Changes in v6:
 - add Marek review approval

 drivers/usb/gadget/f_fastboot.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/f_fastboot.c b/drivers/usb/gadget/f_fastboot.c
index 2160b1c..7cd6d24 100644
--- a/drivers/usb/gadget/f_fastboot.c
+++ b/drivers/usb/gadget/f_fastboot.c
@@ -432,9 +432,15 @@ static void cb_getvar(struct usb_ep *ep, struct usb_request *req)
 		else
 			strcpy(response, "FAILValue not set");
 	} else {
-		char envstr[32];
+		char *envstr;
 
-		snprintf(envstr, sizeof(envstr) - 1, "fastboot.%s", cmd);
+		envstr = malloc(strlen("fastboot.") + strlen(cmd) + 1);
+		if (!envstr) {
+			fastboot_tx_write_str("FAILmalloc error");
+			return;
+		}
+
+		sprintf(envstr, "fastboot.%s", cmd);
 		s = getenv(envstr);
 		if (s) {
 			strncat(response, s, chars_left);
@@ -442,6 +448,8 @@ static void cb_getvar(struct usb_ep *ep, struct usb_request *req)
 			printf("WARNING: unknown variable: %s\n", cmd);
 			strcpy(response, "FAILVariable not implemented");
 		}
+
+		free(envstr);
 	}
 	fastboot_tx_write_str(response);
 }
-- 
1.9.1