[PATCH v2] gatt-server: Fix integer overflow

By using size_t for realloc len and rejecting allocations exceeding
UINT16_MAX , to prevent truncation into the uint16_t field.
---
 src/shared/gatt-server.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/shared/gatt-server.c b/src/shared/gatt-server.c
index 709a8f94b..1ec826a69 100644
--- a/src/shared/gatt-server.c
+++ b/src/shared/gatt-server.c
@@ -1174,12 +1174,12 @@ static bool append_prep_data(struct prep_write_data *prep_data, uint16_t handle,
 					uint16_t length, uint8_t *value)
 {
 	uint8_t *val;
-	uint16_t len;
+	size_t len;

 	if (!length)
 		return true;

-	len = prep_data->length + length;
+	len = (size_t)prep_data->length + (size_t)length;

 	val = realloc(prep_data->value, len);
 	if (!val)
@@ -1188,7 +1188,10 @@ static bool append_prep_data(struct prep_write_data *prep_data, uint16_t handle,
 	memcpy(val + prep_data->length, value, length);

 	prep_data->value = val;
-	prep_data->length = len;
+
+	if (len > UINT16_MAX)
+		return false;
+	prep_data->length = (uint16_t)len;

 	return true;
 }
--
2.43.0

Handle the CheckPatch failure reported by BluezTestBot.