[PATCH] telemetry: avoid truncation of strlcpy return before check

[Tyler Retzlaff]

strlcpy returns type size_t when directly assigning to
struct rte_tel_data data_len field it may be truncated leading to
compromised length check that follows

Since the limit in the check is < UINT_MAX the value returned is
safe to be cast to unsigned int (which may be narrower than size_t)
but only after being checked against RTE_TEL_MAX_SINGLE_STRING_LEN

Signed-off-by: Tyler Retzlaff <roretzla at linux.microsoft.com>
---
 lib/telemetry/telemetry_data.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/telemetry/telemetry_data.c b/lib/telemetry/telemetry_data.c
index 3b1a240..52307cb 100644
--- a/lib/telemetry/telemetry_data.c
+++ b/lib/telemetry/telemetry_data.c
@@ -41,12 +41,13 @@
 int
 rte_tel_data_string(struct rte_tel_data *d, const char *str)
 {
+	const size_t len = strlcpy(d->data.str, str, sizeof(d->data.str));
 	d->type = TEL_STRING;
-	d->data_len = strlcpy(d->data.str, str, sizeof(d->data.str));
-	if (d->data_len >= RTE_TEL_MAX_SINGLE_STRING_LEN) {
+	if (len >= RTE_TEL_MAX_SINGLE_STRING_LEN) {
 		d->data_len = RTE_TEL_MAX_SINGLE_STRING_LEN - 1;
 		return E2BIG; /* not necessarily and error, just truncation */
 	}
+	d->data_len = (unsigned int)len;
 	return 0;
 }
 
-- 
1.8.3.1