[PATCH v2 1/3] ethdev: remove use of strncpy

The use of strncpy is not generally recommended, so replace it in code
tokenizing the representor list. Since its use in the function is not
involving null-terminated strings (we know that copied block will
not involve a null value in it), we can replace strncpy with memcpy
rather than a string function. This keeps the original intent of the
code.

For extra safety, also add in an explicit bounds check on the length
value before doing the memcpy.

Fixes: 9a9eb104edf6 ("ethdev: parse multiple representor devargs")
Cc: [email protected]

Signed-off-by: Bruce Richardson <[email protected]>
Reviewed-by: Andrew Rybchenko <[email protected]>
Reviewed-by: Chengwen Feng <[email protected]>
---
 lib/ethdev/ethdev_driver.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/ethdev/ethdev_driver.c b/lib/ethdev/ethdev_driver.c
index eab5c15d12..e6f8d6fe85 100644
--- a/lib/ethdev/ethdev_driver.c
+++ b/lib/ethdev/ethdev_driver.c
@@ -583,10 +583,15 @@ eth_dev_tokenise_representor_list(char *p_val, struct rte_eth_devargs *eth_devar
 		return devargs;
 	}
 
+	/* len - 2 strips the outer '[' and ']'; guard against underflow and overflow */
+	if (len < 2 || (len - 2) >= BUFSIZ) {
+		RTE_ETHDEV_LOG_LINE(ERR, "Representor list too long or malformed: %s", p_val);
+		return -EINVAL;
+	}
 	memset(str, 0, BUFSIZ);
 	memset(da_val, 0, BUFSIZ);
 	/* Remove the exterior [] of the consolidated list */
-	strncpy(str, &p_val[1], len - 2);
+	memcpy(str, &p_val[1], len - 2);
 	while (1) {
 		if (str[i] == '\0') {
 			if (da_val[0] != '\0') {
-- 
2.53.0