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

[Bruce Richardson <bruce.richardson@intel.com>]

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: stable@dpdk.org

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
---
 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 70ddce5bfc..4043ce898f 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