Subject: [PATCH v2 net] net: iosm: Prevent underflow in ipc_chnl_cfg_get()

From: Dan Carpenter <[email-masked]>
Date: Mon, 16 Aug 2021 14:13:33 +0300

The bounds check on "index" doesn't catch negative values.  Using
ARRAY_SIZE() directly is more readable and more robust because it prevents
negative values for "index".  Fortunately we only pass valid values to
ipc_chnl_cfg_get() so this patch does not affect runtime.

Reported-by: Solomon Ucko <[email-masked]>
Signed-off-by: Dan Carpenter <[email-masked]>
---
v2: Remove underscore between "array" and "size".
    Use %zu print format specifier to fix a compile warning on 32 bit.

 drivers/net/wwan/iosm/iosm_ipc_chnl_cfg.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wwan/iosm/iosm_ipc_chnl_cfg.c b/drivers/net/wwan/iosm/iosm_ipc_chnl_cfg.c
index 804e6c4f2c78..016c9c3aea8e 100644
--- a/drivers/net/wwan/iosm/iosm_ipc_chnl_cfg.c
+++ b/drivers/net/wwan/iosm/iosm_ipc_chnl_cfg.c
@@ -64,10 +64,9 @@ static struct ipc_chnl_cfg modem_cfg[] = {
 
 int ipc_chnl_cfg_get(struct ipc_chnl_cfg *chnl_cfg, int index)
 {
-	int array_size = ARRAY_SIZE(modem_cfg);
-
-	if (index >= array_size) {
-		pr_err("index: %d and array_size %d", index, array_size);
+	if (index >= ARRAY_SIZE(modem_cfg)) {
+		pr_err("index: %d and array size %zu", index,
+		       ARRAY_SIZE(modem_cfg));
 		return -ECHRNG;
 	}
 
-- 
2.20.1