gpib: Fix memory leak in ni_usb_init()

In ni_usb_init(), if ni_usb_setup_init() fails, the function returns
-EFAULT without freeing the allocated writes buffer, leading to a
memory leak.

Additionally, ni_usb_setup_init() returns 0 on failure, which causes
ni_usb_init() to return -EFAULT, an inappropriate error code for this
situation.

Fix the leak by freeing writes in the error path. Modify
ni_usb_setup_init() to return -EINVAL on failure and propagate this
error code in ni_usb_init().

Fixes: 4e127de14fa7 ("staging: gpib: Add National Instruments USB GPIB driver")
Suggested-by: Greg KH <gregkh@linuxfoundation.org>
Suggested-by: Dave Penkler <dpenkler@gmail.com>
Co-developed-by: Jianhao Xu <jianhao.xu@seu.edu.cn>
Signed-off-by: Jianhao Xu <jianhao.xu@seu.edu.cn>
Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
Link: https://patch.msgid.link/20251230034546.929452-1-zilin@seu.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpib/ni_usb/ni_usb_gpib.c b/drivers/gpib/ni_usb/ni_usb_gpib.c
index fdcaa6c00bfeac4547bfce41300e974ae728ce16..b6fddb437f5524ecc5aba35cc55acddcab69e50b 100644 (file)
--- a/drivers/gpib/ni_usb/ni_usb_gpib.c
+++ b/drivers/gpib/ni_usb/ni_usb_gpib.c
@@ -1780,7 +1780,7 @@ static int ni_usb_setup_init(struct gpib_board *board, struct ni_usb_register *w
        i++;
        if (i > NUM_INIT_WRITES) {
                dev_err(&usb_dev->dev, "bug!, buffer overrun, i=%i\n", i);
-               return 0;
+               return -EINVAL;
        }
        return i;
 }
@@ -1799,10 +1799,12 @@ static int ni_usb_init(struct gpib_board *board)
                return -ENOMEM;
 
        writes_len = ni_usb_setup_init(board, writes);
-       if (writes_len)
-               retval = ni_usb_write_registers(ni_priv, writes, writes_len, &ibsta);
-       else
-               return -EFAULT;
+       if (writes_len < 0) {
+               kfree(writes);
+               return writes_len;
+       }
+
+       retval = ni_usb_write_registers(ni_priv, writes, writes_len, &ibsta);
        kfree(writes);
        if (retval) {
                dev_err(&usb_dev->dev, "register write failed, retval=%i\n", retval);