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gpiolib: cdev: switch from kstrdup() to kstrndup() 

Use kstrndup() to copy line labels from the userspace provided char
array, rather than ensuring the char array contains a null terminator
and using kstrdup().

Note that the length provided to kstrndup() still assumes that the char
array does contain a null terminator, so the maximum string length is one
less than the array.  This is consistent with the previous behaviour.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20201005070246.20927-1-warthog618@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Kent Gibson 2020-10-05 15:02:46 +08:00 committed by Linus Walleij
parent 8c270fbceb
commit f188ac1251
1 changed files with 13 additions and 14 deletions
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23
drivers/gpio/gpiolib-cdev.c
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@ -307,10 +307,10 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
lh->gdev = gdev;
get_device(&gdev->dev);
/* Make sure this is terminated */
handlereq.consumer_label[sizeof(handlereq.consumer_label)-1] = '\0';
if (strlen(handlereq.consumer_label)) {
lh->label = kstrdup(handlereq.consumer_label,
if (handlereq.consumer_label[0] != '\0') {
/* label is only initialized if consumer_label is set */
lh->label = kstrndup(handlereq.consumer_label,
sizeof(handlereq.consumer_label) - 1,
GFP_KERNEL);
if (!lh->label) {
ret = -ENOMEM;
@ -1322,11 +1322,10 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
}
/* Make sure this is terminated */
ulr.consumer[sizeof(ulr.consumer)-1] = '\0';
if (strlen(ulr.consumer)) {
if (ulr.consumer[0] != '\0') {
/* label is only initialized if consumer is set */
lr->label = kstrdup(ulr.consumer, GFP_KERNEL);
lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
GFP_KERNEL);
if (!lr->label) {
ret = -ENOMEM;
goto out_free_linereq;
@ -1711,10 +1710,10 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
le->gdev = gdev;
get_device(&gdev->dev);
/* Make sure this is terminated */
eventreq.consumer_label[sizeof(eventreq.consumer_label)-1] = '\0';
if (strlen(eventreq.consumer_label)) {
le->label = kstrdup(eventreq.consumer_label,
if (eventreq.consumer_label[0] != '\0') {
/* label is only initialized if consumer_label is set */
le->label = kstrndup(eventreq.consumer_label,
sizeof(eventreq.consumer_label) - 1,
GFP_KERNEL);
if (!le->label) {
ret = -ENOMEM;