Re: [PATCH] PCI: fix memory leak in reset_method_store()

From: Bjorn Helgaas
Date: Wed Oct 02 2024 - 17:37:51 EST


On Tue, Oct 01, 2024 at 11:11:47PM +0000, Todd Kjos wrote:
> In reset_method_store(), a string is allocated via kstrndup()
> and assigned to the local "options". options is then used
> in with strsep() to find spaces:
>
> while ((name = strsep(&options, " ")) != NULL) {
>
> If there are no remaining spaces, then options is set to NULL
> by strsep(), so the subsequent kfree(options) doesn't free the
> memory allocated via kstrndup().
>
> Fix by using a separate tmp_options to iterate with
> strsep() so options is preserved.
>
> Fixes: d88f521da3ef ("PCI: Allow userspace to query and set device reset mechanism")
> Signed-off-by: Todd Kjos <tkjos@xxxxxxxxxx>

Applied to pci/misc for v6.13, thank you!

> ---
> drivers/pci/pci.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 7d85c04fbba2..0e6562ff3dcf 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -5244,7 +5244,7 @@ static ssize_t reset_method_store(struct device *dev,
> const char *buf, size_t count)
> {
> struct pci_dev *pdev = to_pci_dev(dev);
> - char *options, *name;
> + char *options, *tmp_options, *name;
> int m, n;
> u8 reset_methods[PCI_NUM_RESET_METHODS] = { 0 };
>
> @@ -5264,7 +5264,8 @@ static ssize_t reset_method_store(struct device *dev,
> return -ENOMEM;
>
> n = 0;
> - while ((name = strsep(&options, " ")) != NULL) {
> + tmp_options = options;
> + while ((name = strsep(&tmp_options, " ")) != NULL) {
> if (sysfs_streq(name, ""))
> continue;
>
> --
> 2.46.1.824.gd892dcdcdd-goog
>