PCI: Fix reset_method_store() memory leak

[ Upstream commit 2985b1844f3f3447f2d938eff1ef6762592065a5 ]

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.

Link: https://lore.kernel.org/r/20241001231147.3583649-1-tkjos@google.com
Fixes: d88f521da3ef ("PCI: Allow userspace to query and set device reset mechanism")
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 51407c376a22270c1b615e0ed3ec88a3ce80dc21..1a720cae37a1ecdffb1671c1a4692240714fecfd 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5233,7 +5233,7 @@ 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 };
 
@@ -5253,7 +5253,8 @@ 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;