vdpa: solidrun: Fix UB bug with devres

In psnet_open_pf_bar() and snet_open_vf_bar() a string later passed to
pcim_iomap_regions() is placed on the stack. Neither
pcim_iomap_regions() nor the functions it calls copy that string.

Should the string later ever be used, this, consequently, causes
undefined behavior since the stack frame will by then have disappeared.

Fix the bug by allocating the strings on the heap through
devm_kasprintf().

Cc: stable@vger.kernel.org	# v6.3
Fixes: 51a8f9d7f587 ("virtio: vdpa: new SolidNET DPU driver.")
Reported-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Closes: https://lore.kernel.org/all/74e9109a-ac59-49e2-9b1d-d825c9c9f891@wanadoo.fr/
Suggested-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20241028074357.9104-3-pstanner@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vdpa/solidrun/snet_main.c b/drivers/vdpa/solidrun/snet_main.c
index 99428a04068d2d4f1c3507455a63dd522187b745..c8b74980dbd1725465e7d3b1567d63d03487cf72 100644 (file)
--- a/drivers/vdpa/solidrun/snet_main.c
+++ b/drivers/vdpa/solidrun/snet_main.c
@@ -555,7 +555,7 @@ static const struct vdpa_config_ops snet_config_ops = {
 
 static int psnet_open_pf_bar(struct pci_dev *pdev, struct psnet *psnet)
 {
-       char name[50];
+       char *name;
        int ret, i, mask = 0;
        /* We don't know which BAR will be used to communicate..
         * We will map every bar with len > 0.
@@ -573,7 +573,10 @@ static int psnet_open_pf_bar(struct pci_dev *pdev, struct psnet *psnet)
                return -ENODEV;
        }
 
-       snprintf(name, sizeof(name), "psnet[%s]-bars", pci_name(pdev));
+       name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "psnet[%s]-bars", pci_name(pdev));
+       if (!name)
+               return -ENOMEM;
+
        ret = pcim_iomap_regions(pdev, mask, name);
        if (ret) {
                SNET_ERR(pdev, "Failed to request and map PCI BARs\n");
@@ -590,10 +593,13 @@ static int psnet_open_pf_bar(struct pci_dev *pdev, struct psnet *psnet)
 
 static int snet_open_vf_bar(struct pci_dev *pdev, struct snet *snet)
 {
-       char name[50];
+       char *name;
        int ret;
 
-       snprintf(name, sizeof(name), "snet[%s]-bar", pci_name(pdev));
+       name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "snet[%s]-bars", pci_name(pdev));
+       if (!name)
+               return -ENOMEM;
+
        /* Request and map BAR */
        ret = pcim_iomap_regions(pdev, BIT(snet->psnet->cfg.vf_bar), name);
        if (ret) {