staging: media: ipu7: fix double-free and use-after-free in error paths

In both ipu7_isys_init() and ipu7_psys_init(), pdata is allocated and
then passed to ipu7_bus_initialize_device(), which stores it in
adev->pdata. The ipu7_bus_release() function frees adev->pdata when the
device's reference count drops to zero.

Two error paths incorrectly call kfree(pdata) after the device teardown
has already freed it:

1. When ipu7_mmu_init() fails: put_device() is called, which drops the
   reference count to zero and triggers ipu7_bus_release() ->
   kfree(pdata). The subsequent kfree(pdata) is a double-free.

2. When ipu7_bus_add_device() fails: it calls auxiliary_device_uninit()
   internally, which calls put_device() -> ipu7_bus_release() ->
   kfree(pdata). The subsequent kfree(pdata) is again a double-free.

Note that the kfree(pdata) when ipu7_bus_initialize_device() itself
fails is correct, because in that case auxiliary_device_init() failed
and the release function was never set up, so pdata must be freed
manually.

Additionally, the error code was not saved before calling put_device(),
causing ERR_CAST() to dereference the already-freed adev pointer when
constructing the return value. Fix this by saving the error from
dev_err_probe() before put_device() and returning ERR_PTR() instead.

Remove the redundant kfree(pdata) calls and fix the use-after-free in
the return values of the two affected error paths.

Fixes: b7fe4c0019b1 ("media: staging/ipu7: add Intel IPU7 PCI device driver")
Cc: stable@vger.kernel.org
Reviewed-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Alexandru Hossu <hossu.alexandru@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

diff --git a/drivers/staging/media/ipu7/ipu7.c b/drivers/staging/media/ipu7/ipu7.c
index c771e763f8c50aa8a7ef3b2d8e3ce45eadef26ec..310e3f24e571feaeea90666e22bd89efd8f92483 100644 (file)
--- a/drivers/staging/media/ipu7/ipu7.c
+++ b/drivers/staging/media/ipu7/ipu7.c
@@ -2169,21 +2169,18 @@ ipu7_isys_init(struct pci_dev *pdev, struct device *parent,
        isys_adev->mmu = ipu7_mmu_init(dev, base, ISYS_MMID,
                                       &ipdata->hw_variant);
        if (IS_ERR(isys_adev->mmu)) {
-               dev_err_probe(dev, PTR_ERR(isys_adev->mmu),
-                             "ipu7_mmu_init(isys_adev->mmu) failed\n");
+               ret = dev_err_probe(dev, PTR_ERR(isys_adev->mmu),
+                                   "ipu7_mmu_init(isys_adev->mmu) failed\n");
                put_device(&isys_adev->auxdev.dev);
-               kfree(pdata);
-               return ERR_CAST(isys_adev->mmu);
+               return ERR_PTR(ret);
        }
 
        isys_adev->mmu->dev = &isys_adev->auxdev.dev;
        isys_adev->subsys = IPU_IS;
 
        ret = ipu7_bus_add_device(isys_adev);
-       if (ret) {
-               kfree(pdata);
+       if (ret)
                return ERR_PTR(ret);
-       }
 
        return isys_adev;
 }
@@ -2216,21 +2213,18 @@ ipu7_psys_init(struct pci_dev *pdev, struct device *parent,
        psys_adev->mmu = ipu7_mmu_init(&pdev->dev, base, PSYS_MMID,
                                       &ipdata->hw_variant);
        if (IS_ERR(psys_adev->mmu)) {
-               dev_err_probe(&pdev->dev, PTR_ERR(psys_adev->mmu),
-                             "ipu7_mmu_init(psys_adev->mmu) failed\n");
+               ret = dev_err_probe(&pdev->dev, PTR_ERR(psys_adev->mmu),
+                                   "ipu7_mmu_init(psys_adev->mmu) failed\n");
                put_device(&psys_adev->auxdev.dev);
-               kfree(pdata);
-               return ERR_CAST(psys_adev->mmu);
+               return ERR_PTR(ret);
        }
 
        psys_adev->mmu->dev = &psys_adev->auxdev.dev;
        psys_adev->subsys = IPU_PS;
 
        ret = ipu7_bus_add_device(psys_adev);
-       if (ret) {
-               kfree(pdata);
+       if (ret)
                return ERR_PTR(ret);
-       }
 
        return psys_adev;
 }