net: mana: fix use-after-free in add_adev() error path

If auxiliary_device_add() fails, add_adev() jumps to add_fail and calls
auxiliary_device_uninit(adev).

The auxiliary device has its release callback set to adev_release(),
which frees the containing struct mana_adev. Since adev is embedded in
struct mana_adev, the subsequent fall-through to init_fail and access
to adev->id may result in a use-after-free.

Fix this by saving the allocated auxiliary device id in a local
variable before calling auxiliary_device_add(), and use that saved id
in the cleanup path after auxiliary_device_uninit().

Fixes: a69839d4327d ("net: mana: Add support for auxiliary device")
Cc: stable@vger.kernel.org
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Link: https://patch.msgid.link/20260323165730.945365-1-lgs201920130244@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index 9017e806ecdaa94f70dd81d5612c4134bc1be361..dca62fb9a3a9ef42500b40463647ca346b426601 100644 (file)
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -3425,6 +3425,7 @@ static int add_adev(struct gdma_dev *gd, const char *name)
        struct auxiliary_device *adev;
        struct mana_adev *madev;
        int ret;
+       int id;
 
        madev = kzalloc_obj(*madev);
        if (!madev)
@@ -3434,7 +3435,8 @@ static int add_adev(struct gdma_dev *gd, const char *name)
        ret = mana_adev_idx_alloc();
        if (ret < 0)
                goto idx_fail;
-       adev->id = ret;
+       id = ret;
+       adev->id = id;
 
        adev->name = name;
        adev->dev.parent = gd->gdma_context->dev;
@@ -3460,7 +3462,7 @@ add_fail:
        auxiliary_device_uninit(adev);
 
 init_fail:
-       mana_adev_idx_free(adev->id);
+       mana_adev_idx_free(id);
 
 idx_fail:
        kfree(madev);