Re: [PATCH v2] ALSA: hda: handle UAF at probe error

[Lucas De Marchi <lucas.demarchi@intel.com>]

On Thu, Apr 14, 2022 at 08:24:37PM +0200, Nirmoy Das wrote:
>Call snd_card_free_on_error() on probe error instead of
>calling snd_card_free() which should handle devres call orders.
>
>Issues: https://gitlab.freedesktop.org/drm/intel/-/issues/5701
>Fixes: e8ad415b7a55 ("ALSA: core: Add managed card creation")
>Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>

This failure in i915 CI seems suspicious since is around module removal.
https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_102714v1/fi-tgl-1115g4/igt@i915_suspend@system-suspend-without-i915.html

And it seems it didn't fix the issue in dg2:

https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_102714v1/bat-dg2-8/igt@gem_lmem_swapping@random-engines.html

Lucas De Marchi

>---
> sound/pci/hda/hda_intel.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
>diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
>index 82a45f2b31c4..eb4228c9e37f 100644
>--- a/sound/pci/hda/hda_intel.c
>+++ b/sound/pci/hda/hda_intel.c
>@@ -1730,7 +1730,9 @@ static void azx_check_snoop_available(struct azx *chip)
> static void azx_probe_work(struct work_struct *work)
> {
> 	struct hda_intel *hda = container_of(work, struct hda_intel, probe_work.work);
>-	azx_probe_continue(&hda->chip);
>+	struct azx *chip = &hda->chip;
>+
>+	snd_card_free_on_error(&chip->pci->dev, azx_probe_continue(chip));
> }
>
> static int default_bdl_pos_adj(struct azx *chip)
>@@ -2028,7 +2030,7 @@ static void azx_firmware_cb(const struct firmware *fw, void *context)
> 		dev_err(card->dev, "Cannot load firmware, continue without patching\n");
> 	if (!chip->disabled) {
> 		/* continue probing */
>-		azx_probe_continue(chip);
>+		snd_card_free_on_error(&chip->pci->dev, azx_probe_continue(chip));
> 	}
> }
> #endif
>@@ -2338,7 +2340,6 @@ static int azx_probe_continue(struct azx *chip)
> out_free:
> 	if (err < 0) {
> 		pci_set_drvdata(pci, NULL);
>-		snd_card_free(chip->card);
> 		return err;
> 	}
>
>-- 
>2.35.1
>