[PATCH v2] staging: rts5208: add check on NULL before dereference

Anton Vasilyev
2018-06-13T16:55:28Z

If rtsx_probe() fails to allocate dev->chip, then NULL pointer
dereference occurs at release_everything()->rtsx_release_resources().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
---
v2: Add error handling into rtsx_probe based on Dan Carpenter's comment.
I do not have corresponding hardware, so patch was tested by compilation only.

I faced with inaccuracy at rtsx_remove() and original rtsx_probe():
there is quiesce_and_remove_host() call with scsi_remove_host() inside,
whereas release_everything() calls scsi_host_put() after this
scsi_remove_host() call. This is strange for me.

Also I do not know is it require to check result value of
rtsx_init_chip() call on rtsx_probe().
---
drivers/staging/rts5208/rtsx.c | 38 +++++++++++++++++++++++-----------
1 file changed, 26 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/rts5208/rtsx.c b/drivers/staging/rts5208/rtsx.c
index 70e0b8623110..69e6abe14abf 100644
--- a/drivers/staging/rts5208/rtsx.c
+++ b/drivers/staging/rts5208/rtsx.c
@@ -857,7 +857,7 @@ static int rtsx_probe(struct pci_dev *pci,
dev->chip = kzalloc(sizeof(*dev->chip), GFP_KERNEL);
if (!dev->chip) {
err = -ENOMEM;
- goto errout;
+ goto chip_alloc_fail;
}

spin_lock_init(&dev->reg_lock);
@@ -879,7 +879,7 @@ static int rtsx_probe(struct pci_dev *pci,
if (!dev->remap_addr) {
dev_err(&pci->dev, "ioremap error\n");
err = -ENXIO;
- goto errout;
+ goto ioremap_fail;
}

/*
@@ -894,7 +894,7 @@ static int rtsx_probe(struct pci_dev *pci,
if (!dev->rtsx_resv_buf) {
dev_err(&pci->dev, "alloc dma buffer fail\n");
err = -ENXIO;
- goto errout;
+ goto dma_alloc_fail;
}
dev->chip->host_cmds_ptr = dev->rtsx_resv_buf;
dev->chip->host_cmds_addr = dev->rtsx_resv_buf_addr;
@@ -915,7 +915,7 @@ static int rtsx_probe(struct pci_dev *pci,

if (rtsx_acquire_irq(dev) < 0) {
err = -EBUSY;
- goto errout;
+ goto irq_acquire_fail;
}

pci_set_master(pci);
@@ -935,14 +935,14 @@ static int rtsx_probe(struct pci_dev *pci,
if (IS_ERR(th)) {
dev_err(&pci->dev, "Unable to start control thread\n");
err = PTR_ERR(th);
- goto errout;
+ goto control_thread_fail;
}
dev->ctl_thread = th;

err = scsi_add_host(host, &pci->dev);
if (err) {
dev_err(&pci->dev, "Unable to add the scsi host\n");
- goto errout;
+ goto scsi_add_host_fail;
}

/* Start up the thread for delayed SCSI-device scanning */
@@ -950,18 +950,16 @@ static int rtsx_probe(struct pci_dev *pci,
if (IS_ERR(th)) {
dev_err(&pci->dev, "Unable to start the device-scanning thread\n");
complete(&dev->scanning_done);
- quiesce_and_remove_host(dev);
err = PTR_ERR(th);
- goto errout;
+ goto scan_thread_fail;
}

/* Start up the thread for polling thread */
th = kthread_run(rtsx_polling_thread, dev, "rtsx-polling");
if (IS_ERR(th)) {
dev_err(&pci->dev, "Unable to start the device-polling thread\n");
- quiesce_and_remove_host(dev);
err = PTR_ERR(th);
- goto errout;
+ goto scan_thread_fail;
}
dev->polling_thread = th;

@@ -970,9 +968,25 @@ static int rtsx_probe(struct pci_dev *pci,
return 0;

/* We come here if there are any problems */
-errout:
+scan_thread_fail:
+ quiesce_and_remove_host(dev);
+scsi_add_host_fail:
+ complete(&dev->cmnd_ready);
+ wait_for_completion(&dev->control_exit);
+control_thread_fail:
+ free_irq(dev->irq, (void *)dev);
+ rtsx_release_chip(dev->chip);
+irq_acquire_fail:
+ dev->chip->host_cmds_ptr = NULL;
+ dev->chip->host_sg_tbl_ptr = NULL;
+ if (dev->chip->msi_en)
+ pci_disable_msi(dev->pci);
+dma_alloc_fail:
+ iounmap(dev->remap_addr);
+ioremap_fail:
+ kfree(dev->chip);
+chip_alloc_fail:
dev_err(&pci->dev, "%s failed\n", __func__);
- release_everything(dev);

return err;
}
--
2.17.1