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USB: usbip: fix null-ptr-deref in status_show_vhci()

PATCH Superseded Qasim Ijaz 2 participants 2 messages Jan 21, 2025 – Jan 22, 2025

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Qasim Ijaz

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#0 lore raw

PATCH 1/1 USB: usbip: fix null-ptr-deref in status_show_vhci()

If usb_add_hcd() fails in vhci_hcd_probe() (i.e., a probe failure), the error path calls usb_remove_hcd() and also sets pdev->dev.driver_data to NULL.

Consequently, any subsequent call to platform_get_drvdata(pdev) (which returns pdev->dev.driver_data) may yield NULL, causing a crash if that pointer is dereferenced.

Fix this by adding a sanity check to ensure "hcd" is non-NULL before proceeding with further operations.

Fixes 03cd00d538a6 ("usbip: vhci-hcd: Set the vhci structure up to work")
---
 drivers/usb/usbip/vhci_sysfs.c | 4 ++++
 1 file changed, 4 insertions(+)
drivers/usb/usbip/vhci_sysfs.c +4 -0
index d5865460e82d..a5e6c3c4af06 100644
@@ -76,6 +76,10 @@ static ssize_t status_show_vhci(int pdev_nr, char *out)
 	}
 
 	hcd = platform_get_drvdata(pdev);
+
+	if (!hcd)
+		return 0;
+
 	vhci_hcd = hcd_to_vhci_hcd(hcd);
 	vhci = vhci_hcd->vhci;
 
Signature · 1 line
2.39.5
#1 lore raw
Quoted 25 lines · Qasim Ijaz

If usb_add_hcd() fails in vhci_hcd_probe() (i.e., a probe failure), the error path calls usb_remove_hcd() and also sets pdev->dev.driver_data to NULL.

Consequently, any subsequent call to platform_get_drvdata(pdev) (which returns pdev->dev.driver_data) may yield NULL, causing a crash if that pointer is dereferenced.

Fix this by adding a sanity check to ensure "hcd" is non-NULL before proceeding with further operations.

Fixes 03cd00d538a6 ("usbip: vhci-hcd: Set the vhci structure up to work")
---
 drivers/usb/usbip/vhci_sysfs.c | 4 ++++
 1 file changed, 4 insertions(+)
drivers/usb/usbip/vhci_sysfs.c +0 -0
index d5865460e82d..a5e6c3c4af06 100644

drivers/usb/usbip/vhci_sysfs.c static ssize_t status_show_vhci(int pdev_nr, char *out) · line 79

Quoted 4 lines
drivers/usb/usbip/vhci_sysfs.c +1 -0
@@ -76,6 +76,10 @@ static ssize_t status_show_vhci(int pdev_nr, char *out)
 	}
 
 	hcd = platform_get_drvdata(pdev);
+

Empty line net really needed here...

drivers/usb/usbip/vhci_sysfs.c static ssize_t status_show_vhci(int pdev_nr, char *out) · line 85

Quoted 6 lines
drivers/usb/usbip/vhci_sysfs.c +3 -0
+	if (!hcd)
+		return 0;
+
 	vhci_hcd = hcd_to_vhci_hcd(hcd);
 	vhci = vhci_hcd->vhci;
 

MBR, Sergey