Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
usb: cdns3: gadget: fix state inconsistency on gadget init failure
When cdns3_gadget_start() fails, the DRD hardware is left in gadget mode while software state remains INACTIVE, creating hardware/software state inconsistency.
When switching to host mode via sysfs: echo host > /sys/class/usb_role/13180000.usb-role-switch/role
The role state is not set to CDNS_ROLE_STATE_ACTIVE due to the error, so cdns_role_stop() skips cleanup because state is still INACTIVE. This violates the DRD controller design specification (Figure22), which requires returning to idle state before switching roles.
This leads to a synchronous external abort in xhci_gen_setup() when setting up the host controller:
[ 516.440698] configfs-gadget 13180000.usb: failed to start g1: -19 [ 516.442035] cdns-usb3 13180000.usb: Failed to add gadget [ 516.443278] cdns-usb3 13180000.usb: set role 2 has failed … [ 1301.375722] xhci-hcd xhci-hcd.1.auto: xHCI Host Controller [ 1301.377716] Internal error: synchronous external abort: 96000010 [#1] PREEMPT SMP [ 1301.382485] pc : xhci_gen_setup+0xa4/0x408 [ 1301.393391] backtrace: … xhci_gen_setup+0xa4/0x408 <– CRASH xhci_plat_setup+0x44/0x58 usb_add_hcd+0x284/0x678 … cdns_role_set+0x9c/0xbc <– Role switch
Fix by calling cdns_drd_gadget_off() in the error path to properly clean up the DRD gadget state.
Details
- Affected product:
- AlmaLinux 9.2 ESU , Oracle Linux 7 ELS , TuxCare 9.6 ESU , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 5.4.0 (+3 more)
In the Linux kernel, the following vulnerability has been resolved:
usb: cdns3: gadget: fix state inconsistency on gadget init failure
When cdns3_gadget_start() fails, the DRD hardware is left in gadget mode while software state remains INACTIVE, creating hardware/software state inconsistency.
When switching to host mode via sysfs: echo host > /sys/class/usb_role/13180000.usb-role-switch/role
The role state is not set to CDNS_ROLE_STATE_ACTIVE due to the error, so cdns_role_stop() skips cleanup because state is still INACTIVE. This violates the DRD controller design specification (Figure22), which requires returning to idle state before switching roles.
This leads to a synchronous external abort in xhci_gen_setup() when setting up the host controller:
[ 516.440698] configfs-gadget 13180000.usb: failed to start g1: -19 [ 516.442035] cdns-usb3 13180000.usb: Failed to add gadget [ 516.443278] cdns-usb3 13180000.usb: set role 2 has failed … [ 1301.375722] xhci-hcd xhci-hcd.1.auto: xHCI Host Controller [ 1301.377716] Internal error: synchronous external abort: 96000010 [#1] PREEMPT SMP [ 1301.382485] pc : xhci_gen_setup+0xa4/0x408 [ 1301.393391] backtrace: … xhci_gen_setup+0xa4/0x408 <– CRASH xhci_plat_setup+0x44/0x58 usb_add_hcd+0x284/0x678 … cdns_role_set+0x9c/0xbc <– Role switch
Fix by calling cdns_drd_gadget_off() in the error path to properly clean up the DRD gadget state.