ipmi: si: Fix NULL pointer dereference after failed registration

Summary

In the Linux kernel, the following vulnerability has been resolved: ipmi: si: Fix NULL pointer dereference after failed registration try_smi_init() allocates new_smi->si_sm and later calls ipmi_register_smi_mod(), which maps to ipmi_add_smi(). During ipmi_add_smi(), the upper IPMI message handler obtains the initial BMC device information through __bmc_get_device_id(). This can fail if the BMC does not return a successful response to the Get Device ID command. When the BMC returns a nonzero completion code, the device-id helper retries the command and eventually returns -EIO if the device ID still cannot be fetched. On this failure path, ipmi_add_smi() logs "Unable to get the device id" and goes to out_err_started, where it invokes the lower driver's shutdown callback. try_smi_init() then logs the returned registration failure: ipmi_si IPI0001:00: IPMI message handler: Unable to get the device id: -5 ipmi_si IPI0001:00: Unable to register device: error -5 For ipmi_si, the shutdown callback is shutdown_smi(), which cleans up the SI state machine data, frees smi_info->si_sm, and sets smi_info->si_sm and smi_info->intf to NULL. However, intf->in_shutdown is not set on this failed-registration rollback path. Therefore, the asynchronous redo_bmc_reg work item can still retry BMC device-id probing after the lower driver has already cleared its SI state machine data. In the observed case, that retry path reached start_next_msg(), which passed the NULL smi_info->si_sm pointer to the selected KCS state machine handler: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 Workqueue: events redo_bmc_reg [ipmi_msghandler] RIP: start_kcs_transaction+0x2c/0x190 [ipmi_si] Call Trace: start_next_msg+0x50/0x80 [ipmi_si] check_start_timer_thread.part.9+0x3b/0x50 [ipmi_si] sender+0x69/0x80 [ipmi_si] i_ipmi_request+0x2ac/0x9d0 [ipmi_msghandler] __get_device_id.isra.29+0xaa/0x180 [ipmi_msghandler] __bmc_get_device_id+0xef/0x950 [ipmi_msghandler] redo_bmc_reg+0x52/0x60 [ipmi_msghandler] process_one_work+0x1a7/0x360 Set intf->in_shutdown on the out_err_started path before invoking the lower driver's shutdown callback. This prevents later redo_bmc_reg retries from using an interface whose lower driver state has been cleaned up, and applies the same shutdown state to other IPMI interfaces as well.

Timeline

1. Sep 11, 2026, 7:42 PM UTCCVE published
2. Oct 19, 2026, 8:46 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 · fixed in 75ecc80ef0614a9f8441ab476fb748d3e919bea8; From 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 · fixed in b11a1e545ad7a2f8f9ba7276b4ae9429c3399456; From 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 · fixed in f390b0e781ca689515b659f94ef05f01497ed833; From 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 · fixed in d377bf743f29b41729a084a633874ef9c1a13c6a; From 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 · fixed in d4be659a3e56f4eb16039ab8a1162efea086a714; From 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 · fixed in 53af3a8bae0a93c1342e1b5519812203332aca8e; From 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 · fixed in 8ada17dd4c4ffd6b94621e735d77eda196ce118f; From 2512e40e48d21d8bac09f7e91d2c3ceb2d3b50b2 · fixed in 6d920a75df9a83ab096b3cde7a643b656e4fdfeb; From 4.18.10 · fixed in 4.19

• Linux Linux

  4.19

• KernelLinux

  From 4.19.0 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.109; From 6.13.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4

References 8