Commit message: ipmi_si: fix use-after-free of resource->name

When we excute the following commands, we got oops
rmmod ipmi_si
cat /proc/ioports

[ 1623.482380] Unable to handle kernel paging request at virtual address ffff00000901d478
[ 1623.482382] Mem abort info:
[ 1623.482383]   ESR = 0x96000007
[ 1623.482385]   Exception class = DABT (current EL), IL = 32 bits
[ 1623.482386]   SET = 0, FnV = 0
[ 1623.482387]   EA = 0, S1PTW = 0
[ 1623.482388] Data abort info:
[ 1623.482389]   ISV = 0, ISS = 0x00000007
[ 1623.482390]   CM = 0, WnR = 0
[ 1623.482393] swapper pgtable: 4k pages, 48-bit VAs, pgdp = 00000000d7d94a66
[ 1623.482395] [ffff00000901d478] pgd=000000dffbfff003, pud=000000dffbffe003, pmd=0000003f5d06e003, pte=0000000000000000
[ 1623.482399] Internal error: Oops: 96000007 [#1] SMP
[ 1623.487407] Modules linked in: ipmi_si(E) nls_utf8 isofs rpcrdma ib_iser ib_srpt target_core_mod ib_srp scsi_transport_srp ib_ipoib rdma_ucm ib_umad rdma_cm ib_cm dm_mirror dm_region_hash dm_log iw_cm dm_mod aes_ce_blk crypto_simd cryptd aes_ce_cipher ses ghash_ce sha2_ce enclosure sha256_arm64 sg sha1_ce hisi_sas_v2_hw hibmc_drm sbsa_gwdt hisi_sas_main ip_tables mlx5_ib ib_uverbs marvell ib_core mlx5_core ixgbe mdio hns_dsaf ipmi_devintf hns_enet_drv ipmi_msghandler hns_mdio [last unloaded: ipmi_si]
[ 1623.532410] CPU: 30 PID: 11438 Comm: cat Kdump: loaded Tainted: G            E     5.0.0-rc3+ #168
[ 1623.541498] Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.37 11/21/2017
[ 1623.548822] pstate: a0000005 (NzCv daif -PAN -UAO)
[ 1623.553684] pc : string+0x28/0x98
[ 1623.557040] lr : vsnprintf+0x368/0x5e8
[ 1623.560837] sp : ffff000013213a80
[ 1623.564191] x29: ffff000013213a80 x28: ffff00001138abb5
[ 1623.569577] x27: ffff000013213c18 x26: ffff805f67d06049
[ 1623.574963] x25: 0000000000000000 x24: ffff00001138abb5
[ 1623.580349] x23: 0000000000000fb7 x22: ffff0000117ed000
[ 1623.585734] x21: ffff000011188fd8 x20: ffff805f67d07000
[ 1623.591119] x19: ffff805f67d06061 x18: ffffffffffffffff
[ 1623.596505] x17: 0000000000000200 x16: 0000000000000000
[ 1623.601890] x15: ffff0000117ed748 x14: ffff805f67d07000
[ 1623.607276] x13: ffff805f67d0605e x12: 0000000000000000
[ 1623.612661] x11: 0000000000000000 x10: 0000000000000000
[ 1623.618046] x9 : 0000000000000000 x8 : 000000000000000f
[ 1623.623432] x7 : ffff805f67d06061 x6 : fffffffffffffffe
[ 1623.628817] x5 : 0000000000000012 x4 : ffff00000901d478
[ 1623.634203] x3 : ffff0a00ffffff04 x2 : ffff805f67d07000
[ 1623.639588] x1 : ffff805f67d07000 x0 : ffffffffffffffff
[ 1623.644974] Process cat (pid: 11438, stack limit = 0x000000008d4cbc10)
[ 1623.651592] Call trace:
[ 1623.654068]  string+0x28/0x98
[ 1623.657071]  vsnprintf+0x368/0x5e8
[ 1623.660517]  seq_vprintf+0x70/0x98
[ 1623.668009]  seq_printf+0x7c/0xa0
[ 1623.675530]  r_show+0xc8/0xf8
[ 1623.682558]  seq_read+0x330/0x440
[ 1623.689877]  proc_reg_read+0x78/0xd0
[ 1623.697346]  __vfs_read+0x60/0x1a0
[ 1623.704564]  vfs_read+0x94/0x150
[ 1623.711339]  ksys_read+0x6c/0xd8
[ 1623.717939]  __arm64_sys_read+0x24/0x30
[ 1623.725077]  el0_svc_common+0x120/0x148
[ 1623.732035]  el0_svc_handler+0x30/0x40
[ 1623.738757]  el0_svc+0x8/0xc
[ 1623.744520] Code: d1000406 aa0103e2 54000149 b4000080 (39400085)
[ 1623.753441] ---[ end trace f91b6a4937de9835 ]---
[ 1623.760871] Kernel panic - not syncing: Fatal exception
[ 1623.768935] SMP: stopping secondary CPUs
[ 1623.775718] Kernel Offset: disabled
[ 1623.781998] CPU features: 0x002,21006008
[ 1623.788777] Memory Limit: none
[ 1623.798329] Starting crashdump kernel...
[ 1623.805202] Bye!

If io_setup is called successful in try_smi_init() but try_smi_init()
goes out_err before calling ipmi_register_smi(), so ipmi_unregister_smi()
will not be called while removing module. It leads to the resource that
allocated in io_setup() can not be freed, but the name(DEVICE_NAME) of
resource is freed while removing the module. It causes use-after-free
when cat /proc/ioports.

Fix this by calling io_cleanup() while try_smi_init() goes to out_err.
and don't call io_cleanup() until io_setup() returns successful to avoid
warning prints.

Fixes: 93c303d2045b ("ipmi_si: Clean up shutdown a bit")
Cc: stable@vger.kernel.org
Reported-by: NuoHan Qiao <qiaonuohan@huawei.com>
Suggested-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
CVE: CVE-2019-11811
CWE: CWE-416
Vulnerability description: An issue was discovered in the Linux kernel before 5.0.4. There is a use-after-free upon attempted read access to /proc/ioports after the ipmi_si module is removed, related to drivers/char/ipmi/ipmi_si_intf.c, drivers/char/ipmi/ipmi_si_mem_io.c, and drivers/char/ipmi/ipmi_si_port_io.c.

Project: linux
File: ipmi_si_intf.c

static void cleanup_ipmi_si(void)
{
	struct smi_info *e, *tmp_e;

	if (!initialized)
		return;

	ipmi_si_pci_shutdown();

	ipmi_si_parisc_shutdown();

	ipmi_si_platform_shutdown();

	mutex_lock(&smi_infos_lock);
	list_for_each_entry_safe(e, tmp_e, &smi_infos, link)
		cleanup_one_si(e);
	mutex_unlock(&smi_infos_lock);
}

Project: linux
File: ipmi_si_intf.c

static int dell_poweredge_bt_xaction_handler(struct notifier_block *self,
					     unsigned long unused,
					     void *in)
{
	struct smi_info *smi_info = in;
	unsigned char *data = smi_info->curr_msg->data;
	unsigned int size   = smi_info->curr_msg->data_size;
	if (size >= 8 &&
	    (data[0]>>2) == STORAGE_NETFN &&
	    data[1] == STORAGE_CMD_GET_SDR &&
	    data[7] == 0x3A) {
		return_hosed_msg_badsize(smi_info);
		return NOTIFY_STOP;
	}
	return NOTIFY_DONE;
}

Project: linux
File: ipmi_si_intf.c

static inline bool enable_si_irq(struct smi_info *smi_info)
{
	if ((smi_info->io.irq) && (smi_info->interrupt_disabled)) {
		smi_info->interrupt_disabled = false;
		start_check_enables(smi_info);
		return true;
	}
	return false;
}

Project: linux
File: ipmi_si_intf.c

void ipmi_irq_finish_setup(struct si_sm_io *io)
{
	if (io->si_type == SI_BT)
		/* Enable the interrupt in the BT interface. */
		io->outputb(io, IPMI_BT_INTMASK_REG,
			    IPMI_BT_INTMASK_ENABLE_IRQ_BIT);
}

Project: linux
File: ipmi_si_intf.c

static enum si_sm_result smi_event_handler(struct smi_info *smi_info,
					   int time)
{
	enum si_sm_result si_sm_result;

restart:
	/*
	 * There used to be a loop here that waited a little while
	 * (around 25us) before giving up.  That turned out to be
	 * pointless, the minimum delays I was seeing were in the 300us
	 * range, which is far too long to wait in an interrupt.  So
	 * we just run until the state machine tells us something
	 * happened or it needs a delay.
	 */
	si_sm_result = smi_info->handlers->event(smi_info->si_sm, time);
	time = 0;
	while (si_sm_result == SI_SM_CALL_WITHOUT_DELAY)
		si_sm_result = smi_info->handlers->event(smi_info->si_sm, 0);

	if (si_sm_result == SI_SM_TRANSACTION_COMPLETE) {
		smi_inc_stat(smi_info, complete_transactions);

		handle_transaction_done(smi_info);
		goto restart;
	} else if (si_sm_result == SI_SM_HOSED) {
		smi_inc_stat(smi_info, hosed_count);

		/*
		 * Do the before return_hosed_msg, because that
		 * releases the lock.
		 */
		smi_info->si_state = SI_NORMAL;
		if (smi_info->curr_msg != NULL) {
			/*
			 * If we were handling a user message, format
			 * a response to send to the upper layer to
			 * tell it about the error.
			 */
			return_hosed_msg(smi_info, IPMI_ERR_UNSPECIFIED);
		}
		goto restart;
	}

	/*
	 * We prefer handling attn over new messages.  But don't do
	 * this if there is not yet an upper layer to handle anything.
	 */
	if (si_sm_result == SI_SM_ATTN || smi_info->got_attn) {
		unsigned char msg[2];

		if (smi_info->si_state != SI_NORMAL) {
			/*
			 * We got an ATTN, but we are doing something else.
			 * Handle the ATTN later.
			 */
			smi_info->got_attn = true;
		} else {
			smi_info->got_attn = false;
			smi_inc_stat(smi_info, attentions);

			/*
			 * Got a attn, send down a get message flags to see
			 * what's causing it.  It would be better to handle
			 * this in the upper layer, but due to the way
			 * interrupts work with the SMI, that's not really
			 * possible.
			 */
			msg[0] = (IPMI_NETFN_APP_REQUEST << 2);
			msg[1] = IPMI_GET_MSG_FLAGS_CMD;

			start_new_msg(smi_info, msg, 2);
			smi_info->si_state = SI_GETTING_FLAGS;
			goto restart;
		}
	}

	/* If we are currently idle, try to start the next message. */
	if (si_sm_result == SI_SM_IDLE) {
		smi_inc_stat(smi_info, idles);

		si_sm_result = start_next_msg(smi_info);
		if (si_sm_result != SI_SM_IDLE)
			goto restart;
	}

	if ((si_sm_result == SI_SM_IDLE)
	    && (atomic_read(&smi_info->req_events))) {
		/*
		 * We are idle and the upper layer requested that I fetch
		 * events, so do so.
		 */
		atomic_set(&smi_info->req_events, 0);

		/*
		 * Take this opportunity to check the interrupt and
		 * message enable state for the BMC.  The BMC can be
		 * asynchronously reset, and may thus get interrupts
		 * disable and messages disabled.
		 */
		if (smi_info->supports_event_msg_buff || smi_info->io.irq) {
			start_check_enables(smi_info);
		} else {
			smi_info->curr_msg = alloc_msg_handle_irq(smi_info);
			if (!smi_info->curr_msg)
				goto out;

			start_getting_events(smi_info);
		}
		goto restart;
	}

	if (si_sm_result == SI_SM_IDLE && smi_info->timer_running) {
		/* Ok it if fails, the timer will just go off. */
		if (del_timer(&smi_info->si_timer))
			smi_info->timer_running = false;
	}

out:
	return si_sm_result;
}

Project: linux
File: ipmi_si_intf.c

static int try_get_dev_id(struct smi_info *smi_info)
{
	unsigned char         msg[2];
	unsigned char         *resp;
	unsigned long         resp_len;
	int                   rv = 0;

	resp = kmalloc(IPMI_MAX_MSG_LENGTH, GFP_KERNEL);
	if (!resp)
		return -ENOMEM;

	/*
	 * Do a Get Device ID command, since it comes back with some
	 * useful info.
	 */
	msg[0] = IPMI_NETFN_APP_REQUEST << 2;
	msg[1] = IPMI_GET_DEVICE_ID_CMD;
	smi_info->handlers->start_transaction(smi_info->si_sm, msg, 2);

	rv = wait_for_msg_done(smi_info);
	if (rv)
		goto out;

	resp_len = smi_info->handlers->get_result(smi_info->si_sm,
						  resp, IPMI_MAX_MSG_LENGTH);

	/* Check and record info from the get device id, in case we need it. */
	rv = ipmi_demangle_device_id(resp[0] >> 2, resp[1],
			resp + 2, resp_len - 2, &smi_info->device_id);

out:
	kfree(resp);
	return rv;
}

Project: linux
File: ipmi_si_mem_io.c

static void mem_outq(const struct si_sm_io *io, unsigned int offset,
		     unsigned char b)
{
	writeq((u64)b << io->regshift, (io->addr)+(offset * io->regspacing));
}