ipmi: Fix memory leak in __ipmi_bmc_register

commit 4aa7afb0ee20a97fbf0c5bab3df028d5fb85fdab upstream.

[ Fixes: CVE-2019-19046 ]

In the impelementation of __ipmi_bmc_register() the allocated memory for
bmc should be released in case ida_simple_get() fails.

Fixes: 68e7e50f ("ipmi: Don't use BMC product/dev ids in the BMC name")
Signed-off-by: NNavid Emamdoost <navid.emamdoost@gmail.com>
Message-Id: <20191021200649.1511-1-navid.emamdoost@gmail.com>
Signed-off-by: NCorey Minyard <cminyard@mvista.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NShile Zhang <shile.zhang@linux.alibaba.com>
Acked-by: NCaspar Zhang <caspar@linux.alibaba.com>

drivers/char/ipmi/ipmi_msghandler.c

@@ -2957,8 +2957,11 @@ static int __ipmi_bmc_register(struct ipmi_smi *intf,
 		bmc->pdev.name = "ipmi_bmc";
 
 		rv = ida_simple_get(&ipmi_bmc_ida, 0, 0, GFP_KERNEL);
-		if (rv < 0)
+		if (rv < 0) {
+			kfree(bmc);
 			goto out;
+		}
+
 		bmc->pdev.dev.driver = &ipmidriver.driver;
 		bmc->pdev.id = rv;
 		bmc->pdev.dev.release = release_bmc_device;