powerpc/xive: Add some error handling code to 'xive_spapr_init()'

JIRA: https://issues.redhat.com/browse/RHEL-80849

CVE: CVE-2022-49437

commit e414e29
Author: Christophe JAILLET <[email protected]>
Date:   Tue Feb 1 13:31:16 2022 +0100

    powerpc/xive: Add some error handling code to 'xive_spapr_init()'

    'xive_irq_bitmap_add()' can return -ENOMEM.
    In this case, we should free the memory already allocated and return
    'false' to the caller.

    Also add an error path which undoes the 'tima = ioremap(...)'

    Signed-off-by: Christophe JAILLET <[email protected]>
    Reviewed-by: Cédric Le Goater <[email protected]>
    Signed-off-by: Michael Ellerman <[email protected]>
    Link: https://lore.kernel.org/r/564998101804886b151235c8a9f93020923bfd2c.1643718324.git.christophe.jaillet@wanadoo.fr

Signed-off-by: Mamatha Inamdar <[email protected]>

Author: Mamatha Inamdar

arch/powerpc/sysdev/xive/spapr.c

@@ -69,6 +69,17 @@ static int xive_irq_bitmap_add(int base, int count)
 	return 0;
 }
 
+static void xive_irq_bitmap_remove_all(void)
+{
+	struct xive_irq_bitmap *xibm, *tmp;
+
+	list_for_each_entry_safe(xibm, tmp, &xive_irq_bitmaps, list) {
+		list_del(&xibm->list);
+		kfree(xibm->bitmap);
+		kfree(xibm);
+	}
+}
+
 static int __xive_irq_bitmap_alloc(struct xive_irq_bitmap *xibm)
 {
 	int irq;
@@ -802,7 +813,7 @@ bool __init xive_spapr_init(void)
 	u32 val;
 	u32 len;
 	const __be32 *reg;
-	int i;
+	int i, err;
 
 	if (xive_spapr_disabled())
 		return false;
@@ -827,23 +838,26 @@ bool __init xive_spapr_init(void)
 	}
 
 	if (!xive_get_max_prio(&max_prio))
-		return false;
+		goto err_unmap;
 
 	/* Feed the IRQ number allocator with the ranges given in the DT */
 	reg = of_get_property(np, "ibm,xive-lisn-ranges", &len);
 	if (!reg) {
 		pr_err("Failed to read 'ibm,xive-lisn-ranges' property\n");
-		return false;
+		goto err_unmap;
 	}
 
 	if (len % (2 * sizeof(u32)) != 0) {
 		pr_err("invalid 'ibm,xive-lisn-ranges' property\n");
-		return false;
+		goto err_unmap;
 	}
 
-	for (i = 0; i < len / (2 * sizeof(u32)); i++, reg += 2)
-		xive_irq_bitmap_add(be32_to_cpu(reg[0]),
-				    be32_to_cpu(reg[1]));
+	for (i = 0; i < len / (2 * sizeof(u32)); i++, reg += 2) {
+		err = xive_irq_bitmap_add(be32_to_cpu(reg[0]),
+					  be32_to_cpu(reg[1]));
+		if (err < 0)
+			goto err_mem_free;
+	}
 
 	/* Iterate the EQ sizes and pick one */
 	of_property_for_each_u32(np, "ibm,xive-eq-sizes", prop, reg, val) {
@@ -854,10 +868,16 @@ bool __init xive_spapr_init(void)
 
 	/* Initialize XIVE core with our backend */
 	if (!xive_core_init(np, &xive_spapr_ops, tima, TM_QW1_OS, max_prio))
-		return false;
+		goto err_mem_free;
 
 	pr_info("Using %dkB queues\n", 1 << (xive_queue_shift - 10));
 	return true;
+
+err_mem_free:
+	xive_irq_bitmap_remove_all();
+err_unmap:
+	iounmap(tima);
+	return false;
 }
 
 machine_arch_initcall(pseries, xive_core_debug_init);