s390/ipl: add missing intersection check to ipl_report handling

The code which handles the ipl report is searching for a free location
in memory where it could copy the component and certificate entries to.
It checks for intersection between the sections required for the kernel
and the component/certificate data area, but fails to check whether
the data structures linking these data areas together intersect.

This might cause the iplreport copy code to overwrite the iplreport
itself. Fix this by adding two addtional intersection checks.

Cc: <[email protected]>
Fixes: 9641b8c ("s390/ipl: read IPL report at early boot")
Signed-off-by: Sven Schnelle <[email protected]>
Reviewed-by: Vasily Gorbik <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

Author: svens-s390

arch/s390/boot/ipl_report.c

@@ -57,11 +57,19 @@ static unsigned long find_bootdata_space(struct ipl_rb_components *comps,
 	if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && initrd_data.start && initrd_data.size &&
 	    intersects(initrd_data.start, initrd_data.size, safe_addr, size))
 		safe_addr = initrd_data.start + initrd_data.size;
+	if (intersects(safe_addr, size, (unsigned long)comps, comps->len)) {
+		safe_addr = (unsigned long)comps + comps->len;
+		goto repeat;
+	}
 	for_each_rb_entry(comp, comps)
 		if (intersects(safe_addr, size, comp->addr, comp->len)) {
 			safe_addr = comp->addr + comp->len;
 			goto repeat;
 		}
+	if (intersects(safe_addr, size, (unsigned long)certs, certs->len)) {
+		safe_addr = (unsigned long)certs + certs->len;
+		goto repeat;
+	}
 	for_each_rb_entry(cert, certs)
 		if (intersects(safe_addr, size, cert->addr, cert->len)) {
 			safe_addr = cert->addr + cert->len;