s390/ipl: add missing intersection check to ipl_report handling

commit a52e5cdbe8016d4e3e6322fd93d71afddb9a5af9 upstream.

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: <stable@vger.kernel.org>
Fixes: 55590fd945be ("s390/ipl: read IPL report at early boot")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/s390/boot/ipl_report.c b/arch/s390/boot/ipl_report.c
index 0b4965573656f668fe84e56f0df27e2a536414d5..88bacf4999c47fe7c3f9d253b7b0d3e48303ba4c 100644 (file)
--- a/arch/s390/boot/ipl_report.c
+++ b/arch/s390/boot/ipl_report.c
@@ -57,11 +57,19 @@ repeat:
        if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && INITRD_START && INITRD_SIZE &&
            intersects(INITRD_START, INITRD_SIZE, safe_addr, size))
                safe_addr = INITRD_START + INITRD_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;