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From 0e9bdb960045f98d70f765bbb585f1647e5fea08 Mon Sep 17 00:00:00 2001
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From: Thomas Huth <thuth@redhat.com>
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Date: Tue, 18 May 2021 13:51:23 -0400
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Subject: [PATCH 3/5] pc-bios/s390-ccw: fix off-by-one error
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Thomas Huth <thuth@redhat.com>
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Message-id: <20210518135125.191329-2-thuth@redhat.com>
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Patchwork-id: 101548
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O-Subject: [RHEL-8.5.0 qemu-kvm PATCH 1/3] pc-bios/s390-ccw: fix off-by-one error
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Bugzilla: 1942880
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RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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RH-Acked-by: David Hildenbrand <david@redhat.com>
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RH-Acked-by: Cornelia Huck <cohuck@redhat.com>
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This error takes effect when the magic value "zIPL" is located at the
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end of a block. For example if s2_cur_blk = 0x7fe18000 and the magic
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value "zIPL" is located at 0x7fe18ffc - 0x7fe18fff.
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Fixes: ba831b25262a ("s390-ccw: read stage2 boot loader data to find menu")
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Reviewed-by: Collin Walling <walling@linux.ibm.com>
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Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
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Message-Id: <20200924085926.21709-2-mhartmay@linux.ibm.com>
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Reviewed-by: Thomas Huth <thuth@redhat.com>
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[thuth: Use "<= ... - 4" instead of "< ... - 3"]
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Signed-off-by: Thomas Huth <thuth@redhat.com>
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(cherry picked from commit 5f97ba0c74ccace0a4014460de9751ff3c6f454a)
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Signed-off-by: Thomas Huth <thuth@redhat.com>
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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---
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 pc-bios/s390-ccw/bootmap.c | 2 +-
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 1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c
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index e91ea719ff..bb6e003270 100644
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--- a/pc-bios/s390-ccw/bootmap.c
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+++ b/pc-bios/s390-ccw/bootmap.c
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@@ -163,7 +163,7 @@ static bool find_zipl_boot_menu_banner(int *offset)
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     int i;
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     /* Menu banner starts with "zIPL" */
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-    for (i = 0; i < virtio_get_block_size() - 4; i++) {
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+    for (i = 0; i <= virtio_get_block_size() - 4; i++) {
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         if (magic_match(s2_cur_blk + i, ZIPL_MAGIC_EBCDIC)) {
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             *offset = i;
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             return true;
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-- 
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2.27.0
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