Blame SOURCES/kvm-multiboot-Check-validity-of-mh_header_addr.patch

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From 9ea892729b9c77eaf7b923da8a3e370dbb022e6e Mon Sep 17 00:00:00 2001
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From: Kevin Wolf <kwolf@redhat.com>
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Date: Thu, 26 Jul 2018 16:24:48 +0200
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Subject: [PATCH 6/8] multiboot: Check validity of mh_header_addr
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RH-Author: Kevin Wolf <kwolf@redhat.com>
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Message-id: <20180726162448.22072-7-kwolf@redhat.com>
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Patchwork-id: 81515
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O-Subject: [RHEL-7.6/7.5.z qemu-kvm PATCH 6/6] multiboot: Check validity of mh_header_addr
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Bugzilla: 1549822
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RH-Acked-by: John Snow <jsnow@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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I couldn't find a case where this prevents something bad from happening
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that isn't already caught by other checks, but let's err on the safe
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side and check that mh_header_addr is as expected.
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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Reviewed-by: Jack Schwartz <jack.schwartz@oracle.com>
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(cherry picked from commit dbf2dce7aabb7723542bd182175904846d70b0f9)
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 hw/i386/multiboot.c | 4 ++++
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 1 file changed, 4 insertions(+)
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diff --git a/hw/i386/multiboot.c b/hw/i386/multiboot.c
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index 6f489a5..e1f6e56 100644
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--- a/hw/i386/multiboot.c
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+++ b/hw/i386/multiboot.c
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@@ -208,6 +208,10 @@ int load_multiboot(FWCfgState *fw_cfg,
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             error_report("invalid load_addr address");
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             exit(1);
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         }
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+        if (mh_header_addr - mh_load_addr > i) {
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+            error_report("invalid header_addr address");
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+            exit(1);
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+        }
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         uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr);
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         uint32_t mb_load_size = 0;
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-- 
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1.8.3.1
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