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38 lines
1.2 KiB
38 lines
1.2 KiB
8 months ago
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Daniel Axtens <dja@axtens.net>
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Date: Fri, 22 Jan 2021 14:43:58 +1100
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Subject: [PATCH] disk/lvm: Sanitize rlocn->offset to prevent wild read
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rlocn->offset is read directly from disk and added to the metadatabuf
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pointer to create a pointer to a block of metadata. It's a 64-bit
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quantity so as long as you don't overflow you can set subsequent
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pointers to point anywhere in memory.
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Require that rlocn->offset fits within the metadata buffer size.
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Signed-off-by: Daniel Axtens <dja@axtens.net>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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---
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grub-core/disk/lvm.c | 8 ++++++++
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1 file changed, 8 insertions(+)
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diff --git a/grub-core/disk/lvm.c b/grub-core/disk/lvm.c
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index 267be7b95..9eda28d85 100644
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--- a/grub-core/disk/lvm.c
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+++ b/grub-core/disk/lvm.c
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@@ -212,6 +212,14 @@ grub_lvm_detect (grub_disk_t disk,
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}
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rlocn = mdah->raw_locns;
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+ if (grub_le_to_cpu64 (rlocn->offset) >= grub_le_to_cpu64 (mda_size))
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+ {
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+#ifdef GRUB_UTIL
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+ grub_util_info ("metadata offset is beyond end of metadata area");
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+#endif
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+ goto fail2;
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+ }
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+
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if (grub_le_to_cpu64 (rlocn->offset) + grub_le_to_cpu64 (rlocn->size) >
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grub_le_to_cpu64 (mdah->size))
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{
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